Author Roald Dahl was particularly well known for darkly humorous children's books that form a riotous part of almost every childhood in Britain. Less well known is that he also made some significant contributions to neurology, as detailed in a brief article for Advances in Clinical Neuroscience and Rehabilitation.
The article is available online as a pdf and starts by noting that several of his books contain possible nods to neurological syndromes or fantastical fictional experiments.
These descriptions may hardly be termed “contributions”, but two personal tragedies certainly did lead to developments of clinical import. Whilst living in New York in 1960, Dahl’s son Theo, aged 3-4 months, was involved in a road traffic accident which caused some brain damage and secondary hydrocephalus [a dangerous problem preventing cerebrospinal fluid drainage in the brain], the latter requiring shunting. Problems with blocked shunts occurred. The family returned to England and Theo came under the care of Kenneth Till, a neurosurgeon at Great Ormond Street Hospital (1956-80). Prompted by Dahl, and in collaboration with Stanley Wade, an hydraulic engineer, a new type of shunt valve was designed. Reported in the Lancet by Kenneth Till, under the rubric of “New Inventions”, the special characteristics were reported to be “low resistance, ease of sterilisation, no reflux, robust construction, and negligible risk of blockage”. The author acknowledged that the valve was “designed by Mr Stanley C.Wade... with the assistance of Mr Roald Dahl and myself”. The Wade-Dahl-Till (or WDT) valve became widely used.
Kenneth Till subsequently wrote a preface for a new edition of Valerie Eaton Griffith’s book entitled A stroke in the family, a manual of home therapy, wherein lies another Dahl connection. In 1965, Dahl’s first wife, the American actress Patricia Neal, suffered a stroke due to a ruptured intracranial aneurysm, one of the consequences of which was marked aphasia, a potential career-ending misfortune for an actress (her illness and recovery are recorded in a book by Barry Farrell). Dahl appealed to Valerie Eaton Griffith, who lived in the same village, for help. With Dahl, she devised a rota of volunteer carers to engage the patient in conversation and hence to stimulate language recovery. This approach, different from formal speech therapy, was documented in Griffith’s book (initially published in 1970, with an introduction by Roald Dahl). It earned the approbation, as “treatment of a surreptitious character”, of no less a neurological figure than Macdonald Critchley, and still has advocates today. It has been suggested that Patricia Neal’s aphasia may have influenced Dahl’s creative processes, for example in the neologisms of The BFG (1982).
The EEG unit at Liverpool's Alder Hey Children's Hospital is called the Roald Dahl EEG Unit but I'd never made the connection before.
Dahl was not the first father to be motivated to create a shunt to treat his child. As we discussed previously, engineer John Holter found himself in a very similar position and invented the Holter shunt to treat hydrocephalus in his daughter.
pdf of article on Roald Dahl's neurological contributions.
A brain scanning technology called MEG is being used to track the function of unborn babies' brains as they grow inside the womb until after they've been born.
The full name for MEG is magnetoencephalography and it works by reading the magnetic fields created by the electrical signalling in the brain.
One of the advantages is that it can be used at various angles, doesn't require the person to be in a cramped space, and is less sensitive to movement, so is ideally suited to scanning babies.
This includes unborn babies and with a bit of modification, as illustrated in the picture, researchers can pick up signals from the fetal brain in response to flashes or light or sounds.
We discussed the use of fMRI to scan the fetal brain previously, but this is a remarkable study that scanned the brains of babies inside the womb, every two weeks from week 27 until delivery, and then once after they were born.
Clearly, unborn babies are not the best at doing tasks set by experimenters, but there are various tests that just require the individual to experience changes in what's presented to them.
One is called the auditory oddball task, where a series of tones are played that can either be similar ('beep beep beep') or can have include an 'oddball' ('beep beep boop'). The brain is very good at picking out differences and the oddball is known to reliably trigger brain signals related to detecting changes.
This was the exact task used with the babies and the researchers looked to see if they could pick out a brain reaction to the 'oddball'.
They found that they could detect this response 83% of the time in unborn babies, and that the reaction to the 'oddball' increased in speed throughout pregnancy. The newly born babies showed the response every time without fail.
This is an impressive finding as it shows how the brain development of the unborn child can be tracked over time with a brain scanner.
In a recent review article that discusses the development of this technology, the same group of researchers suggest that these and similar techniques could help track how different conditions in the mother affect the developing brain and even how the brain begins to develop its understanding of speech sounds before birth.
Link to PubMed entry for MEG study of developing fetus. Link to PubMed entry for review article on fetal MEG.
Neuroskepticcovers a fascinating case of a man born with a genetic mutation meaning he had a severe lifelong deficiency of both serotonin and dopamine.
The case report concerns a gentleman with sepiapterin reductase deficiency, a genetic condition which prevents the production of the enzyme sepiapterin reductase which is essential in the synthesis of both dopamine and serotonin.
The most widely recognised symptoms of the condition, linked to the deficiency in dopamine which has an important role in controlling movement, are problems coordinating both conscious movements and the unconscious control of muscles that allows simple actions. Unconscious control requires that the brain signals one muscle to contract while releasing the complementary muscle, and problems with this process cause spasticity.
The effects the condition on serotonin, often stereotyped as the 'happy chemical', are less well known, but in this case it was clear that the patient wasn't depressed but did some other difficulties:
These included increased appetite - he ate constantly, and was moderately obese - mild cognitive impairment, and disrupted sleep:
"The patient reported sleep problems since childhood. He would sleep 1 or 2 times every day since childhood and was awake during more than 2 hours most nights since adolescence. At the time of the first interview, the night sleep was irregular with a sleep onset at 22:00 and offset between 02:00 and 03:00. He often needed 1 or 2 spontaneous, long (2- to 5-h) naps during the daytime."
After doctors did a genetic test and diagnosed SRD, they treated him with 5HTP, a precursor to serotonin. The patient's sleep cycle immediately normalized, his appetite was reduced and his concentration and cognitive function improved (although that may have been because he was less tired)...
Overall, though, the biggest finding here was a non-finding: this patient wasn't depressed, despite having much reduced serotonin levels. This is further evidence that serotonin isn't the "happy chemical" in any simple sense.
This is another piece of evidence against the common myth that depression is "caused by low serotonin" although Neuroskeptic speculates whether the link between disrupted sleep and depression may indicate an effect of serotonin dysfnction.
Link to Neuroskeptic on 'Life Without Serotonin'. Link to summary of scientific paper.
This morning's edition of BBC Radio 4's brilliant In Our Time was dedicated to the infant brain and has a wide ranging discussion about how ideas about the early development of the child developed into the modern age of neuroscience.
The streamed version will be available on the website permanently, but if you want to download the podcast you only have a week to do so from this page.
For obvious reasons, what happens in the minds of very young, pre-verbal children is elusive. But over the last century, the psychology of early childhood has become a major subject of study.
Some scientists and researchers have argued that children develop skills only gradually, others that many of our mental attributes are innate.
Sigmund Freud concluded that infants didn't differentiate themselves from their environment.
The pioneering Swiss child psychologist Jean Piaget thought babies' perception of the world began as a 'blooming, buzzing confusion' of colour, light and sound, before they developed a more sophisticated worldview, first through the senses and later through symbol.
More recent scholars such as the leading American theoretical linguist Noam Chomsky have argued that the fundamentals of language are there from birth. Chomsky has famously argued that all humans have an innate, universally applicable grammar.
Over the last ten to twenty years, new research has shed fresh light on important aspects of the infant brain which have long been shrouded in mystery or mired in dispute, from the way we start to learn to speak to the earliest understanding that other people have their own minds.
Link to In Our Time 'The Infant Brain' (thanks Petra!)
The March edition of The Psychologist has just appeared online and has two freely available articles: one article investigates whether women really suffer a reduction in mental sharpness during pregnancy, and another interviews baby psychologist Alison Gopnik about her work.
This idea that pregnancy causes a slight reduction in mental sharpness, sometimes known as 'baby brain' or 'pregnesia', is widespread but the results from scientific studies are mixed, and at best show only a negligible effect:
We’ve seen that whilst many women report experiencing cognitive difficulties during pregnancy, objective evidence for a link between pregnancy and cognitive decline has been inconsistent. This begs the question: does the memory deficit, if it exists, matter? Is there sufficient cause for women to worry about it? On the other hand, if there is no deficit, should we be doing more to combat what amounts to a pervasive sexist myth?
Crawley says that even if there is a real deficit, it’s nothing to worry about. ‘In a previous study of mine, before I gave women the standard questionnaire comparing their cognition now to before they were pregnant, I asked them to tell me about the kinds of changes they’d noticed about themselves since they’d become pregnant. Out of 198 women, only three spontaneously mentioned cognitive changes, so I don’t think they’re very salient.’
The interview with Alison Gopnik, is, as always, thoroughly engaging and largely riffs on themes from her new bookThe Philosophical Baby.
Link to Psychologist article 'The Maternal Brain'. Link to interview with Alison Gopnik.
Full disclosure: I'm an unpaid associate editor and occasional columnist for The Psychologist and I worked as a baby early in my career.
Sleep is a nightmare for neuroscientists but a new study using electrodes implanted deep within the brains of people going about their daily lives has revealed that the brain falls asleep from the inside out, contrary to what was expected.
Most neuropsychology studies require people to complete tasks while the brain is being monitored and the technologies that allow passive recording either only measure activity on the brain surface (EEG, MEG) or are too uncomfortable to measure realistic sleep (fMRI, PET). This is one of the reasons human sleep has been difficult to study and why we still understand little about it.
A new study just published online in the Proceedings of the National Academy of Sciences used the innovative technique of recording from semi-permanent electrodes implanted in the brains of 13 people undergoing assessment for difficult-to-treat epilepsy. These electrodes stay in for several weeks, meaning the researchers had access to brain activity as people continued their lives and, of course, as they drifted off to sleep.
Certain types of epilepsy don't respond to normal treatment and neurosurgery to remove a small part of the brain that triggers the seizures is known to be an effective treatment in many cases. However, this is only feasible when it's possible to locate where the seizures originate.
In rarer cases still, a standard EEG or brief surgical test doesn't give a good idea of where this might be, so surgeons can insert depth electrodes into the most likely areas. These remain in place and record any unusual activity directly from locations across the brain.
The researchers, led by neuroscientist Michel Magnin from the University of Lyon, asked the patients if they could also use this data to help understand what happened during sleep onset.
They found that as people drifted off to sleep, the deep brain area the thalamus wound down several minutes before the cortex.
This is surprising because the thalamus has traditionally been considered a structure that regulates alertness and 'relays' information to the rest of the brain from the body and the spinal cord.
It was often assumed that it would 'shut down' the cortex first, because this is often considered to be where our 'higher' conscious functions like abstract thought and complex perception lie, while continuing with its minimal vigilance functions. A bit like a neural 'standby' setting.
Instead, what seems to happen is that the thalamus 'disconnects' itself and leaves the cortex freewheeling before it finally settles down into inactivity.
Indeed, freewheeling is, perhaps, a good description here. The researchers found lots of uneven activity in the upper brain areas as they were left to drift off.
Interestingly, sleep onset is one of the times when we are most likely to experience hallucinations. In fact, they are so common as to have been given their own name - hypnagogic hallucinations - while this drifting off period is known as hypnagogia.
Although they didn't specifically ask about the whimsical thoughts and unusual perceptions that typically occur in this state, the researchers speculate that this pattern of freewheeling close-down might explain why hallucinations are so common at this time.
The Times has just released its monthly science magazine, Eureka, with a special issue on the brain and all the articles freely available online.
There doesn't seem to be a way to link to a whole issue, but inside you'll find an excellent piece on the use of transcranial magnetic stimulation (TMS) to temporarily switch off bits of the working brain, a profile of neurosurgeon Huma Sethi, an article on commercial brain-computer interfaces, a remarkable piece on how old injuries can 'return' to affect phantom limbs as well as an exploration of the link between brain activity and sporting skill.
Probably my favourite is an article on how forensic science and criminology are increasingly using neuroscience, and there's also an account of a writer's experience of being brain scanned and a description of the Total Recall project which aims to digitally record everything about day-to-day life.
There's also a piece by me, where I go to head-to-head with Baroness Susan Greenfield in the Fight Club section where we debate 'Is screen culture damaging our children’s brains?'.
Greenfield goes for the usual "maybe.. perhaps... could it be?... tada! compulsive gambling and schizophrenia!" argument, so I hope I'm a little more evidence-based. Anyway, you can read for yourself.
I also debated exactly the same thing with psychologist Tracey Alloway live earlier today, and you can read the transcript here. It's more in-depth but is less coherent and has typos and bad jokes.
Also don't miss out on the fantastic downloadable brain poster, which is available online as a (big) jpg file.
I'm still reading through all the articles but the ones I've read so far have been excellent. A motherlode of neuroscience reading.
A study just published in the New England Journal of Medicine reports on how a subset of patients diagnosed as being in a coma-like state can be trained to show specific brain activity to answer yes / no questions despite seeming to be unconscious and unresponsive.
Many news reports seem to suggest that researchers have found a way of 'reaching inside coma' with a brain scanner to communicate with patients but the findings are much more modest, only 5 out of 54 patients could reliably produce specific brain activity on command and only one was tested who could answer simple yes / no questions in this way.
Despite this, the study is still incredibly impressive and it indicates that some patients who seem unconscious may have a much richer inner life than we assume and it may be possible to communicate with some of them by measuring their brain activity.
The researchers put people in brain scanners and, in one condition, asked them to imagine standing still on a tennis court while swinging an arm to "hit the ball" back and forth to an imagined instructor, and in the other, to imagine navigating the streets of a familiar city or to imagine walking from room to room in their home. These were chosen because they show distinct patterns of brain activity on a scan.
This was tested both on healthy people, for a comparison of how activity should normally look, and in brain injured patients in a coma-like state.
Only 5 of the 54 patients responded with distinct brain activity, similar to the type found in all the healthy comparison participants, but in this subset, it indicated that they were likely following simple verbal commands.
This has been established before, but one criticism of these past studies was this this could just be an automatic response to the words in the command. We know that the brains of unconscious people respond briefly but automatically to words, even the person is not aware of hearing them.
The brain activity for the 'tennis' and 'walking' commands was much longer and more sustained than we might expect from the normal automatic response to words, so this was unlikely, but you might still argue that these are automatic, non-conscious responses.
To rule this out in one patient, the researchers asked six yes/ no questions about simple personal details and instructed the patient to imagine tennis for yes and walking for no.
Crucially, during the questions, the researchers prompted the patient with just the word "answer?", meaning any different reactions that showed up couldn't be just an automatic response to the word itself which was always the same.
Out of these six simple questions, the patient 'responded' correctly to 5, suggesting that they were genuinely understanding, considering and making a conscious response. This was in a patient who had no external signs of consciousness.
The scans for a couple of the questions are in the image above (click for a bigger version). You can see how different the responses are, but also how serious the brain damage is.
Importantly, these correct answers do not necessarily mean that the patient was completely mentally fine but 'trapped' their body. One common test used on definitely conscious patients after brain damage asks lots of these yes / no type questions (like "Do cinemas show films?" / "Are bottles edible?") to test understanding.
Some patients can be fully conscious but their language so damaged that they can't answer these questions, others can manage the less complex ones (the easiest are usually simple personal details) but not others, for the same reason.
All of the patients in coma-like states were clearly very brain damaged, so it could be that even the one who could make conscious responses might not have full understanding. On the flip side, it could also mean that some of the other patients may have been conscious but could not understand the task, and so did not show up on this test. You can see it's a tricky area.
However, the discovery that it is possible to communicate, even in a simple terms, with a patient previously though to be in a coma is huge news and this research is likely to lead to further work trying to detect which patients are conscious and to develop methods to communicate with them.
Link to study summary in NEJM Link to good write-up from New Scientist.
Film-maker Noah Hutton has just released an excellent 15-minute documentary on the Blue Brain project that captures the team as they work and explains the goals of the ambitious attempt to simulate animal, and eventually, human scale neural networks on computer.
It's an interesting look both inside the scientific mission and inside the mind of project leader Henry Markram, whom it must be said, is largely talking about the potential of the project rather than what it can do now.
It's probably worth saying that Markram is not known for underselling his efforts, and some of his projections seem a little unrealistic.
At one point he mentions that the project could be used in hospital so doctors can simulate the effects of drugs on a digital brain to see if they'll work before giving patients the real thing. Best of luck with that chaps.
It's a great short piece, however, and apparently there are more to come in the future.
BBC Radio 4 has just concluded a wonderful series on medical imaging that overs everything from the microscope, to ultrasound, to the brain scanner.
The series is five 15 minute programmes that tackles the technology and its controversies. The brain scanning programme is particularly good and shows both ends of the spectrum of enthusiasm for the use of functional brain scans to understand human nature.
Because of the BBC's black hole of death archive, the programmes will start being sucked into the void in three days time, so do catch them before then.
The programmes also cover DNA imaging and X-rays and the website apparently has a gallery of images on but I have given up trying to find them on the dreadful Radio 4 website.
Link to 'Images That Changed The World' audio links.
In massive news for neurology, The New England Journal of Medicine has published threeimportantstudies reporting that two new drugs for multiple sclerosis are more effective than existing treatments and can be taken in pill form.
Multiple sclerosis is a bitch. It's a neurological disorder where the immune system starts attacking myelin - the protective covering of nerves in the brain and spinal cord - leading to unpredictable attacks that typically leave the person a little more disabled each time.
Problems can include movement difficulties, chronic pain, fatigue, cognitive problems, mood instability and impairments to the body's automatic processes like digestion, bladder and bowel control.
One problem with the the current treatments that try and slow down the disease itself, rather than just manage the effects, is that they all require regular injections or infusions via a drip.
These new studies report on two drugs: one is cladribine which is already widely used in leukaemia, and the other is fingolimod, which is not yet available commercially. Crucially, both can be taken as pills without the need for injections.
The studies that investigated these drugs were very impressive. They had large numbers of patients in many countries; they were conducted with the co-operation of drug companies but were led by independent researchers; they continued for about two years; they were compared against placebo and, in the case of fingolimod, against the current best available treatment - beta interferon; and they looked at both chances of relapse and at changes in brain structure.
The studies did not include the most disabled people with MS are all were able to walk, although patients with mild and moderate disability were included.
The results suggest that the drugs are not only easier to take but are better than the current best available treatments and reduced the chances of the patient having a relapse of MS as well as the damage to the white matter in the brain.
The drugs work quite differently from current treatments - which largely reduce inflammation directly - by changing the balance of how the immune system releases T cells so more antiinflammatory 'helper' T cells are available.
Unfortunately, the drugs are not without side effects, and although these effects were rare, altering the immune system led to more herpes infections and an increase in the development of cancer.
Herpes infections can take the form of the annoying but relatively benign, like in local infections such as cold sores, shingles and genital herpes, but when it gets into the whole body or brain it can cause serious damage or even lead to death, which happen to two patients in the trial, although in this case it was out of more than 1,100 people in total. The people with cancer generally recovered well - there was one death but it isn't entirely clear it was linked to the treatment.
Although these drugs are not cures, they only slow the disease down, this is still massive news and a major development in neurology.
One of the practical big issues will be how the drugs are priced by the pharmaceutical companies and you can be sure they're not going to be cheap.
However, one small hope is that the two compounds are owned by rival companies and as they seem to have broadly equivalent effects it will be hoped that competition will drive the price down.
Link to good write-up from The Times. Link to good technical summary in the NEJM, sadly paywalled.
Patients with no skull are a window on brain activity:
I've just clocked a stunning experiment, shortly to be published in the Journal of Cognitive Neuroscience, that recorded brain activity from patients who had part of their skull surgically removed for several months and had only flaps of skin between their brain and the outside world.
The operation is called a hemicraniectomy and is often used when the brain swells or the pressure builds up inside the skull to the point where it is damaging the brain.
Neurosurgeons will sometimes remove a portion of the skull (see the scans on the left) and just leave the scalp protecting the brain until the swelling subsides, before replacing the skull flap some months later.
As an aside, sometimes the surgeons will surgically insert the piece of skull into the abdomen so the bone marrow doesn't die and it can be replaced 'alive' when the time comes. There's a great description of this here.
The patients normally wear helmets, for obvious reasons, but they are unique in having such a thin covering of the brain.
A team of researchers, led neuroscientist Bradley Voytek, realised this provided a unique opportunity to examine the exactly how the skull affects EEG, one of the most common techniques for measuring the electrical activity of the brain.
EEG records brain activity from electrodes on the skull, but the signal gets 'smeared' as the electrical charge passes through the bone and so the source of the activity can't be located very precisely to specific brain areas.
By working with the hemicraniectomy patients, the researchers could compare electrical activity on one side of the brain - recorded through just the skin, and the other, where recordings were made normally - through electrodes on the skull.
The researchers found that the non-skull signals were richer, were less subject to interference, were more closely tied to specific tasks and could be better linked to specific brain areas.
On the right is a comparison of the signal coming from a listening task, where participants are suddenly presented with an 'oddball' noise in the midst of a bunch of otherwise identical sounds. The brain reacts strongly to the change and this is reliably reflected in a positive spike in the electrical activity at about 50 milliseconds (consequently, the wave is called the 'P50' signal).
You can see that the activity on the craniectomy side is much stronger, tighter and cleaner whereas on the skull side it is quite indistinct. The team found similar results in several other tasks.
This not only helps us better understand EEG results on people with intact skulls, but it also meshes with brain activity recordings that are taken from electrodes implanted directly in the brains of patients undergoing neurosurgery.
Link to PubMed entry for study. pdf of scientific article. Link to Bradley Voytek's blog post about his work.
The New York Daily Newsreports on a 14-month old Chinese boy who survived brain surgery to remove a chopstick that accidentally ended up in his brain after entering through the nose.
If your jaw has dropped, amazed at such a freaky and unusual accident, you may comfortably close your mouth - there is a surprisingly large medical literature on stray chopsticks that have become lodged in the brain.
In fact, there are no less than 13 published articles on this serious neurological condition. Here are some of the more notable ones:
A case of unusual difficult airway because of an intracranial foreign body of bamboo chopstick. [link]
Transoral penetration of a half-split chopstick between the basion and the dens. [link]
Transorbital penetrating injury by a chopstick--case report [link]
Intracerebellar penetrating injury and abscess due to a wooden foreign body--case report. [link]
The pictures are the interesting results of an MRI scan on a 15-year-old boy who had his hair in 'twists' that were held in place with beeswax coloured black with iron oxide.
The iron oxide is magnetic and it interfered with the scanners' magnetic field causing the rather lovely aura effect on the images.
This is not the only case of a hair style interfering with a brain scan in the medical literature. An earlier report is remarkably similar, as the iron oxide coloured braids of a 51-year-old lady caused similar flame-like patterns on the scans.
Link to MRI 'aura' in 15-year-old boy. Link to MRI 'aura' in 51-year-old lady.
A veterinary deworming drug called levamisole has mysteriously appeared in almost two-thirds of cocaine seized in the United States and is now common throughout the world.
No-one is quite sure why, although some researchers have suggested that it may be added to boost the effect of cocaine in the brain.
Now a brief article in the Journal of Analytical Toxicology suggests this may indeed be the case based on the neurological effects of the two substances.
Street drugs are typically 'cut' with additional substances, often to bulk them out, but occasionally to alter the effect of the main substance. As we discussed in a post on adulterants in heroin, this can be a way of changing the drug to give it a different effect to benefit the dealer.
As an excellent article on Erowid notes, the fact that cocaine is cut with only small amounts of levamisole (only 6% of the deal in one study) suggests that it is not being used just as a handy powder to thin out the coke - more likely, it is being added for a specific effect.
Levamisole is, in some respects, similar to nicotine and the drug binds to specific nicotine-triggered receptors for the neurotransmitter acetylcholine and causes the nerve cell to respond. It turns out that this is most likely to increase activity in the body's 'fight-or-flight' system - the sympathetic nervous system.
In fact, this is exactly how the drug has its deworming effect. In worms, it targets nerve cells involved in muscle activity, causing the muscles to contract. The worm is paralysed and so can be easily expelled from the body.
As cocaine also stimulates the body, the two drugs could combine to cause additional arousal.
This effect would largely be on the peripheral nervous system, outside the brain, but levamisole might also boost the effect of cocaine directly within the brain - enhancing pleasurable feelings.
In the brain, levamisole likely also enhances the release of glutamate, a neurotransmitter that is known to encourage or excite the function of neurons.
We known cocaine boosts dopamine function in the reward system, but the reward system is not single brain area. It's actually a network of related structures deep within the brain that have connections that communicate and feedback their activity levels to carefully tune their running. An essential part of the feedback mechanism uses glutamate.
To use a sound system analogy, if cocaine cranks up the volume by boosting dopamine, levamisole might work by increasing power to the speakers by upping glutamate levels. The effects add up and the high is amplified.
What this means is that dealers can sell less actual cocaine but users get a similar effect from the smaller amount.
However, this comes at a price. The additional ramping up of the 'fight-or-flight' system is likely to put an additional strain on the heart and heart failure is one of the most common cocaine-associated fatalities.
Levamisole also causes the immune system to stop working so well by killing off white blood cells (in fact, this is why it is rarely used in humans in modern medicine) and several cases of life-threatening illness caused by levamisole-cut cocaine have already been reported.
The fact that this additive has been appearing at all, is, in itself, quite surprising. The fact that this relatively obscure compound has become so common in the global cocaine industry might suggest that it was selected on the basis of its pharmacological properties.
In other words, on the basis of the study of neuroscience. One study reported that professional heroin cutters can charge up to $20,000 a kilo and I wouldn't be surprised whether the big players in the cocaine industry can afford to pay for neuroscientists or pharmacologists to tweak their products.
Link to PubMed entry for brief article on possible effects of levamisole. Link to excellent Erowid reviewing findings on levamisole-cut cocaine. Link to Wall Street Journal on prevalence of levamisole in US cocaine.
Discover Magazine has an excellent Carl Zimmer piece discussing efforts to understand the speed of the human nerves - a quest that has lasted for well over one hundred years.
Although our experience of the world seems instantaneous, different nerves in the body work at different speeds and, of course, cover different distances - to the point where taller people experience a slight sensory lag compared to shorter people owing to the greater length of some of the nerve pathways.
Speed is not necessarily of the essence, however, and as with dancing, it is timing and co-ordination that seems key:
Sometimes our brains actually need to slow down, however. In the retina, the neurons near the center are much shorter than the ones at the edges, and yet somehow all of the signals manage to reach the next layer of neurons in the retina at the same time. One way the body may do this is by holding back certain nerve signals—for instance, by putting less myelin on the relevant axons. Another possible way to make nerve impulses travel more slowly involves growing longer axons, so that signals have a greater distance to travel.
In fact, reducing the speed of thought in just the right places is crucial to the fundamentals of consciousness. Our moment-to-moment awareness of our inner selves and the outer world depends on the thalamus, a region near the core of the brain, which sends out pacemaker-like signals to the brain’s outer layers. Even though some of the axons reaching out from the thalamus are short and some are long, their signals arrive throughout all parts of the brain at the same time—a good thing, since otherwise we would not be able to think straight.
Link to Discover article 'What Is the Speed of Thought?'
I've just found a short case study in the British Journal of Neurosurgery of a 12-year-old boy who suffered a bleed in the brain after taking part in a 'head shaking competition'. Somewhat curiously, the case study notes that he won, and reports his winning time.
The patient was a 12-year-old, developmentally normal, healthy boy who presented to his primary care doctor with 2 weeks of headache accompanied by intermittent nausea and vomiting. The headaches began after the patient entered a 'head shaking contest' with his peers. The object of the contest was to vigorously rotate the head back and forth for as long as one could tolerate. The patient won, with a time of approximately 2 min. Afterwards he noted a mild headache that gradually worsened over the course of 2 weeks. When it was at its most severe, the headache was occasionally accompanied by nausea and vomiting. There were no visual disturbances or other focal neurological signs.
On a follow-up, he was found to have a large subdural haematoma, a type of bleed that happens under the brain's covering which is known as the dura mater, possibly related to an otherwise benign cyst that existed before hand but may have caused damage during the rather vigorous competition.
Psychosurgery: new cutting edge or short sharp shock:
The New York Times has an excellent article on how the development of new and more focused brain surgery techniques for the treatment of mental illness are leading to a tight-rope situation where doctors are trying to balance enthusiasm for a potential new treatment while avoiding its inappropriate use and bad publicity.
The use of neurosurgery for treatment of psychiatric disorders has a bad name. It is associated with the frontal lobotomy and leucotomy procedures which were carried out in large numbers in the 1940s, 50s and 60s on the basis on poor evidence and with very little oversight.
The dreadful excesses of this era have thankfully passed, and, with an increased understanding of brain circuity, it has been possible to trial the effect of very focused surgical interventions on certain neurological and psychiatric disorders.
Deep brain stimulation (DBS) is the most popular procedure, which is partly because the implanted brain electrode can be very accurately targeted, and partly because, in principle, the effect is reversible as it relies on electrical current for its effect, although the dangers of brain surgery still remain.
Neurosurgical procedures are also being used to permanently alter the brain by making cuts or lesions to specific areas.
This has been used for many years in Parkinson's disease to treat tremors (the distinctive 'shaking') because the circuits that control movement are quite well understand and easy to study because there are many objective and accurate ways of measuring movements.
Although the numbers are still tiny, the same strategy is being increasingly to treat severe mental illness. Searching PubMed for its common scientific name - 'functional neurosurgery' - brings up studies where it has been used on everything from addiction to chronic pain.
And this is where people get nervous, because the procedures are quite experimental still and the researchers are well aware of the dangers of being labelled as 'modern day lobotomists' if something goes wrong.
As the article nicely outlines, the challenge is not so much the control of symptoms, which is relatively easy, it's doing this while avoiding of adverse effects, like cognitive impairments, brain damage or additional mental instability.
Link to NYT piece 'Surgery for Mental Ills Offers Both Hope and Risk'.
Patient HM became famous for having a dense surgically-induced amnesia and taking part in numerous neuropsychology studies that told us a great deal about the structure of memory. He died last year but left his brain to science and Project HM has been set up to co-ordinate the scientific analysis of his brain.
According to a post on the Project blog, the process of dissecting and digitally recording the structure of HM's brain will begin on Wednesday 2nd December and apparently you'll be able to watch it live via video streamed from the site.
The best write up of the Project is over at Nature News who have unfortunately jailed their article behind a pay wall. However, here's the punch line:
On 2 December, exactly one year after Molaison's death, [Neuroanatomist Jacopo] Annese, of the University of California, San Diego, will begin dividing the brain into roughly 2,400 slices, each thinner than a human hair, and digitizing them. Annese hopes that Molaison's brain will become the first of many in a digital human-brain library at the university.
Annese is one of the few people with the sophisticated equipment needed to slice whole human brains, which is how he came by Molaison's brain. Most labs cut human brains into blocks before slicing them — the fate that befell Albert Einstein's brain.
Annese will mount and stain about every 30th slice for cell nuclei and projections, which will allow him to map the cellular architecture in three dimensions. The remaining slices will be available to the neuroscience community, with researchers able to view the particular slice they want to study before requesting it.
New Scientistreports on a new study on how a gene that gives protection against the deadly brain disease kuru became more common in people exposed to the condition through their cannibalistic tradition of eating the bodies of dead relatives.
Kuru is a prion disease, meaning the damage is caused by a poorly arranged or folded protein molecule which can trigger the same damaging changes in other proteins it comes into contact with.
The condition is related to what we know as 'mad cow disease' and causes a distinctive form of shaking, brain degeneration and eventually leads to death. It was restricted to the South Fore people of Papua New Guinea who seemed to pass on the condition by their tradition of to eating deceased relatives at mortuary feasts.
This new study shows that over time a new variant of the PRNP gene emerged in the population which gave protection against kuru.
Because kuru is deadly and was widespread, the emergence of the gene shows evolution in action:
The mutation first arose about 200 years ago by accident in a single individual, who then passed it down to his or her descendants. "When the kuru epidemic peaked about 100 years back, there were maybe a couple of families who found that they and their children survived while all their neighbours were dying, and so on to today's generation, who still carry the gene," says Mead. "So it was a very sudden genetic change under intense selection pressure from the disease," he says.
If you want some background on kuru and how prion diseases affect the brain, you can't go far wrong with a fantastic Neurophilosophyarticle from last year.
Link to NewSci on 'Gene change in cannibals reveals evolution in action'. Link to abstract of study. Link to excellent Neurophilosophy article on kuru.
The New York Times has a fascinating article on how surgeons are attempting to treat aggressive and fatal brain tumours by injecting chemotherapy drugs directly into the brain.
One of the challenges for drug makers is that there are many substances that would otherwise have an effect in the brain, but it's very hard to get them there from the bloodstream because the blood-brain barrier filters out all but the smallest molecules.
The NYT article discusses a technique borrowed from stroke treatment to deliver chemotherapy directly to the tumour or area from where the tumour has been removed.
In certain sorts of stroke a blood clot forms and blocks blood vessels, depriving the brain of oxygen. One important treatment is called thrombolysis where doctors can inject a clot dissolving enzyme through super fine flexible tubes called microcatheters.
They can insert these into a blood vessel in the lower body and then pass them through the the network of veins and arteries until they reach the affected blood vessel in the brain, delivering the 'clot busting' enzyme to exactly where it's needed.
This new technique for brain cancer has apparently borrowed this technology to deliver chemotherapy to a specific area to treat one of the deadlist form of brain tumours - the glioblastoma.
The treatment is still in the research phase, so it's not clear it has any benefits, but the article is an interesting take on a new approach to treating this condition with a life expectancy of little over a year:
The study, which began in August, is still in its earliest phase, meaning its main goal is to measure safety, not efficacy — to find out if it is safe to spray Avastin directly into brain arteries and at what dose. Nonetheless, the doctors were pleased when M.R.I. scans of the first few patients showed that the treatment seemed to erase any sign of recurring glioblastomas. But how long the effect will last remains to be seen...
The complexity of a study like this goes beyond the science. Clinical trials are also a complicated pact, emotionally and ethically, between desperate patients and doctors who must balance their ambition as researchers against their duty as clinicians, and must walk a fine line between offering too much hope and not enough.
Link to NYT piece 'Breaching a Barrier to Fight Brain Cancer'.
Wired UK has a fantastic investigative article concerning a recent case in India, where, for the first time, an 'EEG lie detector' was used to convict a 23-year-old woman of murder.
Aditi Sharma was described as being in a love triangle and her ex-boyfriend died through arsenic poisoning. She maintained it was suicide but the prosecution successfully argued that her and her new boyfriend murdered the ex. The judge apparently felt that the EEG was decisive and revealed 'experiential knowledge' which proved her to be guilty.
The general idea does have a scientific basis, but its not widely considered to be anything except a research tool because its never been tested thoroughly enough or proved to be reliable enough to form the basis of legal evidence.
The research version is called the guilty knowledge or concealed knowledge test and is based on the fact that, on average, recognising something you've seen before has a distinct EEG waveform when compared to seeing something completely new.
The idea is that the investigator can show you things from the crime scene and just 'read off' your brain's electrical activity and infer whether you were there or not. The technology described in the Indian case apparently uses a technique where statements are read out to the accused, although this is not a common format.
It is currently not admissible as evidence in court, but as the Wired UK article reveals, a similar technology has now been turned into a minor industry in India and there is a shocking acceptance by the legal system that the technology is a genuine 'lie detector' - way beyond what anyone has shown reliably in the lab.
The laboratory of the Directorate of Forensic Science in Mumbai has been running Brain Electrical Oscillations Signature (BEOS) tests on criminal suspects for two years. Business is good: when Wired visits, another room is being added to accommodate a second EEG machine, which sits covered in bubble wrap. “We consider the brain as a computer, where information is stored and can be retrieved,” explains Sunny Joseph, the lab’s 33-year-old assistant chemical analyser. The psychology department has two other staff members – both in their twenties, both rushed off their feet, with case after case being sent by the courts. “Referral rates have been really high,” Joseph adds. “We do possibly 15 cases a month.” A growing heap of brown-foldered case reports sit in the corner...
A colleague of Joseph’s later points out that brain-imaging allows an overstretched police force to speed up the conviction process by eliminating innocent suspects from their enquiries and by corroborating evidence. That is why Mumbai is not the only Indian city to have invested in BEOS technology. The government’s forensic science directorate in Gandhinagar, in Gujarat, has been using it since 2003 and has now tested 163 subjects in 88 criminal cases. Support came directly from India’s chief forensic scientist, Dr MS Rao. “The technique has great potentiality to become an infallible tool in crime investigation,” he wrote in a paper presented to the All-India Forensic Science Conference in January. “It can become a revolutionary technique like DNA fingerprinting if its evidential strength and judicial acceptability are established.” A third such facility opens soon in the northern Indian city of Chandigarh.
The young lady accused of murder, Aditi Sharma, has apparently been sentenced to life imprisonment on the basis of the technology, although I've not been able to find out if there has been an appeal since her sentencing in June.
Link to article 'The brain police: judging murder with an MRI'.
Full disclosure: I'm a contributing editor to Wired UK and have never been EEG lie-detected.
Discover Magazine has an article on an innovative project to create silicon chips which work like neurons. If you're thinking these are standard digital chips that run neural network software you'd be wrong, they're part-analogue devices that are specifically built to emulate the physical operation of brain cells.
The article riffs on the work of neuroscientist Kwabena Boahen who leads the 'Brains in Silicon' project.
If you're not familiar with the difference between analogue and digital calculation it's worth just briefly getting to grips with it so you can see how revolutionary this project is.
Most computer chips are digital. They encode numbers as lists of 0s and 1s because they are made up of millions of transistors which can switch on (a '1') and off (a '0'). The chip can then do operations or maths on the numbers, by flipping the switches, depending on what functions are built-in and how software makes use of them.
So if you wanted to calculate, lets say, how fast a crowd of people walk through a door, you would need to enter numbers for the size of the door, how fast the people are walking, the amount of interference caused by jostling and crowding and your mathematical formulae which ties it all together. The chip would do the calculation, and you would get your answer.
An analogue calculation is more more like a simulation. For example, you might find that ball bearings and a funnel give you a good approximation of the answer. You just change the size of the funnel, the number of ball bearings and the pressure from behind and you just observe what is happening to get the answer. It might not be as pinpoint accurate, but its much easier to build and run.
The traditional approach to artificial neural networks is the first. Each virtual neuron is a mathematical simulation of the electrical and chemical processes and how it influences other virtual neurons. This needs huge amounts of calculations because each of the simulated neurons is mathematically complex and any change means every connected neuron needs also to be recalculated.
This is the approach taken by the Blue Brain Project and it is no accident that they use one of the world's biggest supercomputers to run the simulation.
This is where Boahen's project comes in. While the traditional digital approach is very accurate, its very time and energy intensive. While the Blue Brain project needs a warehouse of tech to support it, the actual noisy error-prone brain runs in the space of a bag of Doritos.
So instead of going for the pinpoint accuracy of digital simulation, Boahen has created chips that are an analogue simulation, or really, an analogue emulation of neurons.
As neurons use electrical impulses, much of their function can be described as electrical circuits. In fact, the Hodgkin-Huxley model of the neuron can be drawn as an electrical circuit.
So instead of writing mathematical equations to simulate the circuit and then getting a chip to do the digital calculations, you could just build the circuit. Using the circuit would tell you exactly how the neuron would behave.
Complete neurons are more complex than the simple Hodgkin–Huxley circuit (which just aims to describe the electrical action potential signal) but the same approach applies. Instead of building a chip to run digital simulations of circuits, just build the circuits. The result is noisy, dirty but fast, very low power and good enough - just like the human brain.
We covered Boahen's work back in 2007 and there's a great talk he did which introduces the project, but the Discover article is a great update on the research which has the potential to turn neurally inspired computing on its head.
It also has loads of background information and is a great introduction to how the brain deals with its noisy and surprisingly unreliable neurons.
Dramatic sexuality changes after brain disturbance:
The Neurocritic has compiled a collection of interesting neurological studies where a number of patients seems to have experienced a profound change in their sexual preferences as a result of brain disturbance.
One of the most well-known of these studies is a recent case of a man who was convicted of paedophilia late in life, but was later found to have a brain tumour, and on removal of the tumour his sudden interest in children disappeared. It reappeared again when the tumour once more began to grow.
The case has raised questions about free will and self-determination in light of the fact that such morally reprehensible acts seemed only to occur when a tumour was affecting brain function.
It's importantly to mention that brain damage rarely causes such tragic events, although sexual difficulties, in general, are not uncommon. Problems can range from difficulties with arousal and enjoyment, to behavioural disturbances and inappropriate behaviour.
In some rare cases, preferences themselves seem to be affected, although it's never clear whether it's actually that the person has different desires, or whether they always had them but now are, perhaps, less able to stop themselves acting on them.
It's easier to think that damage has changed people's desires when the behaviour markedly unusual, such as this case of a man who was, to put it bluntly, screwing the coin return tray of a public telephone after brain deterioration.
But one thing we know from the forensic literature and cases of healthy people who accidentally die during sexual practices (for example, thesetwo), is that no matter how strange the attraction seems to you, someone is out there expressing it.
Not all of the cases of changes sexuality after brain damage are where people act outside of the norm, of course. In one, admittedly, not brilliantly detailed case, an apparently exclusively homosexual man found he developed heterosexual attraction after a stroke.
Sadly, this area is massively under-researched so we really know relatively little about how different aspects of desire, emotional attachment and sexual behaviour are handled by the brain, but these case studies give us a window into the possibilities.
Link to The Neurocritic on 'Unusual Changes in Sexuality'.
I've just discovered a curious medical finding that can be detected on MRI brain scans called the 'face of the giant panda sign' where, quite literally, it looks like there's a panda face in the middle of the brain, indicating a specific pattern of neural damage.
The image you can see on the left is the 'face of the giant panda sign' that appeared in a brain scan of a patient with multiple sclerosis who started showing unusual sexual behaviour and is taken from a 2002 study. Click the image if you want to see the whole scan.
The pattern is apparently caused by "high signal in the tegmentum, normal signals in the red nuclei and lateral portion of the pars reticulata of the substantia nigra, and hypointensity of the superior colliculus".
It is most associated with Wilson's disease, a genetic condition which causes a toxic build-up of copper in the body, but obviously can appear in other disorders as well.
Technology Review has a fantastic photo essay that tracks how we've visualised the brain from times past and includes some of the most stunning images from the last century of neuroscience.
It's been put together by Mo Costandi, the writer you may know from the Neurophilosophyblog, with each image concisely described so you can get an insight into exactly what you're seeing.
Link to 'Time Travel Through the Brain' photo essay.
BBC News has a fascinating short video report of a robotic hand that is connected to the nerve fibres of an amputated arm and which allows the patient to actually feel touches with the robot fingers.
Although it doesn't mention it in the report, the technology is from the SmartHand research group who are attempting to use knowledge about the cognitive neuroscience of action and body sensation to make fully integrated naturally controlled prosthetics.
There's an interesting part of the video where the patient says "When I grab something tightly I can feel it in the finger tips, which is strange because I don't have them anymore".
In other words, despite the fact that the robot hand feeds touch information into the nerve fibres into the arm stump, the patient feels the sensations 'in' the robot fingers.
This is essentially the 'rubber hand illusion' and the same research group demonstrated exactly this in a recent experiment where they induced touch sensations in a robot hand by stroking it and the stump simultaneously.
This is interesting because a recent study found that sensations in people with intact arms only transferred to a realistic looking rubber hand and not a wooden one, whereas this research team uses a obviously false robot limb.
The fact that touches transfer to an obviously false hand for someone with an amputation but not for people with intact limbs is interesting, because it suggests that brain's remaining body-image 'maps' for the amputated hand may be being recruited to enhance the illusion.
Link to BBC News video report "New robotic hand 'can feel'". Link to SmartHand project.
The latest edition of the Journal of Neuroscience has a fantastic collection of articles by leading neuroscientists who look back on the last 40 years of discoveries in brain research.
The collection is to celebrate the 40th anniversary of the Society for Neuroscience. As the articles make clear, the last four decades have seen a huge expansion in our knowledge of how the brain works and the Society asked leading lights in the field to reflect on this scientific revolution.
Memory and Brain Systems: 1969–2009 by Larry R. Squire [link]
Neurotransmitters, Receptors, and Second Messengers Galore in 40 Years by Solomon H. Snyder [link]
Four Decades of Neurodegenerative Disease Research: How Far We Have Come! by Anne B. Young [link]
A Paradigm Shift in Functional Brain Imaging by Marcus E. Raichle [link]
The Development of Developmental Neuroscience by Carol Mason [link]
The Biology of Memory: A Forty-Year Perspective by Eric R. Kandel [link]
Strictly speaking, they're not all retrospectives. For example, while Larry Squire gives a whistle-stop tour through the last 40 years of the cognitive neuroscience of memory (and you'll probably not read a better brief article in this area), Marcus Raichle takes the opportunity to look forward and is clearly enthusiastic about the 'default network' which he is co-credited with discovering.
They're all academic articles, so are not the most accessible if you're not familiar with the scientific literature, but as brief guides to some of the major areas of neuroscience they're fantastic and freely available online.
Science News has a brilliant special issue on the 'science of slumber' that tackles sleep disorders, the mental impact of sleep deprivation, how sleep differs across species and the still mysterious question of why we need to sleep.
I found the article on two seemingly straightforward sleep disorders, insomnia and narcolepsy, the most interesting. They seem straightforward because they appear as a lack and an excess of sleep, but as the piece makes clear, they are still quite mysterious.
Insomnia is particularly interesting because having trouble sleeping happens to everyone at some point, so in itself, it's not abnormal - meaning that research into what triggers it is unlikely to find anything striking.
Instead research has shifted to try and understand what prevents insomnia from resolving naturally so it becomes a chronic condition:
Sleeplessness may be brought on by traumatic events such as a death in the family, an illness such as cancer or anything else distressing, causing a person to lie awake at night with a racing mind. For a subset of people, though, insomnia has no prompting signal — a condition called primary insomnia.
Regardless of the trigger (or lack thereof), temporary insomnia has a nasty way of becoming a habit. Poor sleep habits can become ingrained. When trouble sleeping persists for three or four nights a week over several months, insomnia is considered chronic.
It may turn out that untangling the prompting signals of insomnia, as many sleep researchers attempt, is a fool’s errand, says Michael Perlis, director of the University of Pennsylvania’s Behavioral Sleep Medicine Program in Philadelphia. “The whole zeitgeist has changed,” he says. Most sleep researchers now agree that “once insomnia goes chronic, it stays that way,” regardless of the prompting signal, Perlis says. So rather than focusing on the immediate trigger for insomnia, many scientists are trying to figure out why it becomes chronic and how to prevent that from happening.
I also liked the short piece that briefly compares the amount of type of sleep between lots of different animals. It seems dolphins don't have REM sleep. I wonder if that means that they lack or have very limited dreams?
Anyway, a great collection of articles and all freely available online.
There's a curious case published in the medical journal Epilepsy and Behavior of a young man who had his epilepsy triggered by the sight of stairs. This would cause seizures that would trigger "repetitive hugging and affectionate kissing of one of the people around him".
Our patient is currently 24 years old. He is a right-handed male with a history of right temporal lobe epilepsy. He had his first seizure when he was 10 years old. His seizures usually started with an aura of a “feeling” inside his body or abdomen. This feeling, described at times as pain or nausea, lasted a few seconds or a few minutes. His eyes would then widen, he would become confused, and he would look around right and left as if wondering. The seizure would last 1 to 2 minutes with altered consciousness, spitting, and often repetitive hugging and affectionate kissing of one of the people around him.
At times this was followed by head and eye deviation to the left and, sometimes, rotation of the whole body to the left side. Occasionally, he would walk around for a few seconds. These seizures were often precipitated by looking at stairs, whether or not he was walking up the stairs. He learned to avoid looking at stairs to avoid having seizures. He also noted that looking down a flight of stairs did not precipitate his seizures.
I am constantly amazed by both how seizures can be triggered by very specific experiences (such as seeing a certain thing, or hearing a specific sound) and how they can lead to very selective actions.
This is by no means a typical effect of epilepsy but it does raise the interesting question of how these very narrow experiences lead to destabilising brain states which trigger a seizure.
I have heard anecdotal reports from several clinicians that they've met patients who can 'think their way out' of a seizure by deliberately focusing their thoughts on a specific topic, presumably which reduces the destabilising effect of their original 'trigger experience'.
I've not seen this discussed in the medical literature though, so if you know of any articles that do tackle it, I'd love to hear about them.
Link to PubMed entry for stair triggered epilepsy case.
Electrical readings from seven patients who died in hospital suggest that the brain undergoes a surge of activity at the moment of death, according to a study just published in the Journal of Palliative Medicine.
Palliative care is a medical approach that aims to make dying patients as comfortable as possible. As part of this, doctors from George Washington University Medical Centre's intensive care unit were using standard alertnessmonitors for seven patients that include EEG measurements of the frontal lobes.
The monitors are commercial devices designed to help anaesthetists monitor how 'awake' patients are, and they combine the electrical readings from the brain into a single signal that reflects alertness.
For each of the seven patients, the researchers noticed that at the point where blood pressure dropped to zero there was a surge in brain activity. The graph on the right is from one of the patients and shows a typical activity burst.
This is not the first time these have been noticed, but previous reports were single cases and the electrical surges were explained away as due to electrical interference from other sources. In these new cases, the doctors could be pretty confident that previously suggested sources of interference weren't present.
Instead, they suggest that the surge was due to 'anoxic depolarisation' - a process where the lack of oxygen destabilises the electrical balance of the neurons leading to one last cascade of activity.
Now, this is just a case series and the neuroelectrical measures aren't the best. The researchers encourage more systematic research with appropriate tools, but they do suggest an intriguing hypothesis with regard to 'near death experiences':
We speculate that in those patients who suffer cardiac arrest who are successfully revived, they may recall the images and memories triggered by this cascade. We offer this as a potential explanation for the clarity in which many patients have "out of body experiences" when successfully revived from a near death event.
One of the difficulties, of course, is that although 'near death experiences' are a well-known phenomenon, we only know about them from people who weren't really dying (or even from people who were never actually 'near death' as one of my favourite studies attests).
Nevertheless, neuroscience studies on the dying are likely to be of increasing interest especially as the debate about what counts as death become more prominent.
I just found a curious case study of a man who developed 'robotic speech' after being hit by lightning. Rather than the "I am a Dalek!" style mechanical sound it seems to be more like the very. deliberate. and. exact. speech synthesis style, somewhat like Data from Star Trek the Next Generation
Lightning-induced robotic speech
Neurology. 1994 May;44(5):991-2.
To the Editor
Because of a recently observed case, I was intrigued by the communication of Cherington et al[1] concerning lightning encephalopathy. The authors referred to evidence by Critchley[2] that the cerebellum can be selectively injured in lightning-struck patients, Two of their there patients had signs of cerebellar dysfunction. MRI in one of their patients evidenced superior cerebellar atrophy.
The force of a lightning strike threw a 20-year-old roofer to the ground from the truck in which he was standing. Panicked, he immediately began to run. A numbness and weakness of his arms and back cleared after several days, but the more striking abnormality was a profound alteration of his speech, which he described as having become robotic. Each syllable was clearly enunciated with a slight pause between syllables, so that while the flow of his speech was slowed, he was able to communicate well. His speech was actually easier to comprehend than that of some normal persons. His brother had indeed complained that the patient's premorbid speech had been too rapid and word-jumbled; that speech was transformed to robotic speech, with fine diction and super-clear enunciation. Each morning, his speech was "normal" until shortly after he began to talk, when it reverted to the robotic pattern for the remainder of the day. The neurologic examination was normal except for right upper extremity hypalgesia. Brain MRI was normal.
I considered his robotic-speech problem to be most like the "scanning speech" of cerebellar disease. I have found no references to similar cases, but the reports of selective cerebellar injury by lightning strike[1-3] lead-me to suspect that robotic speech maybe a more common sequel than has been recognized.
Gordan J. Gilbeft, MD
St. Petersbutg, FL
1. Cherington M, Yarnell P, Hallmark D. MRI in lightning encephalopathy. Neurology 1993; 43(7):1437-8
2. Critchley M. Neurological effects of lightning and electricity. Lancet 1934;1:68–72
3. Morocutti C, Spadaro M, Amabile G. TRH treatment in cerebellar ataxia following a lighting stroke. Ital J Neurol Sci 1989;10:531.
The original authors reply and seemed somewhat baffled, saying that it could equally arise from the shock of the experience rather than damage to the brain.
The New York Times has an absolutely fantastic article on the psychology and neuroscience of anxiety and how an anxious temperament at birth can ebb and flow during our lifetime.
It's an in-depth article that really does justice to the topic, looking at extensive research into our anxious states, but also carefully questioning some of the sloppy assumptions of many article where brain activity is described as directly representing mental states.
But having all the earmarks of anxiety in the brain does not always translate into a subjective experience of anxiety. “The brain state does not make it a disorder,” Kagan told me. “The brain state exists, and the statement ‘I’m anxious,’ exists, and the correlation is imperfect.” Two people can experience the same level of anxiety, he said, but one who has interesting work to distract her from the jittery feelings might do fine, while another who has just lost his job spends all day at home fretting and might be quicker to reach a point where the thrum becomes overwhelming. It’s all in the context, the interpretation, the ability to divert your attention from the knot in your gut.
The article is incredibly well written and it tackles a huge range of topics in the understanding of fear and anxiety. Highly recommended.
Link to NYT article 'Understanding the Anxious Mind' (via @mocost)
I've just found this remarkable TV interview with Oliver Sacks from 1986, only a year after the publication of his famous bookA Man Who Mistook His Wife for a Hat.
It's a fascinating discussion, not least because it's something you don't see much these days - an extended interview that focuses solely on a neuroscientist and his work.
There are no gimmicks or attempts to jazz it up with fancy editing and graphics. We see everything during the discussion, including Sacks' many 'ums' and 'ahs' and even hear a telephone going off half way through!
Still, it's a really wide ranging discussion which covers everything from the effects of brain injury to the role of doctors in exploring their patients' lives.
From what I can make out, the interviewer is Harold Channer who did the piece for a Manhattan-based public access TV network probably before Sacks became well-known.
The video quality is a bit ropey but Sacks has a spectacular beard and is as chaotically engaging as ever. Classic stuff.
I've just found a brief but interesting study finding that migraines are much more common in neurologists than the general public which inspired an interesting reply by Oliver Sacks.
The prevalence of migraine in neurologists
Neurology. 2003 Nov 11;61(9):1271-2.
Evans RW, Lipton RB, Silberstein SD.
To assess the prevalence of migraine among neurologists and neurologist headache specialists, the authors performed a survey of neurologists who attended a headache review course. The 1-year and lifetime prevalences of migraine in the 220 respondents were as follows: male neurologists, 34.7%, 46.6%; male headache specialists, 59.3%, 71.9%; female neurologists, 58.1%, 62.8%; and female headache specialists, 74.1%, 81.5%. Migraine is much more prevalent among neurologists than in the general population.
Sacks later wrote to the journal to mention an earlier study finding much higher levels of migraine-related visual disturbances in doctors than other people. He also wonders:
Speculating on the possible reasons for the prevalence of migraine in neurologists, and particularly headache specialists, Evans et al. wonder, among other possibilities, whether "a personal history of migraines might stimulate an interest in neurology and headache as a subspecialty." For myself, with a personal history of classical migraines (and, more often, isolated visual ones) going back to childhood, the extraordinary phenomena of the aura (which for me included transient or partial achromatopsia, akinetopsia, as well as visual agnosias, alexias, etc), excited an interest in the brain, and especially in visual processing, at an early age. These migraines were certainly one of the reasons I was attracted to neurology, why I chose migraine as the subject of my first book, and why I devoted a large part of this book to illustrating the varied presentations of visual auras in my patients
However, he gets short shrift from the researchers who curtly point out that their survey asked whether neurologists' experience of migraine had influenced their career choice and they said no, so it can't be true.
This is clearly not the finest psychological reasoning in the world and I remain fascinated by whether personal experience shapes the specialisation of clinicians.
It only happens in some cases of course. It's probably rare that neurologists had their interest sparked after major brain damage or oncologists after experiencing cancer.
We do know, however, that psychiatrists are morelikely to have experienced mental illness than other doctors and I wonder how many other links between clinical speciality and illness experience there might be.
Neurosurgical Focus has an excellent article on the development of stereotactic neurosurgery where an external frame is usually screwed into the skull and fixes the head in place to allow surgeons to precisely locate brain areas in a standard 3D space.
In modern stereotactic surgery, the system is usually used with an electronic tracking system that maps the surgeon's instruments onto a previously acquired brain scan in real-time. The frame allows the brain scan and the actual brain to be precisely aligned.
This means the surgeon can, for example, place a depth electrode into a precise spot without having to physically see that area while still being confident that they're in the right place.
The system is also used in research labs to ensure that, for instance, the brain is stimulated in precisely the right spot with magnetic pulses, using a technology called transcranial magnetic stimulation or TMS.
For example, if researchers wanted to see the effect of stimulating the auditory cortex they could run a listening experiment in an fMRI machine, see exactly where your auditory cortex is by mapping the activity on your brain scan, and then use a stereotactic system (e.g. this one) to guide the TMS machine to exactly this spot on your actual brain.
With all of its high-tech trappings, I never realised that the first human stereotactic system was created in 1918 with the system you can see in the picture.
The Neurosurgical Focus article looks at how the technology has developed from the original brass contraptions to the modern age of neurosurgery.
Link to Neurosurgical Focus on the history of stereotactic brain surgery.
I've just found this alarming case study [pdf] from the Singapore Medical Journal about a patient who had a nail banged into their head by a local healer in an attempt to treat persistent headaches.
Craniocerebral penetrating wounds caused by nails are rare and reported as curious experiences. A 45-year-old female patient presented with a metal nail in situ in the middle of her head, very close to the right side of the midline. The patient had been unconscious since the time of injury. There was no history of vomiting or seizures. Neurologically, the eye opening and verbal response were nil, but she was localised to the pain and moved all four limbs equally. The pupils were bilaterally symmetrical and reactive to light. General and systemic examinations were unremarkable.
The relatives revealed that she had been suffering from a headache (more on the right side) for the last ten years, with off and on exacerbation. They took the patient to a Tantrik, who hammered the nail into her head to get rid of the bad omen. Anteroposterior and lateral radiographs of the skull showed a foreign object inside the skull, very near to the midline. As there were no facilities to perform computed tomography (CT) in the peripheral hospital, the nail was removed under local anaesthesia, based on the radiographical findings. After the removal of the nail, she was managed conservatively and made a gradual recovery in her sensorium. The patient was doing well at follow-up.
As medical historian Owsei Temkin discussed in his definitive book on the history of epilepsy The Falling Sickness (ISBN 0801848490) banging nails into the head was also a Roman 'treatment' for seizures.
Link to PubMed entry for case study. pdf of full text of case study.
I just found a curious article from the Journal of the American Medical Association about a case of 'laugh syncope' - a condition where the patient passes out when they crack up with laughter.
Syncope is the medical term for when someone feints and it is caused by a reduction of oxygen to the brain.
At 4 PM on a March day, a 32-year-old, previously healthy barber was standing and cutting a client’s hair. The client related a funny story, upon which the barber broke out into a very strong, sustained, loud, and unrestrained laughing fit during which, according to observers, he "blacked out" and fell to the floor. Although he sustained interscapular bruising and minor trauma to the right shoulder, he exhibited no seizure activity and no bladder or bowel incontinence.
He regained consciousness within a few seconds, was completely oriented, had no apparent neurological deficit, and immediately resumed his work. He had been working on his feet throughout the day, but this was customary for him and he had never had a syncopal or near-syncopal episode before. The temperature at the time had been mild. The timing of his most recent meal was not recorded. The patient did not reveal the content of the story.
I love that last sentence. It reminds me of an earlier medical warning about the dangers of powerful jokes.
I note there's another case of 'laugh syncope' that was published last year.
Apparently these cases can be caused simply by problems with getting the blood to the brain (such as heart difficulties), problems with the brain itself (for example, difficulties with its own blood supply network or the occurrence of a seizure) or due to what is known as a vasovagal episode that can be due to psychological triggers or vagus nerve dysfunction.
Link to 'Shear hilarity leading to laugh syncope in a healthy man'.
I've just had pick my jaw up from the floor after reading an article on the brain scanning of unborn babies. I was idly wondering whether anyone had attempted to do an MRI scan of the fetal brain only to find that researchers are so advanced that they can do almost any sort of adult neuroimaging on the fetus - including psychological studies of brain activation.
One of the main difficulties with brain scanning unborn babies is that they move about a lot. You can asks adults and children to stay still, but fetuses are a little bit harder. One of the major advances in the field has been the development of algorithms to reconstruct high definition scans from blurred images.
Researchers have also completed diffusion scans that can create 3D maps of the white matter 'cabling' of the brain in the unborn baby, as with a recent study [pdf] on how brain connections develop during gestation. Recent studies have similarly been able to measure developing brain metabolism and examine how the size and shape of specific areas change during pregnancy.
But most amazingly, several studies have conducted functional MRI experiments on fetuses. In other words, they measured neural activity in specific brain areas in response to specific experiences.
The two scans on the right are from a 2008 study that looked at whether unborn babies at the 33rd week of development would show brain responses to sound in their auditory cortex, part of the temporal lobes. The researchers simply put headphones on the belly of the pregnant women and scanned while they played tones.
The top scan is from an adult, while the one from the bottom is from one of the fetuses, showing clear and selective activity the auditory cortex nearest the sound source.
I was completely blown away by that, and researchers are continuing to develop new and intriguing ways of presenting experiences to the fetus (such as shining lights through the belly to look for visual brain responses!).
Link to PubMed entry for paper on brain scanning fetuses.
The Llullaillaco mummies are the spectacularly preserved bodies of three sacrificial children from a 500-year-old Inca civilisation found at more than 6,500m above sea level in the Peruvian Andes. I've just found a study that brain scanned the mummies and the results are nothing short of stunning.
I've tried to link each scan to the picture of the relevant mummy (although I have to say, the online photos of the mummies are a bit inconsistently labelled so I apologise for any mismatching) and you can see how remarkably well-preserved they are both inside and out.
The mummies are of a 15-year-old girl, a 7-year-old boy and a 6 year-old girl that are thought to have been left as part of a ritual Inca sacrifice. From the article:
The scientific excavation was carried out at an altitude of 6,739 m above sea level on the summit of Mount Llullaillaco in the northwestern Argentinean Andes at an average temperature of –15°C. These children had been sacrificed 500 years ago in times of the Inca Empire to appease the mountain deities and to ensure the emperor's well-being. In addition, the mummies were buried with more than 100 objects, including textiles, gold and silver statues, pottery, and feathered headdresses.
The children had been buried in three pit tombs built by the Incas by enlarging natural niches in the bedrock at the summit shrine of Mount Llullaillaco, which is considered to be the highest archaeological site in the world. The mummies were individually buried 1.7 m deep with their associated offerings. The funerary sites were covered with a mixture of soil and stones, which was also used to fill in the platform that was later built to cover the burials.
According to a National Geographicnews story, the older girl was found to have chewed coca leaves and drunk corn liquor, the latter possibly to put her asleep.
Link to study on brain scans of Llullaillaco mummies. Link to NatGeo story on the mummy of the older girl.
Gizmodo has picked up on an interesting new neurosurgery simulator that not only provides virtual reality skills training but also allows doctors to use data from MRI scans to practice on the brain of a specific patient.
The system also gives tactile feedback through the instruments, so you can feel the resistance in the brain tissue as you 'cut' through it.
According to a piece in TechReview, it's the result of an ongoing project to create a neurosurgery simulator that started last year in Canada.
Check the Gizmodo page for a news clip where you can see the simulator in action.
Link to Gizmodo with video of NeuroTouch. Link to TechReview write-up.
Instant reflex may reveal brain injury after knock out:
I've just found a fascinating video clip reporting on newly discovered reflex action that occurs after a knockout blow. The researchers scoured YouTube for videos of nasty bangs the head and found many examples of the reflex appearing in people as they hit the deck.
The news clip is a a bit American (Americans, if you're not sure what this means, to us, all your news seems like this) but includes some video clips which illustrate the response in sportsmen who have been knocked out.
The researchers who have discovered the response have named it the 'fencing response' apparently because it looks like the en gard position in fencing - presumably though, only if you've never actually seen any fencing.
It actually looks more like the boxing stance with both hands out in front with elbows bent.
They suggest in their study that the response is a visible marker of moderate brain injury.
Link to news clip on the 'fencing response'. Link to abstract of study.
Your gut has its own neural network. Called the enteric nervous system, it controls digestion and has as many neurons as the spinal cord.
Parkinson's disease is a brain disorder that has been long associated with stomach upsets. These were often explained away as due to poor diet or stress, but it seems increasingly likely that the disease may also be affecting the neurons in the digestive system.
It was originally thought just to destroy dopamine neurons in a deep brain structure called the nigrostriatal pathway, an effect which causes the distinctive movement problems, but it has become clear that the disorder causes damage throughout the nervous system via the formation of protein clumps called Lewy bodies.
A new article in European Journal of Neuroscience suggests that Parkinson disease affects the enteric nervous system, which might tie together some curious findings in the medical literature that have remained unexplained for many years.
Stomach upsets, swallowing and digestion problems have long been associated with Parkinson's but it has never really been clear why.
While we commonly think of it purely in mechanical terms, digestion is remarkably complex process and the enteric nervous system is involved in the careful regulation of the muscle ripples of the gut, secretion of digestive fluids and blood flow to aid absorption.
Damage to this system would cause exactly the sorts of problems that have been reported in Parkinson's disease patients and this fits with some previous findings that have been ignored for many years.
Until recently, only one study had investigated whether the enteric nervous system was damaged in Parkinson's patients. It found that large numbers of the gut's dopamine neurons seemed to be missing in patients with the disorder.
The next study appeared more than ten years later, this time looking for protein clumps in the gut of deceased patients, and found evidence that not only were these tell-tale signs present, but that the distribution suggested that neurons in the gut may be the first to be damaged.
The author of this study, neuroscientist Heiko Braak now proposes the radical idea that while we know part of the risk for Parkinson's is genetic, maybe an environmental trigger - a virus - could get into the nervous system via the stomach, eventually triggering the brain changes that lead to the debilitating tremors and movement problems.
Link to Parkinson's and gut nervous system article summary.
Discover Magazine has an excellent Carl Zimmer article on glial cells. They make up the majority of the brain's volume but they get relatively little attention from the neuroscience community who would rather focus on the seemingly more lively neurons.
There's a traditional format for these stories, that says that we used to think that glial cells were just 'scaffolding' for the brain that gave protected padding for the neurons, but now we are on the verge of a breakthrough in understanding what they do.
Here's one from New Scientist in 1994, and a pdf of another from Scientific American in 2004.
One difficulty has been integrating the action of glial cells into the popular cognitive model of the brain that suggests that it works as an information processing device.
While there have been various discoveries about the biological function of glia, this is the first article I've read which gives a clear idea of how one type of glial cell, the astrocyte, might be involved in information processing.
For some brain scientists, these discoveries are puzzle pieces that are slowly fitting together into an exciting new picture of the brain. Piece one: Astrocytes can sense incoming signals. Piece two: They can respond with calcium waves. Piece three: They can produce outputs—neurotransmitters and perhaps even calcium waves that spread to other astrocytes. In other words, they have at least some of the requirements for processing information the way neurons do. Alfonso Araque, a neuroscientist at the Cajal Institute in Spain, and his colleagues make a case for a fourth piece. They find that two different stimulus signals can produce two different patterns of calcium waves (that is, two different responses) in an astrocyte. When they gave astrocytes both signals at once, the waves they produced in the cells was not just the sum of the two patterns. Instead, the astrocytes produced an entirely new pattern in response. That’s what neurons—and computers, for that matter—do.
If astrocytes really do process information, that would be a major addition to the brain’s computing power. After all, there are many more astrocytes in the brain than there are neurons. Perhaps, some scientists have speculated, astrocytes carry out their own computing. Instead of the digital code of voltage spikes that neurons use, astrocytes may act more like an analog network, encoding information in slowly rising and falling waves of calcium. In his new book, The Root of Thought, neuroscientist Andrew Koob suggests that conversations among astrocytes may be responsible for “our creative and imaginative existence as human beings.”
Obviously this is based on the idea that we need to fit new biological findings into the computational model, rather than fitting our model of the mind into the biology, but that's a whole different battle.
Link to Discover article 'The Dark Matter of the Human Brain'.
The Wellcome Trust is putting its archive of medical films online which includes some fascinating footage of some 1933 neurosurgery to remove a tumour from the frontal lobe.
The film says the tumour is a tuberculoma. While we typically link tumours to cancer, the name also refers to other types of abnormal growths.
In this case, it's an abnormal growth caused when tuberculosis (TB) reaches the brain and leads to an infected mass that can have a similar effect - damaging the cortex by taking up space where the brain should be.
Because TB can be treated effectively with antibiotics, tuberculomas are now very rare in the West, but they are still unfortunately quite common in parts of the developing world where access to medical care is limited.
The Wellcome archive footage is from a time where TB was much more common and shows how surgeons of the days would have removed the mass and how the patient is left after recovery.
Link to Wellcome archive footage of 1933 brain surgery.
Today's Nature has a fantastic article about how psychoactive drugs are being developed into a new generation of chemical weapons design to have specific psychological effects on the enemy.
This has long been part of military research (see the famous and unintentionally hilarious footage of British troops being given LSD presumably from the 1950s) but the effects of the mind altering weapons have generally been thought to be too unpredictable and largely restricted to the lab.
However, the Nature article argues that as our knowledge increases and specific biochemical pathways in the body are discovered, chemical and biological weapons are likely to be deployed that target highly selective biological mechanisms to incapacitate and disable.
Some researchers are actively facilitating the development of new chemical weapons. For example, a research group from Pennsylvania State University in University Park has identified several drug classes as potential non-lethal agents or 'calmatives', including benzodiazepines and alpha2-adrenoreceptor agonists, as well as individual drugs such as diazepam and dexmedetomidine...
Those who support the development of incapacitating agents often argue that using them in conflict situations stops people being killed. Historical evidence suggests otherwise. At the Nord-Ost [Moscow theatre] siege, for instance, terrorists exposed to the fentanyl mixture were shot dead rather than arrested. Likewise, in Vietnam, the US military used vast quantities of CS gas — a 'non-lethal' riot-control agent — to increase the effectiveness of conventional weapons by flushing the Viet Cong out of their hiding places.
The piece notes that the current international laws on chemical and biological weapons do not address this form of armament which are typically marketed under the 'non-lethal weaponry' banner.
From past experience, including the fact that the fentanyl-based 'incapacitating' gas seemed to have killed the majority of people during the Moscow theatre siege, it is likely that they will be used in anything but a non-lethal manner.
Link to Nature 'Biologists napping while work militarized'.
There's a curious historical snippet in the latest edition of Neurology about how the famous French neurologist Jean-Martin Charcot designed a shaking chair for patients with Parkinson's disease after they reported sleeping better after a train or carriage ride.
The most obvious symptom of Parkinson's disease is tremor and name first given to the condition, by James Parkinson in his famous essay, was the 'shaking palsy'.
While Charcot's 19th century contemporaries had tried 'vibration therapy' here and there, he was the first to systematically apply it to patients with Parkinson's and found it helped with stiffness, discomfort and poor sleep.
Later Gilles de la Tourette, a one-time student of Charcot, developed the treatment into a type of electrical vibrating hat to specifically apply a 600 rpm treatment 'directly' to the brain.
The treatment was seemingly forgotten for many years but recently it has been revived and studies have found modestbenefits for vibration therapy in Parkinson's disease.
One of the mysteries of the human brain concerns why the surface is wrinkled into 'ridges' and 'trenches'. We covered some of the theories a couple of weeks ago but a new study in the Journal of Biomechanics suggests a completely different take - the rippled surface protects against the effects of head injury.
The research team created a 3D computer model of the brain taken from an MRI brain scan (top) and then generated a second model (bottom) but with the sulci (the 'trenches') smoothed out.
They then took each model and simulated a few smacks upside the head from different directions. As well as 'striking' the head head on, the researchers also simulated blows causing 'rotation'.
This is where the brain moves as if it is pivoting around a point. For example, if you look straight on and loll your head from side to side, your brain is following the path of a 'coronal rotation'. These sorts of blows are known to be a particular cause of tears in the white matter, your brain's 'cabling'.
It turns out that a brain with sulci on the surface suffers significantly less strain when the head is struck. And this isn't just for areas near the surface.
The sulci also had a protective effect almost everywhere, including deep brain structures like the brain stem and the corpus callosum.
So it seems that having a wrinkly brain may be a good protective measure for when your head has to bounce off a hard surface.
Link to paper 'Can sulci protect the brain from traumatic injury?' Link to PubMed entry for same.
The Boston Globe has a short but interesting article on cerebral folding - the science of why the brain is wrinkled up like a damp walnut.
The wrinkled surface of the brain folds into 'ridges' known as gyri and the 'trenches' known as sulci. This rippled landscape forms perhaps the most recognisable aspect of the human brain but we still don't really know why we need this rather odd arrangement.
The standard answer "to fit more brain surface in the skull" really tells us nothing on its own as it's not clear why the same material in the outer brain layers couldn't be distributed differently.
Some answers are starting to emerge, however, not least from studies which look at differences in brain folding during the pre-birth growth phase and between people with different neurological conditions.
The article is full of fascinating findings from this research, not least of which is that the brain is smooth until quite late in pregnancy and only starts to fold in the last few months of development.
Premature babies seem to have this process partially disturbed for reasons that aren't yet clear:
For example, because so much of the folding takes place during the latter weeks of fetal development, premature infants arrive with much of their cortical development yet to be completed. And the folding patterns of preemies relegated to the neonatal intensive care unit don’t match those of their counterparts who spend their full nine months in the womb. New research from Van Essen’s lab shows that even when preemies reach their originally forecasted due dates, their brains are not as large or as folded as those of full-term newborns.
“That means there’s something different in how those brains are organized and in the connections that have formed,’’ Grant said. Perhaps some extra environmental influence in the hospital is disrupting folding or preemies are missing out on some vital influence that their counterparts get in the uterus, though researchers haven’t yet narrowed down what these influences may be.
The article is brief but is packed full of eye-opening discoveries on brain folding. It's one of those areas were we know so little but what we do know is quite compelling.
Link to Globe article 'Unfolding the mysteries of the brain'.
According to pressreports Michael Jackson will be buried without his brain because it is still 'hardening'. Although this may seem unusual, the 'hardening' process is actually a standard part of any post-mortem examination where the brain is thought to be important in the cause of death, such as in suspected overdose.
It involves removing the brain from the skull and leaving it to soak in a diluted mixture of formaldehyde and water called formalin. This soaking process usually takes four weeks and the brain genuinely does harden.
A 'fresh' brain is a pinkish colour and has the consistency of jelly, gello or soft tofu meaning it is difficult to examine and the various internal structures are often hard to make out.
After soaking the brain, it has the consistency and colour of canned mushrooms making it easier to slice, examine and photograph. However, because the brain is so soft to start with, it can't just be dropped in a tank of fixing solution, because it will deform under its own weight.
To solve the problem it is usually suspended upside down in a large bucket of formalin by a piece of string which is tied to the basilar artery.
After it has 'hardened' or 'fixed' it is sliced to look for clear damage to either the tissue or the arteries. Small sections can also be kept to examine under the microscope.
Because this part of the post-mortem takes several weeks preparation it is usually only carried out with the family's permission as the body may need to be buried without it, or the burial delayed until the procedure is finished.
This also means that this form of post-mortem brain examination is usually only carried out where there is a feeling that examining the brain can help clarify the cause of death - which is what pathologists are often most concerned with.
In cases such as Michael Jackson's, where the effects of drugs are suspected to play a part, pathologists will be looking for evidence of both sudden-onset and long-term brain damage. If they find it, they'll be trying to work out how much it could have been caused by drug use and how much it contributed to the death.
Over the last couple of days, there's been a great deal of coverage of threenewstudies on the genetics of schizophrenia. While the coverage has actually been pretty good, almost all the news stories make the same error when talking about the 'genetic risk' for the condition.
Twenty years ago, geneticists were searching for the 'gene for schizophrenia' until it became apparent that there was not going to be a single gene, or even a handful, found responsible for the mental illness.
It since became a mantra that the genetic risk for schizophrenia would be conferred by 'many genes of small effect'. In other words, the cumulative effect of lots of genes that, on their own, would be quite benign.
Nature has just published three studies that use the only-recently-feasible technique of scanning the whole genome and has reported the first convincing positive evidence for the 'many genes of small effect' theory by finding that a whole bunch of genes, when considered together, account for about a third of the total difference in schizophrenia risk.
Interestingly, all three studies find that many of the genes lie in a region called the 'major histocompatibility complex' - a series of genes involved in the function of the immune system.
However, lots of the newsreports, even from science publications give variations on the theme that 'genetic factors account for 80 percent of the total risk of getting schizophrenia'.
This 80% figure (which can vary, some give 90%) is not an estimate of risk and shows a misunderstanding of estimated heritability taken from twin studies.
Luckily, I tackled exactly this issue in a column for July's edition of The Psychologist:
Nature versus nurture is a lie. Music is not melody versus rhythm, wine is not grapes versus alcohol and we are not environment versus genes. We are their sum, their product and their expression. They dance together and we are their performance, but neither is an adversary. The art of understanding this elegant ballet is complex and arcane but you may never realise this from reading the quoted results of genetic studies, because the extent to which a trait is heritable, that is, accounted for by genetics, is usually expressed as a simple percentage.
If you search Google for the phrase “80 percent genetic”, you will discover hundreds of sources that claim that everything from schizophrenia, to height, to intelligence has been found to be four fifths ‘genetic’. Pick any other figure and you can find everyone from psychologists, to politicians, to journalists claiming that this or that is explained by genes to a given percentage. Geneticists know the subtly of this percentage and why these statements, usually lifted from the results of twin studies, are misleading, but clearly many others do not.
Imagine a mental illness is described as being 80% heritable. This is often taken to mean that four fifths of an individual’s risk is down to his or her genes, but this is not the case. What it means is that 80% of the variance in the measured illness was explained by genetic factors in the specific group that was studied. If this seems like a frivolous distinction, bear with me, because it is key in understanding heritability and it becomes crystal clear when tackled as an example.
Imagine that we could study a population where everybody lived in an identical environment. They did the same things everyday; they ate identical foods, had identical relationships and were stressed by identical events. Their lives were carbon copies of each other. A twin study would find that mental illness would be close to 100% heritable, because if the environment is fixed, any difference must be down to genetics. In fact, twin studies would find that everything is close to 100% heritable, for exactly the same reason. To flip our thought experiment on its head, if we only studied genetically identical clones, everything would be 0% heritable, because any difference must be down to the environment.
These figures do not necessarily tell us anything about the potential for a trait to be influenced by nature or nurture, because heritability is rarely an immutable and absolute fact about biology; it is an overall measure of how things are for that group, at that moment. In other words, the process of measuring the influence of genetics is, itself, subject to environmental factors. It captures the dance, not the dancers.
Thanks to Jon Sutton, editor of The Psychologist who has kindly agreed for me to publish my column on Mind Hacks as long as I include the following text:
"The Psychologist is sent free to all members of the British Psychological Society (you can join here), or you can subscribe as a non-member by emailing sarsta[at]bps.org.uk"
Link onetwothree to Nature genetics of schizophrenia studies. Link to good write up from Science News, despite 80% genetic risk slip-up.
A 64 year old woman developed a phantom third arm after a stroke, but unusually, the patient was able to see and feel the illusory limb. A study just published online in the journal Annals of Neurology used brain scans to examine the patient. They established that the phantom sensations were accompanied by similar sorts of brain activity as you'd get from a real arm.
Unlike a classic 'phantom limb', where a patient feels sensations as if they're coming from the previously amputated body part, a 'supernumerary phantom limb' is where a phantom seems to appear additional to the already existing arm or leg.
The condition is rare but has been reported before and is known as the 'supernumerary phantom limb' in the medical literature. As we discussed last year, it is usually associated with strokes that affect the subcortical areas of the brain.
One of the reasons this new case is so interesting is because not only could the patient feel their additional limb, but they claimed to be able to see it and feel touches from it as well.
Tactile sensations in the SPL [supernumerary phantom limb] happened when she clenched her hand (she could then feel her phantom palm with her phantom fingers) and when she “touched” certain parts of her body (in which case, the sensation was felt both in the phantom and the touched body part).
She could touch parts of her head, as well as her right shoulder. She claimed to be able to use the SPL to scratch an itch on her head (with an actual sense of relief). Moreover, she reported that the phantom could not penetrate solid obstacles (see supplementary materials for more details).
While a handful of cases of 'visible' supernumerary phantom limbs have been reported, this combination of seeing and feeling the touch of one is unique.
Importantly, the patient was not delusional - they didn't believe they had an extra limb - they knew the sensations were unrealistic, but the experience was still there.
The limb was also not permanently felt - the patient could trigger it at will - and it appeared "pale," "milk-white," and "transparent."
The researchers were keen to see if these sensations were reflected in the activity of the brain by using fMRI scans.
They found that 'moving' the phantom limb in front of the line of sight caused increased activation in the visual cortex of the brain.
Most strikingly, they found that when asked to 'touch' her cheek with the illusory hand, activity in brain areas representing cheek sensation increased.
There is always the chance that someone with very bizarre symptoms could be lying, but it is also the case that brain disturbance can cause all sort of confusions and distortions - so in some cases a patient's description of what's happening may not always be a reliable guide to exactly what they're experiencing.
In this case, the brain imaging suggests that the 'supernumerary phantom limb' was genuinely being perceived as a visible additional arm and that its 'touches' were being processed by the sensory system in a similar way to touches from existing limbs.
Because the condition is so rare, and so conceptually bizarre, there is no good explanation of why it occurs except that it may be linked to the disturbance of our already established body and action 'maps' in the brain.
Apparently, there is more information about the case in supplementary material which can be found 'in the online version of this article', but the additional information doesn't seem to be online. Ironically, the study seems to have a phantom of its own.
Newsweek has a short but smart essay by neuroscientist Eric Kandel who riffs on some of the latest developments that have pushed forward our understanding of the neurobiology of mental disorder.
Kandel gives a description of one of the big biological discoveries from recent years, namely copy number variations, and explores what they might tell us about the development of psychiatric disorders:
One major advance has been the discovery that there is much more variability in the genome than had been anticipated, and that this takes the form of copy number variation (CNV). These are duplications or deletions of segments of a chromosome, often involving several or tens of genes, that enhance or depress the actions of specific genes. A well-known example of a CNV is the extra copy of chromosome 21 resulting in Down syndrome. It has recently been discovered that this type of variation is extremely common in everyone's genome.
As he goes on to explain, CNVs have caused a lot of excitement in the world of mental illness research, not least because they've been found to occur in 'out of the blue' cases of schizophrenia - people without a family history of the disorder - suggesting that the disorder could be partially explained in some people by DNA 'lesions'.
Some rare CNVs have been found to greatly increase the risk for schizophrenia, but unfortunately they don't help explain the genetics of schizophrenia in general because there are many people with schizophrenia who don't have these rare CNVs.
Nevertheless, this rare CNV finding may help us understand the neurobiology of the disorder by giving us clues based on how these unusual copy variations affect brain growth and protein expression.
Interestingly, those CNVs which have been found to increase the risk of schizophrenia also increase the risk for other disorders such as autism and intellectual disability (what the Americans call 'mental retardation') - suggesting that our diagnostic divisions between disorders may not be well supported by genetics.
Despite the title of the article, Kandel also highlights recent developments in psychotherapy, which have given us far the biggest advance in effective treatments for mental disorders in recent years.
Newsweek seem to have just released a whole collection of articles on biomedical sciences of which Kandel's contribution is a part. But don't miss a good article on 'how science will enhance your brain' and another piece on epigenetics.
Look on the right hand side for links to all the articles in the series.
Link to Newsweek on 'A Biology of Mental Disorder'. Link to Newsweek on 'How Science Will Enhance Your Brain'. Link to Newsweek piece on epigenetics.
The straight dopamine theory could be up in smoke:
There is now growing evidence that cannabis use causes a small but reliable increase in the chance of developing psychosis. Traditionally, this was explained by the drug increasing dopamine levels in the brain but a new study shortly to be published in NeuroImage suggests that the active ingredient in cannabis doesn't effect this important neurotransmitter.
Despite some dissenting voices, disruption to the mesolimbic dopamine pathway is widely thought to be the key problem in the development of delusions, hallucinations and the other psychotic symptoms commonly diagnosed as schizophrenia.
This has led to the assumption that the small increased risk of psychosis reliably associated with cannabis use is due to the drug increasing dopamine levels in a deep brain structure called the striatum.
In itself, this is partly based on another assumption - the virtual mantra of recreational drug research that 'all drugs of abuse increase dopamine levels in the reward system' of which the striatum is a part.
This new study, led by neuroscientist Paul Stokes, tested dopamine levels by using a type of PET brain scan where participants are injected with a radioactive tracer that binds to free dopamine receptors. Higher dopamine levels will mean that there are less free dopamine receptors and, therefore, lower tracer levels.
Participants were tested twice, once when given placebo and once when given a dose of pure THC - one of the most important active ingredients in cannabis. The dose was designed to be roughly equivalent to the amount you might absorb from a single joint.
The researchers found no difference in dopamine levels between the THC and the sugar pill, even though the participants clearly reported the effects of the drug.
Although they only tested 13 participants, this is the largest study of its kind so far. These type of neurotransmitter tracer studies are know to produce conflicting results at times, so further experiments will be needed to be sure of the result.
But if it is the case that cannabis does not cause a significant increase in dopamine levels, this will mean our ideas about cannabis and psychosis will need a rethink.
It also shakes up the idea common idea that all recreational drugs are pleasurable because they affect the 'dopamine reward system'.
Forbes magazine has an excellent special issue that is rammed full of diverse and interesting articles on artificial intelligence.
It's a large collection of short articles that covers everything from the mathematics of free will to the likelihood of there being a robot war in the future (see, it's not just me).
There are a fair few speculative pieces, so those who like their transhumanists with a pinch of salt may have to be ready with the seasoning, but wide variety of articles means there should be something for everyone.
Each intends to introduce an idea rather than explore it in detail. I liked the pieces on whether AI can help fight terrorism and another on how the use of AI to explore theories of the mind has declined, and I'm still reading through the rest.
The only slight annoyance is that the series starts with the cliché question "Can machines think?"
Perhaps the single most sensible response I ever read to this was a quote from a speech but the much missed Dutch computer scientist Edsger Dijkstra:
"The question of whether machines can think... is about as relevant as the question of whether submarines can swim."
I've just found this remarkable case study of a woman with an unpredictable form of 'alien hand syndrome' that was triggered when she had a seizure.
The syndrome, where you lose conscious control of one of your hands while it carries out unbidden actions, is normally associated with permanent damage to the brain, often in the frontal lobes, but this version only occurred when an epileptic seizure was in progress.
A 65-year-old right-handed Cuban woman experienced her first seizure while driving. She described an initial tonic posturing of her left foot with march throughout the leg.
This was followed by a counterclockwise truncal contortion and repetitive clonic movements of the foot, followed by her left hand viciously slapping her face, “as if it was fighting with me.”
Subsequent seizure semiology [presentation] has been similar, although her nondominant left hand has refined its movements as to pretend it is applying lipstick.
Because of the embarrassing smearing of her preferred loud cherry-red lipstick, the patient has been forced to use more natural colors.
A new study has surveyed 17 astronauts to see what sort of headaches they experienced while on space missions. Headaches were much more frequent than on earth and didn't fit a known type, suggesting that zero or micro gravity may be a specific trigger for a pounding head.
Below is the part of the article where the researchers discuss how the weightless conditions of space might affect the brain to cause the headache.
To describe headache, most astronauts used terms such as 'exploding' and/or 'a heavy feeling', confirming previous observations and suggesting a change in intracranial pressure. This is compatible with headache attributed to disorders of homeostasis, which can change during a state of microgravity. Certain haemodynamic [blood flow] changes might explain the occurrence of space headache. Alteration of cerebral blood flow and volume have been shown during exposure to microgravity.
The most striking change is the cephalad fluid shift, when body fluid redistributes and the blood volume in the upper body increases. The fluid shift towards the brain and probable brain oedema [swelling] could lead to an increase in intracranial pressure. Insofar as microgravity is also known to induce hypoxia [reduced oxygen supply to brain tissue], it also might be considered as a plausible trigger for space headache
Link to article. Link to PubMed entry for same. Link to write-up from BBC News.
I've just discovered there's a form of neurotoxic honey, genuinely known as "mad honey", created by bees taking nectar from the beautiful rhododendron ponticum flower, pictured on the right.
The nectar from these plants, prevalent around the Black Sea region of Turkey, occasionally contains grayanotoxins, a class of neurotoxin that interferes with the action potential (electrical signalling) of nerve cells by blocking sodium channels in the cell membranes. This leads to problems with the muscles, peripheral nerves, and the central nervous system.
Mad honey apparently causes "a sharp burning sensation in the throat" and poisoning leads to dizziness, weakness, excessive sweating, hypersalivation, nausea, vomiting and 'pins and needles' although severe intoxication can cause dangerous heart problems.
Luckily, most cases aren't fatal and resolve after 24 hours.
Mad honey was known to the Romans, and was specifically discussed by Pliny the Elder.
Link to brief review article on mad honey. Link to PubMed entry for same.
New Scientist has a tantalising snippet reporting on a shortly to be released and potentially important new study challenging the idea of 'mirror neurons'.
Mirror neurons fire both when we perform an action and when we see someone else doing it. The theory is that by simulating action even when watching an act, the neurons allow us to recognise and understand other people's actions and intentions...
However, Alfonso Caramazza at Harvard University and colleagues say their research suggests this theory is flawed.
Neurons that encounter repeated stimulus reduce their successive response, a process called adaptation. If mirror neurons existed in the activated part of the brain, reasoned Caramazza, adaptation should be triggered by both observation and performance.
To test the theory, his team asked 12 volunteers to watch videos of hand gestures and, when instructed, to mimic the action. However, fMRI scans of the participants' brains showed that the neurons only adapted when gestures were observed then enacted, but not the other way around.
Caramazza says the finding overturns the core theory of mirror neurons that activation is a precursor to recognition and understanding of an action. If after executing an act, "you need to activate the same neurons to recognise the act, then those neurons should have adapted," he says.
The study is to appear in the Proceedings of the National Academy of Sciences and apparently is embargoed so the full text is not yet available, although it should appear here when it is.
The announcement is interesting because using adaptation is a novel way of testing 'mirror neurons' and the lead researcher, Alfonso Caramazza, is known for a long series of influential neuropsychology studies.
He has a reputation for being a sober and considered scientist so it will be interesting to see if the final study is really the challenge to mirror neurons as it seems.
Although the hype has subsided a little, the years following the initial reports saw these now famous neurons being used to explain everything from language, to empathy, to why we love art.
We're now in a period where we're taking, if you'll excuse the pun, a somewhat more reflective look at the topic and developing more nuanced theories about how this brain system functions.
UPDATE: Grabbed from the comments. Looks like this paper might have the potential to cause a ruckus. A comment from mirror neuron researcher Marco Iacoboni:
Caramazza’s paper is seriously flawed. The technique of fMRI adaptation seemed very promising ten years ago, but careful studies on its neurophysiological correlates have demonstrated that its findings are uninterpretable. Indeed, Caramazza’s manuscript has been around for many years and nobody wanted to publish it. Caramazza managed to publish with an old trick that only PNAS allows: he handed it personally to a friend of his. The paper is basically unrefereed (this is what it means ‘Edited by...’ under its title).
Link to NewSci on 'Role of mirror neurons may need a rethink'.
NPR has an interesting audio series on brain function, spiritual experience and the growing field of neurotheology. It's takes a fairly broad brush approach and has audio, video, an interactive thingy, and plenty of supporting material.
You might get slightly annoyed at some of the section titles ('The God Chemical', 'The God Spot') but there are some great little audio vignettes in there where people describe their spiritual experiences, whether they've been caused by prayer or even psilocybin - the main active ingredient in magic mushrooms.
The project borders on the edge of being a bit hokey at times but it saved by the commentary and interviews with neuroscientists working in the area.
There's also a good article in June's Scientific American entitled 'Why People Believe Invisible Agents Control the World' which looks at the origin of belief in angels, demons, spirits and the like.
Link to NPR interactive brain / god thingy. Link to 'Why People Believe Invisible Agents Control the World'.
Bolt from the blue triggers bizzare hallucinations:
I just found this amazing case study of a female mountaineer who was struck by lighting while climbing the Latemar Peak in the Alps and subsequently experienced a series of unusual symptoms.
She was taken off the mountain by helicopter and was so agitated in hospital she had to be put under for three days. On wakening she was having some remarkably bizarre hallucinations.
On 3 September 2004, a 23-year-old healthy woman was hit by a "bolt from the blue" while climbing on a ridge at 2750 m shortly before reaching the Latemar Peak in the Alps from a southern direction. The accompanying climber was about 50 m from the casualty, and reported that at the time of the incident (about 15:00 Central European Time (CET)), the sky was clear and sunny. He heard cracking thunder and was thrown to the ground by a massive shock wave.
The patient was also thrown to the ground, lost consciousness for a few seconds and was confused afterwards. She had no vision, dazzled by a bright light. On arrival of the air rescue team, her Glasgow Coma Scale was 9. She was hospitalised and because of extreme agitation, set to a drug-induced coma for 3 days. The initial CT scan showed bilateral occipital oedema, but no intracerebral or subarachnoid haemorrhages or skull fractures...
In the evening, still awake and 6 h after extubation, strange phenomena occurred. These exclusively visual sensations consisted of unknown people, animals and objects acting in different scenes, like a movie. None of the persons or scenes was familiar to her and she was severely frightened by their occurrence. For example, an old lady was sitting on a ribbed radiator, then becoming thinner and thinner, and finally vanishing through the slots of the radiator.
Later, on her left side a cowboy riding on a horse came from the distance. As he approached her, he tried to shoot her, making her feel defenceless because she could not move or shout for help. In another scene, two male doctors, one fair and one dark haired, and a woman, all with strange metal glasses and unnatural brownish-red faces, were tanning in front of a sunbed, then having sexual intercourse and afterwards trying to draw blood from her.
These formed hallucinations, partially with delusional character, were in the whole visual field and constantly present for approximately 20 h. At the time of appearance, the patient was not sure whether they were real or unreal, but did not report them for fear that she might be considered insane.
Frontal Cortex has alerted me to an interesting NPRradio segment on the fact that taller people have longer nerves and so will have slight sensory lag in comparison to shorter people.
It prompted me to look up some of the research in the area and I found an eye-opening study looking at a range of factors that can effect nerve conduction.
The researchers found that, after controlling for sex, age and temperature (it turns out your nerves are quicker when you're warm), there was a 0.27 m/s decrease in the conduction speed of one of the leg nerves (the sural nerve) for each additional centimetre in height.
This is interesting because it is not only a reduction in time because the same speed signal is travelling a longer distance, but it actually seems that nerve signals travel more slower through longer nerves as well, owing to the fact the nerves get thinner the longer they are.
The radio segment suggests that taller people don't experience the world as any different, because our brains try to make everything seem 'in sync'.
In fact, this is a problem for everyone, no matter how tall we are, because we know we can update our actions quicker than the sensory signals can reach the brain.
In one of the most popular theories that attempt to explain this it it thought that we have an internal simulation of our actions that we can use to make fast decisions which is updated as and when sensory information arrives.
However, I tried to find some studies on whether taller people actually have slower reaction times, but I couldn't find any, so let me know if you do.
Link to NPR 'The Secret Advantage Of Being Short'. Link to study on nerve conduction factors. Link to DOI entry for same.
I've just read an elegant study on the neuroscience of gambling that wonderfully illustrates why the dopamine equals pleasure myth, so often thrown around by the media, is too tired to be useful.
I have seen countless news reports that claim that some activity or other causes dopamine to be released; that dopamine is the 'pleasure chemical'; and that it's also released by 'drugs', 'sex', 'gambling' and 'chocolate' (a quartet I have named the four dopamen of the neurocalypse).
Normally, this breathless attempt to make something sound sexy is followed by a slightly sinister bit where they say that this dopamine activity is also likely to make it 'addictive'.
Dopamine is involved in drug addiction, but the over-extended cliché is drivel, not least because the dopamine neurons start firing in the nucleus accumbens when any reward is expected. Whether it be heroin, a glass of water when you're thirsty, or your favourite book on calculus - if that's what floats your boat.
And herein lies the subtlety. Our best evidence tells us that while the dopamine system has many functions, it's not really a reward system - it's most likely a reward expectancy system of some kind. Theories of exactly what form this takes differ in the details, but it certainly seems to be active when we're expecting a reward, whether it actually turns up or not.
The study on gambling, led by neuroscientist Luke Clark, demonstrates that this is true even when the actual experience is unpleasant.
The research team looked at the activity differences in the dopamine-rich mesolimbic system in a gambling task - comparing wins, misses and near-misses. Near-misses were where the reels on a slot machine just missed the payout.
It turns out that near-misses activate almost exactly the same dopamine circuits as actual wins - but here's the punchline - they were subjectively experienced as the most unpleasant outcome, even worse than total misses.
In other words, the dopamine system was firing like a rocket display but the experience was awful.
Interestingly, although near-misses were experienced as aversive they increased the desire to play the game but only when the person had some perception of control, by choosing what the 'lucky' picture would be.
Of course, like choosing 'heads or tails', it's only an illusion of control because the outcome is random anyway.
But because of reward expectancy the dopamine system is most active when we think we can control the outcome and modify our strategy next time, even if that sense of control is completely false.
Link to full-text of study on near-misses and dopamine. Link to good coverage of study from Quirks and Quarks.
I've just found a video of someone with alien hand syndrome - a condition which usually occurs after brain injury or stroke where the affected person loses conscious control over the hand and where it seems to move with a will of its own.
In this case, the video was uploaded by YouTube user frankenerin, who asked someone to video her when she was in intensive care after suffering a stroke and having brain surgery while her 'alien hand' was still present.
There's a couple of things to notice in the video. The first is that the clinician asks the patient to do the actions for using scissors and brushing teeth. This is to check the problem is not a form of general ideomotor apraxia, where common action patterns are damaged.
She can do the actions with one hand but not the other, suggesting her strange movements are not due to global action planning problems.
The clinician then asks whether the patient recognises the arm as hers.
This may seem an odd question, but he's checking for somatoparaphrenia, where patients can deny ownership of a paralysed or action-impaired limb, sometimes saying that it belongs to someone else.
As it turns out, the patient says she generally knows it is hers, but when it is draped across her body in a certain position and making involuntary movements she can think it is someone else's limb. In other words, she seems to have fleeting somatoparaphrenia.
The video then shows the hand moving of its own accord and the patient having to use the other hand to keep it out of trouble.
Despite looking like she's in pretty bad shape, frankenerin later posted a wonderful follow-up video where she is back on her feet and feeling fine, although discusses how she's had to adjust her career aspirations owing to the longer-term effects of the brain injury.
Unfortunately, the Wikipedia page on alien hand syndrome, also known as anarchic hand syndrome, is dreadful, but there's an excellent 2005 article from The Psychologist by neuropsychologist Sergio Della Sala that covers the neuropsychology of the condition and what it tells us about free will. You can read it online as a pdf.
Link to alien hand syndrome video. pdf of The Psychologist on alien / anarchic hand.
A new article from Trends in Cognitive Sciences explores how cognitive neuroscientists are becoming increasingly interested in understanding hypnosis and are using it to simulate unusual states of consciousness in the lab.
Hypnosis was typically treated with suspicion by mainstream cognitive science, although an important turning point came when a 2000 study demonstrated that people hypnotised to see colour on grey panels showed activity in the colour perception areas of the brain.
Myths about hypnosis are still common, but it is nothing more than a participant's willing engagement in a process of suggestion. The hypnotic induction, sterotypically the counting backwards and the 'you are feeling sleepy' patter, helps but is not necessary.
Crucially, and for reasons that are still unclear, we all vary in our hypnotisability. This characteristic is known to be more stable than IQ, and normally distributed, like many other psychological traits.
In other words, we can all experience the relaxation and focus, and we can all imagine what the 'hypnotist' is suggesting, but only more highly hypnotisable people experience the suggestions as involuntary, as if they're happening 'by themselves'.
Recent research has suggested that highly hypnotisable people can disengage the process that looks out for rival demands on our attention, from the process that allows us to focus on which of the competing tasks we need to home in on.
In other words, in highly hypnotisable people, suggestions to experience things contrary to everyday reality may be able to take effect because the normal detect and disentangle mechanism has been temporarily suspended.
Combined with carefully crafted suggestions, this ability allows researchers to simulate certain mental states and experiences in the lab.
For example, hypnotically suggested paralysis, blindness or loss of feeling have been used to simulate the symptoms of 'hysteria' or conversion disorder, a condition where neurological symptoms appear without any damage to the nervous system being present.
Other studies have used hypnosis to simulate the feeling that the body is being controlled by outside forces, a common symptom in psychosis, or where a patient thinks their reflection in the mirror is another person, a delusion called mirror misidentification.
And we covered a fantastic study last year, where researchers used hypnosis to simulated psychogenic amnesia, a loss of memory just for old information despite the fact that the patients have none of the brain damage associated with the classic amnesia syndrome.
This new in-depth article covers research attempting to understand hypnosis itself, and science that uses hypnosis as a lab tool, and is a great introduction to the neuroscience research in this developing area.
In the long history of outrageous drinking stories, this has got to be one of the best.
The Emergency Medical Journal has a case study of a man who woke up in hospital after being admitted for alcohol poisoning. He couldn't remember what happened the night before but when his hangover didn't clear a precautionary brain scan revealed a knife blade embedded in his temporal lobe.
A left handed, 22 year old man was brought to the hospital by friends at 0200 because of alcohol intoxication. Events preceding the admission and motivation for the patient to go to the hospital were unclear. The patient's relatives confessed to a binge drinking of rum and beer, and then being moved suddenly, probably to avoid police control...
The patient woke up 8 hours after admission, complaining of severe headache covering the whole head and gradually increasing in intensity... Surprisingly, brain computed tomography revealed a right temporal haematoma 34 mm in diameter, with a knife blade that had entered from the temporal fossa and was deeply retained in the right temporal lobe (fig 1).
The foreign body was surgically withdrawn, and postoperative recovery was uneventful. After awakening from surgery, the patient could not remember involvement in an altercation, but witnesses retrospectively confirmed that he was attacked with a knife after drinking with his assailant.
There's also a lovely sentence in the paper which has an apt typo: "Vigorous stimulations only induced growling and repelling movements of the harms and legs".
Link to 'an unusual cause for headache following massive alcohol intake'.
I've just found an article with two interesting cases of 'exploding head syndrome' - a medical condition where affected people spontaneously hear an exceptionally loud explosion-like noise.
The condition is relatively harmless, causing people only to be startled, and it doesn't seem linked to seizure activity or epilepsy. Owing to the fact it's both benign and uncommon, it's not been widely studied and so its cause remains a mystery.
Case 1
A 48-year-old man was seen in December 2006. For the past several months about three to four times a month, he had been having attacks of a peculiar sensation in the head likened to the noise of an exploding bomb only at night while going off to sleep. The 'explosion' would wake him up and disappear completely the moment he woke up.
There was no headache and no associated symptoms such as nausea, vomiting or any visual sensation. For the past 3 months, the frequency of these sensations had increased and had been occurring nearly daily at the time of consultation. The noise occurred only once during every night, after which he could go off to sleep. His past medical history had been unremarkable and he had never suffered from any significant headache problem. General physical and neurological examination had been unremarkable. Magnetic resonance imaging (MRI) of brain with contrast had been normal. He was prescribed Flunarazine 10 mg daily. At 6 months' follow-up he had much improved and noticed the exploding head symptom only on two occasions.
Case 2
A 65-year-old man was seen in February 2007. He was hypertensive and diabetic (both well controlled on oral medication) and had been having infrequent attacks of International Headache Society migraine headache (every 2–4 months) without aura since the age of 15 years. For the past 4 months prior to consultation, every 2–3 weeks, he had been awakened while going off to sleep only during taking a daytime nap by a sudden exploding (like a bomb bursting) noise in his head lasting for only few moments.
This noise was always accompanied with jerky elevation of his right arm and a queer sensation in the right side of his chest (not arm) and again lasting only momentarily. He felt quite well on waking up and could go off to sleep again. These were never accompanied by any visual flashes and never occurred during sleep at night. These sensations were very different from his migraine headaches, which lasted for several hours and the noises were not accompanied by any nausea or vomiting.
Physical examination was normal and his blood presswure in the clinic was 136/80 mmHg. He had already had a MRI of brain with contrast, MR angiography of brain and two interictal sleep EEG recordings performed before consultation with the author, all of which were normal. A video EEG with daytime sleep recording was performed, but no event could be captured.
Link to article with case studies. Link to PubMed entry for same.
It's now well known that high altitude mountain climbing damages the brain and causes a marked reduction in mental functioning.
I naively assumed this was true for everyone but I just found an intriguing 1996 study that compared brain function of lowland mountain climbers and Nepalese Sherpas after ascent to high altitude, which found that the Sherpas suffer few of these neurological problems.
Are Himalayan Sherpas better protected against brain damage associated with extreme altitude climbs?
Garrido E, Segura R, Capdevila A, Pujol J, Javierre C, Ventura JL.
Clin Sci (Lond). 1996 Jan;90(1):81-5.
1. The potential risk of brain damage when low-landers attempt to climb the highest summits is a well-known fact. However, very little is known about what occurs to Himalayan natives, perfectly adapted to high altitude, when performing the same type of activity.
2. Taking into account their long-life climbing experience at extreme altitudes, we examined seven of the most recognized Sherpas with the aim of performing a comprehensive neurological evaluation based on medical history, physical examination and magnetic resonance brain imaging. We compared them with one group of 21 lowland elite climbers who had ascended to altitudes of over 8000 m, and another control group of 21 healthy individuals who had never been exposed to high altitude.
3. While all of the lowland climbers presented psychoneurological symptoms during or after the expeditions, and 13 of them (61%) showed magnetic resonance abnormalities (signs of mild cortical atrophy and/or periventricular high-intensity signal areas in the white matter), only one Sherpa (14%) showed similar changes in the scans, presenting neurological symptoms at extreme altitude. The neurological examination was normal in all three groups, and no neuroimaging abnormalities were detected in the control group.
4. The significant differences, in both clinical and neuroimaging terms, suggest that Sherpa highlanders have better brain protection when exposed to extreme altitude. Although the key to protection against cerebral hypoxia cannot be established, it is possible that an increase in the usually short period of acclimatization could minimize brain damage in those low-landers who attempt the highest summits without supplementary oxygen.
Link to study of neurology of lowland climbers and Sherpas.
A 2003 study in Epilepsy and Behavior has some descriptions of the ecstatic seizures experienced by some patients with epilepsy.
They include intense erotic and spiritual experiences, feelings of become close to and blending with other people, and some sensations that couldn't be fully captured in words.
I've put some of the descriptions below because they sound absolutely wonderful:
Patient 1
The first seizure occurred during a concert when he was a teenager. He remembers perceiving short moments of an indefinable feeling. Such episodes recurred and a few months later evolved into a GTC [generalized tonic–clonic seizure]. He characterizes these sensations as “a trance of pleasure.” “It is like an emotional wave striking me again and again. I feel compelled to obey a sort of phenomenon. These sensations are outside the spectrum of what I ever have experienced outside a seizure.” He also describes cold shivering, increased muscle tension, and a delicious taste, and he swallows repeatedly. He enjoys the sensations and is absorbed in them in a way that he can barely hear when spoken to. When in a particular, relaxed mood, he can sometimes induce seizures by “opening up mentally” and contracting muscles. He denies any religious aspects of the symptoms. “It’s the phenomenon, the feeling, the fit taking control.” It lasts a few minutes and afterward he is tired with difficulties expressing himself for about 1 hour.
Patient 6
This man has a multifaceted symptomatology and a tendency to interpret bodily sensations as supernatural phenomena. Nevertheless, from the beginning of his forties, he experienced distinct, stereotypical attacks with a “change of concept of the surrounding world.” He reports an “oscillating erotic sensation, like twinkling polar light” in his pelvic region and down the inside of his thighs. This is described as different from sexual excitement, more like “an erogenous charge of the skin.” He may also have a clairvoyant feeling of a “telepathic contact with a divine power.” These sensations are of short duration and may be accompanied by faintness and followed by drowsiness. With carbamazepine treatment, the frequency of these attacks has been considerably reduced.
Patient 11
The attacks started in his first school year. The experiences are beyond what can be described in words. “I can sense the colours red and orange without seeing them. The feeling has an erotic aspect. It starts in the stomach and spreads upwards. It is pleasant, but not similar to ordinary joy. It is like an explosion.” In the close presence of another person, he can feel a sort of peculiar unification. An intense déjà vu sensation, a queer taste, and “gooseflesh” are also components of the seizures. As a child he was surprised that his friends denied having similar feelings, and he learned to keep them to himself. Sometimes these attacks evolved into CPSs with reduced consciousness and complex automatisms and afterward he had transient difficulties speaking. Before the diagnosis of epilepsy was made in his late teens, he was referred to a psychiatrist. A right-sided temporal lobe calcification was diagnosed by computed tomography at about 30 years, but he refused surgery. At 42, an expansion in the same region was found by MRI, and he was operated for an anaplastic oligodendroglioma. He was seizure-free for 6 years until recurrence of the tumor.
One of the striking things about epilepsy is how different each person's experience of having a seizure can be.
While it is stereotypically assumed to be a negative experience, some aspects can be remarkably beautiful.
The Russian author Dostoyevsky famously said of his epilepsy "I would experience such joy as would be inconceivable in ordinary life - such joy that no one else could have any notion of. I would feel the most complete harmony in myself and in the whole world and this feeling was so strong and sweet that for a few seconds of such bliss I would give ten or more years of my life, even my whole life perhaps."
There are several more case descriptions in the article, all of which have some aspect which touch at least the edge of ecstasy, if not the very heart of the experience.
I just noticed that neurotechnology analyst Zack Lynch has a forthcoming article in Epilepsy and Behavior on the latest developments in the commercial brain science field. Avid neuroscience fans may be familiar with most of it but the section on new technologies to cross the blood-brain barrier was eye-opening.
The blood-brain barrier (BBB) is a sieve-like border crossing that allows only certain molecules to pass from the blood into the brain.
It's remarkably restrictive and many molecules are just too big to get past, meaning that many drugs that could affect the brain are virtually useless, simply because they can't cross the border.
This has led neuroscientists to think of ways of smuggling, tunnelling and sneaking this these molecules past the barrier, and Lynch's article lists some of the latest technologies which aim to jump the fence.
• Implantable devices: Implantable pumps bypass the blood–brain barrier (BBB) and deliver highly accurate amounts of drugs to specific sites in the brain or spinal cord.
• Expression systems: A French company is circumventing the BBB using encapsulated cell technology (ECT), a polymer implant containing cells that provide continuous, long-term release of the therapeutic protein to the brain or eye.
• Receptor-mediated transport: Receptors that transport nutrients to the brain from the blood can be tricked into transporting therapeutic chemicals, peptides, and proteins across the BBB. Insulin, transferrin, and lipoproteins, for example, cross the BBB by facilitated transport, and can be combined with therapeutic proteins or other molecules to promote access to the brain.
• Cell-penetrating peptides: During the past decade, several arginine-rich peptides have been described, such as SynB vectors, which allow for intracellular delivery and BBB transport. The mechanism for this transport is unknown. A Swiss company is using cell-penetrating peptides to develop treatments for stroke and myocardial infarction.
• Focused ultrasound: Some research shows that focused ultrasound can temporarily open the BBB in a targeted area for a window of time. A seed stage company is working to commercialize this technology and improve it for use in humans.
• Nanoparticle formulations: Nanoparticle formulations refer to therapeutics encapsulated in nanoscale particles that can pass the BBB. Although there is great interest in using nanotechnology to improve neuropharmaceutical delivery to the brain, it will take some time to overcome challenges of this platform, including the need for intravenous delivery, manufacturing, and clearance by the liver.
Jonah Lehrer has an excellent piece in today's Boston Globe about how babies' brains develop and what psychologists are starting to understand about the infant mind.
It's largely riffing on the work of Alison Gopnik, one of the world's leading developmental psychologists, who has long argued that babies might be more conscious than adults and that we learn to filter the world and mentally manage its initial chaos.
While this less focused form of attention makes it more difficult to stay on task - preschoolers are easily distracted - it also comes with certain advantages. In many circumstances, the lantern mode of attention can actually lead to improvements in memory, especially when it comes to recalling information that seemed incidental at the time.
Consider this memory task designed by John Hagen, a developmental psychologist at the University of Michigan. A child is given a deck of cards and shown two cards at a time. The child is told to remember the card on the right and to ignore the card on the left. Not surprisingly, older children and adults are much better at remembering the cards they were told to focus on, since they're able to direct their attention. However, young children are often better at remembering the cards on the left, which they were supposed to ignore. The lantern casts its light everywhere.
I'm a bit sceptical of one bit of the article though, where it claims that babies have more neurons than adults, as researchers have only very recently attempted to make this estimate and, in fact, found that babies and adults have about the same in the cortex, which makes up the vast majority of the brain.
In terms of synapses, connections between neurons, this varies on the age of the infant. For example, have a look at this graph of synapse density as we grow, taken from a study of the human cortex.
Newborns start with fewer synapses than adults but this number rockets, so by six months of age we have approximately twice as many connections. This tails off as the brain prunes connections on a 'use it or lose it' basis.
I'm always slightly awestruck whenever I view that graph as it is a vivid illustration of the incredibly rapid changes changes that take place as we grow and learn to make sense of the world.
It's this same sense of awe that the Boston Globe manages to capture as it explains how understanding the baby's brain can help us make sense of the adult mind.
Link to Boston Globe article 'Inside the baby mind'.
The New Yorker has a fantastic in-depth article about 'cognitive enhancement' that talks to some of the neuroscientists studying the effects and some of the mind tweakers who regularly pop pills to give themselves an edge.
One of the issues it touches on is whether cognitive enhancers really 'enhance' people, and there's good evidence that for the highest achievers, the pills might not be of much benefit.
Even worse, it's also likely that the amphetamine-based drugs (Ritalin, Adderall) could actually impair your performance even though you might feel as if you've had a mental boost.
Amphetamine has the effect of increasing focus, confidence and giving a euphoric feeling. Although the effects are less marked in the slow release amphetamines used for ADHD and appropriated for illicit mind tweaking, the effect is certainly still there.
What we do know, however, is that people with certain genotypes actually show a decrease in working memory performance when they take amphetamine.
And it turns out that these are the people most likely to already be at the high end of mental performance. This is from a classic study on the effect:
Amphetamine enhanced the efficiency of prefrontal cortex function assayed with functional MRI during a working memory task in subjects with the high enzyme activity val/val genotype [of the COMT gene], who presumably have relatively less prefrontal synaptic dopamine, at all levels of task difficulty.
In contrast, in subjects with the low activity met/met genotype who tend to have superior baseline prefrontal function, the drug had no effect on cortical efficiency at low-to-moderate working memory load and caused deterioration at high working memory load
In other words, it's possible that high achievers might be popping stimulants, feeling like it boosts their performance, when in fact, it's doing exactly the opposite.
The article explores more than just this area though, and is incredibly wide-ranging, looking at the neuroscience, the underground use of the drugs, legal aspects, new and current compounds, and so on.
It's also one of the most interesting articles I've read on the subject for a while, which, for an area which attracts of lot of attention, has got to be a good thing.
Link to 'The underground world of “neuroenhancing” drugs'.
Newsweek has an excellent article on the neuroscience and personal impact of epilepsy. It's well-researched, gripping in parts and bang up-to-date as it takes us through how neurologists tackle the seizure-prone brain.
I was particularly impressed by the following section as it avoids the common cliché of the epileptic 'brain storm' because, as we've discussed before on Mind Hacks, a seizure is not a storm of random brain activity.
In fact, it's completely the opposite. During a seizure neurons become super-synchronised, pulsing together, so they can't do their normal job. In effect, it's an anti-storm.
Conceptually, the job of the cardiologist is straightforward: he needs to restore a damaged heart to its normal rhythm. But epilepsy is the opposite. A normal brain is governed by chaos; neurons fire unpredictably, following laws no computer, let alone neurologist, could hope to understand, even if they can recognize it on an EEG. It is what we call consciousness, perhaps the most mathematically complex phenomenon in the universe.
The definition of a seizure is the absence of chaos, supplanted by a simple rhythmic pattern that carries almost no information. It may arise locally (a "partial" seizure), perhaps at the site of an old injury, a tumor or a structural malformation. A network of neurons begin firing in unison, enlisting their fellows in a synchronous wave that ripples across the brain.
Or it may begin everywhere at once ("generalized" epilepsy), with an imbalance of ions across the cell membrane, usually the result of an inherited mutation. At a chemical signal, whose origin is still a mystery, billions of neurons drop the mundane business of running the body and join in a primitive drumbeat, drowning out the murmur of consciousness. And so in contrast to the cardiologist, the epilepsy doctor must attempt to restore not order, but chaos.
The article is very much epilepsy from the medical perspective, but it is probably the single best mainstream piece I've read that attempts to tackle this area.
If you only read a handful of epilepsy articles in your life, make this one of them. Well done Newsweek.
Link to Newsweek article 'In the Grip of the Unknown'.
Discover Magazine has an interesting Carl Zimmer article on one of the most intriguing questions in neuroscience - why do we have two cortical hemispheres? And why are they not quite the same?
It turns out that the 'brain of two halves' is incredibly common in the animal kingdom and that many creatures also show the behavioural lateralisation that we most readily see in humans as someone being left or right handed.
But it's no entirely sure why we, or indeed, or animal compatriots, have evolved this way, although various theories are kicking around:
David Stark of Harvard Medical School recently found additional clues about lateralization in his studies of 112 different regions in the brains of volunteers. He and his collaborators discovered that the front portions of the brain are generally less tightly synchronized across the hemispheres than are the ones in the back. It may be no coincidence that the highly synchronized back regions handle basic functions like seeing.
To observe the world, it helps to have unified vision. At the front of the hemispheres, in contrast, we weave together streams of thought to produce complex, long-term plans for the future. It makes sense that these areas of the brain would be more free to drift apart from their mirror-image partners.
Zimmer goes on to puncture the myth of 'left brained' and 'right brained' people, or indeed, thinking styles, erroneously labelled with these pseudoscientific terms.
While certain cognitive styles have been correlated to greater activation in the left or right hemisphere, to describe a whole class of problems of thinking methods like this is nonsensical because the two hemispheres of the brain work together.
It's like claiming someone is a good cook solely because they come from Italy. The generalisation is so broad it just doesn't apply to individual people or situations.
Anyway, the Discover article is an excellent whistle-stop tour through the curious world of brain lateralisation.
Link to Discover on the brain of two hemispheres (via @mocost).
I've just found this fascinating case study in American Journal of Physical Medicine and Rehabilitation about a man who lost conscious control over one of his hands after brain injury and suffered involuntary public masturbation episodes as a result.
Involuntary masturbation as a manifestation of stroke-related alien hand syndrome
Ong Hai BG, Odderson
Am J Phys Med Rehabil. 2000 Jul-Aug;79(4):395-8.
Alien hand syndrome is a perplexing and uncommon clinical diagnosis. We report an unusual manifestation of alien hand syndrome in a 73-yr-old man with a right anterior cerebral artery infarct affecting the right medial frontal cortex and the anterior portion of the corpus callosum. We conclude that alien hand syndrome should be considered in patients who present with a feeling of alienation of one or both upper limbs accompanied by complex purposeful involuntary movement.
We tend to think of the cognitive impairments after brain injury as the most disabling - things like loss of memory or speech or language impairment, but we often neglect what we might call social impairments.
Especially when the effect is embarrassing, these can have just as strong an impact because many people massively restrict their lives to prevent causing social discomfort to themselves or others.
I am pleased to see a letter in this week's Nature that shows that I'm not the only neuroscientist concerned about the coming robot war. Brain researchers Olaf Blanke and Jane Aspell wrote in to warn about the use of brain-machine interfaces, not to control machines with thoughts, but to control thoughts with machines.
Imagine if insights from the field of cortical prosthetics in human and non-human primates were combined with research on bodily self-consciousness in humans. Signals recorded by multi-electrodes implanted in the motor cortex can already be used to control robotic arms and legs. Cognitive cortical prosthetics will allow the use of other cortical signals and regions for prosthesis control. Several research groups are investigating indications that the conscious experience of being in a body can be experimentally manipulated.
The frontal and temporoparietal signals that seem to be involved encode fundamental aspects of the self, such as where humans experience themselves to be in space and which body they identify with (O. Blanke and T. Metzinger Trends Cogn. Sci. 13, 7–13; 2009). If research on cortical prosthetics and on the bodily self were applied to humans using brain-controlled prosthetic devices, there might be no clear answer to Clausen's question: which of them is responsible for involuntary acts?
It may sound like science fiction, but if human brain regions involved in bodily self-consciousness were to be monitored and manipulated online via a machine, then not only will the boundary between user and robot become unclear, but human identity may change, as such bodily signals are crucial for the self and the 'I' of conscious experience. Such consequences differ from those outlined by Clausen for deep brain stimulation and treatment with psychoactive drugs.
The letter is a follow-up to a recent Naturepiece on potential new ethical issues raised by the development of implantable brain technology.
Unfortunately, these sort of in-house scientific debates rarely do much to raise the public consciousness about the importance of such issues.
However, I have high hopes for the future. Not least because a new film in the Terminator documentary series is soon to be released.
In C.S. Lewis' Narnia novelThe Voyage of the Dawn Treader the heroes find a man stranded on an island where dreams come true. They initially express delight but the man rages "Fools!" "Do you hear what I say? This is where dreams - dreams, do you understand? - come to life, come real. Not daydreams: dreams."
But dreams can come to life and the effect is no less fantastical. In REM sleep behaviour disorder (RBD), normal sleep paralysis breaks down and sleepers act out their dreams - giving observers a remarkable insight into the dreaming mind.
An article recently published in Neurology charted the range of sleep behaviours seen in people with neurological disturbances such as narcolepsy, Parkinson's disease or other types of dementia, all of which can trigger the problem.
Incidental cases of nonviolent behaviors during RBD included masturbating-like behavior and coitus-like pelvic thrusting, mimicking eating and drinking, urinating and defecating, displaying pleasant behaviors (laughing, singing, dancing, whistling, smoking a fictive cigarette, clapping and gesturing "thumbs up"), greeting, flying, building a stair, dealing textiles, inspecting the army, searching a treasure, and giving lessons. Speeches were mumbled or contained logical sentences with normal prosody [voice tone, rhythm and stress].
The paper also contains two case studies which describe, in detail, exactly what each patient was doing when they were acting out their dreams. This is from the description of 'Patient 2':
These behaviors, which occurred with eyes closed, were complex, various, and usually accompanied with sentences resembling a teacher with children (first sequence) or a captain inspecting his troop (second sequence): “(Professorial) Can we all return to our seats! (pause) (Overbearing) What do you do, standing there in the middle? (pause) Remove your finger away from the switch! (pause) Well, if that’s so, I’ll take the numbers. (Ironic) And . . . late! (pause). (Professorial) Get back to your seats. I’m going to start.”
Mumbles for 6 minutes. Then: “(bossy) Raise your hands, raise your hands, raise your hands, I said raise! I didn’t say to pull away! I said: raise your hands!” Here the patient quickly raised his left arm and waved his hand it as if he were showing something. “(Bossy and rhythmic) Halt! (pause) Halt! (pause) Halt!” Three minutes later, he shouted “(Bossy, like in a military parade) Attention! Gentleman, please, attention! (pause) Halt, halt, I said! (pause) Halt, I said!”
This study specifically focused on the less researched non-violent sleep behaviours, as the disorder is more typically associated with acting out aggressive dreams.
This is possibly because the disturbances that cause the disorder also affect the content of the dreams.
An earlier study found that patients with the disorder reported having more aggressive dreams, even though they were not more aggressive in waking life.
It's a fascinating article and worth reading in full as it contains many 'wow, that's amazing' moments, both for the scientific insights, and the windows into the mental life of sleep.
Link to Neurology article on sleep behaviours. Link to PubMed entry for same.
For the first time, the brain structure of male-to-female transsexuals has been investigated in living individuals using MRI brain scans, helping to fuel the debate over the possible neural basis of gender identity.
The scientific article, shortly to appear in the neuroscience journal NeuroImage, used MRI brain scans and a technique called voxel based morphometry to compare grey matter in a group of male-to-female transexuals to groups of males and females who have never had gender-identity concerns.
This is not the first time that brain structure has been compared in this way, but earlier studies had been based on post-mortem comparisons. Thesethreestudies had found that certain areas in male-to-female transsexuals more commonly resembled the equivalent area in females than males.
This has led some researchers to go as far as suggesting that perhaps the differences are present from birth and that gender-identity difficulties could result from the body and brain following different paths as the developing foetus begins to develop into a specific sex.
However, one difficulty is that all the transgender people examined in these post-mortem studies had been on oestrogen treatment to feminize their bodies, and it hasn't been clear whether the differences were due to the effect of this hormone rather than something present before.
This new study, led by neuroscientist Eileen Luders, specifically recruited male-to-female transsexuals who had never taken oestrogen and, being in living people, wasn't affected by whatever led to the person's death.
In contrast to previous investigations, this new study found that male-to-female transsexuals grey-matter was similar in most areas of the brain to the male rather than female comparison group.
Except, that is, for one area, the putamen, a deep brain structure that forms part of the basal ganglia - known for its wide range of functions and connections to the frontal lobes and action control areas.
Because we know so little about the neuroscience of self-image and gender-identity it's almost impossible to draw any conclusions for the fact that this specific area seems more 'feminine', or that the majority of the other areas seem more 'masculine' in terms of size.
What this study does do, however, is add to the increasing evidence that there are some detectable neurological differences in the brains of transgendered people. We're just not in a position to say much about the significance of this yet.
New Scientist has an excellent cover article on 'The five ages of the brain', looking at how the brain changes as we grow and how these transformations are reflected in our lives.
Each gives a concise introduction to some of the latest findings on how the brain differs in each time period, although for a slight counter-point, I would recommend a recent edition of ABC Radio National's All in the Mind.
The programme takes a sceptical look at the emerging neuroscience of adolescence, largely based on the fact that adolescence as a distinct developmental stage is a relatively recent cultural invention of the Western world.
Psychologist Robert Epstein argues that the differences in the teen brain are relatively minor, and that the stereotype of the 'teen in turmoil' is not a biological fact of brain development, but a result of the cultural pressures put upon adolescents.
The NewSci collection and the All In the Mind programme complement each other nicely and tackle some of the current hot issues in developmental neuroscience.
Link to NewSci 'Five Ages of the Brain' special. Link to AITM on 'The modern teenager: myth or marvel?'
Rendered frantic, crazy by unbroken concentration:
Advances in the History of Psychology has just alerted me to a fascinating short article on the work of the influential 18th-century physician Samuel Tissot, who wrote a book arguing that concentrating on books for too long damaged the mind.
The 18th century was when books were becoming cheap enough to be widely available to the middle classes and it's interesting that this new cultural development produced a similar pseudo-medical concern about damage to the mind that we often hear today, but in a completely different direction.
While modern day technological doom-sayers suggest that technology damages the mind because it interrupts concentration, 18th century technological doom-sayers suggested that reading damaged the mind because it required too much concentration.
Neither have an evidence base, but I maintain a morbid interest in medicalised concerns about new technology and cultural innovations, which often take the same basic form but cite a cause which is always curiously in line with the authors' prejudices.
It turns out Tissot, like many of this medical contemporaries, was also obsessed with masturbation, which he cited as the cause of madness and a host of other psychological problems.
Catholic church aside, it seems a ridiculous view to us now, but it was widely held by some of the most prominent and influential medical men of the time.
Link to Guardian 'Beware: studying can make you ill'. Link to AHP on 'Read Till You’re Crazy'.
Wired has an excellent article on the Allen Institute for Brain Science's ambitious mission to map where each gene is expressed in the brain.
We tend to think of genes in terms of their ability to pass on characteristics to new generations, but the moment the egg and the sperm combine, genes start coding for proteins which the body uses to do its work.
Of course, this includes the brain, so knowing what type of genes produce proteins in which areas of the brain gives us a big clue to some of the brain's functions.
The article is, perhaps, a little overly hopeful about the significance of a having a gene map for understanding complex mind functions or disorders (autism is mentioned as an example) - suggesting that some research hits a dead end without it.
Perhaps something useful to mention is that one of the key pieces in the puzzle of gene expression in the brain is not where genes are expressed but under what conditions they are expressed.
While your DNA has the ability to express every protein it has genes for, the cell regulates this process so it reacts to current conditions dynamically.
In other words, the genes are more of a reference book, and the cell's other regulation processes decide how and when to use this information.
As far as we know, all learning in the brain happens through proteins, meaning that experience, learning, thought, motivation - or any other 'psychological level' process we can think of, acts through the many, complex and not fully understood regulation processes.
So understanding the reference book is an essential but insufficient part of the picture. The real deal is in understanding how the brain's cellular workers use the information to mediate between genes and the processes we understand at the psychological, behavioural or experiential level.
This is part of the new science of epigenetics, and there are high hopes that this will be a big part of future neurobiology.
This doesn't imply that we don't need to understand the role of experience and the environment in deference to purely reductionist neurobiological models. In fact, these new developments have stressed the importance of integrating these bigger concepts.
And this is largely because we now have the beginnings of a science that could help us make links between these different levels of explanation.
Nevertheless, the Allen Brain Atlas is an important and exciting part of this new science and the Wired article is a great introduction to the project.
Link to Wired article 'Scientists Map the Brain, Gene by Gene'. Link to Wired image gallery of the Allen project.
The New York Times has an obituary for Earl Wood, the man who invented the G-suit, the pressurised suit for fighter pilots that prevents them losing consciousness when g-forces drain blood from the brain.
The problem became apparent as fighter plane technology advanced to the stage where they became so fast and manoeuvrable that pulling tight corners or sharply accelerating put huge strains on the pilots' bodies.
The acceleration temporarily impedes the heart’s pumping power and cuts blood supply to the brain. A tight turn might cause the pilot to lose consciousness briefly, leading to a crash...
To counter a precipitous drop in blood pressure, the team designed a suit that placed air bladders at a pilot’s calves, thighs and abdomen; a valve inflated the bladders as G-forces increased. Constriction of the bladders on the arteries raised blood pressure and helped keep blood flowing to the brain. The suit’s prototype was tested successfully by Dr. Wood and others in a dive bomber on flights that involved steep descents.
At the same time, the Mayo team developed an exercise, called the M1 maneuver, in which a pilot would shout or grunt under G-force conditions. The grunting compressed arteries and tensed muscles and was at least as important as the revolutionary suit for resisting G-forces.
Permanently altering brain function, outside the skull:
A surgical team from Italy have just reported that they've altered human brain function through neurosurgery conducted from outside the skull, by using beams of radiation.
The technique is known as radiosurgery and, in itself, isn't novel. The team used the Cyberknife system, specifically designed to do this sort of operation.
However, the technique is typically used to treat brain tumours, and what is new is that the team have adapted this method to permanently knock out targeted areas to alter overall brain function.
They were inspired by deep brain stimulation and functional brain surgery. These aim to do a similar thing and are most commonly used to treat tremors and movement problems in Parkinson's disease by altering the movement circuits in the brain.
This new operation aimed to do something similar, but with radiosurgery.
Their report appears in the journal Medical Physics, where they describe the treatment of two patients with, until then, untreatable disorders. One with chronic pain, stemming from nerve damage, and other with dystonia, a neurological disorder that causes certain muscles to painfully contract.
One of the challenges with this sort of operation is hitting exactly the right spot, and to achieve the necessary accuracy the team built a 3D computer model of the key areas from the brain scans which they then used to electronically direct the radiosurgery equipment.
The patient with dystonia had a pallidotomy, where part of his basal ganglia was ablated (destroyed), whereas the patient with chronic pain had a thalamotomy, taking out a section of his medial thalamus.
Both patients recovered well, significantly improved and showed no major side-effects at 15 months.
The image on the left shows where the radiation beams entered the head during the operation on the patient with chronic pain.
Link to research report. Link to PubMed entry for same.
Sweet anaesthesia and the mystery of consciousness:
Discover Magazine has an excellent article on the science of anaesthesia and why doctors need to struggle with the problem of consciousness to make someone comfortably numb.
If you're not familiar some of the mysteries of anaesthesia, you may be surprised to know that we don't actually know how most anaesthetics work and we have no reliable way of telling whether someone is unconscious.
This is important because general anaesthesia usually involves two types of drug, muscle relaxants and hypnotics. It's possible that the muscle relaxants have their paralysing effect but the hypnotics don't fully work, so you're awake and aware, but don't respond when you're touched or talked to.
Hence anaesthetists would love a device which says whether someone is concious or not, but unfortunately, divining consciousness from the brain is one of the hardest problems in science. So, they've come up with various other methods:
Sometimes the anesthesiologist will use a blood pressure cuff on a patient’s arm to block the muscle relaxants in the bloodstream. Then the doctor asks the patient to squeeze a hand.
This sort of test can distinguish between a patient who is awake and one who is out cold. But at the borderline of consciousness, it is not very precise. The inability to raise your hand, for example, doesn’t necessarily mean that you are unconscious. Even a light dose of anesthesia can interfere with your capacity to keep new pieces of information in your brain, so you may not respond to a command because you immediately forgot what you were going to do. On the other hand, squeezing an anesthesiologist’s hand may not mean you’re wide awake. Some patients who can squeeze a hand will later have no memory of being aware.
Seeking a more reliable measuring stick, some researchers have started measuring brain waves. When you are awake, your brain produces fast, small waves of electrical activity. When you are under total anesthesia, your brain waves become deep and slow. If you get enough of certain anesthetics, your brain waves eventually go flat. Most anesthesiologists monitor their patients using a machine known as a bispectral index monitor, which reads brain waves from electrodes on a patient’s scalp and produces a score from 100 to 0. But these machines aren’t precise either. Sometimes patients who register as unconscious can still squeeze a hand on command.
The article then goes on to discuss some fascinating neuroscience studies that use anaesthesia to try and understand what changes in the brain as someone slips into unconsciousness.
It's a great read and an interesting look into what you might called 'applied consciousness research'.
Link to 'Could a Dose of Ether Contain the Secret to Consciousness?'
Frontiers in Human Neuroscience has a great two page article that nicely summarises the thinking about how blood flow measured by brain scans relates to the workings of the neurons.
No one with common sense would believe that in a house, water movements in pipes could tell you how many lamps are on and how much fuel is used for heating. Surprisingly most neuroscientists are convinced that in the brain monitoring local cerebral blood flow (CBF) what I call plumbing, is a reliable surrogate method to localize electrical neuronal activity and monitor metabolic events.
The piece is by neuroscientist Jean Rossier, and he discusses the two main theories of how blood flow relates to what the neurons are doing.
The 'metabolic hypothesis' assumes there is a causal link between how much energy the neurons need, in the form of glucose, and the subsequent regulation of blood flow in the brain. In other words, the neurons signal the need for energy, which is delivered later.
The 'neurogenic hypothesis' hypothesis, suggest that blood flow can be 'pre-ordered', in anticipation of neural activity.
Needless to say, it's important to understand the exact relation between the operation of the neurons and blood flow, because brain scanning studies typically measure blood flow to infer the working of neurons and hence the relationship to cognitive or mental processing.
The Frontiers in Human Neuroscience article is a concise piece which discuss the neuroscience of this link, and covers some of the most recent studies which have attempted to make sense of what brain scans tell us when we're doing psychology experiments.
Link to article 'Wiring and plumbing in the brain'. Link to PubMed entry for same.
I like this sentence in the summary from a recent paper on an unusual penetrating head injury:
We present a unique instance of a severe, high-energy, penetrating orbitocranial injury caused by a solid metallic rod that corresponded to the spray valve lever handle of a kitchen sink pre-rinse spray tap, which was fractured and projected at high speed for an unknown reason.
An article just published online for the Behavioural Science and Law journal discusses whether magnetic brain stimulation could be used in lie detection and interrogation.
It is based on the premise that as cognitive neuroscience works out the brain circuits for lying, a technique called transcranial magnetic stimulation (TMS) could be used during an interview to disrupt the function of these pathways.
The article specifically pitches this idea as a possible 'lie detection' method, as so far, research conducted by the authors suggest that disrupting parietal cortex function, on average, slows the response time for lies and but doesn't affect response time for truthful responses - albeit in a very controlled laboratory experiment.
In other words, the idea is that TMS could be used to help distinguish truthful responses from untruthful ones.
My first thought on reading this was that someone is bound to be thinking of this technique as a way of inhibiting the relevant circuits to prevent lying, or at least increase the likelihood of truthful responses.
It's probably true to say that deception research is in its very early days and its not even clear whether such things as distinct 'deception circuits' even exist.
However, from what we know from now-public secret military research in this area, it's clear that many of these sorts of techniques are simply tested empirically.
Essentially, whether there is a good theoretical basis or not, national security agencies are much more likely simply to try the techniques and see what the outcome is.
The Behavioural Science and Law article sticks firmly to the possible civilian uses for this technology, discussing the legal and ethical issues within a domestic law framework, but you can bet that the spooks are already thinking ahead on this one.
Link to 'Non-invasive brain stimulation in the detection of deception'. Link to PubMed entry for same.
We've reportedbefore on brain imaging research that shows brain activity in those in a 'persistent vegetative state'. What I didn't know until today was that one subject in this research, Kate, has since woken up. This YouTube video tells Kate's story:
Kate suffered from what was probably brain stem encephalitis at the age of 23. She was the first patient to be scanned by Adrian Owen as part of his research into the mental lives of those in persistent vegetative states. Findings from this research support what Kate herself is able to say in the video: we need to be very careful before making life and death decisions on behalf of people who appear unresponsive.
Wired has just published an excellent twopart article on neuroengineering, the practice of altering the brain with electronics or optics.
It looks at a number of interesting projects, from light controlled neurons to magnetic brain stimulation, and focuses on the work of talented neuroengineer Ed Boyden who I had the pleasure of doing a joint talk with at a SciFoo conference.
In fact, TMS gets electricity into the brain peacefully, without either cutting it open or shocking it with millions of volts.
The target area of the brain is treated like the coil in a generator, subjected to rapidly changing magnetic fields until electricity begins to dance across its neurons. Unlike the optical switch developed by Boyden and Stanford's Dr. Karl Deisseroth, TMS doesn't reach the deeper regions of the brain, but there are a lot of important and interesting areas in the cortex where TMS delivers its current. It's also far less precise than the optical switch, although TMS seems positively surgical when compared to the imprecisions of the pharmaceuticals we pump into our bodies.
The second part is probably the highlight, discussing the possibilities of having these technologies more widely available so your average garage hacker can tinker with them (and themselves), and what ethical dilemmas this might cause.
Link to 'Inside the New Science of Neuroengineering'. Link to 'How Neuroengineering May Change Your Brain.
Brain implants and cognitive side-effect trading :
This week's Nature has an interesting article on the ethics of electronic brain enhancements. It does something quite unusual for an article on technological brain enhancements - it talks about the side effects.
Brain implants and 'neuroprosthetics' have been widely covered by the science media in recent years owing to a number of impressive advances but very little discussion has focused on the adverse effects.
In considering the ethics of using brain implants to enhance both the damaged and healthy brain, this article actually touches on some of the research on unwanted effects of deep brain stimulation.
Many patients with Parkinson's disease who have motor complications that are no longer manageable through medication report significant benefits from DBS. Nevertheless, compared with the best drug therapy, DBS for Parkinson's disease has shown a greater incidence of serious adverse effects such as nervous system and psychiatric disorders and a higher suicide rate. Case studies revealed hypomania and personality changes of which the patients were unaware, and which disrupted family relationships before the stimulation parameters were readjusted.
Such examples illustrate the possible dramatic side effects of DBS, but subtler effects are also possible. Even without stimulation, mere recording devices such as brain-controlled motor prostheses may alter the patient's personality. Patients will need to be trained in generating the appropriate neural signals to direct the prosthetic limb. Doing so might have slight effects on mood or memory function or impair speech control.
The author of the piece argues that this does not raise any new ethical questions, as many psychiatric drugs also have side effects.
However, it's probably true to say that ethical difficulties often arise with regard to specific side effects - talking about unwanted effects in general is a bit too vague to be useful.
Risk-benefit analyses are only useful when you know both the extent and quality of the risks and benefits and this is where it truly gets interesting.
The neuropsychology literature is full of surprising findings about what sort of functions the brain performs, suggesting that specific effects, wanted and unwanted, may have to be traded off against each other.
For example, is the loss of the ability to have an unconscious emotional reaction to a loved one worth a change in pathological gambling behaviour?
This is a hypothetical example based on the role of the ventromedial cortex in bothsituations, but who knows what sort of effects might need to be weighed up against each other.
Nature Network has an online discussion about the issues the piece raises which also links to the weekly podcast which has an interview with the author.
Link to Nature article 'Man, machine and in between'.
I've just found this remarkable CT scan in a 1997 article entitled 'Trans-orbital penetrating head injury with a door key'.
The paper reports that "A 71-year-old-female was answering the door when she misjudged the step and fell forward impaling herself on the large key protruding from the lock."
She was found with the key still embedded in her head and was transferred to neurosurgery where the key was removed.
Thankfully, the patient recovered with no neurological impairment and only slight difficulties with her vision.
Time magazine has an interesting article on the neuroscience of spiritual experience and why religious belief has been linked to better health.
It's not the most gripping article in the world and starts with some annoying experience = brain area phrenology but it does gives a good overview of some of the main research areas.
Probably the most interesting aspect is where it tackles the link between religious belief and health in light of other belief based health benefits such as the placebo effect or beliefs about illness itself.
The section on the effects of prayer also has this fascinating snippet about early experimental psychologist Francis Galton:
As long ago as 1872, Francis Galton, the man behind eugenics and fingerprinting, reckoned that monarchs should live longer than the rest of us, since millions of people pray for the health of their King or Queen every day. His research showed just the opposite — no surprise, perhaps, given the rich diet and extensive leisure that royal families enjoy.
Studies on the curative properties of prayer have a long and interesting history, with one of the most striking moments also linked to a psychologist and an (in)famous study - discussed in a 2002 Wiredarticle.
Stanford University have put a series of engaging TED style 10 minute lectures up on YouTube where some of their leading researchers discuss cutting-edge cognitive science research - curing blindness with neural implants, brain computer interfaces, neural pathway mapping, creating brain inspired computer hardware, visualising desire and controlling neurons with light.
Getting lab scientists to do short, engaging online lectures aimed at a bright and curious audience is a fantastic idea. These new Stanford talks have a high production quality and have obviously been prepared with a great deal of care as they are incredibly easy to watch.
I've not watched them all yet, but so far the talk on the neuroscience and stem cell treatment of blindness is a particular highlight.
In this presentation, psychologist Brian Wandell discusses the science of perception and the treatment, as well as the remarkable case of Mike May, the world-record holder for blind downhill skiing who volunteered to try the experimental treatment.
A fantastic series that's well worth checking out.
Locked-in syndrome is a dramatic condition where, after brain stem damage, patients are conscious but paralysed and can only communicate with the outside world by an eye-blink or muscle twitch.
Because of limited communication it has been difficult to assess the impact of the damage on thinking and reasoning, but a French team have created tests that can be completed by simple yes / no movements - allowing the first comprehensive study into the cognition of the locked-in mind.
The syndrome usually occurs after a stroke, where an interruption to the blood supply selectively damages the neurological 'relay station' that transmits movement impulses to the rest of the body, leaving an almost total paralysis - classically except for a facial muscle.
It has been assumed that affected people are paralysed but cognitively intact - their thinking isn't affected.
In one famous example, the editor of Elle magazine, Jean Dominique Bauby, wrote the bookThe Diving Bell and the Butterfly after suffering locked-in syndrome by painstakingly selecting letters with an eye-blink. It's both stunningly beautiful and eloquent, demonstrating a keen and focused mind.
But because of extremely limited communication, it's difficult to say whether this level of preserved mental ability is common because traditional neuropsychological tests usually require relatively complex responses.
To address the problem, a French team, led by neurologist Marc Rousseaux, designed tests to assess nine patients that included everything from visual recognition tasks to logical-mathematical reasoning problems, all which could be answered with yes / no responses - just eye-blinks in some cases.
The appendix of their article has the full list of the tests and they are remarkable for their ingenious design.
They team found that while the patients were generally mentally sharp, problems in particular areas were not uncommon, with a significant minority showing selective impairments in areas such as comprehension, understanding meaningful connections, or problem solving.
Sadly, this means that it is unlikely that all locked-in patients share Jean-Dominique Bauby's remarkably preserved intellect, but the development of these ingenious tests means that we can better understand the impact of the syndrome, and the strengths and weakness of affected patients.
The long term effects of banging heads on the field:
Sportsmen who suffer concussion in early adulthood may experience long-term reduction in brain function well into later life, according to a study released this week.
Although the study had only 40 participants, it is striking as it looked at the effects 30 years after the original concussions and used a wide and diverse range of tests for cognitive and neurological function, the majority of which showed some level of impairment.
This comes in the same week that Boston University School of Medicine reported that former American football player, Tampa Bay Buccaneer Tom McHale, was suffering from chronic traumatic encephalopathy (CTE), a degenerative brain disease caused by head trauma, when he died in 2008 at the age of 45.
CNN has a good write-up of the news with photos and images of the long-term effects of persistent sports concussion and we covered the work of Dr Bennet Oamlu, who does post-mortems on cognitively impaired American football players, back in 2007.
Repititive sports concussion is now recognised as having a significant neurological impact and has also been found in rugby and boxing.
Interestingly, ex-professional football players (known as soccer players to Americans and other football philistines) probably have higher levels of dementia and there is an ongoing debate about whether this is due to the low level impact of heading the ball.
Some think it is, other think it might be due to the fact footballers consume a lot of alcohol, and so the higher levels of dementia just might be wear and tear from all the booze.
Link to full text of long-term sports concussion study. Link to CNN on sports concusion and dementia (via NeuronCulture).
Neuroscience textbooks often suggest that the ability to image the structure of the brain in living patients started in the 1970s with the introduction of the CT scanner. What they tend to forget is that brain surgeon Walter Dandy was already neuroimaging patients as early as 1918.
We think of x-rays as only being useful for getting pictures of bones but soft tissue does show up on an x-ray.
The images rely on certain bits of the body having a higher density and therefore blocking more of the rays falling on the photographic plate.
Bones are obviously very dense so show up well but look at this image of a hand x-ray. You can clearly see the difference between bone, flesh and air. What you can't see is any difference in the soft tissue.
The crucial difference that struck Walter Dandy was the possibility of distinguishing flesh and air on an x-ray.
Knowing that the brain is surrounded by cerebrospinal fluid (CSF), which also fills internal spaces called the ventricles, he decided to simply replace the fluid with air and x-ray the patient.
He published his first results in 1918. He described how he drilled a hole in the skull of a patient and carefully removed the CSF from the ventricles and replaced it with air.
Now known as ventriculography, one of the images he took is illustrated on the top left. For the first time, you could clearly see the ventricles in a living patient.
During the procedure, he noted that some of the air has escaped the ventricles and was occupying the space between the skull and the brain.
The following year he published another study where he deliberately filled this space with air as well, so the surface of the brain was surrounded by the gas and so could show up on an x-ray.
The bottom left image shows the result of this, and you can see it clearly shows some of the 'trenches', the cerebral sulci, on the surface of the brain.
Now called pneumoencephalography, the procedure was immensely useful, but, extremely unpleasant. In his 1918 article he noted that the patient's reaction "was characterized by a rise of temperature, nausea, vomiting, and increased headache".
Furthermore, it takes weeks, if not months, for the CSF to be replaced by the body, leaving the patient in a debilitated and fragile state.
However, it was used throughout the 20th century and the research literature is peppered with the results of this early neuroimaging research.
Link to 1918 paper on imaging of the ventricles. Link to 1919 paper on imaging the brain surface.
The great British neurologist John Hughlings-Jackson famously described the 'dreamy state' reported by some epileptic patients during seizures where they experienced complex hallucinations - sometimes of scenes and faces, feelings of false familiarity and a feeling of 'weirdness' or 'strangeness'.
A study published last year in neurology journal Brain re-examined these experiences by deliberately triggering them by electrically stimulating the brain.
The participants were all patients with epilepsy who were having neurosurgery to treat their otherwise untreatable seizures and the researchers, led by neurologist Jean-Pierre Vignal, specifically stimulated areas in the mesial [inner] temporal lobes.
The feelings of false familiarity are what we normally called déjà vu, but actually we tend to misapply this term as it means 'already seen' and refers specifically to a false familiarity for visual perception.
However, it can also occur for anything we experience, such as hearing other people say things, and is more correctly called déjà vécu ('already experienced') in the literature.
Here are a few of the triggered experiences:
Déjà vécu (3 volts, right amygdala) - "It's like yesterday evening ... I have the impression that everything around me has been here before, that it has already happened, I feel as if I am going backwards in time"
Scene: reliving a parachute jump (3.5 volts, right hippocampus)
Familiar television advertisement (4 volts, right amygdala)
Impression of being elsewhere (3 volts, right hippocampus)
Scene from childhood (2 milliamps, right amygdala) - "Vision of a bald man dressed in black, coming towards her from behind; associated with a feeling of imminent death; she is pale, with piloerection. She is re-experiencing an experience of anaesthesia by facemask during a tonsillectomy at the age of 14 years"
Impression of being someone else (2 milliamps, left amygdala)
Impression of leaving his body (2.5 milliamps, left amygdala)
Night-time scene (1.2 milliamps, left hippocampus) - "I'm starting to see lots of things, loads of people ... it's still vague and strange. I've got an initial picture, a memory ... I feel locked in again, something to do with the evening, the night ... it's strange ... . like after a party, sad things ... there is a mixture of last night and this morning ... ’ These remarks were peri-ictal [during the seizure]. After the end of the discharge, there was complete amnesia."
Scene (4 milliamps, right hippocampus) - "It's starting, it's rising up to my eyes ... I'm always frightened of something ... I feel something, like in dreams, I always see people, loads of people, people that I see in the hospital..."
Familiar character from a film (1.5 millamps, left amygdala)
Ill-defined, unpleasant vision (1.5 milliamps, left hippocampus)
Familiar vision that he is unable to describe (1.5 milliamps, left parahippocampal gyrus)
Vision of a familiar person (1.5 milliamps, left parahippocampal gyrus)
Recent scene (1.5 milliamps, right hippocampus) - "I see myself playing the drums, with people from my family listening to me"
The technique of electrically stimulating the brain to trigger certain experiences was pioneered by Canadian neurosurgeon Wilder Penfield and there's an excellent account of his life and work on Neurophilosophy if you'd like some background.
This new study is open-access and completely fascinating, so is definitely worth a read.
Link to 'The dreamy state: hallucinations of autobiographic memory evoked by temporal lobe stimulations and seizures'.
The British Medical Journal has just published one of the greatest and funniest research articles ever to grace the pages of the medical literature with a paper on the potential neurological consequences of headbanging to heavy metal.
As someone who once caused himself concussion and several hours of puking from head banging to Metallica at the age of 14, I feel this is important and invaluable research.
The researchers, Australian rockers Declan Patton and Andrew McIntosh, attended a number of heavy metal concerts to observe the most common forms of headbanging (the 'up-down style' apparently), and then did a biomechanical analysis to estimate the forces operating on the head and brain.
They also convened a focus group of local rockers to list their favourite headbanging classics, and modelled the physical stresses based on the tempo of the tracks.
They discovered that headbanging to songs with a tempo above 146 beats per minute when the head motion was more than 75 degrees was the point at which brain injury was likely to occur.
It's traditional that the Christmas edition of the BMJ has a more light-hearted article. This study is a little different in that the science is completely bona fide, but the scientific paper is a very funny read.
Their public health recommendations are a particular gem:
Though exposure to head banging is enormous, opportunities are present to control this risk—for example, encouraging bands such as AC/DC to play songs like "Moon River" as a substitute for "Highway to Hell"; public awareness campaigns with influential and youth focused musicians, such as Sir Cliff Richard; labelling of music packaging with anti-head banging warnings, like the strategies used with cigarettes; training; and personal protective equipment.
Great article, fantastic title, and completely open access.
Rock on!
Link to 'Head and neck injury risks in heavy metal'.
I've just found this fascinating article on how legendary neurologist Gordon Holmes discovered how the visual cortex represents visual space after studying World War One soldiers who had experienced bullet or shrapnel wounds to the brain.
World War One taught us a great deal about neuropsychology largely due to developments in weapons technology. The German Mauser was an accurate rifle that used small bore ammunition where previous conflicts had largely used single shot rifles mostly designed so a group of soldiers could create a 'wall of lead', rather than a carefully aimed shot.
Developments in shell technology also meant that high explosives could be launched with reasonable accuracy into groups of soldiers causing significant shrapnel injuries.
However, both the rifles and shells were at a stage where the velocity of either a bullet or a piece of shrapnel was relatively slow by today's standards, meaning that the brain was not additionally damaged by shock waves, like with modern munitions.
In other words, they could create small discrete areas of brain damage that left the rest of the brain largely unaffected.
The British Brodie helmet, which sat like a tin bowl on the top of the head, left the lower parts of the head, and hence the brain, exposed. This meant a significant number of injuries were to the visual cortex, at the rear of the brain.
Neurologist Gordon Holmes studied the link between small lesions to this area and which areas of vision had been lost in soldiers coming back from the front.
The diagram on the right is one of his drawings where he demonstrated the link between a very specific shrapnel wound and a crescent-like area of blindness in the visual field. The full diagram is in the article where he also shows how it affected the right eye.
These studies taught us that the visual cortex is 'retinoptically mapped', meaning that each part of the cortex corresponds to a specific area of vision. It also taught us that some brain areas can be very specifically localised to certain functions, whereas previously we'd only known of very general connections between function and brain area.
The article, published in opthamology journal Documenta Ophthalmologica, describes Holmes' wartime experiences, his discoveries and something of his character.
It also contains this curious episode, related by one of his junior doctors, largely notable for the fact that they hid a blonde beauty queen in a bathroom on the hospital ward to boost morale of the medical house officers.
Holmes had no time for neurotics and hysterics, and less ... for psychoanalysis ... [Once] In the ward there was a blonde bombshell of twenty-one with mild tension headaches. She was as pretty as a picture, plump as a partridge, who the previous year had been the Daily Mirror Bathing Beauty Queen. The first time I took Holmes around, he stopped at the foot of the bed and said 'Who is this woman?' I explained, whereupon he jerked his thumb towards the door and said 'Get rid of her'.
Of course, I did nothing of the sort, for she was useful in keeping up the morale of us house officers. A week later he came around and said 'I thought I told you to get that woman out of here?' Yet another week passed. On this occasion I got the Sister of the ward to hide the patient in the bathroom during the ward round. Standing at the foot of the empty bed, Holmes paused, then said to me 'Look here, my boy, either she leaves the hospital or you do - and I don't care which.
Link to 'Gordon Holmes, the cortical retina, and the wounds of war'. Link to DOI for same.
Discover magazine has a thought-provoking article on the question of whether 'shaken baby syndrome', claimed to be a specific type of brain damage that occurs to young children if shaken, actually exists as a useful syndrome. If it doesn't, it might not only be a medical miscategorisation but also a legal disaster that may have falsely convicted innocent families of child abuse.
Critics argue it's a bit like calling a broken nose 'punched in the face syndrome'. The label is for a non-specific injury but which automatically leads us to assume that an aggressor must exist.
Once a doctor says that an infant must have been shaken, it triggers a hunt for the shaker. In one diagnostic step, the legal system is brought to bear on the baby’s family and anyone else near the infant at the time of the supposed shaking.
The symptomatic triad of bleeding between the brain and skull (known as subdural or subarachnoid hematomas), bleeding behind the retinas, and brain swelling is both the core of an SBS diagnosis and the point of departure for the syndrome’s skeptics. The medical proof that shaking alone can cause these internal head injuries is questionable, the skeptics say, when many other things, from infections to malnutrition to falls onto a hard surface, are known to be causes of similar symptoms in infants.
In contrast, supporters of the condition, which came to world-wide attention in the case of British nanny Louise Woodward, argue that shaking causes babies specific injuries that are unlikely to be triggered by anything else. The article quotes Eli Newberger, an assistant professor of pediatrics at Harvard Medical School:
“By the time I was asked to testify in the Louise Woodward case...there was a great deal of clinical understanding about [SBS-related] trauma,” Newberger says. “The infant’s head is disproportionately larger in relation to the rest of its body than our heads are. A child can’t stop the to-and-fro excursions of the head with its neck. The brain bobbles about. The infant’s brain is softer than the adult’s.”...
Money, Newberger suspects, has brought otherwise good people over to what he and his colleagues call the “dark side,” doubting SBS. “I have never ceased to be amazed about what highly regarded, well published, scientifically informed doctors will do when they’re offered large amounts of money,” he says.
And indeed, experts on both sides seem to charge a great deal for their time.
The article walks us through some of the studies that have attempted to look at how many children with these symptoms show other signs of abuse, or have tried to simulate the damage with computer or physical models.
It's a fascinating look at a syndrome I just took for granted as being widely validated and looks at the implications of the scientific work for the legal system, where incorrect diagnosis can lead to abusers going free or loving parents being jailed.
Link to 'Does Shaken Baby Syndrome Really Exist?'.
Walking the line: the danger of sinus neurosurgery :
I've just found this gripping article from The Guardian by photojournalist Tom Bible who was diagnosed with a rare and life threatening brain tumour and had an equally rare and life threatening operation to remove it.
The tumour was located in the superior sagittal sinus, one of the major veins that drains blood from the brain.
Operating on it is very dangerous because it is incredibly difficult to stem the bleeding once it's damaged. As the author mentions in this passage, it's so dangerous that the operation needs to be carried out while the patient's heart is stopped:
I now had a challenge: to find a neurosurgeon who was both willing and able to remove my tumour. Dr Thomas recommended two vascular neurosurgeons in the UK. I arranged an appointment with the first one, who subsequently cancelled, saying that it was not the type of operation he would perform. I visited the second neurosurgeon at the National Hospital in London - the leading UK neurosurgery hospital (and one of the most highly rated in the world). He said he had only heard of one of these before. They had had to remove it by resorting to a practice called the 'cardiac standstill'. In this, they stop the patient's heart, drain the blood from the body and reconstruct the tumour-infested sinus area, pump the blood back into the body and kick-start the heart again.
Blimey.
The author eventually had the operation in the US, and gives a compelling description of the process from first symptoms to the extended procedure that eventually also needs the radiation-based gamma knife treatment.
The eternal quest for the cut-and-dry brain injury:
The annual Society for Neuroscience conference is currently underway in Washington DC and Technology Review has a couple of article that reports on some of the highlights.
One piece is particularly interesting as it focuses on the use diffusion tensor imaging (DTI), a type of MRI scan that identifies the white matter nerve pathways in the brain, to detect otherwise undetectable brain damage.
These white matter pathways are like cabling that runs through the brain and in some forms of head injury they can get twisted, pulled or suffer sheering injuries which may not be easily visible on standard MRI scans.
A minority of people who suffer head injury with no detectable injury on standard MRIs will suffer emotion and behaviour disturbance, memory difficulties, diffuse headaches and problems with concentration.
This is sometimes diagnosed as post concussion syndrome and the researchers hope that DTI scans will find that people with these sorts of complaints will be found to have clear white matter disturbance.
Actually, this is one of the oldest debates in head injury and stretches back to the time when soldiers were first returning from the First World War with 'shell shock'.
One of the theories, largely championed by Maudsley psychiatrist Frederick Mott, was that the shock waves from the shells disturbed the brains of the individuals causing microscopic brain damage.
However, it soon became clear that some soldiers who had 'shell shock' had never been near a shell explosion, while others had genuine brain injury but had similar sorts of problems which weren't easily explained by the physical damage they'd endured.
One of the key lessons from this time was that our expectations, beliefs, emotions and interpretation of experiences and injuries contributed as much to the actual symptoms and disability as the physical damage.
Interestingly, similar sorts of problems have been reported in soldiers returned from Iraq and, as echoed in the TechReview article, there is a big push to clearly separate cases of 'genuine brain injury' from 'emotional trauma'.
History tells us that attempting a clear separation is likely to be futile, because the same symptoms can be produced by either one, or a combination, and knowing that one definitely plays a part doesn't rule out the other.
So it's interesting to hear the people quoted in the article suggest that DTI imaging could help assess who is cognitively able or not, who has a 'real injury or is faking', or whether someone should be sent back to the battlefield, because it relies on a cut-and-dry distinction between 'brain injury' and 'psychological problem' which doesn't exist in the real world.
As an aside, white matter isn't invisible on MRI or CT scans, as suggested in the article, although some white matter injuries might be.
And if you're still hungry for more SfN news, TechReview has another bulletin with several highlights.
Link to article 'Detecting Subtle Brain Injuries'. Link to latest SfN brain research write-up.
BBC Radio 4's excellent discussion programme In Our Time just had an interesting edition on neuroscience - what it does, how it does it, and what it's telling us about the function of the mind and brain.
It's generally a very interesting discussion, although does get a bit confused towards the end during a discussion of conscious - largely due to a misunderstanding of a famous study.
The discussion touches on neuroscientist Adrian Owen's study where they wanted to find out whether a patient in a persistent vegetative state (PVS) was conscious by asking them to imagine things and then using fMRI to see if the relevant parts of the brain were active - in other words, if the person was able to consciously hear, understand and carry out the request.
Famously, the patient could - demonstrating that it is possible to be diagnosed with PVS and still be conscious.
However, the guests on the programme discuss the study as if the patient was unconscious and was in a coma, and suggest that this shows the brain can do remarkable things when someone is unconscious which is exactly what it didn't show.
Otherwise, a fascinating discussion as we'd expect from In Our Time.
Neurophilosophy has recently published two excellent articles that discuss the recent discovery of very selective psychological problems: one person can't recognise people by their voice, the other can't navigate through streets.
In themselves, these sorts of disorders are not that surprising, but they help us understand how the brain develops.
Actually, scratch that last sentence. If you're familiar with the brain injury literature, these sorts of disorders are not that surprising, but if you're not, they're completely mind blowing.
Take prosopagnosia for example. Sometimes rather inaccurately called 'face blindness' (people see faces, they just don't seem distinctive) it was first identified in a patient with a bullet wound to the head who lost the ability to recognise faces but could still recognise other objects.
If you think about it, this is incredible. When we look out onto the world, faces don't seem different from the rest of the things we look at, but damage to a specific area of the brain (most commonly the right fusiform gyrus) can selectively damage our ability to see faces, suggesting that there are brain functions specialised for this task. How specialised, whether only for faces, is a matter of ongoing debate, but the fact that they are specialised at all is incredible enough.
The explanation for these selective impairments goes something like this: our brain functions are shaped by a combination of the broad outline of genetics and the fine tuning of experience during growth. When we reach adulthood they are fairly fixed. Damaged can knock out these fairly fixed pathways leading to selective impairments.
What has become clear over the last decade is that some people can have selective impairments without suffering brain injury. They seem to have them from birth.
This is the case with the two people discussed by Neurophilosophy. An inability to recognise people by just their voice or an inability to navigate streets after brain damage is interesting but not earth shattering. These sorts of cases have been reported before.
But the fact that these are developmental disorders is an interesting and important twist, not least for what they suggest about how much certain functions might be 'set' in the brain early on, but also for what they suggest about the 'life history' or our cognitive skills.
The two case studies discussed by Neurophilosophy are both fascinating as life stories of people with atypical difficulties but also scientifically compelling because they help us understand complex dance of brain growth and development.
Link to piece on developmental topographagnosia. Link to piece on developmental phonagnosia.
Scientific American Mind's Mind Matters blog has a great interview with neuroanthropologist Daniel Lende who discusses why we need an understanding of both culture and neuroscience to get a fully integrated account of human thought and behaviour.
Lende discusses his work on integrating cultural factors and the neuroscience of the dopamine reward system in a study of addiction in Colombian teenagers.
A common approach in neuroscience is to take experiences labelled by everyday words and try and find what changes in the brain when someone says they are having the experience.
The problem is that the definitions of the labelling words may be indistinct ('love'), incoherent ('belief') or understood differently in different cultures ('anxiety').
The approach Lende advocates is to take an anthropological approach to the problem. In other words, attempting to understand what a concept or label means in a particular culture so the neuroscience can be integrated in full knowledge of the diversity of the experience.
This predicament is where neuroanthropology can be so helpful. In order to draw connections between neuroscience and real world situations, I went out and talked to people to understand craving and addiction from their point of view. This type of real-world data can both challenge and inform ideas based on animal models and neuroimaging studies.
In translating the dopamine research, my work with adolescents proved crucial. They knew what they experienced far better than I did. Using systematic interviews across a range of involvement with drugs (hard-core users to having never tried drugs), I saw three areas of overlap between research on dopamine and compulsive involvement with addictive substances.
First was the emphasis that researchers placed on “wanting.” I was lucky in Colombia; addicted adolescents often described their experiences as “querer más y más,” to want more and more. Second, dopamine affects shifts in attention, which meant that some adolescents couldn’t focus on anything else when they knew an opportunity to consume was about to come along. Third, adolescents described a sense of being pushed toward something—an urge that rose up without conscious desire.
You may recognise Lende from the excellent Neuroanthropologyblog and he also discusses some of the work of his co-bloggers in the interview, including some fascinating work looking on how people learn balance.
However, if you're interested in more details about the study on Colombian teenagers, he's recently posted some moreinformation including links to the full text of the papers.
Link to SciAmMind Mind Matters interview. Link to Neuroanthropology post on Colombia study. Link to follow-up and more information.
I've just found another curious case report of complex movements in a brain dead patient, following on from our recent piece on the Lazurus Sign.
These reports are fascinating and bizarre in equal measure, not least when you try and imagine what was happening in the room at the time.
Uncommon reflex automatisms after brain death
Rev Neurol (Paris). 1995 Oct;151(10):586-8.
Awada A.
Two cases of unusual complex movements observed in brain dead patients are described. Rapid and sustained flexion of the neck induced slow abduction of the arms with flexion of the elbows, wrists and fingers over 5 to 10 seconds. These movements have been rarely described and although they have similar clinical patterns, they are pathophysiologically different from the Lazarus sign which is observed few minutes after respiratory support cessation. While Lazarus sign is supposed to be due to an agonal discharge of anoxic spinal neurons, the movements described in this article result probably from complex reflexes generated in a disinhibited spinal cord. It is however surprising that they have never been described in patients with high cervical spinal injuries.
For those of you not familiar with the medical terms for movement, I shall briefly translate. When the doctors rocked the dead person's head side to side forward in a 'rapid and sustained' fashion, the body extended its arms to the side and waved them about.
I have two thoughts.
Firstly, isn't it fascinating that such complex movements can be triggered solely by the spinal cord?
Secondly, what the bloody hell were they doing with that dead body?
Normally, these reports are of spontaneous movements in isolated brain dead patients, but on this occasion the medical team seem to have been rather more involved.
Unfortunately, the full text of the article is in French, so the exact turn of events (e.g. "hey looks what happens when I do this!") shall have to remain a mystery.
UPDATE: Neuroshrink has added a fantastic correction and comment to this post that suggests what might have been happening and recounts his own experience of observing the Lazurus sign.
Link to PubMed entry for article. Link to Mind Hacks on the Lazurus Sign. Link to another Mind Hacks article on the moving dead.
Tim Harford, who blogs as the Undercover Economist, presents a rollercoaster ride through the field of neuroeconomics, for Radio 4. The documentary is available via Radio 4's Listen Again site for the next week, and reportedly via a podcast (which I unfortunately can't find). This whistle-stop tour covers neuromarketing, behavioural economics and the possible effects of hormone levels on risk tasking among stockmarket brokers. The programme features great interviews with some top researchers, such as Paul Glimcher and, Glimcher aside, many of these researchers have an almost relgious optimism about the potential for fMRI-scanning, believing it will eventually tell us how economic decisions are made, why we follow crowds, what we're thinking at any point in time, what age we should be able to vote and how much we value things like clean air. Admist this heady atmosphere the psychologist Gerd Gigerenzer brings us back to earth again: "You can't read the mind. We understand quite little about the brain." he begins. And then,
A former chairman of the Harvard Psychology deptartment once asked me "Gerd, do you know why they love those pictures [the fMRI activity maps]? It is because they are like women: they are beautiful, they are expensive and you don't understand them"
If you read a classical article on neuroeconomics what you will find is mostly results which have been already known and recycled, and very little new insight.
ABC Radio National's All in the Mind recently had an excellent programme on amphetamine, discussing its varying uses from its original selling point as a widely abused nasal decongestant to its modern popularity as a kiddie behavioural control agent in the age of methylphenidate (Ritalin).
One of the most fascinating parts is where the guest, history of science professor Nicolas Rasmussen, discusses how after amphetamine was discovered in the 1930s the drug companies desperately tried to find an illness which it could be prescribed for.
Smith, Kline & French wanted to find a big market and so they looked at common diseases that you know might plausibly be treated by an adrenaline derivative and they tried it out on a huge range of conditions. Menstrual cramps, bed wetting, you name it -- it turns out actually to work for bed wetting if you give it to little kids who have that problem, probably by making them sleep shallower -- but also in psychiatry for depression, and that's what really caught on.
They tried it for an enormous range of conditions through medical experts and the clinical trials where the drug didn't work out well weren't published, because that was already the arrangement then, when a drug company funded a trial unless it fit their marketing needs the results wouldn't be published.
Great to see the spirit of the 1930s is still with us today.
The programme also discusses how the subculture use of the drug interacted with its 'official' uses in the mind of the public and policy makers to give speed the image it has today.
It seems the programme is based on a new book by Rasmussen called On Speed and I love the link at the bottom of the book's website which says 'Purchase On Speed'. I've drunk a lot of coffee. Will that do?
If you're interested in a book on the science of amphetamines, Leslie Iverson's bookSpeed, Ecstasy, Ritalin is simply wonderful and just so much fun to read, as I noted in an enthusiastic review last year.
The AITM programme is a fantastic introduction to the fascinating story of amphetamine, so a great place to begin.
Link to 'Wakey Wakey! The many lives of amphetamine'.
Occasionally, brain-dead patients make movements, owing to the fact that the spinal reflexes are still intact. The most complex, and presumably the most terrifying, is called the Lazarus Sign. It is where the brain-dead patient extends their arms and crosses them over their chest - Egyptian mummy style.
About 20% to 40% of brain dead patients can show spontaneous movements particularly when the body is pricked with sharp objects.
While these movements are usually brief twitches, occasionally the movements can be in an extended sequence, as reported in this 1992 Journal of Neurosurgerycase study about a 67-year-old lady who died from a brain haemorrhage.
At 11:15 am on February 20, brain death was declared and consent for final respirator removal was obtained from the patient's family. The possibility of the appearance of Lazarus' sign was explained to the family, and a video recording was made.
Five minutes after respirator removal, respiratory-like movements occurred three times; both shoulders adducted and slow cough like movements were identified. Lazarus' sign immediately followed these respiratory-like movements. The forearms were pronated and the wrist joints extended bilaterally. Fingers on the left hand were extended, but those on the right were flexed as if grasping. Subsequently, flexion and extension in the knee and foot joints were repeatedly observed. Slow supination of both feet occurred. Finally, the left forearm was adducted to the side of the body, and the right hand pronated.
The movements continued for about 3.5 minutes, during which time blood pressure was 46/35 mm Hg and pulse rate was about 90 beats/min with a regular sinus rhythm. Cardiac arrest occurred at 11:35 am.
Link to PubMed entry for case study. Link to brief popular article on Lazarus sign.
Seed Magazine has got video of a great talk by Henry Markham, the director of the Blue Brain Project which is developing the world's largest simulation of networks of individual neurons in an attempt to understand the large scale dynamics of the brain.
Their ambition is to be able to run a simulation on the scale of the whole human brain within a decade.
If you want a good summary of where the ambitious project is at, Seed recently had an excellent Jonah Lehrer piece on the research that we featured earlier this year.
Markham's talk is interesting not solely for his take on the project and its aims, but also for the fantastic visualisation he uses to illustrate what it's doing.
Surely this must be the greatest headline for a BBC Newsstory ever: Banjo Used in Brain Surgery.
Although the banjo wasn't in the hands of the surgeons it was still an essential part of the operation. It was played by legendary Blue Grass musician Eddie Adcock who was having surgery to install a deep brain stimulation device to treat an essential tremor that had been affecting his playing.
The BBC News story has a video of the neurosurgery and the banjo playing, and it is pure genius. Probably the best thing you'll see all year.
Essential tremor is a condition where there is a continuing deterioration in areas of the brain that control movement. This causes a tremor that usually appears when the person tries to act or move, although can lead to a 'resting tremor' that's also present at other times.
Essential tremor is not Parkinson's disease, which, while also associated with tremor, is a much more serious and disabling condition in many ways. There does seem to be a link though, as people with essential tremor are more likely to develop Parkinson's, although this still only happens in the minority of cases.
However, deep brain stimulation can be used to treat the movement difficulties of both Parkinson's and essential tremor. It involves sinking an electrode into the thalamus, a deep brain area that is part of the motor loop - a circuit that helps co-ordinate movement.
In fact, there are two parts to the motor loop - the direct and indirect pathway - an each play a complementary part in directing movement, and each of which needs to be balanced with itself and with each other. When damage to these circuits affects this balance, the result is that it causes too much activity one way, which causes a compensatory response the other, and so on.
Imagine two people, completely unaware of each other, trying to balance an uneven seesaw. The oscillations in the control system cause oscillations in movement, and this is what you can see in tremor.
DBS works by sending electrical impulses at a certain frequency into the thalamus to dampen down the oscillations. However, the oscillatory push-push cycle is not the same for everyone, and the best spot in the motor loop itself will also differ.
To get the best result the surgeons tweak the electrical pulse settings and try different areas.
To make sure it's having the desired effect, the patient is awake and they ask them to move. When they see that they've hit the sweet spot and the pulses are in time, they know their job is done.
One of Eddie Adcock's impairments is that he has tremor, but the main impact on his life is that it affects his banjo playing. So the most sensible thing to do is to tweak the system while he's playing the banjo to optimise the effect for the thing that's most important to him.
And that's why a banjo was used in brain surgery.
Link to BBC video of 'Banjo Used in Brain Surgery'.
I just came across these two beautiful images in a paper by neuroscientist Marek Kubicki and colleagues on diffusion tensor imaging studies in schizophrenia.
DTI is a technique that using MRI scans to track how water moves throughout the brain. As water tends to move in one particular direction when its trapped inside nerve fibres, a technique called MRI tractography can be used to map out all the white matter 'cabling', separate from the rest of the brain.
I think the technique produces some of the most beautiful images in neuroscience. You get to see the brain's connections, disconnected, and suspended in space.
Link to full-text of paper (see page 27 for images). Link to PubMed entry for same. Link to more DTI tractography images.
The San Francisco Chronicle has a great article about Dr Charles Cobbs, a neurosurgeon who had the seemingly wacky idea that malignant brain tumours called gliomas might be caused by a viral infection. Initially dismissed, there is now growing evidence for his idea and how it might lead to better prevention and treatment for these usually fatal forms of brain cancer.
Gliomas are tumour that form from glial cells - non-neuronal brain cells that provide support, nutrition protection and some just-recognised roles in signalling.
As you might expect, they are an essential part of almost every part the brain and a malignant tumour which grows from glial cells can be fatal (without treatment, within about 3 months) as they are very difficult to remove and treat.
Cobbs had observed that his patients diagnosed with malignant glioma - an aggressive brain cancer that leaves victims with a two-year life expectancy - were mostly older, well-educated and from higher socioeconomic backgrounds. Their "hyper-hygienic" lifestyles had possibly left their immune systems susceptible to more common viruses, such as the human cytomegalovirus, or CMV, a herpes virus so ubiquitous that it infects 4 of 5 Americans.
During off-hours, and without formal research funding, Cobbs and a lab partner analyzed dozens of brain tumor samples: All of them were riddled with CMV. In 2002, the doctor published his novel finding in a leading medical journal Cancer Research where it was quickly dismissed by many of his peers. "I was left with a lot of self doubt," said Cobbs, now 45. "My fear was that we'd done something incorrect. But now, my confidence is growing."
In February, brain cancer researchers at Duke University Medical Center published the first peer-reviewed report that confirmed Cobbs' discovery, followed by two reports from independent labs at the M.D. Anderson Cancer Center at University of Texas in Houston and the Karolinska Institute in Stockholm, Sweden. And this month, the National Brain Tumor Society is sponsoring a first-of-its-kind gathering in Boston of the world's top virologists and glioma experts to examine the possible link between CMV and the deadly brain tumors that are diagnosed in 10,000 Americans every year.
The photos accompanying the piece are excellent by the way. The image I've used to illustrate this post is particularly impressive - click on it to see the full-size version which you need to get the full effect.
Nature also ran a piece about Cobbs last month owing to the publication of one of his studies in the same issue where he discovered one of key receptors on which the CMV virus has its action.
Unfortunately, I can't read either as Nature's Athens login system is currently broken [insert your own rant about open-access publishing here].
Link to SFChronicle article 'Surgeon changes study of brain tumors'.
A list of things that deep brain stimulation has been used to treat. DBS involves surgically implanting an electrode into the brain which is stimulated with a 'pacemaker' like device.
I've just been looking over the DBS literature and I was quite surprised to see that it has been used to try and treat just about anything you can think of.
Maybe someone should try it for over-optimistic repetitive surgery syndrome? Anyway, here's the one's I've found, if you know of any others, do send them in or add them to the comments.
This is quite a remarkable study from a 1985 edition of the International Journal of Neuroscience that investigated whether the apparent greater use of mental imagery during masturbation by men than women was due to differences in hemispheric specialisation.
To test whether this might be to do with brain organisation, rather than gender itself, the researchers tested the idea by asking about imagery during masturbation in right-handed males, who typically show strong hemispheric specialisation, and left-handed men, who typically show less specialisation.
Unfortunately, I don't have access to the full paper and have no idea whether the claim that women typically report less imagery and fantasy is still thought reliable, as these sorts of findings are notoriously influenced by how the question is asked.
However, the study seemed to find partial support for it's own hypothesis at least.
Sex and handedness differences in the use of autoerotic fantasy and imagery: a proposed explanation.
Int J Neurosci. 1985 May;26(3-4):259-68.
Gottlieb JF.
Previous research has described a greater use of fantasy and imagery during masturbation by men, than women. This study suggests that this gender disparity results from the increased frequency of bilateral speech representation found in the female brain. Support for this theory was obtained by comparing the use of autoerotic fantasy and imagery in another group distinguished by their degree of cerebral lateralization: dextral vs. sinistral males. The prediction that masturbatory fantasy and imagery would be more common in the more lateralized dextral males was partially confirmed in this study.
I gave up looking for a suggestive yet tasteful image than combined the concepts of sex and hemispheric specialisation, so I've illustrated this post with picture of a flower instead.
As an aside, brain anatomy has a few rude jokes thrown in. For example, the mammillary bodies are two small round areas that are part of the limbic system. Their name comes from the fact that the look like breasts.
I was told by a neuroanatomy lecturer that one of the reasons given for why women shouldn't study medicine in the 1900s was because they'd be offended by the blue humour.
However, the tradition has continued and there are many bawdy mnemonics that help modern students of the nervous system learn the names and functions of the cranial nerves.
Link to PubMed entry for hemispheric fantasy study.
KQED Quest has another excellent online feature where they discuss the curious effect where some patients with fronto-temporal dementia, a form of degenerative brain disease, suddenly have burst of creative talent creating some stunning and original works.
The videos were taken at UCSF over the course of many hours doctors spent studying Keith and his symptoms. In them, we glimpse of two of Keith’s FTD-caused obsessions: joke telling and music. (We also see one of the first symptoms to have emerged: his Jerry Garcia hairdo.)
At first glance, Keith’s behavior might strike you as more eccentric than brain-damaged, which is precisely why FTD can take so long to diagnose. If you’re a doctor with a 15-minute appointment slot, frontotemporal dementia might just look like a midlife crisis...
FTD can turn Democrats into Republicans, and vice versa. People with no interest in art begin to paint obsessively. As the neurons in Keith’s right frontotemporal lobe (just behind the right eyebrow) died, his taste in music, his sense of humor, his relationships with his family members and friends changed completely. Our self, in other words, may owe much more to the way our brains are built than we’d care to acknowledge.
It's probably worth making clear that this is quite a rare effect. Most people with FTD will not become artistically inspired.
More common effects are problems with inhibiting behaviour sometimes leading to problems with appropriate social interaction (largely owing to frontal lobe damage) and difficulties with language and meaning (largely owing to the problems with the temporal lobes).
But because dementia trends to affect the brain in a progressive but patchy way, it can sometimes result quite unusual or surprising symptoms.
The Quest programme is a radio show, a video of Keith Jordan - a patient affected by FTD, and a narrated photo essay.
Another great production from Quest, who we featured recently because of their similarly high-quality programme on the curious pseudobulbar affect.
If you're interested in more information on the release of artistic talents after FTD, we featured a fantastic New York Timesarticle on the same topic which makes a great complement to the Quest programme.
Link to Quest radio programme. Link to Quest video section. Link to Quest narrated photo essay.
A 48-year-old woman with a stimulating electrode implanted in her right ventral thalamus started to compulsively self-stimulate when she discovered that it could produce erotic sensations.
This is a report from the early days of deep brain stimulation, way back in 1986, from an article for the medical journal Pain which discussed some unintended side-effects from one patient's DBS treatment for chronic pain.
Soon after insertion of the nVPL electrode, the patient noted that stimulation also produced erotic sensations. This pleasurable response was heightened by continuous stimulation at 75% maximal amplitude, frequently augmented by short bursts at maximal amplitude. Though sexual arousal was prominent, no orgasm occurred with these brief increases in stimulation intensity. Despite several episodes of paroxysmal atrial tachycardia [heart disturbance] and development of adverse behavioural and neurological symptoms during maximal stimulation, compulsive use of the stimulator developed.
At its most frequent, the patient self-stimulated throughout the day, neglecting personal hygiene and family commitments. A chronic ulceration developed at the tip of the finger used to adjust the amplitude dial and she frequently tampered with the device in an effort to increase the stimulation amplitude. At times, she implored her to limit her access to the stimulator, each time demanding its return after a short hiatus. During the past two years, compulsive use has become associated with frequent attacks of anxiety, depersonalization, periods of psychogenic polydipsia and virtually complete inactivity.
Similar cases are still being reported today. A 2005 case report described a gentleman who had a DBS electrode inserted into the right subthalamic nucleus to treat the symptoms of Parkinson's disease. He found that switching the device on and off produced a 'morphine like' sensation that he became quite fond of.
This effect was first discovered in humans in the early 1960s, when controversial psychiatrist Robert Heath reported on two cases of people with a number of electrodes implanted in the brain, including some in similar areas to the patients mentioned above.
In 1972, he undertook a notorious study where he implanted electrodes into the brain of a consenting 24-year-old gay male who had been repeatedly hospitalized for chronic suicidal depression and found to have temporal lobe epilepsy.
The brain implant was specifically introduced for non-sexual reasons but Heath decided to test whether pleasurable brain stimulation would encourage the man, known only as B-19, to engage in heterosexual sexual activity with a prostitute.
The study was a 'success' but has become infamous as one of the more distasteful episodes in the history of 'gay conversion therapy', which is quite hard going in a field that is well-known for its distasteful episodes.
Heath was apparently funded by the CIA as part of their abortive research programme into 'mind control' techniques, but I can't find any reliable reference for that, so it might need to be taken with a pinch of salt.
Link to paper 'Chronic Thalamic Self-Stimulation'. Link to PubMed entry for paper. Link to Heath 'gay brain stimulation' study. Link to doi link for same.
ABC Radio National's All in the Mind recently broadcast a gripping programme on patients in the coma-like persistent vegetative state (PVS) and how new brain imaging techniques might be able to identify people who are conscious but unable to communicate with the outside world.
The programme talks to neuropsychologist Adrian Owen, whose work we've featured previously on Mind Hacks, who conducted a brain imaging study on a 23-year-old woman in PVS suggested that she could understand what was being said to her.
The neuroimaging team asked her to practice mental tasks when and could pick up and distinguish the related brain activity using an fMRI scanner.
The programme discusses Owen and colleagues research, including a peak at some ongoing studies to try and turn this into a method of communication, and debates the ethics of dealing with patients who are effectively unresponsive to the world.
It's also got some striking excerpts from a Kate Cole-Adams' novelWalking to the Moon about a woman who emerges from coma. If you want to hear more, another ABC show interviewed Cole-Adams and discussed the book.
Link to AITM on 'Beyond coma'. Link to Life Matters on 'Walking to the Moon'.
Lawrence of Arabia is dead, long live the crash helmet:
I just found this fascinating article from a 2002 edition of Neurosurgery that tells how a brain surgeon who unsuccesfully operated on Lawrence of Arabia after his fatal motorcyle crash was inspired to research and design crash helmets that now save thousands of lives.
T.E. Lawrence, better known as Lawrence of Arabia, was a hero of the First World War who worked as a covert agent leading a revolt against the Ottoman Empire in the Middle East and was immortalised in the 1962 film.
Lawrence was also a fan of motorbikes. In fact, he's pictured on one in the image on the left. Sadly, his interest eventually led to his death after a motorcycle crash in Dorset.
The Neurosurgery article tells the story of Hugh Cairns, a young neurosurgeon who attempted unsuccessfully to save Lawrence's life as part of the surgical team who treated him.
His experience led him to research the benefits of early crash helmets on Army motorcycle riders during the Second World War, finding that they were one of the major life-saving factors.
He later went on to use his knowledge of how the brain becomes damaged during impact to design and test various types of crash helmet that could best protect against these forms of injury.
Cairns' work was a major influence on both the legal system, that has mandated helmets in many countries, and the design of the headgear itself - preventing thousands of fatal brain injuries in the process.
Link to article on Lawrence, Cairns and the origin of crash helmets. Link to PubMed entry for article.
The Boston Globe has an interesting piece on daydreaming, touching on the link between daydreaming and creativity and discussing the possibly brain networks that might support our pleasant mental wanderings.
The article discusses some of the recent work on the default brain network and how this might be related to daydreaming:
Every time we slip effortlessly into a daydream, a distinct pattern of brain areas is activated, which is known as the default network. Studies show that this network is most engaged when people are performing tasks that require little conscious attention, such as routine driving on the highway or reading a tedious text. Although such mental trances are often seen as a sign of lethargy - we are staring haplessly into space - the cortex is actually very active during this default state, as numerous brain regions interact. Instead of responding to the outside world, the brain starts to contemplate its internal landscape. This is when new and creative connections are made between seemingly unrelated ideas.
"When you don't use a muscle, that muscle really isn't doing much of anything," says Dr. Marcus Raichle, a neurologist and radiologist at Washington University who was one of the first scientists to locate the default network in the brain. "But when your brain is supposedly doing nothing and daydreaming, it's really doing a tremendous amount. We call it the 'resting state,' but the brain isn't resting at all."
It's worth bearing in mind that the connection between this network and daydreaming is only one theory, and other researchers think of it quite differently.
The 'default network' was suggested owing to measurements of how the brain uses energy at rest, and when brain imaging researchers noted that certain parts of the brain (mainly midline areas) were more active when participants didn't seem to be doing very much but showed reduced activity when we participants were most engaged in attention-demanding tasks.
Neurologist Marcus Raichle has been most vocal in proposing that the network is linked to what we might broadly call daydreaming, mostly notably on the basis of a study that found that default network activity was related to what they called 'stimulus independent thought'.
They determined this by training people on a memory task until they could do it so easily their minds wandered. They then put people in a scanner, compared brain activation in this condition to brain activation with a similar memory task but where the material was new, so they had to concentrate and weren't able to think about other stuff.
They found that the practised condition was associated with activity in a default network, and, therefore, they linked it to daydreaming.
The trouble is, is that they only confirmed that participants were doing more off topic thinking, not what they were thinking about.
We might think of daydreaming as having thoughts about being the lead singer of an all-girl skiffle band, fighting a dragon if it happened to burst through the lab door, or screwing the research assistant who took us through the consent form, but it could be that the participants were just focused on the other stuff that was happening around them at the time.
Like the horrendous noise of the fMRI scanner, as some commentators suggested. Or perhaps, they were just being more aware of their wider environment.
And in fact, one theory suggests that the default network is not concerned with daydreaming, but maintains a background level of watchful attention to detect potentially dangerous external events (real dragons, for example), or perhaps processes memories - essentially doing our mental filekeeping.
One big problem with this area, is that it attempts to study a network which is supposedly most active when when not doing deliberate mental tasks, by extrapolating from data that involves the participants doing deliberate mental tasks.
This makes it difficult to tie it specifically to daydreaming, which is a subjective mental state that has a tendency of dancing away whenever we try and catch it.
Wikipedia has a short but fascinating page listing animals by the number of neurons they have. There's only about a dozen entries on there, but most interesting is that there is an animal with no nerve cells at all.
It's called Trichoplax and apparently is a "a simple balloon-like marine animal with a body cavity filled with pressurized fluid".
Apparently humans don't come top of the pile, as both elephants and whales have more neurons.
However, it's not the best referenced article in the world, to say the least, so I'm taking this last claim with a pinch of salt for the time being.
If you know better, do update the article with some more reliable sources.
The BBC has just begun broadcasting a fantastic series called Blood and Guts on the history of surgery with the first episode on neurosurgery. If you live in the UK you can watch it again on the BBC iPlayer for a few days more, or otherwise, it has appeared online as a torrent.
It's not the most coherent trip through the history of neurosurgery, more a collection of highlights (or, in some cases, lowlights), but it's very well made and has some fantastic historical footage and interviews with modern neurosurgeons.
It covers Harvey Cushing, Phineas Gage, José Delgado, Walter Freeman and the frontal lobotomy, transcranial magnetic stimulation, deep brain stimulation and the cutting edge of brain surgery today. There's a particularly interesting bit where lobotomy survivor Howard Dully has a brain scan and you can see the effect of his operation.
If you're still hungry for more, BBC News website has an article and video clip of neurosurgery while the patient is conscious, and you can even buy the book of the series.
Link to BBC iPlayer archive (for 7 days). Link to torrent of Blood and Guts brain surgery episode.
Wired Sciencecovers a recent US military report on military threats from the latest developments in neuroscience as well as how brain research could be 'weaponised' to enhance soldiers' capabilities or disable enemy fighters.
It's a bit difficult to judge the quality of the report, as unlike the recent in-depth report from the JASON Pentagon advisory panel, they're charging people to download it.
From the Wired summary, it seems to cover similar ground although is perhaps a little more wide-ranging and focuses on policy and foresight rather than the nuts and bolts of brain science.
It apparently covers four main areas: mind reading; cognitive enhancement; mind control and brain-machine interfaces. As you can probably tell from the list, there's likely to be a fair amount of speculation going on there.
It's also interesting that the US military are really promoting their 'military neuroscience' angle, which is not to say that it is not a research priority. Whole wings of military research are now devoted to 'human research', as illustrated by the extensive science portfolio of the US Army's Research Lab.
Nevertheless, the discussions about drug-based enhancements have so far been largely reiterating what soldiers have already done for millennia - using drugs to reduce fatigue, increase confidence and cope with trauma.
Drugs have been used for soldiering as long as there have been wars and the low-tech still prevails - from the use of coca leaves by Inca warriors to the use of the khat by modern-day Sudanese militias.
If anyone does happen to stumble across an unrestricted copy of the report online, do let me know as it'd be great to be able to link to the original.
Link to Wired Science article 'Uncle Sam Wants Your Brain'. Link to online shop for report.
I've uploaded a fascinating video clip where a TV presenter is intravenously injected with the active ingredients of cannabis as part of the BBC documentary Should I Smoke Dope?
It's part of an experiment to compare the effects of intravenous THC and cannabidiol combined, with intravenous THC on its own. The mix of both gives the presenter a pleasant giggly high while THC on its own causes her to become desolate and paranoid.
Both are these are known to be key psychoactive ingredients in cannabis but the video is interesting as it is a reflection of the fact that THC has been most linked to an increased risk of developing psychosis while cannabidiol seems to have an antipsychotic effect.
As we discussed earlier this year, one study found that cannabis smokers who had higher levels of cannabidiol in hair samples had the lowest levels of psychosis-like experiences.
Another study we covered reported that, at least in the UK, 'skunk' has virtually no cannabidiol, while hash, although variable, was more likely to contain high cannabidiol levels.
And if you're after a more balanced view on the link between cannabis and psychosis than you normally get in the media, I've also uploaded a clip from the same programme where psychiatrist and leading cannabis researcher Robin Murray discusses the findings from the latest research.
If you want to check out the whole documentary, where BBC reporter Nicky Taylor gets stoned for 30 days in a row while investigating the science, culture and legal status of cannabis, it's available as a torrent or in six parts on YouTube (1, 2, 3, 4, 5, 6).
Link to video of IV cannabidiol and THC experiment. Link to video of psychiatrist Robin Murray on cannabis and psychosis.
Cannabalism gave Western medicine its first understanding of prion diseases as an epidemic of the neurological disorder swept the South Fore tribe in Papua New Guinea. Neurophilosophy has written a remarkably lucid article on the history and neuroscience of how prion diseases, of which 'mad cow disease' is one, affect the brain.
The piece starts with some archive footage of a tribe member with the devastating disorder and continues to describe how this class of diseases are probably caused by misfolded proteins that can trigger the same misfolding in other proteins leading to a chain reaction of neural damage.
The Fore tribe had a tradition of ritually consuming the brain and body of deceased relatives, which likely lead to the outbreak.
The word kuru means "shaking death" in the Fore language, and describes the characteristic symptoms of the disease. Because it affects mainly the cerebellum, a part of the brain involved in the co-ordination of movement, the first symptoms to manifest themselves in those infected with the disease would typically be an unsteady gait and tremors. As the disease progresses, victims become unable to stand or eat, and eventually die between 6-12 months after the symptoms first appear.
Kuru belongs to a class of progressive neurodegenerative diseases called the transmissible spongiform encephalopathies (TSEs), which also includes variant Creutzfeldt-Jakob Disease (vCJD) and bovine spongiform encephalopathy (BSE, more popularly known as "Mad Cow Disease"). TSEs are fatal and infectious; in humans, they are relatively rare, and can arise sporadically, by infection, or because of genetic mutations. They are unusual in that the infectious agent which transmits the diseases is believed to a misfolded protein. (Hence, the TSEs are also referred to as the prion diseases, "prion" being a shortened form of the term "proteinaceous infectious particle").
Prion diseases are a complicated area and you probably won't find a better written introduction that captures both the science and the intrigue of these relatively new disorders.
Link to article 'Cannibalism and the shaking death'.
The best is yet to come: reward prediction in the brain:
Jonah Lehrer has written an excellent piece for the latest issue of Seed Magazine on the work of neuroscientist Read Montague who's been discovering the essential function of dopamine in predicting rewards.
Reward prediction is the process where dopamine neurons fire when a reward is expected and also seem to code the amount of error between the prediction and what actually happens. Importantly, the process seems to be accurately described by an algorithm that was already used in computer science.
This has been an area of intense interest over the last decade as it ties together neurobiology, learning, motivation, mathematics and can be demonstrated in a variety of simple lab-based tasks. The fact that dopamine has been linked to numerous disorders in the past makes it a popular paradigm in which to understand psychiatric symptoms.
The Seed article looks at the work of Read Montague who has been studying the process and has been using ingenious methods to look at the role of this system in social reasoning.
In recent years Montague has shown how this basic computational mechanism is a fundamental feature of the human mind. Consider a paper on the neural foundations of trust, recently published in Science. The experiment was born out of Montague’s frustration with the limitations of conventional fMRI. “The most unrealistic element [of fMRI experiments] is that we could only study the brain by itself,” Montague says. “But when are brains ever by themselves?” And so Montague pioneered a technique known as hyper-scanning, allowing subjects in different fMRI machines to interact in real time. His experiment revolved around a simple economic game in which getting the maximum reward required the strangers to trust one another. However, if one of the players grew especially selfish, he or she could always steal from the pot and erase the tenuous bond of trust. By monitoring the players’ brains, Montague was able to predict whether or not someone would steal money several seconds before the theft actually occurred. The secret was a cortical area known as the caudate nucleus, which closely tracked the payouts from the other player. Montague noticed that whenever the caudate exhibited reduced activity, trust tended to break down.
One thing I notice a little of in the quotes from Montague, which is incredibly common in discussion of dopamine and reward, is a kind of 'reward system dogma'.
Reward is usually linked to the function of the striatum and nucleus accumbens and the dogma goes something like this: "no matter what is happening when the nucleus accumbens or striatum is activated, something about the activity is rewarding".
I was interesting to read a recent study comparing brain activation in people with 'normal' and 'complicated' (i.e. extreme) grief in response to viewing pictures of their deceased relative.
The study found additional nucleus accumbens activation in people with complicated grief and suggested that this reflects the fact they find the thoughts of them more rewarding. This is despite the fact that the nucleus accumbens has also been found to also represent salience - i.e. how likely something is to grab our attention.
It's probably also worth mentioning that there may be some serious problems with the elegant reward prediction theory of dopamine which are were outline in a 2006 paper in Nature Reviews Neuroscience and summarised by the excellent Developing Intelligence.
The Seed is generally an excellent read though and covers an important finding and some innovative new ideas. I especially like the fMRI machines linked in parallel, like multi-player arcade machines.
Neurology journal Brain has just published an elegant open-access study on how just six weeks of mental imagery training can help reduce phantom limb pain as well as reorganising the sensory and motor maps in the brain.
Phantom limbs are when amputees feel sensations that seem to be coming from the missing limb. Sometimes this can include pain which can either be constant or transitory.
Sensations from the nonexistent limb are thought to be due to the brain reorganising the areas which represent the body.
In the case of a phantom arm, for example, the area is no longer receiving sensations from the limb and so stops being so carefully defined. Areas serving other body areas (like the face) start to creep in and facial stimulation can be felt in the missing arm due to the fuzzy neurological boundaries.
This new study, led by neuroscientist Kate McIver, decided to test whether mental imagery can help keep these areas active and prevent the fuzziness creeping in, potentially reducing the phantom pain.
This is based on extensive research to show that imagining something activates similar brain areas to actually perceiving the sensation or executing the action. For example, imagining the sensation of a cool breeze across your arm actually increases activity in the brain areas responsible for arm sensations, while imaging picking something up activates arm-related motor areas.
The research team asked participants to rate their phantom limb pain and used fMRI to look at which brain areas were most active during some movement-related tasks. While in the scanner, the participants were asked to imagine actions with either the existing or phantom hand, to move the existing hand or were asked to purse (push together) their lips.
This last action tends to activate what was previously the hand area in the brain in people with phantom limbs, but doesn't in people with intact limbs. Indeed, this is exactly what the initial brain scans reported, indicating that their brains had reorganised sensory boundaries.
The researchers then invited each participant for six weekly sessions that involved a mental 'body scan' technique that involved imagining free and comfortable movement in their phantom limb such as they could "stretch away the pain" and "allow the fingers, hand and arm to rest in a comfortable position". Participants also practised in their own time.
After six weeks, pain ratings were taken again and the brain scanning was re-run. The painful sensations had significantly reduced and lip pursing no longer activated the hand area.
The mental imagery seemed to have 'simulated' arm actions and sensations well enough so that the neurological boundaries remained sharp and cross-area fuzziness didn't encourage phantom pain.
Link to full text article in Brain. Link to PubMed entry.
Juggling can change brain structure within 7 days:
A new study just published in PLoS One reports that learning to juggle alters the structure of motion detection areas in the brain within as little as 7 days.
Led by neuroscientist Joenna Driemeyer, the study builds on a previous research that also found juggling could alter brain structure, although this previous study waited three months before the brain was checked for alterations using high resolution structural MRI scans.
This new study also took 20 non-jugglers and asked them to learn to juggle, but scanned them after 7, 14 and 35 days.
After only 7 days, a motion specialised part of the occipital lobe known as V5 had increased in density. In both studies, the changes were maintained over the subsequent weeks of practice, but these areas returned to their pre-learning state after several weeks without juggling.
This is an interesting example of rapid 'neuroplasticity', the ability of the brain to adapt structurally to new situations.
However, the authors are careful to note that they can't tell whether the brains of the participants had generated more neurons, or whether existing cells grew in size, or additional glial cells were developed, or maybe there were just changes in how much blood or other brain fluids packed the area.
Also, the fact that changes seemed to occur at the beginning of the learning cycle but that further practice maintained but didn't cause additional changes led the researchers to speculate that learning a variety of new things, rather than simply practising old skills, may be most effective in terms of brain structure alterations.
Link to 'Changes in Gray Matter Induced by Learning — Revisited'. Link to PubMed entry for paper.
Full disclosure: I'm an unpaid member of the PLoS One editorial board.
Scientific American has an article on migraines that takes a comprehensive look at the science of this painful and hallucinatory disorder.
The piece updates the science on migraines from the traditional but oversimplified 'constricted blood vessels' explanation to explore the interplay between nerves, neurotransmitters and lifestyle.
A crucial process seems to be cortical spreading depression that may be responsible, at least in part, for both the intense pain and the aura:
Aura appears to stem from cortical spreading depression—a kind of “brainstorm” anticipated as the cause of migraine in the writings of 19th-century physician Edward Lieving. Although biologist Aristides Leão first reported the phenomenon in animals in 1944, it was experimentally linked to migraine only recently. In more technical terms, cortical spreading depression is a wave of intense nerve cell activity that spreads through an unusually large swath of the cortex (the furrowed, outer layer of the brain), especially the areas that control vision. This hyperexcitable phase is followed by a wave of widespread, and relatively prolonged, neuronal inhibition. During this inhibitory phase, the neurons are in a state of “suspended animation,” during which they cannot be excited.
Neuronal activity is controlled by a carefully synchronized flow of sodium, potassium and calcium ions across the nerve cell membrane through channels and pumps. The pumps keep resting cells high in potassium and low in sodium and calcium. A neuron “fires,” releasing neurotransmitters, when the inward flow of sodium and calcium through opened channels depolarizes the membrane—that is, when the inside of the cell becomes positively charged relative to the outside. Normally, cells then briefly hyperpolarize: they become strongly negative on the inside relative to the outside by allowing potassium ions to rush out. Hyperpolarization closes the sodium and calcium channels and returns the neurons to their resting state soon after firing. But neurons can remain excessively hyperpolarized, or inhibited, for a long time following intense stimulations.
The article is remarkably comprehensive, probably as it's written by neurologists David Dodick and John Gargus.
Link to SciAm article 'Why Migraines Strike' (via 3Q).
Today's Nature has an excellent feature article on the heated scientific debates over why its so hard to link genes to specific mental illnesses.
Genetics is a complex business, but psychiatric genetics even more so, because it attempts to find links between two completely different levels of description.
Genes are defined on the neurobiological level, while psychiatric diagnoses are defined on the phenomenological level - in other words, verbal descriptions of behaviour, or verbal descriptions of what it is like to have certain mental states.
There is no guarantee, and in many people's opinion, probably no likelihood, that these 'what it is like' descriptions actually clearly demarcate distinct processes at the biological level.
It's a bit like classifying people as heavy metal fans if they have five or more heavy metal albums.
By definition, there's a biological difference between people who like heavy metal and those who don't, but it could be a whole number of distinct differences at the level of brain function which are all just recognised as 'being a heavy metal fan' in day-to-day life.
Actually, psychiatric diagnosis has an additional problem, in that for some diagnoses, the same classification can be made when the people don't share any symptoms. For example, two people could be classified as having schizophrenia / being a heavy metal fan, when they have no symptoms / albums in common.
Some psychiatric geneticists just argue that we don't have enough data yet, because it seems that when connecting genes to psychology each gene contributes very little and the effect is when the influence of many small effect genes add up and interact.
Others argue that we should look for effects on 'endophenotypes' - the cognitive building blocks of more complex mental life. So instead of trying to connect genes to a collection of 'what it is like' experiences, we look at how genes influence neuropsychological processes - such as the mechanisms in the prefrontal cortex that control attention.
Increasingly, some researchers are starting to suggest that the genetic results show that existing psychiatric classifications are invalid, and that we should rethink them as new data comes in.
One thing psychiatry has traditionally been very bad at though, is refining diagnoses on the basis of lab studies.
Definitions are often revised to make them statistically more reliable (i.e. so people can reliably agree what is and what isn't a particular diagnosis), but this is not the same as having something which is a good basis for scientific enquiry.
Unfortunately, psychiatry is (ironically) a bit too emotionally attached to the traditional diagnostic categories because diagnosis is such a core part of what psychiatrists do.
Anyway, the Nature piece is an excellent guide to the debate on whether we should be attempting to link genes to the neuropsychology of mental disorder.
Link to article 'Psychiatric genetics: The brains of the family'.
Wired has picked up on a US military report that warns of the threat posed by neuro-enhanced enemy soldiers, just released by the "Pentagon's most prestigious scientific advisory panel".
The full report is available online as a pdf file, and covers how pharmaceuticals and brain-computer interfaces could be used by enemies of the US to create hordes of sleep-resistant super-intelligent neurosoldiers who can kill at the speed of thought.
Obviously, I paraphrase, but it's interesting that the report is not your usual blue-sky speculation. It actually covers the science in considerable detail.
It also discusses cultural attitudes to cognitive and brain enhancements of various sorts, and how this might affect how and why they might be used.
Non-medical applications of the advances of neuroscience research and medical technology also pose the potential for use by adversaries. In this context, we must consider the possibility that uses that we would consider unacceptable could be developed or applied either by a state-adversary, or by less-easily identified terrorist groups. In the following, we consider first the issues of what types of human performance modification might alter a military balance, and how those issues can be evaluated. We then address two broad areas where there are significant, and highly publicized, advances in human performance modification. These are the areas of brain plasticity (permanently changing the function of an individual’s brain, either by training or by pharmaceuticals), and the area of brain-computer interface (augmenting normal performance via an external device directly linked to the nervous system).
In 1941, brain specialist Russell Brain published an article about the brain in the brain science journal Brain. Owing to Brain's extensive work on the brain, he later became editor of Brain. His work treating brain disorders and his editorship of Brain were some of the reasons he was made Baron Brain, in 1962.
Last year, Brain published a tribute to Brain's brain article in Brain, owing to its massive impact on our understanding of the brain.
A fantastic new study which looked at the 'connectedness' of the human brain has identified which aspects of the underlying network are the most important routes of communication.
The research was led by neuroscientist Patric Hagmann and combines brain imaging with network mathematics to not only visualise the brain's network but also to understand which are the most important hubs and connections.
The study used diffusion spectrum imaging or DSI to map out the white matter wiring of the brain in five healthy individuals.
It's a type of diffusion MRI that identifies water molecules and tracks how they move. In a glass of water, water molecules will move randomly, but when trapped inside nerve fibres, they move along the length of the fibre, allowing maps to be created from the average paths of the moving molecules.
The researchers then took the maps of fibres, as illustrated by the top image, divided the brain up into sections, and created a simplified network map, shown in the bottom image, which allowed them to mathematically test how connected the different areas were.
They used network theory, more typically used in social network analysis, which allows mathematical measures of network properties.
The researchers calculated which areas were the most connected to the rest of the network in terms of connections going directly in and out of the area, but also which areas were the most strategically important 'hubs'.
This meant the researchers could identify areas of the cortex that are the most highly connected and highly important, forming a structural core of the human brain.
You can see two of the maps on the right. The one in red illustrates which brain areas are the most highly connected. You can see it's the area at the top and back of the brain. As you can see better on the original image, its very centrally located, like a neural mohawk.
The image in blue on the right shows the network 'backbone', the information highways of the brain.
What's perhaps most interesting it that the most connected brain areas are many of those which are more active when we're at rest, compared to when we're engaged in a mental task that requires concentration and effort.
This has been dubbed the 'default network' in the scientific literature, and, rather annoyingly, the 'daydreaming network' by the popular press.
It's not entirely clear what the network is for, with some studies directly linked it to 'stimulus independent thought' (yes, daydreaming), while others more explicitly define it as internally focused, rather than externally focused thought and cognition.
Unfortunately, most cognitive neuroscience experiments work by measuring the effect of tasks on brain function, so a brain network which seems to be switched off by any sort of task is quite hard to study. A recent study found that even the noise of the brain scanner affects it.
Link to PLoS Biology article on brain connectivity. Link to write-up from The New York Times. Link to write-up from Neurophilosophy. Link to write-up from Science News.
Out of body experiences and grasping the ungraspable:
This week's ABC Radio National's All in the Minddiscusses what happens in the brain during out of body experiences, and why actions can be accurate even when our perceptions are not.
The first interview is with neurologist Olaf Blanke who discusses some of his recent compelling research, including a virtual reality experiment to induce out-of-body touch sensations in healthy participants and one with implanted brain electrodes to trigger full-blown out-of-body experiences in patients undergoing neurosurgery.
The second interview is with psychologist Melvyn Goodale, famous for his work on distinguishing the visual streams in the brain: the dorsal stream and the ventral stream.
Some of the most striking and important results from this work come from patients who have suffered damage to one or the other stream.
In the programme, Goodale talks about brain-injured patient DF, who can correctly and accurately grasp objects she cannot consciously 'see'. The opposite has been found in other patients, who can accurately see and describe objects they cannot accurately grasp.
This suggests that these two visual pathways, although complimentary, are specialised for different things, one for identifying objects, and the other for working out where they are and how to manipulate them.
The different function of the two pathways can also be demonstrated in healthy people as well.
You may recognise the visual illusion on the left, sometimes called the Titchener or Ebbinghaus illusion. The two circles in the middle are actually the same size, but look different due to their context.
Researchers have created a graspable version of the illusion by putting hoops on a flat surface.
When they've measured how people adjust their fingers to pick up the middle circles, they find that we don't over or underestimate the size. Our fingers are always perfectly adjusted to the actual size.
In other words, it seems that while our perception is fooled by the illusion, our actions aren't, showing how the specialisation of each visual stream can be seen in everyone.
There's now a minor cottage industry of research attempting to understand exactly what influences the effect.
UPDATE: "All in the Mind has been honoured with the Grand Award at 2008 New York Radio festivals for best entry across all categories, as well as a Gold World Medal in the Health / Medical category". - I'm sure it won't come as a surprise to most Mind Hacks readers but fantastic to have it recognised by the non-initiated!
Link to AITM on out-of-body experiences and other tricks of consciousness.
A scene from a thousand horror movies, retold in the medical literature, with an additional lesson about the correct use of cerebral perfusion and angiography in diagnosing the brain dead patient.
Presumably, learnt shortly after the doctors had stopped screaming.
I love the use of the phrase "the situation became confusing", just after the dead guy starts moving again.
Unusual movements, "spontaneous" breathing, and unclear cerebral vessels sonography in a brain-dead patient: a case report.
Bohatyrewicz R, Walecka A, Bohatyrewicz A, Zukowski M, Kepiński S, Marzec-Lewenstein E, Sawicki M, Kordowski J.
Transplant Proc. 2007 Nov;39(9):2707-8.
A patient with a brain injury fulfilled all clinical criteria for brainstem death diagnosis. Two standard sets of tests were performed; according to Polish regulations, the patient could be declared brain dead. However, shortly after the completion of the tests and before the final brain death declaration, 6 triggered "assisted" breaths/min were noticed. After careful analysis of the ventilator settings, it was concluded that low trigger sensitivity and airway pressure oscillations during heart contractions were the reasons.
Additionally, a few minutes later, spontaneous jerking movements of lower limbs and clonic movements of neck muscles secondary to painful stimuli were noticed. The situation became confusing; therefore, cerebral Doppler sonography was performed, showing circulatory arrest in both of the internal carotid, middle cerebral, and left vertebral arteries. The basilar artery was not visualized. Forward flow with increased pulsatility was recorded in extracranial and intracranial segments of the right vertebral artery. Cerebral circulatory arrest was still uncertain; therefore, the diagnostic procedures were completed with conventional cerebral angiography, which showed a lack of cerebral blood flow.
Finally, the patient was declared brain dead; kidneys and bones were harvested. Cardiogenic oscillations associated with incorrect low ventilator trigger settings may falsely suggest persistence of breathing efforts in a brain-dead patient. In the case of any unusual events during brain death diagnosis, cerebral perfusion tests should be performed with cerebral angiography as the "gold standard."
Over the last few months, the soul searching over the shortcomings of fMRI brain scanning has escaped the backrooms of imaging labs and has hit the mainstream.
Numerous articles in hard hitting publications have questioned some common assumptions behind the technology, suggesting a backlash against the bright lights of brain scanning is in full swing.
There are two strands to this debate, and both stem from the fact that the technology and conceptual issues of brain imaging are incredibly complex.
To fully understand what happens during a brain imaging experiment you need to be able to grasp quantum physics at one end, to philosophy of mind at the other, while travelling through a sea of statistics, neurophysiology and psychology. Needless to say, very few, if any scientists can do this on their own.
So the first strand involves how brain imaging experiments are reported in the media. Under the sheer weight of conceptual strain, journalists panic, and do this: "Brain's adventure centre located".
It's a story published this morning on the BBC News website based on an interesting fMRI study looking at brain activity associated with participants choosing a novel option in a simple gambling task. But out of the four words of the headline, only the first is accurate.
And this leads to the second strand of the debate, which, until recently, has been largely conducted away from the media's gaze, amongst the people doing cognitive science themselves.
It starts with this simple question: what is fMRI measuring?
When we talk about imaging experiments, we usually say it measures 'brain activity', but you may be surprised to know that no-one's really sure what this actually means.
Neuroscientist Nikos Logothetispublished an important paper in Nature a couple of weeks ago explaining exactly what we know so far about the link between what brain scans measure and what the brain is actually doing.
It's very wide-ranging and includes lots of grit-your-teeth hardcore neurophysiology, but is, I think, essential reading if you're neuroscientifically inclined.
It focuses on BOLD, the signal that reflects the ratio of oxygenated and deoxygenated blood measured by fMRI, and the fact that it can be altered by a huge range of different biological process and neural firing patterns.
One of the main points of the paper is that the brain is not simply an array of tiny localised processors, but it is more like an an ecosystem of communication.
Activity can result from sending more signals, trying to send less, or, from what seems to be particularly important - maintaining a balance of excitation and inhibition.
Furthermore, it seems that a great deal of neural activity is not from neurons that might be directly involved in a task, but from 'neuromodulation' - general processes of management and coordination, often linked to attention. This can wax and wane, can spread like ripples and can occur in all sorts of non-linear ways that makes interpretation difficult.
What this means is that brain imaging experiments need to be carefully designed to control for these effects, but this entirely depends on our understanding of the effects themselves.
In other words, our understanding of what brain scanning data tells us evolves over time. A study conducted ten years ago might mean something different now.
An article in Science, published in the same week as Logothetis' paper, reports on new statistical methods for interpreting imaging data, a different issue again.
The latest edition of The New Atlantis has an article that attempts to come to grips with some of the philosophical aspects of brain imaging experiments, in terms of the conceptual limits in inferring mental states from biological changes.
I have to say, it's a bit miscued in places, assuming that brain imaging relies on ideas about brain modularity (which it doesn't) and seemingly confusing it with the notion of pure insertion, and suggesting some rather strange notions about mental causation, but it has many good points and is worth a read.
It's important that these sorts of issues come to light, because it hopefully heralds a time of increased caution in our interpretation of brain scans - and that goes for scientists, the media and the general public.
This is essential, because this data is starting to be used, literally, in life or death decisions.
The same issue of The New Atlantis has an article on neuroimaging that discusses the ethical dilemmas in applying this imperfect technology to legal decisions concerning capital punishment.
Link to Logothetis on 'What we can do and what we cannot do with fMRI'. Link to Science article 'Growing pains for fMRI'. Link to New Atlantis on 'The Limits of Neuro-Talk'. Link to New Atlantis on Neuroimaging and Capital Punishment.
Michael Gazzaniga, one of the founding fathers of cognitive neuroscience and a pioneer of 'split brain' research, is interviewed on this week's ABC All in the Mind where he talks about the use and abuse of 'left brain - right brain' metaphors and how our understanding of free will is impacting on the law.
Gazzaniga was a student of Roger Sperry, who won a Nobel prize for his work on 'split-brain patients', people who had the two cortical hemispheres of the brain functional separated by neurosurgery to cut the corpus callosum in an attempt to treat otherwise untreatable epilepsy.
One of the amazing things was that while the people didn't feel any different, it was easy to demonstrate that the each hemisphere processed things in quite different ways and each was, to a certain extent, independently conscious.
The interview discusses some of this early research, and asks how much of the popular 'left brain - right brain' rhetoric that gets thrown around actually stands up to scientific scrutiny. I think you can guess, but it's good hearing it from the man himself.
Gazzaniga also talks about one of his other interests - neuroethics, and particularly the effect that a neuroscientific understanding of free will is having on our concepts of legal responsibility.
I was interested to read that US judges can now take courses in neuroscience to help them makes sense of the sometimes counter-intuitive findings in cognitive science.
As it happens, Gazzaniga's new bookHuman: The Science Behind What Makes Us Unique is published today. If you want a taster an Edgearticle by Gazzaniga from a few months ago seems to be taken from it.
The AITM Blog also has some bonus audio of Gazzaniga discussing his experience of being on George Bush's bioethics council when the President was vetoing stem cell cloning.
The New York Timescovers new research which has found significant cross-species variation in the structure of the synapse - the chemical 'connection points' that allow neurons to communicate.
The study itself has been published in Nature Neuroscience and the full text is available online for those who want the in-depth science.
A whole new dimension of evolutionary complexity has now emerged from a cross-species study led by Dr. Seth Grant at the Sanger Institute in England.
Dr. Grant looked at the interconnections between neurons, known as synapses, which until now have been regarded as a standard feature of neurons.
But in fact the synapses get considerably more complex going up the evolutionary scale, Dr. Grant and colleagues reported online Sunday in Nature Neuroscience. In worms and flies, the synapses mediate simple forms of learning, but in higher animals they are built from a much richer array of protein components and conduct complex learning and pattern recognition, Dr. Grant said.
The finding may open a new window into how the brain operates. “One of the biggest questions in neuroscience is to answer what are the design principles by which the human brain is constructed, and this is one of those principles,” Dr. Grant said.
The paper itself doesn't mention the issue, but I wander what implications this might have for the generalisation of animal experiments to humans.
The majority of cellular-level neuroscience research is done on animal tissue. While some of this focuses on the molecular level, where differences in the structure of, let's say, ion channels, would be easily apparent in comparison to humans, some studies simply look at the 'synapse' as the smallest functional unit.
In fact, a considerable amount of neuroscience research is done on the 1mm long microscopic worm C. elegans and the fruit fly, drosophila. This new research suggests that neuroscientists may need to be additionally cautious when assuming that the findings relate to general laws that might apply in humans.
UPDATE:Neurophilosophy has a great write-up of this study, which discusses it in more detail.
Link to NYT article 'Brainpower May Lie in Complexity of Synapses'. Link to PubMed entry for scientific paper. Link to full text.
New York Magazine has a wonderful article on the culture, controversies and pharmacology of caffeine - the world's most popular psychoactive drug.
Ranging from the recent upturn in coffee's popularity and its inevitable effect on our caffeine consumption to the science of its neurological effects, the article manages to capture some of the key debates about the tremor inducing buzz substance.
One particularly interesting part touches on research that suggests that, like the effect of nicotine, the lift for regular users may be nothing more than withdrawal symptoms being soothed to bring us back to baseline.
That all said, what if the uptick in energy, alertness, and smarts we feel after drinking a cup of coffee isn’t a real uptick at all? What if it’s an illusion? A group of cutting-edge caffeine researchers believes that might be the case...
When Griffiths and Juliano teamed up to review 170 years of caffeine research, much of which confirmed the drug’s reputation as a brain booster, they noticed a pattern: Most studies had been done on caffeine users who, in the interest of scientific rigor, were deprived of the stimulant overnight. Because caffeine withdrawal can commence in just twelve hours, by the time each study’s jonesing test subjects were given either caffeine or a placebo, they had begun to suffer headaches and fatigue.
For the half that received the stimulant—poof!—their withdrawal symptoms vanished. The other half remained uncaffeinated, crabby, and logy, and guess which group scored higher on cognitive tests time after time? The boost the test subjects who got the caffeine felt may have simply been a function of having been deprived of the drug.
Link to 'The Coffee Junkie’s Guide to Caffeine Addiction'.
Fantastic introduction to MRI brain scanning physics:
Magnetic resonance imaging is the most popular method for scanning the brain both for research and for clinical investigations. I've just found a wonderfully written article that gives a great introduction to the physics of how MRI scanners work.
It is both clearly written for the non-specialist and fantastically complete. This is a rare and valuable combination.
There are some other guides to MRI physics which are also wonderfully written but most lack the sufficient detail that would bring you up to 'entry level' in the field.
For example, How Stuff Work'sguide to MRI is a great place to start, but it won't tell you about why and how T1 and T2 imaging are different, or any of the other things you need to know to understand the fundamentals of MRI technology.
You don't need to know maths to understand the article (the downfall of most 'introductory' guides to MRI) and the author uses wonderfully clear analogies throughout.
The article is written by radiologist Robert Pooley, who should give himself a pat on the back for such a great job. It was published as an open-access paper in the journal RadioGraphics. Perfection!
Link to article 'Fundamental Physics of MR Imaging'.
In light of research showing that an ingredient in cannabis, cannabidiol, seems to actually reduce the risk of psychosis, I speculated previously on Mind Hacks whether smokers might be attracted to high-cannabidiol dope.
A study of UK street cannabis published in the Journal of Forensic Sciences suggests that cannabis resin (hashish) has the average highest rates of cannabidiol, while 'skunk' and imported herbal cannabis (weed) have the lowest.
For people who take cannabis, it's not the cannabidiol that makes you 'high', it's mainly a substance called tetrahydrocannabinol or THC.
There's accumulating evidence that THC increases the risk of psychosis, while cannabidiol reduces it - so the ratio of the two substances in the street drug might give a 'risk profile' in terms of mental health.
'Might' is the operative word here, as the research is still preliminary and the studies are still largely correlational with regard to cannabidiol-to-THC ratio and psychosis-like symptoms.
However, if this does turn out to be case, the new survey of UK street cannabis suggests that, on average, cannabis resin has higher levels of cannabidiol, with the implication that this might be less risky in terms of developing schizophrenia or other psychotic disorders.
This finding is an average over all the samples, however, and the study also found that resin had quite a bit of variability with regards to cannabidiol-to-THC ratio.
However, imported herbal cannabis and skunk was generally very low in cannabidiol. Additionally, skunk also had about 6 times the THC content of normal weed, making it especially potent.
The study concludes:
This study suggests that cannabis in England in 2005 remains a very variable drug with unpredictable pharmacological and psychological activity. The potency (THC content) of the cannabis varies widely, as does the content of other cannabinoids, especially in herbal cannabis and cannabis resin. The average potency within the country appears to be increasing, but large variations remain within and between different areas of the country.
CBD affects the pharmacological qualities of THC and reduces it psychoactive potential. The relative proportions of THC and CBD in resin are wide ranging, supporting the view that the potential effects of resin cannot be judged by measuring the THC content alone. The resin samples were all similar in appearance and gave the user no indication of their cannabinoid content.
Of the three principle forms of cannabis, sinsemilla [skunk] commonly had the highest THC content and almost totally lacked CBD. Had CBD been present it would have reduced the psychoactive potential of this material. In addition to having increased in potency, sinsemilla also appears to have become the most widely used form of cannabis. The current trends in cannabis use suggest that those susceptible to the harmful psychological effects associated with THC are at ever greater risk. This is due to the combined rise in potency and popularity of sinsemilla and the absence of CBD in this product.
The lead scientist in the study is called Professor Potter. Do with that fact as you will.
Link to abstract of Journal of Forensic Sciences study.
Neurophilosophy has collected some of the most unusual cases of penetrating brain injury from the medical literature, with x-rays that illustrate how some of the most curious objects can end up on the wrong side of the bony brain protector.
You may recognise a couple that we've notedbefore on Mind Hacks, but this is a far more complete and frankly quite surprising collection.
The most amazing is the case of a "32-year-old Caucasian male with a history of repeated self-injury drilled a hole in his skull using a power tool and subsequently introduced intracerebrally a binding wire from a sketchpad".
A striking, and, in some places, stomach churning collection of case studies.
Link to Neurophilosophy on unusual penetrating brain injuries.
What makes a man a genius? Russian neuroscientists were pondering this exactly this question in the early 1900s and did exactly what seemed sensible at the time - they collected and dissected the brains of some of the greatest cultural figures in a huge collection called 'The Pantheon of Brains'.
It's a fascinating story told in a recent article published in the medical journal Brain. Amazingly, the last brain was only added in 1989.
Rather fittingly, the collection contains the brains of some of the Russia's greatest psychologists and neuroscientists and has many curious aspects to it, such as the mysterious death of its founder. After death, his brain was immediately added to the collection.
In 1927, Bekhterev came up with a plan to organize ‘The Pantheon of Brains’ in Leningrad in order to collect elite brains. It was a severe irony of fate that precisely when the question about creating the Pantheon had been positively solved, the very initiator of this creation, Bekhterev, suddenly passed away. The circumstances are still questionable.
On December 17, 1927, the First All-Union Congress of Neuropathologists and Psychiatrists was held in Moscow. Bekhterev, along with L. S. Minor and G. I. Rossolimo, was elected as honourable chairmen of the congress. On December 23rd, the last day of the congress, Bekhterev gave a presentation during the afternoon session. In the evening, symptoms of a gastrointestinal disorder started and 24 hs later, Bekhterev died of (as officially stated) acute heart failure. Without any further post-mortem pathoanatomical investigation, his brain was removed, in accordance with his will, and his body was cremated the next day. However, the idea did not fade away.
In 1928, the neuroanatomical laboratory of Vogt and his Russian colleagues were reorganized into the Moscow Brain Research Institute, where the structured collecting and mapping of the brains of famous Russians started. Bekhterev did not see his plan come to fruition, but his own brain enriched the collection of the Moscow Institute (the weight of his brain was 1720g). The collection acquired the brains of Soviet politicians, famous writers, poets, musicians, etc.
It is not surprising that these included the brains of prominent Russian neuroscientists, such as neurologist, G.I. Rossolimo (1860–1928) - 1543g; physiologist, I.P. Pavlov (1849–1936) - 1517g; neurologist, M. B. Kroll (1879–1939) - 1520g; psychiatrist, P. B. Gannushkin (1875–1933) - 1495g; psychologist, L.S. Vygotsky (1896–1934). During the Soviet period, the work of the Moscow Brain Research Institute continued behind closed doors.
The collection was still expanding as recently as 1989, when it acquired the brain of A.D. Sakharov [A. D. Sakharov (1921–89) was an eminent Soviet nuclear physicist, dissident and human rights activist. He was an advocate of civil liberties and reforms in the Soviet Union. He was awarded the Nobel Peace Prize in 1975] — 1440g.
You gotta love the fact that the authors have added exactly how much each person's brain weighed.
Sadly, the full text isn't available online, although Brain does fully release articles after a set amount of time (a year I think) so it should eventually see the light.
I've just noticed this review article that concisely reviews what we know about how the street drug ecstasy (MDMA) affects the function of the brain.
In terms of life-threatening physical damage, MDMA is a great deal safer than most other recreational drugs including alcohol and tobacco, but there is increasing evidence that it impacts on memory, and the effect seems to be related to dose.
In other words, the more ecstasy you take, the more likely memory problems will be worse.
The neuropsychology of ecstasy (MDMA) use: a quantitative review.
Hum Psychopharmacol. 2007 Oct;22(7):427-35.
Zakzanis KK, Campbell Z, Jovanovski D.
A growing number of empirical studies have found varying neuropsychological impairments associated with use of 3,4-methylenedioxymethamphetamine (MDMA) use. We set out to determine to what extent neuropsychological abilities are impaired in MDMA users. To do so, meta-analytical methods were used to determine the magnitude of neuropsychological impairment in MDMA users across pre-specified cognitive domains. We found that cognitive impairment secondary to recreational drug use may result in what might be described as small-to-medium effects across all cognitive domains with learning and memory being most impaired. We also found that total lifetime ingestion of MDMA appears to be negatively associated with performance on tasks ranging from attention and concentration to learning and memory. Implications and limitations of these findings are discussed.
Sadly, the full-text of the paper isn't freely available online, but the main punchlines are in the summary.
Wired magazine has just published a must-read article on the hyping of neuroimaging technology by companies wanting to sell brain scans on the deceptive premise that they can tell you something about your mood and personality, the effectiveness of adverts or whether you're being truthful.
Here at Mind Hacks, we've covered several highlights in the ongoing parade of brain scan powered bullshit in the past (FKF Applied Research I'm looking at you) but this new article, by psychiatrist Daniel Carlat, is an engaging guide that tackles many of these issues in one go.
Neuroimaging studies that measure brain function are almost always done on large numbers of people and the results are usually only reliable when average differences between groups are compared. This makes it difficult to make sensible judgements about any one individual.
Brain scanning is also often reported as if it is revealing exactly which parts of the brain do what, but it typically only reports associations.
For example, an experiment might find that fear is associated with amygdala activation. But it's impossible to say the reverse, that every time the amygdala is activated, the person is fearful.
Here's an analogy. On average, people from New York may be more impatient than people from other cities.
If you predicted that all people from New York were impatient on the basis of this, you'd be grossly mistaken so many times that it would make your prediction invalid.
In fact, taking the average attributes of populations and applying them to individuals is stereotyping, and we avoid it because it is so often wrong as to cause us to misjudge people.
Alternatively, if you met an impatient person and therefore concluded that they must live in New York, you'd be equally inaccurate.
But this is essentially what these commercial brain scan companies are doing, but they are selling it as if it is reliably telling us about an individual person or an individual product because people tend to be blinded by the fact it just seems more scientific. After all, it's neuroscience right?
Scientists and responsible clinicians will know about these shortcomings and make sure they don't oversell their findings, but commercial companies are not selling you the data, they're selling you a way of make you feel better about your insecurities, whether they be commercial concerns or health worries.
Interestingly, the Amen Clinic comes in for criticism which seems to specialise in pushing and overinterpreting SPECT scans to patients.
These guys were the subject of a similarly critical article in Salon the other week and were pulled up the the Neurocritic blog last year for suggesting political candidates should be brain scanned to see what sort of people they are.
If you want to be immune to this sort of nonsense, the Wired article looks at some of the current commercial offerings and how they're trying to sell you short.
Link to article 'Brain Scans as Mind Readers? Don't Believe the Hype'.
Scientific American Mind tackles the neuroscience of orgasm in a feature article which has just been released online.
One of the merits of the article is that it avoids the 'men are simple, women are complex' stereotype and presents results from scientific studies that suggest there are both subtle similarities and differences in sexual response.
One problem with the area of sexual neuroscience is that it largely relies on brain scanning studies in humans.
You'll see from the article that there's lots of speculation as to what the changes in orgasm-related brain activity mean. It's largely blue sky thinking though, because it's always difficult to decide what is happening in the mind from the activity of particular brain areas. Take these paragraphs for example:
But when a woman reached orgasm, something unexpected happened: much of her brain went silent. Some of the most muted neurons sat in the left lateral orbitofrontal cortex, which may govern self-control over basic desires such as sex. Decreased activity there, the researchers suggest, might correspond to a release of tension and inhibition. The scientists also saw a dip in excitation in the dorsomedial prefrontal cortex, which has an apparent role in moral reasoning and social judgment—a change that may be tied to a suspension of judgment and reflection.
Brain activity fell in the amygdala, too, suggesting a depression of vigilance similar to that seen in men, who generally showed far less deactivation in their brain during orgasm than their female counterparts did. “Fear and anxiety need to be avoided at all costs if a woman wishes to have an orgasm; we knew that, but now we can see it happening in the depths of the brain,” Holstege says. He went so far as to declare at the 2005 meeting of the European Society for Human Reproduction and Development: “At the moment of orgasm, women do not have any emotional feelings.”
It's like trying to guess what's happening in a city just by looking at changes in traffic flow. The upsurge in traffic on the high street could mean it's a busy shopping day, but it could also mean there's a carnival, or a riot, or funeral, or any other strange or unusual occurrence you might never have predicted.
Brain scanning just finds associations, but to find out whether an area is causally involved in a particular function, or whether it is necessary for the function, research with brain injured patients is one of the most powerful methods.
For example, if you think a brain area is necessary for orgasm, or a certain component of orgasm, a person with damage to that area should not experience what you've predicted.
We know that sexual problems are common after brain injury, but virtually no research has been done to see how damage to specific brain areas affects orgasm.
This would be important, both to help us understand the neuroscience of orgasm beyond general speculation, but also to begin to understand how we can help brain injured people regain satisfying sex lives.
Undercover genetics and the function of the brain:
Science News has an article on one of the most important future topics in neuroscience - epigenetics, the science of how information coded in the genes is used when the brain does its work.
Almost every cell in the body has a copy of the DNA, and therefore has the capability to express any protein.
But you wouldn't want proteins that are used for digesting food produced in the brain, so the body has various ways of regulating which proteins get expressed at any one time. This is epigenetics.
If DNA is like a blueprint, epigenetics is the committee of civil engineers that coordinate the construction site.
We've known from twin studies and molecular genetic research that genes and the environment both influence cognition and behaviour, but these studies only give statistical associations. What they don't tell us is how this happens.
In a sense, epigenetics is the scientific glue that allows us to understand how genes influence learning and behaviour, but also how learning and behaviour influences the expression of genes.
In other words, its goal is to explain how the environment combines with genetic information in the brain.
Needless to say, much epigenetic research is focusing on mental illness, the classic example of how genetic risk, experience and environment combine with sometimes disastrous consequences.
One of the most interesting aspects is that there is growing evidence that epigenetic information can be inherited. So your experiences may actually cause changes to gene regulation that are then passed on to offspring.
Link to Science New article on epigenetics. Link to abstract of good review article on epigenetics and cognition.
Neurophilosophy has a fascinating article on the recent archaeological discovery of numerous ancient Incan skulls of which over 1 in 6 showed signs of trepanation - an ancient form of brain surgery where a hole was drilled in the skull.
What's surprising is just how common it was. 66 skulls from Incan burial sites had a total of 109 trepanation holes. Some, like the one pictured, obviously needed a significant amount of skill and practice to complete.
And with this many examples, the archaeologists could make some fascinating inferences about the purpose and success of these operations:
Andrushko and Verano argue that the Incas performed trepanation primarily to treat head injuries incurred during battle, because the holes are most often found at the front of the skull to the left, consistent with injuries caused by a right-handed opponent during face-to-face combat, and because adult males are overrepresented in the sample. The procedure was evidently used to treat mastoiditis (an infection of the region of the temporal bone behind the ear) as well.
The authors also show that the success rate of the procedure improved with time, as the Inca empire progressed and made advances in medicine. The earliest specimens, dated to around 1,000 A.D., showed no signs of bone growth around the perforations, suggesting that the procedure was often fatal. But specimens dating to around 400 years later suggest a survival rate of around 90%.
Link to Neurophilosophy article on prehistoric Inca neurosurgery.
Phantom limbs are a well-known phenomenon where sensations and feelings are still experienced from a missing limb. In rare cases after brain injury, an additional phantom limb can appear - causing the sensation of a phantom third hand, arm or leg.
The drawings on the left are from two case studies of people with these 'supernumerary phantom limbs' recently published in the journal Neurology. They show an artist's impression of the body sensations of two patients who suffered brain stem strokes.
Both patients had the experience of having a third arm and a third leg, although the male patients had the leg 'appear' along the midline of the body, while the female patient seemed to experience it 'superimposed' upon an existing leg.
One distressing element for the female patient was that although the patient could 'move' the phantom arm voluntarily, "she described occasional loss of control and feeling strangulated by the phantom arm around the neck".
Two earlier case studies from neuropsychologist Peter Halligan and colleagues reported similarly disembodied extra limbs, but this time after damage to the right hemisphere of the brain.
As is more common after right hemisphere damage, these tended to have a delusional quality, so they weren't just sensations - the patients genuinely believe their additional limbs existed.
One gentleman believed that he had a third arm in the middle of his body, and another believed that he had a third hand.
In this last case, the patient reported actually 'seeing' the additional limb, similar to this case study of a gentleman who believed he had a third leg protruding from his left knee after suffering a stroke that affected the thalamus:
He consistently maintained that the phantom leg was attached to his knee with a "bone plate" that "had no flesh on it". However, he reported that the phantom limb itself looked normal and had a shinbone and a foot. It usually "appeared" in the morning when he was helped to put on his trousers. The patient stated that the phantom limb prevented him from turning over in bed, but did not adversely affect him otherwise.
When asked about how he knew about this leg he said that he could see it (despite his severe visual impairment) and feel it with his hand. He believed that the phantom limb belonged to him, although he readily accepted that it was not "normal" to have three legs. Initially he reported that the "leg" was growing from his own knee, but then reasoned that (given its size) he would have noticed it before the stroke.
At other times he believed the leg was attached to him by the nursing staff, but could not explain why. The patient was aware of phantom limb phenomena as his wife was an amputee. He was also aware that a stroke may affect perception and cognition. He did not believe either issue applied in his case.
The experience of a 'supernumerary phantom limb' is usually the result of a brain injury and typically resolves over time.
Phantom limbs are thought to arise because the somatosensory cortex, the part of the brain that represents the body's sensations and feelings, reorganises so that the area previously used to represent the limb is partially 're-used' for other functions, meaning the sensations sometimes get activated when these other functions are active.
Nevertheless, supernumerary phantom limbs are still mysterious, largely due to the small number of cases and diverse brain areas involved.
There is some suspicion that they might be caused because of disrupted communication between parietal lobes, which are known to represent body image, and the sensory feedback from the nerves in the body.
Link to abstract of Neurology case studies. Link to full text of 1993 case study. Link to full text of 1995 study.
I'm thoroughly digging the brain section of the Radiology Picture of the Day website. As you might expect, it's a wonderfully geeky place where radiologists post an image every day, often brain CTs or MRIs, with a little gem of wisdom with each one.
One of the most interesting is the pictured CT scan with a 'ring artefact'. I've contrast enhanced the image so you can see the circle or ring near the centre a little more clearly.
It's a known imaging problem caused by poor calibration of the scanner.
However, the Radiology Picture of the Day entry notes that these were given special significance by the quacktastic German physician Ryke Geerd Hamer who claimed that his 'New Medicine' could cure 98% of all cancers.
He gave these rings the rather immodest name 'Hamer Foci' and if they appeared in the brain, apparently this meant cancer was elsewhere in the body.
For Hamer, cancer was simply the body's reaction to a psychological conflict, and presumably this was what he thought the CT scanner was picking up.
This is despite the fact that CT scans only picture large scale structure on which psychological changes make no recognisable impact.
To coincide with stroke awareness month, a new report from the US Government's Center for Disease and Control and Prevention has highlighted that less than half of people surveyed could identify the potentially life-saving early warning signs of stroke.
A stroke, known medically as a cerebrovascular accident, is where the blood supply to the brain is interrupted because of blockage or damage to an essential blood vessel.
It can be fatal, and more often leads to significant brain damage, but this can be limited or a life potentially saved if it is detected and treated as soon as possible.
The following are warning signs of stroke. If someone you know experiences any of these, call an ambulance or get them medical care as soon as possible.
Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
Sudden confusion, trouble speaking or understanding
Sudden trouble seeing in one or both eyes
Sudden trouble walking, dizziness, loss of balance or coordination
Sudden, severe headache with no known cause
To reduce your chances of having a stroke, you need to look after your cardiovascular health.
Essentially, healthy body, healthy brain - so alcohol, smoking, excess fatty food, little exercise and head injury will increase the chances of blood supply problems in the brain.
Link to CDC report on stroke awareness. Link to write-up from Yahoo! News.
The Telegraph has an article and video on the Harvard 'baby brain lab' and some of its recent discoveries which are helping us understand how the mind and brain develops through the earliest months of life.
The research team is otherwise known as the Laboratory for Developmental Studies and is headed up by developmental psychologist Elizabeth Spelke who's interviewed on the video.
You would think babies are difficult to test with behavioural experiments because they are can't even stick to simple procedures, so developmental psychologists have created a task that takes advantage of the fact that infants stare at things when they're new or interesting, but get bored and stop looking at the things they've seen before.
Let's say you wanted to test whether newborn babies can tell the difference between familiar and unfamiliar people when they see their faces from different angles.
You show a picture of a person's face, facing directly forward, until the infant becomes bored and starts looking away.
Then you flash up two new pictures both taken at the same angle, one of the original person and one of a new person. You then measure how long the infant looks at each face.
Because infants look at new or different things for longer, they would spend more time looking at the unfamiliar face if they can genuinely tell the difference. If they both seem the same to the infant, they should look at both equally, on average.
In fact, this was a recent study done on 1 and 2-day old babies, and it turns out they can tell the difference between a familiar face and a new face when the change in viewing angle isn't too great.
Variations on this simple procedure have taught us a great deal about what babies can perceive, understand or expect, as well as how their brains function when they're doing these tasks.
What is often most surprising is what babies can do within their first few days or birth - such as recognise faces, as in the study above - but the debate about how much these sorts of skills are due to innate knowledge, or innate rapid learning mechanisms, are still raging:
Newborns have no idea what they look like, yet they enter the world equipped with a basic understand of what a face is. They know that the pink blob in the middle of a face is a tongue, and that they can poke out their own tiny tongue in just the same way. This was crucial ammunition for an intellectual war that still rages over whether we emerge from the womb as general-purpose learning machines that soak up details of our environments, or, as Spelke believes, born 'precocious', so we can immediately do things that are key to survival (just as newly-hatched chicks and fish can immediately do things such as navigate, or find and recognise food).
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Spelke has crossed swords with Professor Mark Johnson of Birkbeck's Centre for Brain and Cognitive Development in London, whose studies of infant brains stretch back nearly two decades. He points out that the four and six month olds at Spelkeland have hundreds of hours of experience in categorising the world, which challenges Spelke's 'core knowledge' theory. He believes that we enter the world with 'soft biases to attend to different aspects of the environment, and to learn about the world in particular ways'.
His colleague, Prof Annette Karmiloff-Smith, who once worked with Piaget, praises some of the Spelkeland work ('Liz has done some great behavioural experiments') but adds, 'Paradoxically, although she studies babies, in my view she doesn't raise questions about infants' capacity for learning, which may account for their extraordinary abilities without the need for them to be born with pre-specified knowledge.'
Link to article 'Harvard's baby brain research lab' (via 3QD). Link to video of Spelke interview.
This is an excerpt from quite possibly the geekiest forensic pathology article I have ever read. Three pathologists discuss the physics of how a Mexican coin ended up in the brain of a dead shooting victim.
They speculate he may have been holding it in his hand while shielding his head and the bullet impacted on the coin and both ended up deep in the brain. Oh, but with maths.
The images on the left are an artist's reconstruction of the position of the man when shot and the path of the bullet, and a photo of the coin in the dead man's brain.
Items that become accessory or secondary projectiles usually possess a minimal amount of energy, producing superficial or insignificant wounds. The secondary projectile in this case, a coin, gained sufficient kinetic energy to penetrate the scalp, skull, and brain. We believe the coin was being held by the decedent in his left hand next to his head at the time of the shooting. The bullet passed through the hand, producing the described injury and picking up the coin as a secondary projectile before entering the head.
The coin, a 1970 Mexican 50-centavo piece, was 25 mm in diameter with a weight of 6.4 g. In comparison, the diameter of a 1970 U.S. quarter dollar coin is 24.3 mm with a weight of 5.6 g. Both coins contain a mixture of copper and nickel, and the U.S. coin is coated with silver. The mixture of nickel and copper is relatively soft and permits deformation, as seen in this case. The primary projectile, a .380-caliber automatic Colt pistol 9- × 17-mm Winchester Silvertip bullet, weighs 5.1 g, with a rated muzzle velocity of 304 m/second (1000 feet/second). The mass of the conjoined projectile more than doubled with addition of the coin, yet retained sufficient velocity to produce the described lethal injury.
We attempted to see if this would be theoretically possible using some simple physical principles. Under ideal conditions, this event represents a form of an inelastic collision. We assumed that there was conservation of momentum between the oncoming bullet and the departing conjoined bullet-coin mass that subsequently penetrated the skull and brain. If momentum is conserved during this collision, then the mass of the bullet multiplied by its velocity would equal the mass of the conjoined bullet and 50-centavo coin multiplied by their departing velocity. The velocity of the bullet just prior to striking the coin is unknown and could not be determined.
For our calculations, we used the known muzzle velocity of this ammunition, understanding the limitations of such an assumption. We also calculated the kinetic energy and momentum of the oncoming bullet and exiting conjoined bullet-coin before and after collision. The results indicate two things: as expected in an inelastic collision, the kinetic energy of the conjoined bullet and coin is much less than that of the oncoming bullet, and the velocity of the conjoined projectile drops by greater than a factor of two. No doubt some of this loss in kinetic energy resulted from the energy expended in deforming the Mexican coin. The calculated loss in velocity of the bullet postcollision slows this projectile (i.e., the conjoined bullet/coin) to <150 meters per second (<450 feet/second). However, this velocity would still be well in excess of the minimal velocity needed to penetrate skin and bone, which has been reported to be about 66 meters per second (200 feet/second).
Forensic pathology has this morbid deadpan geekiness about it which just makes it so interesting to read.
You can just see them in the pathology room, arguing about what happened and sketching calculations on the back of envelopes.
In the wake of the Naturesurvey that found that 20% of scientists admit to using brain enhancing drugs, Wired has just published an article detailing what drugs their scientist readers use to keep on keepin' on.
Although the drugs issue is obviously the headline-grabber, the publication also has a great feature on cognitive enhancement that largely covers tips, tricks and techniques to boost your mental skills that aren't drug-related.
The article itself is anecdotally interesting, but has a curious tone throughout:
Surprisingly large numbers of people appear to be using brain-enhancing drugs to work harder, longer and better. They're popping pills normally prescribed for narcolepsy or attention-deficit disorder to improve their performance at work and school.
"We aren't the teen clubbers popping uppers to get through a hard day running a cash register after binge drinking," wrote a Ph.D. research scientist who regularly takes a wakefulness drug called Provigil, normally prescribed for narcolepsy. "We are responsible humans."
Whenever people talk about using drugs, they're always keen to distance themselves from that sort of drug user. You know, the ones that aren't responsible.
This belies the fact that most people use most drugs with few problems. Even teen clubbers popping uppers.
While all drugs have risks and illicit street drugs increase the health risks and definitely have an impact on body and brain function, it's only a minority of drug users who have problems that interfere with their daily lives.
For example, a recent study found that 4% of Australian workers use the (fairly nasty) drug methamphetamine. The figure rises to over 11% for 18-29 year olds. That more than 1 in 10.
While the study found that using methamphetamine significantly increases chances of a range of health problems, it's still the minority of users that report significant problems. This is the typical pattern for studies on drug use.
In other words, drugs are bad for you but most people manage the risks. A small minority, of course, don't, and die instantly or suffer long-term consequences.
The benefit and using and abusing prescription drugs for 'brain doping' is largely in the fact that you can be sure of the purity of the product and that probably (depending on how you acquire them) you're not funding a vicious criminal network.
At the end of the day though, the process is the same, whether you're using legal drugs, illegal drugs, for recreation or for performance.
Just make sure you're educated about the risks and know the consequences. Just like everything else in life.
Link to Wired.com Readers' Brain-Enhancing Drug Regimens. Link to Wired 'Give Your Intellect a Boost' techniques.
This month's Trends in Cognitive Sciences has a fantastic review article on the neuroscience of meditation - focusing on how the contemplative practice alters and sharpens the brain's attention systems.
The full article is available online as a pdf, and discusses what cognitive science studies have told us about the short and long-term impact of meditation on the mind and brain.
Meditation is now being quite extensively studied by cognitive science owing to the clear effects it has on the brain, and on the increasing evidence for its benefit in mental health.
A recent review of 'mindfulness' meditation-based therapy found that although research is in its early stages and not all possibilities have been ruled out, there's good evidence from the existing RCTs that it's particularly good in preventing relapse in severe depression.
The Trends article, which largely focused on the neuroscience research, makes the distinction between two types of meditation: 'focused attention' meditation - that involves focusing on a particular thing and refocusing if you become distracted by thoughts or sensations; and 'open monitoring' meditation which involves nonreactively monitoring the content of experience and acting as almost a detached observer to feelings and mental events.
This is an excerpt where the authors discuss the experimental evidence for the long-term 'open monitoring' or OM meditation:
Long-term practice of OM meditation is also thought to result in enduring changes in mental and brain function. Specifically, because OM meditation fosters nonreactive awareness of the stream of experience without deliberate selection of a primary object, intensive practice can be expected to reduce the elaborative thinking that would be stimulated by evaluating or interpreting a selected object. In line with this idea, Slagter et al. recently found that three months of intensive OM meditation reduced elaborative processing of the first of two target stimuli (T1 and T2) presented in a rapid stream of distracters...
Because participants were not engaged in formal meditation during task performance, these results provide support for the idea that one effect of an intensive training in OM meditation might be reduction in the propensity to ‘get stuck’ on a target, as reflected in less elaborate stimulus processing and the development of efficient mechanisms to engage and then disengage from target stimuli in response to task demands. From the description in Box 2,we anticipate a similar improvement in the capacity to disengage from aversive emotional stimuli following OM training, enabling greater emotional flexibility.
Moreover, the article includes many other studies that have reported interesting effects. For example, highly experienced focused attention meditators need minimal effort to sustain attentional focus, while even shortcourses on meditation can improve attention and decrease stress.
Most of the techniques are taken from Buddhist meditation practices and I'm sure Buddhists are cracking a wry smile as cognitive science is just starting to catch on to what they've been noting for thousands of years.
As for the neuroscience, I'm sure the remarkably science-savvy Dalai Lama is fascinated as he's held a number of conferences with leading researchers to discuss the the intersection between Buddhist practice and cognitive science.
It is now quite widely known that cannabis use is linked to a small but significant increase in the chance of developing psychosis, but it is less widely known that one of the ingredients in cannabis actually has antipsychotic effects.
Unlike THC, it's lesser known cousin cannabidiol is not responsible for the cannabis 'high' but it is naturally present in the plant.
There is accumulating evidence that cannabidiol has an antipsychotic effect, potentially damping down the psychosis-promoting effects of THC.
The amount of this substance varies in street cannabis, with some strains having more cannabidiol than others, and 'skunk' having the least of all - it being mostly eliminated by selective breeding for high THC content.
An ingenious new study looked at levels of cannabidiol consumption in groups of cannabis smokers by testing hair samples, and found that the groups who had the lowest cannabidiol levels had the most psychosis-like experiences.
In contrast, those with the most cannabidiol levels had the least psychosis-like experiences - equal to a comparison group with no detectable cannabis compounds who were presumably non-smokers.
One caveat is that the participants were all recruited from a study on ketamine users (a substance known to raise the risk of psychosis), so the study will have to be repeated on people who solely use cannabis to be sure the effect isn't a specific interaction between the two drugs.
However, the results seem to tie up with what we already know about how THC and cannabidiol work, so may reflect a genuine effect.
As any visitor to Amsterdam will tell you, cannabis breeders often try to maximise THC content to grow a plant with more 'bang for the gram'.
As cannabidiol seems to have no effect on the high itself, perhaps we might see breeders also trying to maximise the cannabidiol content in future, potentially reducing the risk to smokers' mental health.
UPDATE: A reader who prefers to remain anonymous sent in the following interesting comment:
Cannabidiol is in fact bred for in cannabis product, but is mainly done for taste. There are mentions within the cannabis breeding literature (i.e. seed catalogues) on breeds which lack psychosis (often defined as "low paranoid strains"), and these correspond to the "tasty" breeds to a great extent.
Probably 'lacking psychosis' would be considered controversial by the scientific community, but it's interesting that the growing and smoking community make the distinction between high and low 'paranoid strains'. It'd be interested to see whether these stand up to scientific investigation.
The New York Times has a fantastic article on the remarkable artistic talent seemingly released in some people with fronto-temporal dementia (FTD) - a condition where frontal and temporal lobes start deteriorating.
Dementia is any condition where the brain or brain function deteriorates quicker than would be expected through normal ageing.
This can occur because of still poorly understood Alzheimer's-like changes involving abnormal protein accumulation in the brain, or often, because the blood vessels start dying and deteriorating, leading to the death of the brain areas they serve.
A mix of both is not uncommon but the damage to the brain is often uneven and patchy, meaning that while mental function generally declines, specific skills and abilities can be impaired while others are left relatively intact.
Some brain areas are particularly involved in controlling or inhibiting others, meaning if these areas are damaged, the areas they 'control' can suddenly begin to work overtime (its like if you damaged the break on a car, often it would speed up when you didn't want it to).
In fact, if these systems break down due to brain damage, we can regain reflexes we had when we were first born - such as automatically grasping things put in the hand - but which the brain inhibits as it matures.
The NYT article discusses a recent case study published in the medical journal Brain that suggests that this same process may release brain circuits leading to new artistic talents and skills.
From 1997 until her death 10 years later, Dr. Adams underwent periodic brain scans that gave her physicians remarkable insights to the changes in her brain.
“In 2000, she suddenly had a little trouble finding words,” her husband said. “Although she was gifted in mathematics, she could no longer add single digit numbers. She was aware of what was happening to her. She would stamp her foot in frustration.”
By then, the circuits in Dr. Adams’s brain had reorganized. Her left frontal language areas showed atrophy. Meanwhile, areas in the back of her brain on the right side, devoted to visual and spatial processing, appeared to have thickened.
When artists suffer damage to the right posterior brain, they lose the ability to be creative, Dr. Miller said. Dr. Adams’s story is the opposite. Her case and others suggest that artists in general exhibit more right posterior brain dominance. In a healthy brain, these areas help integrate multisensory perception. Colors, sounds, touch and space are intertwined in novel ways. But these posterior regions are usually inhibited by the dominant frontal cortex, he said. When they are released, creativity emerges.
The art of Anne Adams, the subject of the case study, can be seen on twowebsites and the NYT article contains a couple of striking pieces.
Link to NYT article 'A Disease That Allowed Torrents of Creativity'. Link to PubMed abstract of scientific study.
Defining brain death and the controversies of existence:
The Boston Globe has an interesting article on the concept of 'brain death'. The criteria for brain death are being contested and it's become a hot issue, partly because the US allows organs from consenting donors to be removed when brain death has been diagnosed.
The 'dead donor rule' stipulates that it's only possible to remove organs in cases where a person has died, and this can either be after cardiac death, where the heart and lungs stop functioning, or after brain death, where the brain suffers irreversible damage which causes coma where the patient is kept alive solely by life support.
Most organs donated from the deceased come from people who have been diagnosed as brain dead. Organs remain viable for only about an hour or two after a person's last heartbeat. Brain dead patients are ideal candidates for organ donation, then, because they are kept on ventilators, which means their heart and lungs continue to work, ensuring that a steady flow of oxygen-rich blood keeps their organs healthy. Surgeons remove the donor's organs, then shut off the ventilator. The patient's heart eventually stops.
Yet a small but vocal minority in the medical community has always insisted that some brain dead patients may not be dead. For instance, one study documented some kind of brain activity in up to 20 percent of people declared brain dead, suggesting to some critics that doctors sometimes misdiagnose the condition. Although some neurologists contend the claim, University of Wisconsin medical ethicist Dr. Norman Fost points to research showing that many "brain dead" patients have a functioning hypothalamus, a structure at the base of the brain that governs certain bodily functions, such as blood pressure and appetite.
It's an challenging that speaks directly to our idea of what divides life and death. There is no question that any of the patients will recover, regardless of any residual activity detected in their brain.
But it prompts the question of what sort of brain activity we consider human enough to constitute life.
Of course, the issue is compounded by the importance of life-saving organ donation operations, for which suitable organs are almost always in short-supply.
Wired Science have got a great short film that follows a two people who have deep brain stimulation devices implanted in their brains to treat tremors.
Tremor is a symptom of Parkinson's disease and this was one of the earliest targets for early DBS trials.
The film follows someone who has exactly this difficulty, plus someone who has a different form a tremor disorder, known as essential tremor, through the process of the operation.
While most people assume brain surgery is all pre-planned beforehand, for many treatments for cognitive or behavioural functions, the surgeons need to wake up the patient after they've open their skull to make sure they're targeting the right place (and avoiding damaging essential functions).
In this case, they wake the patients up during neurosurgery so they can test out their movements while stimulating different areas of the brain, in a trial and error style.
Wired Science also has a shorter film online about the post-mortem dissection of a brain of a patient who had Alzheimer's disease that's also well worth having a look at.
Link to video of deep brain stimulation neurosurgery. Link to video on 'The Brain of an Alzheimer's Patient'.
A case of a man with unstoppable hiccups has just been published online in the medical literature. Rather unusually, it turned out they were caused by early stage Parkinson's disease.
Parkinson's disease is most commonly associated with movement difficulties and the public most associate it with tremor or shaking.
However, it can have a wide range of other effects (more recently, problems with cognitive functions and mental health have been recognised), although this seems to be the first time hiccups have been reported as an early symptom.
The case study is reported in the journal Parkinsonism and Related Disorders:
The patient was a 62-year-old male who had been suffering from intractable hiccups for more than 6 months. The initial intermittent nature of hiccups became continuous over time. When he was quiet, the hiccups were more prominent, although his symptoms tended to decrease when he was speaking.
The hiccups frequently interrupted his speech particularly towards the end of a sentence. The hiccups tended to disappear when he was asleep. Hiccup frequency increased with emotional stress such as anxiety and anger. The patient was depressed and socially isolated due to the embarrassment caused by his continuous hiccups.
It's a curious case, but the paper also contains a fascinating paragraph on the causes of hiccups. One cause can be with (unsurprisingly) the organs in the chest, but another can be disruption to part of the brainstem called the medulla.
The causes of hiccup can be divided into ‘peripheral’ and ‘central’. A wide variety of peripheral conditions can cause hiccup including: gastroesophageal pathologies, renal failure, malignancies, medications, abdominal surgery and even myocardial infarction.
Central causes can result from structural or functional disorders of the medulla or various other supraspinal neural elements such as multiple sclerosis, medulla oblongata cavernoma, brainstem tumors, basilar artery aneurysm, cerebellar hemangioblastoma, dorsal and lateral medullary infarctions...
The antidopaminergic agent chlorpromazine is the only drug approved for the treatment of intractable hiccups.
I never knew there was an approved drug for difficult to control hiccups, let alone chlorpromazine, the first antipsychotic drug to be developed and widely used in the 1950s.
However, stranger treatments have been discussed in the medical literature.
Perhaps some of the finest moments in hiccup medicine have come from the small but determined literature on the use of digital rectal massage (translation: finger up the arse) as a treatment.
The abstract of 1990 article from the Journal of Internal Medicine is fantastic simply for its deadpan delivery. Needless to say, it was honoured with an IgNobel award.
Could you endure such pain, at any hand but hers?:
I finally got round to having a look at the New York Timesmigraine blog and found it full of fantastic writing and some wonderful artwork that aims to capture the perceptual distortions associated with the mother of all headaches.
There's a particularly good article by Oliver Sacks (his first book was on migraine) who discusses the common geometrical patterns that can occur in the hallucinatory images, known as a form constants.
Interesting, the mathematician Paul Bressloff has suggested [pdf] that these necessarily arise when the firing of neurons in the primary visual cortex is destabilised.
Although Bressloff was particularly addressing certain hallucinations caused by psychedelic drugs, the form constants are, well, constant across conditions, so are likely to arise from a similar process in migraines too.
There are many more articles describing the science, personal stories and art of the head pounding, vision distorting and stomach churning headache. The gallery is particularly good if you're not familiar with the range of visual effects.
However, no one seems to have touched on a poem by Robert Graves where he uses migraine as a metaphor for love (or is it the other way round?) capturing the beauty and pain of both.
Symptoms of Love
Love is universal migraine,
A bright stain on the vision
Blotting out reason.
Symptoms of true love
Are leanness, jealousy,
Laggard dawns;
Are omens and nightmares -
Listening for a knock,
Waiting for a sign:
For a touch of her fingers
In a darkened room,
For a searching look.
Take courage, lover!
Could you endure such pain
At any hand but hers?
Frontal Cortex has alerted me to a wonderful article in The New Yorker about Stanislas Dehaene's work on understanding the neuropsychology of number sense.
Like written and spoken language, human numerical abilities are quite astonishing for how they are organised in the brain.
After brain injury, various maths or numerical abilities can be shown to 'doubly dissociate', meaning that parts of the ability can be independently damaged and so it can be inferred that they rely on independent (but, of course, interacting) brain systems.
The surprise comes from the fact that as a species, abilities like complex language, writing and maths are relatively recent cultural innovations.
While some of the core abilities may be inherited, there must be some aspects of the more complex skills which become tied up with the development of brain structure as we grow to account for the way in which they break down in very selective ways after brain damage.
Dehaene is one of the key researchers in understanding the neuropsychology of numerical ability and what he calls 'number sense' - a more general intuitive perception of quantity and number.
It has been suggested that this is also linked to other ways of perceiving the world, as can be seen from some strange interactions between number and space that can be seen in experiments:
But the brain is the product of evolution—a messy, random process—and though the number sense may be lodged in a particular bit of the cerebral cortex, its circuitry seems to be intermingled with the wiring for other mental functions. A few years ago, while analyzing an experiment on number comparisons, Dehaene noticed that subjects performed better with large numbers if they held the response key in their right hand but did better with small numbers if they held the response key in their left hand.
Strangely, if the subjects were made to cross their hands, the effect was reversed. The actual hand used to make the response was, it seemed, irrelevant; it was space itself that the subjects unconsciously associated with larger or smaller numbers. Dehaene hypothesizes that the neural circuitry for number and the circuitry for location overlap. He even suspects that this may be why travellers get disoriented entering Terminal 2 of Paris’s Charles de Gaulle Airport, where small-numbered gates are on the right and large-numbered gates are on the left. “It’s become a whole industry now to see how we associate number to space and space to number,” Dehaene said. “And we’re finding the association goes very, very deep in the brain.”
The article is a great read and a useful introduction to some of the key findings in the field, as well as containing a whole load of eye-opening findings about number and the brain.
A fantastic study has just been released by open-access science journal PLoS One that investigated the neuroscience of jazz improvisation.
Jazz musicians were put inside an fMRI brain scanner and were asked to do complete a number of different musical exercises using a specially adapted magnet-friendly keyboard.
The musicians were asked to demonstrate musical scales, a pre-practised fixed piece, and an improvisation exercise while their brains were scanned.
A summary of the study by the John Hopkins medical school team gives the main results:
The scientists found that a region of the brain known as the dorsolateral prefrontal cortex, a broad portion of the front of the brain that extends to the sides, showed a slowdown in activity during improvisation. This area has been linked to planned actions and self-censoring, such as carefully deciding what words you might say at a job interview. Shutting down this area could lead to lowered inhibitions, Limb suggests.
The researchers also saw increased activity in the medial prefrontal cortex, which sits in the center of the brain’s frontal lobe. This area has been linked with self-expression and activities that convey individuality, such as telling a story about yourself.
Some years ago, psychiatrist Sean Spence suggested that Jazz music may have been born owing to the 'the father of Jazz', Buddy Bolden, having schizophrenia and suffering from associated frontal lobe impairments.
Spence argued that reduced frontal lobe function meant that Bolden could only improvise, as he didn't have the cognitive control to stick to pre-learnt pieces.
At the time improvisation was considered a sign that you couldn't play 'proper music' well enough, but Bolden took improvisation to a new level with wondrous flights of fancy and, as the legend goes, jazz was born. That's not the whole story of course, but it's possibly an ingredient.
While these new findings don't give us much of a lead on whether this might have been the genuine beginning of jazz music, it's interesting that the idea that reduced frontal lobe function 'frees up' the over-inhibited playing of set pieces, is consistent.
Link to PLoS One article on the cognitive neuroscience of Jazz. Link to study summary. Link to BBC News on Spence's theory.
Dopamine has been the big player in understanding schizophrenia since antipsychotic drugs were discovered. All current antipsychotics have their main effect by blocking dopamine function in the mesolimbic pathway and there's now significant evidence that this is the location of one of the major dysfunctions.
It's been clear for a while that this isn't the whole story though. Ketamine and PCP, two glutamate-focused drugs that barely touch the dopamine system directly, are heavilylinked to schizophrenia and can intensify psychotic symptoms.
Findings such as these have sparked a flurry of interest in understanding the role of glutamate in psychosis, and there's now an intense interest in developing drugs that might target this system.
One of the key hopes is that these newer drugs will have fewer side-effects, as, in some, antipsychotics are have unpleasant and unhealthy adverse consequences.
The New York Times has just published a great article on the development of these new drugs, just in mid-testing stage, and on the neuroscience that motivates them.
People who use PCP often have the hallucinations, delusions, cognitive problems and emotional flatness that are characteristic of schizophrenia. Psychiatrists noted PCP’s side effects as early as the late 1950s. But they lacked the tools to determine how PCP affected the brain until 1979, when they found that it blocked a glutamate receptor, called the NMDA receptor, that is at the center of the transmission of nerve impulses in the brain.
The PCP finding led a few scientists to begin researching glutamate’s role in psychosis and other brain disorders. By the early 1990s, they discovered that besides triggering the primary glutamate receptors — NMDA and AMPA — glutamate also triggered several other receptors.
They called these newly found receptors “metabotropic,” because the receptors modified the amount of glutamate that cells released rather than simply turning circuits on or off. Because glutamate is so central to the brain’s activity, directly blocking or triggering the NMDA and AMPA receptors can be very dangerous. The metabotropic receptors appeared to be better targets for drug treatment.
The article talks about some of the new drugs in development, and the fact that this is where drug companies are placing their (quite substantial) bets at the moment.
Link to NYT article 'Daring to Think Differently About Schizophrenia'.
The American Academy of Neurology are now doing fortnightly super-geeky podcasts that feature discussions about studies published in their journal.
If you're not familiar with the arcane language of neurology - tough luck, as they make no effort to explain anything to the uninitiated.
They're not quite as bad as the American Journal of Psychiatrypodcasts (which I previously described as an 'excessively thorough lecture given by a voice synthesiser' although I'm actually finding the fembot voice rather sexy - is that wrong?) and include some discussion rather than just spoken summaries.
Occasionally, they throw a curve ball and include poetry, or a quick hint or tip for the clinician, but mainly they're neurologists doing what neurologists do best - talking about brain disorders in lots and lots of detail.
Also, I challenge you not to shout out "Space. The Final Frontier!" when you hear the opening fanfare.
I keep mentioning them, but the Royal College of Psychiatrist'spodcasts are excellent - dealing with the nitty gritty of the science but also explaining the concepts and debating the controversial points. They really should be a model for others to follow.
And as an aside, Nature'sNeuroPod seems to be missing in action again.
Mind Hacks. The Perez Hilton of academic neuroscience podcast gossip.
Neurophilosophy has found a gory but completely astonishing film of a Kisi medicine man in Tanzania performing a trepanation operation. A young lady endures the seven hour procedure that puts a hole in her skull without any anaesthetic.
Mo has been doing some fantastic work on the history of trepanation and his illustrated article on the topic is a must read if you want an overview of this ancient procedure.
This film emphasises the importance of the operation in some cultures and highlights quite what a remarkable, if not, somewhat hazardous procedure trepanation really is.
And by the way, if you saw our recent rather whimsical post on 'brain hats', the end of the video gives a whole new meaning to the phrase.
Link to video of Kisi trepanation. Link to illustrated history of trepanation.
Developing Intelligence has a fantastic post on what pharmacology and neuropsychology has told us about getting optimally wired on caffeine.
In small amounts, caffeine boosts mental function, and the article looks at scientific studies that have told us which are the optimal doses, which psychological abilities are most affected and what you can take with caffeine to modulate its effect.
Obviously, caffeine has its health risks. Psychologically speaking, even everyday doses run the risk of withdrawal symptoms and have the tendency to increase anxiety, so as with any drug, it's important to educate yourself so you can judge the risks for yourself.
The Wikipediapage on caffeine is wonderful, so it's a great complement to the fantastic round-up of stimulation-related tips from Developing Intelligence.
Link to article 'A User's Guide to Getting Optimally Wired' (via BadScience). Link to Wikipedia page on caffeine.
This case report from a 2001 study describes a patient with persistent headaches who experienced 'phantom teeth' - the sensation of non-existent vampire-like teeth in her mouth.
'Phantoms' are often the result of having a limb or other appendage removed and can affect almost any part of the body (indeed, phantom penises have been reported in the medical literature).
In this case phantom teeth seem to have occurred after surgical removal of the gums, although this case is particularly interesting because the phantoms are for teeth that were never there in the first place.
Phantoms are thought to arise when the brain's map of the sensory areas becomes distorted during re-organisation, after the actual sensations from the removed appendage stop.
A 52-year-old woman was referred to a neurologist because of right facial pain radiating from the malar region diagonally to the right upper lip area. She had pain for several months following upper and lower surgical resection of hypertrophic gums. The pain was severe, constant, and interfered with her sleep. She had no gustatory sweating or flushing of her face or neck. She developed symptoms of depression because of the chronic pain...
She reported a constant sensation of having two long extra upper canine teeth growing in front of her normal canines that felt like they were pressing on her tongue. The sensation was experienced as someone with vampire-like long upper canines ("Dracula's teeth")...
There was no family history of gum hyperplasia or supernumerary teeth. She complained of poor taste, forgetfulness, sleep fragmentation, and high-pitched ringing noises in her ears of long-standing. She had no burning of her tongue.
Today's edition of Nature has some commentary from scientists responding to their recent feature on 'optimising' the healthy brain with pharmaceutical drugs.
I suspect the letters have been edited a little though, as the first, from developmental psychologist James M. Swanson and neurobiologist Nora Volkow (who is also director of the National Institute on Drug Abuse) seems to suggest that enhancement drugs risk being addictive because:
...cognitive enhancers such as the stimulants methylphenidate (Ritalin) and amphetamine amplify the activity of dopamine, a neurotransmitter that increases saliency, making cognitive tasks and everyday activities seem more interesting and rewarding. This learned experience can lead to abuse of the drug and to compulsive use and addiction in vulnerable people.
These drugs are widely used for cognitive enhancement, but the issue is hardly new as these are relatively old drugs that almost solely target the dopamine system, whereas the newer 'cognitive enhancement' drugs (most notably modafinil) work in a quite different way (modafinil alters dopamine, among other effects, but it's hardly comparable).
Hence, they do not have the same pharmacological potential for abuse and simply aren't found to be as addictive as the amphetamines in the 'real world'.
In fact, when the Nature article asked the hypothetical question whether you would take an enhancing drug if it had no side effects, it was almost certainly inspired by modafinil.
While the drug isn't side-effect free (several are common) it tends to be significantly less risky than your typical high-charge dopamine agonist such as amphetamine, which can cause cardiovascular problems and psychosis to name but a few of its dangerous effects.
That issue aside, one of the most interesting points is made in a letter from philosopher Nick Bostrom who argues that drug companies should be allowed to develop enhancement drugs without having to specify an illness to treat.
He argues this is because the current system demands that drugs are licensed for a specific disorder, which means new disorders get invented ('disease mongering') as a way of legitimising the sale of drugs which are helpful but for less serious problems of living, such as low-level anxiety, persistent tiredness or normal memory decline, but are not significant medical treatments.
So maybe the solution to the drug companies warping medicine is to allow them to sell drugs as 'tonics', rather than medications. Certainly food for thought.
There's several other responses on the ethics and experiences of cognitive enhancement from some of the leaders in the field, so well worth a look through.
It's not often a children's book on hallucinogenic drugs gets written, but this seems to be one of those occasions. Matt Hutson has scanned in some remarkable pages from exactly such a book, published in 1991.
Apparently it's quite comprehensive, covering everything from neurons to shamans, and is also full of funky illustrations.
The prose is lucid, but the pictures crack me up. Take the cover. Look kids, in a drug free zone, you can do all kinds of things, like play tic-tac-toe. Or even watch people play tic-tac-toe! And remember, friends don't let friends wear non-footie pants.
In some cases the book might be counterproductive: "Have you ever looked at yourself in an amusement park mirror? Look what happened to you! Now, try to imagine that the whole world looked that way to you." Awesome! Where can I get some?
Link to Silver Jacket on 'Focus on Hallucinogens'.
Memoirs of a Postgrad has got a great write-up of a new low-power MRI machine, the technology that does most of the structural and functional brain scans. Even the smaller MRI machines need huge electromagnets, but this new technology uses magnets thirty thousand times weaker to image the brain.
In a standard MRI machine, a strong magnetic field is used to align the proton in each of the hydrogen atoms before using an RF pulse to knock them out of alignment. As they snap back into alignment with the magnetic field, they emit a signal which can be detected and used to create a 3D image. In the new version, the very small magnetic field isn't enough to align the protons, so a short duration (1 second) magnetic pulse of slightly higher magnitude (30 millitesla).
The resulting signals are very small, so an array of highly sensitive magnetometers are used (so-called superconducting quantum interference devices, or SQUIDS). A hugely important additional advantage of using these SQUIDS is that they are also used in the MEG (magnetoencephalography) imaging technique. This potential for MRI and MEG using the same machine raises the intriguing possibility of producing simultaneous structural images (using the MRI) and brain activation maps (using the MEG).
Unfortunately, the use of SQUIDs dashes any hopes of making the machines much smaller.
The SQUID sensors need to be extremely cold (working at approximately -170 degrees C) and so are usually bathed in liquid nitrogen, meaning a huge insulated tank sits atop the scan area.
IEEE Spectrum magazine has an article with some images from the new type of scanner, which look pretty fuzzy at the moment, but apparently can better distinguish tumours in the brain and will undoubtedly become clearer as new software is developed.
Link to Memoirs of a Postgrad post. Link to IEEE Spectrum article.
Depression, antidepressants and the 'low serotonin' myth:
Bad Science has a fantastic article on antidepressants and the widely-promoted but scientifically unsupported 'low serotonin theory' of depression.
Owing to a huge advertising push by drug companies, not only the 'man on the street', but also a surprisingly large numbers of mental health professionals (clinical psychologists, I'm look at you) believe that depression is linked to 'low serotonin' in the brain.
The only drawback to this neat sounding theory is that it is almost completely unsupported by empirical evidence or scientific studies.
Experiments that have deliberately lowered serotonin levels in the brain have found that it is possible to induce 'negative mood states' (usually milder and as short-lasting as a slight hangover), but these do not even begin to compare to the depths of clinical depression.
In terms of patients with the clinical mood disorder itself, not a single study has found a link to reduced serotonin.
Bad Science neatly reviews the science, and also discusses a new research study which chased up journalists that propagated the myth to ask for their sources.
Needless to say, none of them had any sound scientific basis for their claims.
This is not to say that antidepressants don't help treat depression, (evidence suggests they do - although the effect is more modest than drug companies would have us believe), or that neurobiology isn't important (by definition, if it's a change in thought and mood, it's a change in brain function).
If you're interested in the history of how the 'low serotonin hypothesis' came to be thought up and then subsequently promoted, despite the lack of evidence, Professional Psychology: Research and Practice recently published a great article on the topic [pdf].
Link to Bad Science on the serotonin myth. pdf of article on the history and popularity of the myth. Link to excellent PLoS Medicine article on evidence and adverts.
SciAm's Mind Matters blog has a completely fascinating post on the common assumption that humans have the the most complex brain of all the animals. Compared to a whale, however, our brain is smaller and has even less cortical folds. Does that mean they're smarter?
The article is by neuroscientist R. Douglas Fields and takes a comparative look at brain size, relation to body size, and function across the species.
It turns out, we're perhaps not quite so special as we like to believe. Even on the ratio of brain to body size, humans are beaten by the humble tree shrew.
We humans pride ourselves on our big brains. We never seem to tire of bragging about how our supreme intelligence empowers us to lord over all other animals on the planet. Yet the biological facts don't quite square with Homo sapiens' arrogance. The fact is, people do not have the largest brains on the planet, either in absolute size or in proportion to body size. Whales, not people, have the biggest brains of any animal on earth.
Just how smart are whales? Why do they have such big brains? Bigger is not always better; maybe the inflated whale brain is not very sophisticated on a cellular level. We're closer to answering such questions now, for a couple of recent papers address them squarely. What they find is helping separate fact from fiction.
It turns out that while whales have bigger brains, humans have more neurons. Nevertheless, whales have more glial cells.
Glial cells were traditionally thought to do nothing more than support and insulate the neurons, but it's becoming increasingly clear that they're actually part of the brain's processing system (although they're exact role is far from clear).
So maybe there's a lot more to the whale brain that it first appears.
I've just discovered a wonderfully simple finger touch procedure that can test the function of your corpus callosum, a key brain structure that connects the two cortical hemispheres.
It is called the 'cross lateralization of fingertips test' and was used in a 1991 study by Kazuo Satomi and colleagues.
It relies on the fact that different hemispheres are responsible for the movements and sensations from each hand.
In other words, each hand is connected to a different side of the brain, and, to allow you to co-ordinate both hands, the brain passes information between the two sides by using the corpus callosum.
The corpus callosum is the largest structure in the brain and works like a huge bundle of white matter 'cables', connecting different areas.
If this structure gets damaged, a patient might have trouble with coordinating their hands, preventing them from matching sensations on one hand with movement on the other, because the information doesn't get to where it's needed.
The test works like this: you need to ask someone to close their eyes and put their hands face up.
You then touch one of their fingertips with a pencil, and with the opposite hand the participant needs to touch the corresponding finger with thumb of the same hand.
For example, if you touched their right ring finger, they would need to touch their left ring finger with their left thumb, as shown in the diagram above.
You need to do this on both hands, with them always touching the corresponding finger on the opposite hand.
It's important that the person keeps their eyes closed, because as soon as they look, they get information from the eyes, which goes to both hemispheres.
Patients who have damage to the corpus callosum (either because of acquired damage or because it just hasn't developed) usually can't do this test, because of the disruption in communication between the two hemispheres of the brain.
Of course, just to be sure its not a problem with movement or sensation in one hand only, the patient is also asked to do another quick test where they're asked touch the exact finger you just touched.
For this part, the sensation and movement happen in the same hand, so information doesn't need to cross the corpus callosum.
The test was shown to me by Dr Emma Barkus, who researches what neurological tests can tell us about psychosis and unusual experiences.
Link to Wikipedia page on the corpus callosum. Link to abstract of Satomi and colleagues study (thanks Emma!).
This is a completely amazing case report published in Acta Neurochirurgica about a man who managed to get a paintbrush stuck in his brain during a fight.
The most astounding thing is that from the outside it only looked like he had a tiny cut on the eye.
Artistic assault: an unusual penetrating head injury reported as a trivial facial trauma.
Mandat TS, Honey CR, Peters DA, Sharma BR.
The authors report a case of penetrating head injury that presented with a deceptively mild complaint. To our knowledge, it is the first report of a paint brush penetrating the brain. The patient reported being punched in the left eye and presented with a minor headache, swelling around the left orbit, a small cut on the cheek and slightly reduced left eye abduction. After radiological evaluation, a penetrating head injury was diagnosed.
Under general anesthesia, through a lateral eyelid incision a 10.5 cm long paint brush, which had penetrated from the left orbit to the right thalamus, was removed. No post-operative infection was seen at six months follow-up. This brief report serves to highlight that penetrating brain injury can occur without neurological deficit and that a minimally invasive surgical approach was successful in avoiding any complications.
I've just found a page with some beautiful pictures of antique neurosurgery tools, including these trephining or trepanning tools for cutting holes in the skull. Can you imagine the elbow work needed to get the job done?
After a bit of a search I discovered that there's a healthy market in neurosurgical tools on the net, old and new.
Advances in the History of Psychology discovered an antique trepanning brace that's currently for sale for a cool $1900.
One antique dealer even has a receipt for a trepanning operation from 1814. It turns out you could get your head drilled for $20 in early 19th century Massachusetts.
If you're after some more modern kit, it turns out you can pick up quite a few contemporary surgical tools on eBay.
Including this VectorVision2 BrainLab system, a snip (excuse the pun) at $15,000.
The VectorVision2 is an 'augmented reality' image guidance system (sometimes called frameless stereotaxy) that allows the surgeon to see where his tools are in relation to both the patient and a matched brain scan image - while the operation is in progress.
While the tools can be bought and sold online, most of the anaesthetics are, of course, controlled drugs.
So while you may be able to get the latest high-tech kit on eBay, you're still going to have to resort to those traditional 19th century surgical painkillers: brandy, and a stiff upper lip.
Link to pictures of antique neurosurgery tools. Link to VectorVision2 for sale on eBay.
Treatment Online has an interesting piece on the development of a cocaine vaccine. Unlike other drugs that reduce the pleasurable effect of addictive drugs, this is genuinely a vaccine - it persuades the immune system to attack cocaine molecules.
There are various drugs that are sometimes described conveniently, but inaccurately, as 'vaccines' for addictive substances.
For example, disufiram (aka Antabuse) creates a severe hangover 10 minutes after taking any alcoholic drink by inhibiting certain enzymes in the liver which break down alcohol. The idea is that it acts as an instant form of aversion therapy.
A drug called naltrexone blocks opioids in the brain which all pleasurable drugs trigger, either directly (in the case of heroin), or indirectly (in the case of alcohol). Naltrexone simply aims to reduce how 'fun' the drug is, leading to extinction of the link between the drug and the 'high'.
However, neither of these are actually 'vaccines' in the proper sense of the word.
Vaccines are substances that stimulate the immune system. The immune system identifies and adapts to the key features of the potentially dangerous invader, and works to destroy it.
Of course, this happens when foreign pathogens (like diseases) enter the body, but the immune system can be triggered by safe or less dangerous substances that share the 'key features' with the more dangerous disease. This safe or less dangerous substance is the vaccine.
Edward Jenner invented the procedure after working out that giving people a tiny amount of the non-lethal cowpox virus vaccinated them against the deadly smallpox virus. In fact, this is where the word 'vaccinate' comes from as 'vacca' means cow in Latin.
The developers of the new cocaine vaccine, known as 'TA-CD', are doing essentially the same thing by cleverly combining a deactivated cocaine molecule with a deactivated cholera toxin molecule.
The deactivated cholera toxin is enough to trigger the immune system, which finds and adapts to the new invader.
Because the cholera toxin and the cocaine molecule are combined, the immune system also adapts to the key features of cocaine, so works out how to seek and destroy cocaine molecules.
This means they never reach the brain in sufficient quantities to cause an effect.
A key advantage is that unlike other anti-addiction drugs, which have to be in the body to have their effect, the cocaine vaccine permanently changes the immune system to neutralise cocaine.
Of course, it may not be completely effective, or it may not work in all people, but that's the aim.
The drug is about to studied with a Phase III clinical trial to see if it useful in treating cocaine addiction, after which, if it is shown to be safe and effective, it could be approved for widespread use.
Unlike the current concerns about the supposed 'new ethical challenges' of medical therapies being used by healthy people (which, as we've noted, are actually as old as drugs themselves), this therapy may present a relatively new ethical dilemma.
If effective, you can see that some parents might want to vaccinate their non-addicted, perfectly healthy children, so they are 'immune' to cocaine.
The difference here, is that once given, the 'immunity' may be permanent. In other words, you would make the decision that your child will never be able to experience the effects of cocaine for the rest of their life.
One interesting effect might be an 'arms race' between illicit drug producers and vaccine makers. As children become 'vaccinated' against the common drugs of abuse, the market for street drugs would fragment and diversify into drugs that don't have vaccines yet.
A Brave New World indeed.
Link to Treatment Online on cocaine vaccine. Link to PubMed papers on cocaine vaccine. Link to Toronto Globe and Mail article on the vaccine.
BBC News has a report on the increasingly popularity of gamma-Butyrolactone or GBL as a recreational drug. Actually, it's not a drug in itself, but once ingested it is metabolised into GHB, a drug often sold under the name 'Liquid Ecstasy'.
Actually, the effects are much more like alcohol than ecstasy (the street name is just a marketing ploy) and the similarities to alcohol can be seen in its structure and effect on the brain, as both affect GABA receptors.
The increasing popularity of GBL is particularly interesting, however, as GBL is legal, but the body transforms it into the illegal UK Class C substance GHB.
Compounds that are weak or inactive until the body transforms them into an active drug are called prodrugs, and this is the first situation that I can think of where a legal prodrug has been found for an illegal drug.
Probably the most commonly used illicit prodrug is heroin, which is metabolised into morphine in the body, but both are Class A drugs in the UK so there's no legal benefit to having one rather than the other.
GHB is usually described as a 'date rape drug' despite the fact that it is barely used in 'date rapes', unlike alcohol, which is used in the vast majority of cases and is a much better candidate for the 'date rape drug' label.
GBL is closely related to 1,4-Butanediol, which is also a GHB prodrug. 1,4-B recently caused a scare because a toy called 'Aqua Dots' was made using the compound and had to be withdrawn after several infants swallowed the plastic pellets and became dangerously intoxicated.
Needless to say, the news inspired some to swallow the plastic pellets for fun and the experience was, inevitably, reported online.
GHB is a nervous system depressant, and like all depressants, a major danger is unconsciousness, coma, and collapse of breathing and circulation.
Consequently, there have been a number of reports of these cases being admitted to hospital emergency rooms.
The long-term toxicity of these substances aren't really known, but as both GBL and 1,4-B are used as industrial solvents and cleaning fluids, it's likely that they give the body a fairly rough time.
Sam Harris is better known as a leading atheist, but he's also completing a PhD in cognitive neuroscience and a forthcoming study by Harris is a flawed but important contribution to how we understand the neuropsychology of belief.
Harris and his colleagues asked participants to respond to a number of statements with buttons presses indicating that they either believed, disbelieved or were undecided about each proposition.
The participants were shown statements relating to mathematics, geography, word meaning, general knowledge, ethics, religion and their own life.
While they were doing this brain activity was measured by a fMRI scanner, with a view to finding out which areas of the brain were involved in 'belief' and 'belief states'.
It's a straightforward study and you may wonder why no-one has ever done it before. It's possibly because, from what we know about belief, it's not clear that this study tells us much more about belief rather than what happens when people respond to questions.
Belief is a concept that is used all the time in psychology but is a pain to define in a way that science would be happy with. If you're not convinced Eric Schwitzgebel's guide to the problem is about as good as you're likely to read, but I'm going to give a quick run through of the most relevant issues here.
One of the main problems is that experimental neuropsychology relies on measuring brain and behaviour during activities, and there is no single activity that represents 'believing'.
When do you believe Paris is the capital of France? Only when you think about it or all the time? Presumably, we believe it all the time as we don't assume someone has stopped believing it when they think about something else or are unconscious, when asleep perhaps.
The above example treats belief as a proposition stored in memory (a semantic memory in psychology parlance), but you can easily respond to a belief question if you've never thought about a proposition before in your life.
Do you believe tigers wear pink pyjamas? Presumably you don't, but it's unlikely you've ever thought about this before. It's an answer reconstructed from fragments of other information you have in memory, reasoning and 'gut instinct' to varying degrees.
Saying you believe something can work the same way, of course. You may never have thought about it before, but you can say you believe it.
Just these two examples show that saying you believe or disbelieve can involve retrieving a 'fact' from memory, or might involve any number of other mental processes to give an answer.
Furthermore, its not even clear that two people retrieving facts from memory are even thinking about the same thing.
Here's another question. Do you believe snow is white? Imagine two people are asked this question. One believes snow is frozen water, the other believes it's star dust.
Considering that each person believes that the subject is something completely different, are they answering the same belief question, or is one answering 'I believe frozen water is white' while the other is answering 'I believe stardust is white'? Now scale that up to concepts like democracy or religion.
This is known as the atomism vs holism debate in philosophy and concerns whether we can ever consider belief is isolation ('snow is white'), or whether we can only consider them in relation to other beliefs that might need to be accessed at the same time (what we believe a word represents, or, even, what we believe the about what we believe).
These issues are essential for neuropsychologists, because they predict different patterns of brain activity, even though the behaviour (e.g. responding 'I believe') is exactly the same.
The point of having so many topics in Harris study is that despite these issues, on average, there might be some brain differences involved in answering 'believe' or 'disbelieve' regardless of the topic, but the mental processes involved in answering these questions might be so diverse that it's difficult to say whether the average brain activity actually describes 'belief' in any meaningful sense.
This doesn't mean the study is worthless though, and in fact, it's an essential step in the scientific study of belief.
Science tends to start big, obvious and practical, and work through objections, new ideas and problems over time with new experiments. This study is one of the early but essential, big, obvious and practical steps.
Interestingly, some philosophers (known as eliminative materialists) argue that the concept of belief is just one we've inherited from everyday or 'folk psychology' and because of the conceptual problems with it, we'll eventually realise there are no distinct mind or brain process that can be coherently identified as 'belief'.
Like the concept of 'rooting for your team', we'll just realise its too broad to be scientifically useful and we'll disregard the idea of 'belief' mechanisms in the brain in favour of a variety of better specified concepts that reliably map onto mind and brain processes.
Importantly, studies into the neuropsychology of belief, like this one, can help answer these questions, and eventually, they are likely to have profound implications for everything from lie detection to clinical medicine.
Link to full-text of Harris's study. Link to Schwitzgebel's on belief for the Encyclopaedia of Philosophy. Link to write-up from Time.
The Children's Hospital Boston have created a fantastic 'virtual neuron' which allows you to explore the basics of neural transmission with an interactive flash demo.
Strictly speaking, of course, it's designed for children, but it's remarkably good fun whatever your age.
Once you've got the demo window up, the options at the top of the screen allow you to choose different demonstrations, and the text below explains what's happening.
Man hammers nail into head every week for 11 weeks:
I just found this jaw-dropping case study of a man who banged 11 nails into his head while sadly quite distressed and psychotic.
The X-ray images are striking on their own, and what is even more astounding is that he made a full recovery.
Penetrating head injury in planned and repetitive deliberate self-harm.
Mayo Clinic Proceedings. 2007 May;82(5):536.
Demetriades AK, Papadopoulos MC.
44-year-old man presented to his local emergency department wearing a baseball cap and complaining of headaches that had progressively worsened over the preceding 11 weeks. After we provided generous analgesia and performed simple investigations that failed to identify a diagnosis, the patient removed his cap to reveal an assortment of metallic objects embedded in his scalp. Plain radiographs showed 11 nails penetrating into his brain. A detailed history revealed a diagnosis of paranoid schizophrenia, and the patient confirmed that he had hammered a nail into his head each week for the past 11 weeks to rid him of evil. The nails were removed with the patient under general anesthesia, and he made an uncomplicated recovery with no neurological deficits.
Today's Nature has a great article [pdf] on the neuroscience of psychopaths, as investigated by an ingenious study being run by a group of Dutch researchers.
Although there is a higher number of psychopaths among violent criminals, a psychopath is not necessarily someone who is violent.
The term describes someone who is considered to lack empathy or conscience, is superficially charming, manipulative, has 'shallow affect' (doesn't have a big emotional range) and has poor impulse control.
More recently, psychopathy has become synonymous with the use of the PCL-R, the diagnostic tool also known as the Hare Psychopathy Checklist after it's creator and psychopathy researcher Robert Hare.
The Dutch team, however, are working with psychopaths who are in prison for presumably quite serious crimes, precisely because they lack empathy.
They are comparing the brain activation between psychopaths and non-psychopaths when they view material that communicates emotions and normally evokes an empathy-driven reaction.
By looking at which areas are less active in the presumably empathy-less psychopaths, they hope to find out the crucial empathy-related brain circuits.
There are more details about the study in the article, but one bit is particularly interesting, where one of the participants, from a high security prison, comments on the study:
When he entered the prison five years ago, Boerema says, 'borderline personality' was the fashionable term, and his designated pigeonhole. "The psychopathy label is more damaging though — it prompts everyone to see you as a potential serial killer, which I could never be." (Note, in reporting this article it was agreed that inmates' crimes would be neither asked about nor reported on.) But Boerema also wears the score as a badge of honour: "I think my high psychopath score is a talent, not a sickness — I can make good strong decisions, and it's good to have some distance with people."
Interestingly, Boerema (not his real name) makes a couple of points that have also been made in the psychological literature.
Ian Pitchford proposed in a 2001 article that psychopathy could be an evolutionary advantage for a minority of individuals, as it allows them act violently or antisocially without any emotional cost to themselves.
Furthermore, discussion in both the psychological and legal literature has focused on whether labelling someone a 'psychopath' is unjustly stigmatising.
One article even goes as far as to suggest that 'psychopathy' is just a modern term we've invented to replace the world 'evil'.
The abstract of a fascinating 1995 review paper by Maria Casagrande and colleagues which gathered experimental data together to try and work out which of the brain's cortical hemispheres falls asleep first.
It turns out, it's the left.
Which hemisphere falls asleep first?
Neuropsychologia, 33(7), 815-22.
Casagrande M, Violani C, De Gennaro L, Braibanti P, Bertini M.
Behavioral tasks (reaction times to acoustic stimuli and finger tapping tasks) performed by normal subjects when sleepy or attempting to fall asleep have been used as indices of hemispheric asymmetries during the sleep onset period. Results show a stronger impairment of the left hemisphere (right hand) both in reacting to external stimuli and in sustaining endogenous motor programs. The left hemisphere seems to fall asleep earlier than the right hemisphere.
Harnessing the brain's power to reorganise after injury:
The online Dana magazine Cerebrum has a great article on neurorehabilitation - the art and science of helping someone to recover from brain injury both by harnessing the brain's natural ability to adapt, and by teaching the injured person new skills and abilities.
The article discuss both rehabilitation medicine, the practice of training patients to adapt and improve, and the neuroscience techniques which are being developed to try and tackle the problem at the cellular level.
One of the key processes which science is trying to understand and optimise is 'neuroplasticity', the process by which the brain makes new connections, reorganises and routes around damage.
The article sets out six key questions for neuroscience that, when answered, should revolutionise who we can treat brain injury:
1. Since so much of what we think we know about regeneration is derived from experiments on immature nerve cells, are the mechanisms of regeneration in the injured mature nervous system the same as those that apply to the developing embryonic nervous system?
2. Since the vast majority of experiments in regeneration of nerve pathways have been done in rats and mice, how predictive are these experiments for results in human patients? Apart from molecular differences, rodents are much smaller than we are. Nerve fibers may have to regenerate much farther in humans in order to achieve the same level of reconnection that underlies functional improvement in smaller animals.
3. Even if sufficient nerve regeneration can be achieved, will the connections made be specific enough to underlie real function?
4. How helpful are stem cells? Can they survive after transplantation into the human spinal cord or will they be rejected? Can they replace damaged neurons or will they serve only as sources of chemical substances that support survival and growth of the brain’s own nerve cells?
5. Will we be able to identify a single approach that is so fundamental that it can yield dramatic improvements in recovery from brain injury, or will we need to develop a cocktail approach, using multiple treatments simultaneously?
6. Will approaches that enhance regeneration in one circumstance, for example spinal cord injury, also work in other situations, such as stroke or traumatic brain injury?
On a related note, Sharp Brains has picked up on the fact that American TV channel PBS will shortly be broadcasting a special on brain fitness and neuroplasticity.
It'll probably focus on normal ageing and brain fitness rather than brain injury, but hopefully should tackle some of the neuroscience behind brain changes in general.
Retrospectacle has found an amazing case of a five year-old boy who impaled his left frontal lobe on a deer antler after he tripped and fell while carrying it.
The business end of the antler (which was thankfully no longer attached to a deer) went through his eye socket and into his brain.
Luckily, the young lad made a full recovery with no loss of eyesight and no long term brain damage.
Brains of children (particularly those under the age of 8) can make recoveries from injuries that would be much more serious in adults.
This is because young brains are still very 'plastic'. In other words, they are still growing and re-shaping.
These recoveries can sometimes be quite astonishing. For example, as we've reported previously, some young kids can make a full recovery even when they've had half their cortex removed.
Interestingly, this child's injury from the deer antler is similar to an 'ice pick lobotomy', detailed in a fantastic Neurophilosophyarticle.
One difference, however, is while both the ice pick and the deer antler have entered the brain the same way, the ice pick would be moved side to side to cause damage over a much wider area.
Link to Retrospectacle on amazing deer antler injury.
Scans, brain waves and pulses: three way neuroscience:
One of the reporters for Wired took part in an experiment that combines several key neuroscience technologies to pinpoint a brain area, switch it off, and measure the effects.
The experiment used a combination of fMRI, transcranial magnetic stimulation (TMS) and EEG.
TMS is a technique that allows parts of the brain to be safely and temporarily shut down or stimulated for a few hundred milliseconds. It's particularly useful because it allows you to be sure that the function of a brain area is involved in causing a particular behaviour.
Brain scans only allow you to see if an area is associated with a behaviour. The brain area might be reliably active when something important is in progress, but like a car radio, it might not actually be driving the outcome.
However, if you guess that an area is part of the cause, you can use TMS to change its function while the behaviour is in progress. If the behaviour changes, you know the brain area is involved.
Often, the brain area is chosen because it is commonly associated with that behaviour. The trouble is, each person varies slightly.
Doing an fMRI brain scanning experiment first will tell you exactly where activity occurs, so later on, you can use TMS to target the spot more precisely in each individual.
While using TMS to alter the function of a brain area, researchers can also use EEG to see the physiological effect of the stimulation. As well as seeing the behavioural outcome, you can also see it's effect on the wider brain networks.
Combining these techniques is becoming increasingly common in cognitive neuroscience.
Some recent studies have even used TMS when people are lying in fMRI scanners using magnetic coils made of non-ferrous materials so as not to be dangerous in the powerful scanner magnet.
My favourite one is a recent study where they used TMS to trigger 'movement' in a phantom limb by stimulating the motor cortex. They then measured the brain activity linked to movement in the non-existent hand.
Link to Wired article. Link to abstract of article on TMS-induced phantom hand movements.
Brave old world: the future of cognitive enhancement:
The British Medical Association has just released a report on the ethics of using medical technology to increase cognitive function and optimise the brain. Although the report looks to possible futures, many of them are already upon us.
The report is an interesting sign that cognitive enhancement, using largely physical interventions such as drugs and implants, is now a topic important enough to trouble the UK's professional medical association.
Many of the ethical concerns centre around a potential future where brain enhancing interventions are largely available to the wealthy, leading to a 'brain gap' where the less well off will have relatively poorer mental functioning because they can't access the same cognitive benefits.
However, this is exactly the situation we already have.
Probably the single best cognitive enhancer available to the human race at the moment is a balanced diet and healthy lifestyle.
Poor health goes hand in hand with poverty, meaning those who have less money are likely to have brains that don't function at their optimum because of increased stress, poor nutrition and increased susceptibility to damage and disease.
Martha Farah's research group has been specifically researching the links between the neuropsychological development of children and poverty, and have found that children from poorer social groups have markedlypoorer mental and neurological functioning.
It is possible that a drug or implant will be discovered in the future that will extend our abilities by an order of magnitude, but more likely the improvement will be much more modest. For example, an improvement of 10% would be considered to be clinically important.
So while it's essential to consider the ethical implications of how specific cognitive technologies will affect us, the inequality-driven 'brain gap' is already here.
One ethical issue less commonly debated is whether we are justified in spending billions developing high-tech cognitive enhancers for a relatively small section of the population rather than support the widespread improvement in nutrition and lifestyle which we know has a strong, reliable and life-long effect.
Link to BMA report 'Boosting your brainpower: Ethical aspects of cognitive enhancements'.
Technology Review has an article that looks at recent work on the neuroscience of chronic pain. While understanding the problem in terms of neurobiology is essential, understanding the psychology and social influences on pain is equally important.
Chronic pain is an interesting condition because it can continue even when the original tissue damage has healed.
The article talks about chronic pain purely in terms of its neurobiology, but there is now a great deal of evidence that we can explain how pain is maintained through social and psychological explanations.
This is remarkably hard for some people to take on board, as there is still the attitude that explaining something in psychological terms somehow implies the pain isn't "real" or is somehow a figment of their imagination.
As he recounted in a recent article for the British Medical Journal, Ben Goldacre came across exactly this when he recently discussed the psychosocial aspects of pain on the radio and got a number of outraged listeners contact the programme to say they were offended by the implication that their suffering was imaginary.
This is exactly the opposite of what the standard scientific approach aims to do though. It accepts that pain is experienced, but attempts to work out the biological, psychological and social factors that can increase or decrease pain.
One of the most important findings in the last few decades is that psychological and social factors have a huge influence.
A recent review article, published in Psychological Bulletin [pdf], examined all of the factors and recounted some fascinating studies that have found that people's beliefs about pain have a huge impact both on how unpleasant they rate the pain to be, and on how disabled they are in everyday life.
This is just a sample from the huge amount of research done on the psychology of pain:
Appraisal and beliefs about pain can have a strong impact on an individual's affective and behavioral response to pain. If a pain signal is interpreted as harmful (threat appraisal) and is believed to be associated with actual or potential tissue damage, it may be perceived as more intense and unpleasant and may evoke more escape or avoidance behavior. For instance, pain associated with cancer is rated as more unpleasant than labor pain, even when the intensity is rated as equivalent (Price, Harkins, & Baker, 1987). Similarly, Smith, Gracely, and Safer (1998) demonstrated that cancer patients, who attributed pain sensations after physiotherapy directly to cancer, reported more intense pain than patients who attributed this pain to other causes... These studies demonstrate the important role of people's interpretations regarding the meaning of pain.
Pain appraisal and pain beliefs are also prominent determinants of adjustment to chronic pain (Jensen, Romano, Turner, Good, & Wald, 1999; Turner, Jensen, & Romano, 2000). The following pain beliefs have been identified as particularly maladaptive in dealing with pain: Pain is a signal of damage, activity should be avoided when one has pain, pain leads to disability, pain is uncontrollable, and pain is a permanent condition (Jensen, Turner, Romano, & Lawler, 1994; Turner et al., 2000). The belief that pain is a signal of damage and the belief that activity should be avoided in order to recover from pain appear to be widespread (Balderson, Lin, & Von Korff, 2004; Ihlebaek & Eriksen, 2003).
Because of the importance of our beliefs about pain on the experience of pain itself, we know that psychological therapy can lead to significant improvement.
A key 1999 study [pdf] gathered evidence from all the relevant clinical trials to date and found that cognitive behaviour therapy was a useful and powerful treatment.
Although we typically associate pain with physical damage to the body, thinking only in terms of physical damage is counter-productive. We also need to tackle the psychology and neuroscience of pain both to fully understand it and to help people affected by it.
Link to TechReview article on the neuroscience of chronic pain. Link to Ben Goldacre on the challenges of communicating psychosocial factors. pdf of scientific article on psychology and neuroscience of pain. pdf of scientific article on effectiveness of CBT for pain.
The August edition of medical journal Epilepsy and Behaviour has an interesting case study of a patient who found that listening to Mozart could reduce his epileptic seizures.
The patient had what are known as 'gelastic seizures', meaning they trigger laughter when they occur.
Anticonvulsive drugs didn't seem to help, and surgery to try and remove the focus of his seizures (often a successful treatment) had little significant effect.
We admitted for assessment a 56-year-old gentleman who had experienced gelastic seizures (laughing fits) since shortly after birth. He developed complex partial seizures during his teenage years and secondarily generalized tonic–clonic seizures in his midthirties...
It was agreed that he should be admitted for reassessment of his condition and to determine whether further surgical intervention could be of benefit.
A few months prior to his admission, he learned that Mozart's music had been used, with some success, to enhance spatiotemporal reasoning. He therefore began to listen to Mozart for an average of 45 min a day. He did not listen to one particular piece of music.
Before he began listening to Mozart, he was having gelastic seizures with intense laughter, in association with altered perception and experiential phenomena, at a frequency of five or six per day, as well as secondarily generalized tonic–clonic seizures at an average frequency of seven per month. Electroencephalography revealed some evidence of right hemisphere involvement during the seizures that lasted 15–30 s. Seizures also were associated with a brief rise in heart rate.
Within days of starting to listen to Mozart regularly, he noticed a difference in the pattern of his seizures. In the 3 months during which he had listened to Mozart, he did not have any secondarily generalized tonic–clonic seizures. He continued to have five gelastic seizures a day, but these manifested as simply a brief smile (5–9 s), which he could disguise in the presence of others; in addition, the altered perception and experiential phenomena ceased.
Repeat MRI at this time revealed no change in the hypothalamic hamartoma and no definite or consistent EEG or ECG changes with any of the brief events.
No significant change has been observed during neuropsychometric testing since 2000.
The authors of the study mention in passing the so-called 'Mozart effect' - where the music supposedly helps the brain operate more effectively owing to its typical rhythm which affects brain function.
It's largely thought to be rubbish by most serious neuroscientists, although that hasn't stopped a whole industry of 'brain enhancing' Mozart products being pushed onto unsuspecting punters.
For some people, epileptics seizures can be triggered by very idiosyncratic things.
As we discussed previously on Mind Hacks, 'musicogenic epilepsy' can be triggered by types of music, specific tones, or even specific songs (there's a good discussion of this in Oliver Sacks' new book).
It is likely, therefore, that from some people, specific music or types of music will also reduced their chances of having a seizure.
Link to PubMed entry for case study in Epilepsy and Behaviour.
Artist Lee Pirozzi creates wonderful three-dimensional fabric brains and neuroanatomical structures.
The piece on the left is called 'Blue Jean Brain II'.
Pirozzi's portfolio also describes a few of the pieces like so:
...in "In Search of the Perfect Blue Jeans," denim, sequins, and satin form the textured and nuanced surfaces of the human brain, while in "Amygdala of Terror," a snakelike coil appears affixed to the brain itself.
The pieces make a lovely complement to The Museum of Scientifically Accurate Fabric Brain Art which displays the work of neuroscientists who carefully depict their favourite subject through needlecraft.
Link to Lee Pirozzi's fabric brain sculptures (thanks mirbrewer!). Link to The Museum of Scientifically Accurate Fabric Brain Art.
Neurophilosophy has just published another wonderfully illustrated article on a key moment in neuroscience: this one focuses on Alois Alzheimer, one of the first to discover the major brain changes in Alzheimer's disease, and Auguste Deter, the middle aged woman in whom he first detected the pathology now inextricably linked to the disorder.
When in his care, Alzheimer carefully recorded Deter's clinical symptoms of memory loss, impaired language and confusion, and later, when she died, he looked carefully at her brain during post-mortem.
Using a recently developed staining technique he found abnormal clumps of protein, peppered throughout the brain - which are now known to be amyloid plaques - one of the most recognisable features of the disease.
The article makes the interesting point that Alzheimer did not in fact discover this, but that the name has stuck because the head of the research group, Emil Kraepelin, highlighted the findings under the name 'Alzheimer's disease' to promote the institution.
Although well known in his own right, it is true that Kraepelin gained much reflected glory from promoting the work of Alzheimer.
Unfortunately, Kraeplin's reputation was to be tarnished by his other all-together less distinguished protégé, Ernst Rüdin.
Rüdin was hired by Kraepelin to study the genetics of mental illness and found evidence of how mental instability could be inherited.
Later, Rüdin became a key player in drafting the Nazi Law to Prevent Hereditarily Sick Offspring which resulted in the forcible sterilisation of thousands of people with physical disabilities, drug addiction, and mental and neurological disorders.
This was the beginning of what was later to become Action T4 in which thousands upon thousands of people with supposed 'hereditary defects' were systematically killed by the Nazis.
Alzheimer's contribution to neuroscience is thankfully notable for the right reasons, and the Neurophilosophy article is a great tour through his work, notes and original drawings.
Link to Neurophilosophy on 'Alois Alzheimer's first case'.
I love the way this completely startling fact is dropped into a sentence about one of the pioneers of German neurology:
The work of Wilhelm Griesinger (1817-1868) (whose father was murdered by the family's insane piano teacher) marks the birth of neurology in Germany.
The excerpt is from a book I'm reading called Forced Normalization (ISBN 1871816378) by Trimble and Schmitz which is nothing to do with forcing people to be normal, but tackles the fascinating phenomenon where some people become psychotic as soon as their epilepsy is successfully treated (their EEG is 'normalised').
The person most associated with this concept is Heinrich Landolt, and the book contains a translation of his key 1958 paper in which he reported a case series of people with epilepsy. It contains this interesting conclusion:
Thus, these cases reveal an unmistakable correlation between the course of the psychotic process and the changes in the EEG, in the the paroxysmal focus which is active before and after the twilight state dissolves during this twilight state, and often so completely that the record is normalized. In other words, and putting it more crudely, there would seem to be epileptics who must have pathological EEG in order to be mentally sane...
Interestingly, this phenomenon may have been the basis of Meduna's false belief that epilepsy and psychosis don't occur together, leading him to try inducing seizures as a treatment. This was the birth of an idea that was later developed into electroconvulsive therapy (ECT).
This is certainly not the most common pattern, however, as for the majority of people, epilepsy makes psychosis slightly more likely to occur.
Narcolepsy is a disorder where the affected person can just drop off to sleep during the day. It's known to be a problem with the brain's arousal system and an interesting article in Discover magazine discusses recent findings that suggest a immune system impairment may be at the root of the problem.
As well as falling asleep unexpectedly, people with narcolepsy can experience other sleep experiences that would usually be a relatively common part of sleep (such as confusing dreams with reality, waking or drifting off hallucinations, sleep walking-like activity and paralysis) but because they are so often dropping in and out of consciousness, they occur more frequently or more intensely than in others.
Because of these strange and unpredictable phenomena, sufferers often appear to be drunk or delusional rather than just extremely sleepy. Why the disease has such a wide range of effects isn’t completely understood, but in recent years a potential cause—the loss of hormone-producing neurons, possibly through an autoimmune response—has been identified. That knowledge in turn promises to pave the way for more precise treatments and stronger relief from narcolepsy’s debilitating symptoms.
Studies looking at the genetics of the disorder have found that about 90% of cases can be linked to a gene which is involved in the regulation of the immune system.
It is thought that this may lead to the erroneous destruction of the hormone hypocretin, which is known to be involved in the sleep-wake cycle.
Link to article 'What Breaks Down the Asleep/Awake Divide?'
I've just discovered a fantastic short article on the curious neurological syndromes that appear in Alice's Adventures in Wonderland. It was published a couple of years ago in a clinical neuroscience journal and is freely available online as a pdf file.
In fact, one condition, 'Alice in Wonderland Syndrome' is named after the book, and is otherwise known as micro or macrosomatognosia - a type of body image distortion where you feel you are very large or very small.
It was first reported by psychiatrist John Todd in a 1955 article that noted its connection with epilepsy and migraine.
There are a variety of other possible syndromes that appear in the story, however.
Dr Andrew Larner, author of the recent article, notes that stammering, mirror phenomena, and prosopagnosia all make an appearance.
In contrast, the strange behaviour of the 'Mad Hatter' was unlikely to have been inspired by the effects of mercury poisoning, supposedly a common result of working in the hat industry at the time, as he displays none of the typical features of this type of neurological impairment.
Instead, he's likely have simply to have been based on an Oxford furniture dealer who was known for his eccentric behaviour.
Believer Magazinecovers the battle over whether neuroscience has supported or undermined Freud's theories on dreaming, who suggested that dreams are symbolic expressions of our unconscious mind.
The debate is particularly interesting because it is largely centred around two larger-than-life personalities.
Allan Hobson is a retired Harvard psychiatry professor who did a great deal of neurophysiological work on dreaming and is vehemently anti-Freud, suggesting that dreams are just the higher cognitive centres creating a narrative out of essentially random brain stem activation.
Mark Solms is a psychoanalyst and neuropsychologist who also researches the neuroscience of sleep, and has argued that dreaming heavily involves higher brain centres and involves a different mechanism from sleep itself, suggesting that there may be involvement of symbolic processing from higher cognitive centres.
The two had a famous debate, which has been made available as an oddly 'Fight Night' packaged DVD, where they trade blows over the nature of dreaming and the brain. Their dispute has been continued in both popular and scientific publications.
Hobson originally congratulated Solms on his research, but when he discovered that Solms was on the board of the New York Psychoanalytic Institute and was working on an English translation of the complete works of Freud, he stopped writing him friendly letters. He has since altered his own theory to allow for more activity in the forebrain, not just the brain stem as he had originally proposed, but still insists that dreams have no inherent meaning: they’re the equivalent of Rorschach blots, and analysts or dreamers can make of them what they choose. He's addressed the controversy in a series of journal publications with titles like "Freud Returns—Like a Bad Dream." Or "In Bed with Mark Solms? What a Nightmare!"
In a somewhat unusual turn of event, Hobson suffered a brain stem stroke in 2001, which seems to have stopped him dreaming, which, he argues, bolsters his claim that dreaming is essentially random activation of the cortex by the brain stem.
However, it's also notable that the stroke has stopped him sleeping, so the issue remains unresolved.
The Believer Magazine does a great job of capturing the debate, as well as the personalities involved.
Link to Believer Magazine article 'Hobson's Choice'.
The New Scientist Invention blog has a short piece on a recent patent application for a radiator which could be installed over a sensitive area of the brain that would allow it to be cooled and prevent epileptic seizures in susceptible people.
It's not actually such a wacky idea and previous research has suggested something similar.
A 2003 paper by Steven Rothman and Xiao-Feng Yang suggested that an electrical cooling system could be implanted to detect seizure activity and temporarily cool the area to prevent a full-blown seizure.
Link to NewSci piece on the 'brain radiator' (via /.).
There's an interesting and in-depth article in The New Yorker on using brain scans to communicate with people who may be trapped in a persistent vegetative state (PVS) - a coma-like condition that can occur after severe brain injury.
The article focuses on the work of Dr Adrian Owen and colleagues who published a key paper [pdf] in Science last year which reported changes in voluntary brain activation in response to verbal request in a patient who was seemingly unconscious when assessed externally.
The research suggests that some of these patients may be misdiagnosed as being unconscious, when, in fact, they are aware of their surroundings but trapped in their immobile bodies.
Needless to say the research has both stirred some primal fears and garnered a great deal of scientific interest.
Recent research by Owen and other neuroscientists may eventually help make diagnoses more accurate, but it is not yet clear how the new brain-scan data will affect the medical understanding of consciousness. As Owen put it, "The thought of coma, vegetative state, and other disorders of consciousness troubles us all, because it awakens the old terror of being buried alive. Can any of these patients think, feel, or understand those around them? And, if so, what does this tell us about the nature of consciousness itself?"
The article goes on to consider what implications this study has for our understanding of consciousness and discusses some other fascinating studies which suggest how disordered brains can give leads into this crucial question.
One important application of this understanding is to work out ways to 'awaken' patients in similar states, which includes using implanted brain electrodes to stimulate under-active arousal-related brain areas.
I found the article via Frontal Cortex, which also has some interesting speculation on the possible links between these states and 'blindsight'.
Link to New Yorker article 'Silent Mind'. Link to information on persistent vegetative state.
The Spanish Journal of Psychology has an interesting English language article [pdf] on the neuropsychology of private thoughts - still one of the most mysterious and poorly understood aspects of our mental life.
Neuropsychology is especially good at looking at how differences in brain function relate to objectively observable behaviour. Private thoughts are quite hard to study in this way, because they are essentially subjective.
Sometimes, of course, we make our private thoughts 'public' by talking to ourselves, and, it seems, this is something we learn to do during childhood.
Infants seem unable to 'think to themselves' and instead 'talk to themselves' when solving problems, usually vocalising the most tricky or novel aspects of the situation. As we grow, we develop the ability to internalise this speech, and can eventually have a purely internal monologue.
Understanding inner speech is also important because it becomes distorted in psychotic disorders such as schizophrenia.
People with psychosis can experience effects like 'thought insertion', where they experience external thoughts being inserted into their stream of consciousness, or 'thought withdrawal', where thoughts seem to be removed from the mind.
This suggests that there must be something that the brain uses to identify thoughts as self-generated, and that this perhaps breaks down in psychosis, so we can have the uncanny experience of having thoughts that don't seem to be our own.
Why we would need this is an interesting question, as surely all thoughts would be our own.
However, the Spanish Journal of Psychology article notes that inner speech often activates areas of the brain also used for 'outloud speech', suggesting that it may be a sort of internal action.
Being able to distinguish bodily movements caused by something external (someone moving your arm) and movements caused by our own will is very important, and, perhaps, this is the sort of mechanism that becomes disturbed for what were originally movements, but have become internalised as we 'think to ourselves'.
pdf of 'A Neurocognitive Approach to the Study of Private Speech'. Link to SciAm article on private speech in children.
Nature Reviews Neuroscience has a fascinating article on drugs that remain dormant in the brain and only respond when damage occurs.
They've been christened pathologically activated therapeutic (PAT) drugs and rely on the fact that brain damage triggers specific chemical changes and drugs can be designed to take advantage of these processes.
For example, memantine is a type of drug that antagonises (blocks) the NMDA receptor which is activated by the neurotransmitter glutamate.
Important, because this receptor is known to be activated to excess in conditions like Alzheimer's and Parkinson's disease.
Several drugs block this receptor, including ketamine and PCP ('Angel dust'), but they block the receptor as soon as they arrive.
Memantine is different - it doesn't do its job unless the receptor has already been activated or 'opened' at least once already - making it a 'non-competative antagonist' - in other words, it doesn't compete with the neurotransmitter, it waits until it's been and gone.
It's as if you wanted to prevent postmen from delivery their parcels by bricking up each door, but the householders will only open their door to the postmen.
So you hang around, wait for the postman to call, and then get in the doorway and block it. You're not fighting the postmen while they deliver the letter, you're avoiding conflict and taking advantage of what they already do.
This gives memantine a very important property. It blocks more receptors the more glutamate is about, or to return to our analogy, it can block more doors when there are more postmen about.
This means the drug 'lies in wait'. As more NMDA receptors are activated owing to Alzheimer's disease, the more it steps in to calm the situation down and prevent constant activation which is what is thought to cause the most damage.
The article outlines several other neurochemical processes that allow drugs to seemingly 'lie in wait' and only react to damage, rather than affecting the brain regardless of what else is happening.
It's an interesting, clever and potentially very important twist on drug design that takes advantage of our growing knowledge of how the brain works in both illness and health.
Salon have just announced the start of a regular series of neuroscience articles with the first tackling whether brain scans might enable us to communicate with people who are conscious but trapped in their paralysed bodies.
The article considers a recent scientific paper [pdf] on the use of brain imaging to detect awareness in people who might otherwise be thought to be in a coma-like state, but actually are largely unable to communicate with the outside world because they're paralysed.
We've covered twostudies during the last few years that have reported consciousness in what were thought to be unconscious patients owing to the fact that their brain activity seemed to reflect complex mental processes or could be altered at will, following verbal requests from the researchers.
There are two main implications of this work, the first is that we could better diagnose patients as being paralysed rather than in comas, and the second is the hope that we could design systems to read the brain activity in a reliable enough way to allow affected people to communicate with the 'outside world'.
With all of the brain scan hype we get subjected to, the article considers an important but rarely discussed point - although revolutionary, fMRI isn't a very accurate measure of brain activity and we can't directly infer subjective mental states from brain scan data.
This means its utility as a tool for detecting consciousness, let alone 'mind reading', is severely limited.
Interestingly, the article is written by a neurologist called Robert Burton, who shares a name with the author of the 17th century bookThe Anatomy of Melancholy which remains one of the best books ever written on the troubled mind.
It seems this article is the first in a new series called Mind Reader - "a new Salon feature exploring the galaxy of the brain."
Link to Salon article 'The light's on, but is anybody home?'. pdf of review article on fMRI detectection of awareness in coma-like states.
Musicogenic epilepsy is a neurological disorder where epileptic seizures are uncontrollably triggered by music. Gloria Estefan's Dr Beat is a catchy 80s pop song where she calls for medical assistance because music is irresistibly moving her body, moving her soul and affecting her brain.
Coincidence? I think not.
Doctor, I've got this feelin' deep inside of me, deep inside of me
I just cant control my feet, when I hear the beat
when I hear the beat
Hey doctor, could you give me somethin' to ease the pain
cause if you dont help me soon gonna lose my brain
gonna go insane
Despite Ms Estefan's requests, painkillers are unlikely to help with the acute effects of seizure.
First-line treatment is usually a rapid acting benzodiazepine and long-term stabilisation with a common anticonvulsant such as sodium valproate.
While her concerns about her mental health are understandable (people with epilepsy are at a slightly higher risk of developing mental illness), the majority of people with the condition lead full and active lives, so her fear of insanity is largely unfounded.
There are many cases of musicogenic epilepsy in the medical literature but, unfortunately, only a few few are freely available online. One is particularly interesting though and is available as a pdf file.
It's a 1957 article published in Psychosomatic Medicine that reports three fascinating cases, including a girl who had her seizures triggered by swing music that induced, among other things, hallucinations of a smartly dressed couple.
For those of you wanting something a bit more up-to-date though, YouTube has the a Dr Beat Mylo remix Dr Who video mashup. Same symptoms, new medical staff.
pdf of 'Musicogenic Epilepsy: Report of Three Cases'. Link to Dr Beat lyrics. Link to original Dr. Beat video. Link to Dr Beat remix Dr Who tribute mashup.
The Financial Times has a slightly bizarre article on the application of neuroscience to architecture that suggests that we're genetically predisposed to feel relaxed around flowers, the hearth and food, and that homes need to be designed to release certain neurotransmitters.
The piece is about the Academy of Neuroscience for Architecture (ANFA) which aims to use neuroscience in building design and encourage brain research into the effects of buildings.
I'm all for the wider application of neuroscience, and I'm sure there are some relevant findings that could be applied, but the article is full of so many erroneous brain clichés that I just despair.
Zeisel is also a director of the Academy of Neuroscience for Architecture (ANFA), an organisation launched in 2003 to encourage scientists to get out of the lab and partner with architects and designers. "It's the future of the field," he says. "People might ask what neuroscience has to do with designing an 'emotional' house but our emotions are managed by our brain," Zeisel says. "When our brains are happy a certain endorphin gets released, so we need to design homes in order to release that neuro-transmitter."
Endorphins are the brain's natural opioids and are released in a wide variety of situations. They are indeed released when we feel pleasure, but are also released when we feel stress or pain.
So designing homes to maximise the release of endorphins will just as likely lead to uncomfortable, stressful hell-holes.
Take our desire for eye contact with others as an example. "A couple of million kitchens are planned each year and probably only about 5 per cent obey the most basic principles for human communication," [kitchen designer!] Grey says. In most, the person preparing the food at the sink, stove or counter has to face away from his or her family or guests, decreasing sociability in what should be a social zone. "As a result the brain continues to produce adrenalin and cortisol, the hormones associated with fear and anxiety," he says. "Whereas if they are facing [into the room] then oxytocin, the bonding hormone, and serotonin, associated with relaxation and enjoyment, are released."
So, it not only makes the common but false link between specific mental states and general neurotransmitters, makes unproven claims between specific activies and the release of these neurotransmitters, but also makes the unsupported claim that facing away from people in the kitchen causes fear and anxiety, while facing towards them causes relaxation and enjoyment.
Zeisel suggests that responses to some features of the home might even be innate. "We are born with genetically developed instincts that make us feel relaxed around flowers, the hearth, food and water," he says. "It's simply an emotional need and using those things in the environment will make us feel more comfortable." On the flip side, places that seem too sterile or too confusing are perceived as dangerous, which can trigger the hypothalamus to release stress hormones.
There's no evidence that we are genetically predisposed to feel relaxed around "flowers, the hearth, food and water". Perceiving things are dangerous does indeed lead to the release of stress-related hormones, but there's no evidence that 'confusing' or 'sterile' buildings do this.
Of course, buildings that are 'too sterile' or 'too confusing' might do, but therein lies a circular argument, because you've already defined them as having a negative influence.
Professor Joan Meyers-Levy of the University of Minnesota's Carlson School of Management is another academic interested in how our surroundings affect our physical and mental states. Her research shows that when people are in a room with high ceilings, it activates sections of the right brain associated with freedom and abstract thinking. In low-ceilinged rooms, more constrained thinking is brought to the fore. "There's a preference in terms of real estate for high ceilings and it’s [not only] the sense of power and wealth that conveys but also [the fact that] vertical space could have a beneficial mental influence," she says.
To be completely fair to Meyers-Levey, her study [pdf] was a perfectly reasonable investigation into the effect of ceiling height on priming - an effect where an initial stimulus quickens your ability to react to related things.
However, the brain is not even mentioned in the paper, let alone measured in any way. The bit about high-ceilings activating the 'right brain' has just been added, seemingly from nowhere, by the journalist.
Twopapers were recently published in Cell about the application of neuroscience to architecture, but importantly, they speculate, but don't actually reference any studies that have looked at the influence of building design on the brain. The article then goes on to repeat several of the speculations as fact.
I think the article may be a candidate for the Dr Alfred Crockus Award for the Misuse of Neuroscience.
As an aside, Crockus fans may be interested to hear that he's been tracked down to the hitherto unknown but undoubtedly endorphin stimulating 'Boston Medical University Hospital'.
UPDATE:Christian just reminded me that he wrote an article for The Psychologist late last year that looked at how psychology is being increasingly used in architecture. It also discusses specific scientific research on psychology and building design. It's an excellent antidote to the Crockus from the FT.
Link to ropey FT article. Link to Psychologist article 'Is there a psychologist in the building?'.
YouTube hosts a classic video of one of the famous 'split-brain' patients who had his corpus callosum surgically cut to treat otherwise untreatable epilepsy, effectively separating the two hemispheres of the brain.
This procedure is intended to stop seizures spreading across the brain and its effects were first studied in depth by Roger Sperry, who won a Nobel prize for his work demonstrating that the patients experienced, in certain situations, a sort of split consciousness.
Split-brain patients have been incredibly important in cognitive neuroscience, because the procedure prevents information travelling from one side of the cortex to the other.
The left-most and right-most areas of your vision go directly to the opposite hemisphere, and the same goes for touch information from your hands. Information from the left hand goes to your right hemisphere and vice versa.
In people who have an intact corpus callosum, the information is then communicated to the other hemisphere as well, so the whole brain has access. In split-brain patients, only one hemisphere has access.
Sperry worked with neuropsychologist Michael Gazzaniga who used this effect to demonstrate how each hemisphere could be specialised for different functions.
In the video, Gazzaniga runs Joe, a split-brain patient, through one of these experiments and demonstrates various interesting effects.
For example, it shows how Joe can read words that appear to the right because they get transmitted to the left hemisphere which is specialised for language.
However, Joe can't read words that appear to the left, because they get transmitted to the language-limited right hemisphere, but he can draw what the word describes with the appropriate hand, because the right hemisphere is specialised for spatial functions.
He can then look at his own picture, making the information available to the left hemisphere, and only then can he name it.
There have been many variations on these experiments that have demonstrated a number of curious effects about brain specialisation and consciousness, some of which are described in a Scientific Americanarticle by Gazzaniga.
One of the most interesting things is that the patients don't feel that their conscious mind is any different, but their split consciousness can be demonstrated experimentally, as shown in the video.
Link to split-brain video. Link to copy of SciAm article 'The Split Brain Revisited'.
A paper in the British Journal of Oral and Maxillofacial Surgery reports on a remarkable case of a man who tried to commit suicide with a crossbow and shot an arrow through his neck into his brain. Thankfully he survived with seemingly little long-term impairment.
The arrow missed all major blood vessels and did not seem to seriously damage any crucial brain areas, although the gentleman lost some sight due to severing part of the optic nerve.
The case report reads:
A 25-year-old man, presented to the accident and emergency department, after having fired an 18-inch arrow with a metal point from a crossbow just beneath his chin in an attempt to kill himself.
He was known to be addicted to cocaine, was depressed, and had been feeling low for several months. He had tried to explain his state of mind to his girlfriend, and a month later he attempted suicide.
The entry point of the arrow was apparent through the anterior part of the neck, and close to the midline. There was no active bleeding. The arrow crossed the mouth and had passed behind the soft palate, which resulted in mechanical trismus and therefore a potentially difficult intubation.
Nasotracheal fibreoptic intubation [camera through the nose] was eventually completed. With the patient anaesthetised, plain radiographs and computed tomograms (CT) were taken urgently; these showed that the arrow had passed up through the brain, and the tip was protruding through a comminuted fracture of the skull vault.
In view of the location, and to assess soft tissue damage further, a magnetic resonance cerebral angiogram was taken, which showed the anatomy clearly, in particular no vascular injury.
The patient was therefore transferred to the nearest neurosurgical centre for definitive treatment. Under general anaesthesia and together with the maxillofacial surgeons, the arrow was withdrawn gently along the precise path of its insertion. This was followed by profuse bleeding from behind the soft palate and base of skull, which had been anticipated and was controlled by a post-nasal pack. No further intervention proved necessary.
His recovery was uneventful, but he lost the sight in his right eye as a result of damage to the right optic nerve. No other neurological deficit was documented. The patient was given psychiatric care for several months for further management of his depression, which had been the cause of his attempted suicide.
Harry Potter, migraines and the neuroscience of self:
A funny article in the medical journal Headache discusses Harry Potter's difficulties with what seems to be a recurrent migraine. This isn't the first time that Harry has turned up in the medical literature. In fact, he's made almost 20 appearances so far.
However, this is the first to consider his neurological problems in detail:
Harry Potter and the curse of headache.
Sheftell F, Steiner TJ, Thomas H.
Headache. 2007, Volume 47, Issue 6, p911-6.
Headache disorders are common in children and adolescents. Even young male Wizards are disabled by them. In this article we review Harry Potter's headaches as described in the biographical series by JK Rowling. Moreover, we attempt to classify them. Regrettably we are not privy to the Wizard system of classifying headache disorders and are therefore limited to the Muggle method, the International Classification of Headache Disorders, 2nd edition (ICHD-II; pdf). Harry's headaches are recurrent. Although conforming to a basic stereotype, and constant in location, throughout the 6 years of his adolescence so far described they have shown a tendency to progression. Later descriptions include a range of accompanying symptoms. Despite some quite unusual features, they meet all but one of the ICHD-II criteria for migraine, so allowing the diagnosis of 1.6 Probable migraine.
The young wizard also appeared in a recent fMRI study [pdf] that investigated which brain areas would be most active when children and adults thought about themselves compared to others.
In the study, participants were brain scanned while being shown short descriptions and were asked to indicate whether they best described themselves or someone else.
One difficulty is that the 'someone else' needs to be well known to both children and adults, so Harry Potter was chosen.
In the final study, when participants judged that the phrase described themself, rather than Harry, the medial (midline) part of the frontal lobes were relatively more active.
Interestingly, this area was significantly more active in children than adults, possibly suggesting that this task requires more effort for children and becomes easier as we age.
Link to PubMed entry for Harry Potter headache article. Link to abstract of self vs other study. pdf of self vs other study.
An article in this week's Science News discusses whether the brain stem may play a more central role in consciousness than it's usually given credit for.
It focuses on children with hydranencephaly, a where the cortex fails to develop in children and instead, the space is filled with cerebral spinal fluid.
Typically, affected children survive only a few months after birth, but those that do survive seem to remarkably more conscious than you would guess based on theories that suggest the cortex is where all the action happens to support consciousness.
Swedish neuroscientist Bjorn Merker wrote an article [pdf] in February's Behavioural and Brain Sciences journal arguing that these cases suggest we need to rethink our ideas about how the brain supports conscious thought, and perhaps, even consciousness itself.
Merker argues that the brain stem supports an elementary form of conscious thought in kids with hydranencephaly. It also contains auditory structures capable of preserving hearing in someone without a cortex. In contrast, optic nerve damage in hydranencephaly frequently impairs vision, regardless of what the brain stem does.
Self-awareness and other "higher" forms of thought may require cortical contributions. But Merker posits that "primary consciousness," which he regards as an ability to integrate sensations from the environment with one's immediate goals and feelings in order to guide behavior, springs from the brain stem.
If he's right, virtually all vertebrates—which share a similar brain stem design—belong to the "primary consciousness" club. Moreover, medical definitions of brain death as a lack of cortical activity would face a serious challenge. At the very least, physicians could no longer assume that individuals with hydranencephaly don't need pain medication or anesthesia during invasive medical procedures.
Link to Science News article 'Consciousness in the Raw'. pdf of BBS article 'Consciousness without a cerebral cortex'.
Brain type responsible for politics, pant wetting:
It's often said that politicians need their head examined, but contrary to recentreports, you're likely to find out more about whether they wear a hair piece than whether their brains 'dictate' their politics.
The fact that there is a brain difference between people with left-wing and right-wing views is hardly news. Because every view we have is supported by the brain, by definition they'll be a difference somewhere - just as there's a brain difference between people who prefer London to Paris, strawberry to vanilla, or Britney to Christina.
What is interesting about this new study, is that the researchers have found a difference in the ability to inhibit habitual responses in a 'detect a letter' task which was linked to brain activity in the anterior cingulate cortex or ACC - a deep mid-line area in the frontal lobes.
Activity in this area correlates with 'conflict monitoring' - the ability to detect a conflict between completing mental demands.
It forms part of the brain's cognitive control and self-regulation system and when it is triggered, the ACC calls in reinforcements to focus attention - in the form of the upper surface areas of the frontal lobes.
Some cases of people with damage to the ACC seem to have perfectly fine conflict monitoring, so it's not certain that it's a clear link, but the evidence increasingly points that way.
So the study found that conservatives showed less ACC activation and were more likely to respond when they weren't supposed to - in other words, were more habitual in their responding.
Cue media pantwetting about brain types 'dictating' politics, conservatives being 'rigid' and liberals being more 'flexible'.
Most of this is over-interpretation and, needless to say, the study only reports an association, so it's just as likely that preferring conservative politics leads to more habitual responding.
Cognitive Daily have a great analysis of the study and I really recommend it if you want to avoid the hype and actually see what's genuinely interesting about it.
It's one of their wonderfully clear explanations and has a demo you can try yourself. Importantly, their pants stay dry throughout.
Link to abstract of scientific study. Link to fantastic Cognitive Daily analysis.
Neurophilosophy has found a series of simply beautiful images created by using the electrical activity of the brain to seed fractal patterns.
They're generated by BrainPaint, a custom system for neurofeedback - a technique in which a person connected to an EEG machine sees the output of their brain visualised in real-time.
This allows people to see the result of modifying mental states that might otherwise be difficult to monitor internally.
For example, the system might be tuned to show a specific pattern when a peak alpha frequency is reached - reported to correlate positively with cognitive performance.
The user can then practice making this pattern appear more often, as the system allows them to see when they're being successful, where previously it might not apparent.
BrainPaint is a neurofeedback system created by researcher Bill Scott who seemed to have come up with the idea of making the feedback appear as beautiful images.
Neurofeedback is being used quite widely outside the mainstream and currently crosses the threshold between a fringe practice and a scientifically validated therapy.
Certainly, there are now a growing number of scientific studies which have demonstrated its modest but reliable effectiveness in some disorders.
However, its not difficult to find neurofeedback therapists on the fringes of the mainstream who claim amazing effects that aren't supported by the research.
If you want to know more about the science of neurofeedback, Scientific American published an article about it last year.
A fascinating study published in this month's Cerebral Cortex reports that a gene known to massively increase the risk of Alzheimer's disease in later life is associated, in young people, with better memory performance and more efficient use of the brain's memory structures.
The research team, led by neuroscientist Christian Mondadori, looked at the genetics and memory performance of 340 volunteers, all in their early 20s.
The team were particularly interested in which version or allele of the apolipoprotein E (ApoE) gene each person had, because the 'Epsilon 4' allele raises the risk for Alzheimer's disease in old age.
In fact, people with two 'Epsilon 4' alleles are virtually guaranteed to the brain disorder by the age of 80.
Each person took part in a word learning test that involved both short-term and long-term memory. This type of test is known to particularly rely on the function of the hippocampus, a key memory area which is known to decline in Alzheimer's disease.
People who were carriers of the Epsilon 4 allele performed better in the long-term memory test, and no different for short-term memory.
The team decided to do more extensive memory tests while brain scanning 34 participants who were picked specifically to represent equal numbers of the three common genetic combinations.
These tests in the scanner involved learning faces and associations with professions over a number of trials and a target detection task that involved manipulating information in short-term memory (working memory).
There was no difference between the groups in terms of their accuracy on these tests, but people with the Epsilon 4 allele showed decreases in brain activity as time went on, suggesting they were using their brain more efficiently.
In contrast, people without the Epsilon 4 allele showed increases in brain activity, suggesting their brain was having to work harder to keep up.
A key question is why people who carry the Epsilon 4 allele would have a more efficient brain system for memory in early life but are more likely to have these same memory systems degrade in later life, as happens in Alzheimer's disease.
As Alzheimer's typically strikes after the time most people have children, the researchers suggest that the Epsilon 4 allele could confer an evolutionary advantage without adversely affecting chances of reproduction.
Some evidence that supports this idea has been found in previous studies where the ApoE Epsilon 4 allele has been associated with higher IQ scores, reduced heart activity under stress, and reduced chance of difficulties during pregnancy and post-birth problems.
The Plymouth Marine Laboratory brings us footage of experiments on the giant axons of the squid --- the work that brought us the action potential. Quoting:
"The Squid and its Giant Nerve Fiber" was filmed in the 1970s at Plymouth Marine Laboratory in England. This is the laboratory where Hodgkin and Huxley conducted experiments on the squid giant axon in the 1940s. Their experiments unraveled the mechanism of the action potential, and led to a Nobel Prize. Long out of print, the film is an historically important record of the voltage-clamp technique as developed by Hodgkin and Huxley, as well as an interesting glimpse at how the experiments were done. QuickTime video excerpts from the film are presented here.
Discover magazine has an article on '10 unsolved mysteries of the brain' which describes some of the biggest challenges in contemporary neuroscience.
It's an interesting list, not least because you'll notice that several of the problems are conceptual rather than empirical.
For example, the list includes 'What are emotions?', 'What is intelligence?' and 'What is consciousness?' that depend on a good philosophical analysis rather than just more data gathering.
In contrast, some of the other mysteries include things such as 'How is information coded in neural activity?' which is a problem of dealing with the complexity of the signals and their effect, rather than us having problems with defining any of the problem.
The fact that brain research relies as much on conceptual developments as laboratory work is one reason why philosophers are so important to cognitive science.
I like to think of them as conceptual engineers.
Link to Discover article '10 Unsolved Mysteries Of The Brain'.
A study published in Forensic Science International has examined how brain scans can be of use to forensic pathologists - clinicians who perform autopsies to better understand how someone has died, often to provide evidence for a criminal investigation.
Head injuries are unfortunately common. Serious head injuries are most commonly caused by trafficaccidents in Europe and Canada, while in the USA they are most commonly caused by firearms.
These cases will typically involve a police investigation, and the usual method is for a forensic pathologist to perform an autopsy on the head and brain to establish exactly what sort of injury occurred.
One of the drawbacks of this method is that it can only be performed once. The tissue is dissected and it's not possible to keep anything except small samples.
This can be a problem in court, because it means the pathology evidence largely rests on a single examination, done in whatever way the pathologist thought was best, and can rely on their subjective interpretation.
A brain scan might be useful in this situation as it could be independently assessed and might actually pick up some things which might otherwise be missed if the head has to be dissected to be examined.
The study, led by Dr Kathrin Yen, compared findings from a structural MRI scan, a CT scan (an older structural brain scanning technique that uses X-rays) and a post-mortem, on 57 people, the majority of whom had died from serious head injury.
The findings from the scans and the autopsies were compared to see how well they agreed with each other.
The examination of the brain scans entirely missed some signs, such as increased brain pressure, but was 100% accurate in others, such as detecting bleeds between the dura mater, the brain's tough outer membrane, and the skull.
The researchers note that some of the poor results are likely to be because radiologists aren't used to forensic examinations as they're trained to examine living people.
However, the brain scans had a distinct advantage in some cases. In one instance, the brain scan better estimated the size of an internal bleed which was exaggerated during autopsy because it bled further as the brain was cut.
The brain scans also allowed 3D reconstructions which could be examined from various angles to better understand how impacts occurred or what sequence of events might have caused the damage.
The image on the left is of a heat-induced fracture in a man who died in an aeroplane crash. The scan allows the pathologist to see the relationship between the skull fractures and the bleeds in the brain from a number of angles.
The study suggests that brain scanning corpses may give important clues in a forensic investigation but that radiologists may need to be specially trained so they know what they're looking for.
Link to abstract of scientific study. Link to more on forensic radiology from Radiology Today.
This week's Nature has an intriguing short paper by a team of neuroscientists who 'awoke' a man from a 'minimally conscious state' by activating a surgically implanted brain electrode.
Like a coma, 'minimally conscious state' (MCS) occurs after severe brain injury, but is not a state of complete unconsciousness.
Instead, the patient seems mostly unresponsive but can occasionally produce simple responses to commands or prompts that suggest inconsistent consciousness, such as short purposeful actions, brief verbalisations or emotional reactions.
Like coma, MCS is not a caused by a specific type a brain injury. It's a description of the person's behaviour, so it could be caused by varying damage to a wide range of brain systems.
However, it is known that MCS can be caused by problems with arousal. In other words, the major brain systems of the cortex might be relatively intact, but the system that regulates how active they are might be damaged, meaning the person has trouble staying conscious, despite having the potential for possible quite complex mental processes.
The man in question had been in a MCS for six years after suffering an assault with a blunt instrument that caused haematoma - bleeding in the brain, and subsequently, hydrocephalus - a build up of cerebral spinal fluid. Both of which put pressure on the brain that deformed and damaged it.
Because the man in question could intermittently respond to commands and give verbal responses, the researchers thought this might be a case where impaired arousal might be responsible.
To try and boost the activity in his arousal system, the team implanted a deep brain stimulation device (DBS) that sent electrical pulses directly into the thalamus via two brain electrodes.
After the initial tests, just 48 hours after surgery, there seemed to be some minor improvement in responses and EEG patterns.
This was a good sign, but because this was a new technique and each patient's pattern of brain injury is distinct, the researchers had to then begin experimenting with different stimulation patterns.
After 18 weeks of testing, they found what seemed to be the optimal stimulation programme.
The patient showed longer periods of eye-opening and increased responsiveness to command and better limb control. He began to name simple objects, chew his own food and could produce up to six-word sentences.
In terms of the patient's pre-injury level of functioning, the results are modest, but as an improvement on MCS, largely thought to be untreatable after 12 months, it's a remarkable achievement.
The researchers note that this might not help all people with MCS, as this patient was specifically chosen because of his 'widely preserved brain structure', but, as with a previous treatment for coma we reported it's more evidence that targeting the arousal system might be key in some cases.
In the same issue of Nature there's an interesting (but closed access) commentary that makes some interesting points about what this tells us about consciousness, and particularly, the brain's unconscious decision about when to rouse us into consciousness:
In essence, the brain does not process information in the abstract but instead consults information acquired through the senses and in memory insofar as it bears on the decisions made about potential actions and strategies. Our brains allow us to decide among possible options — that is, how and in what context to engage with the world around us. The brain makes many such decisions unconsciously. Indeed, the decision to engage at all is, in effect, an unconscious decision to be conscious. Thus, the brain of the sleeping mother queries the environment for the cry of her newborn. We suspect that the normal unconscious brain monitors the environment for cues that prompt it to decide whether to awaken and engage. This mechanism may be disrupted in various disorders of consciousness, including the minimally conscious state, hypersomnolence, concussion, abulia (lack of will) and possibly severe depression.
Previous theories of consciousness have relied on a central executive and magical physiological phenomena (for example, synchronized reverberations) to elevate the subconscious functions of the brain to consciousness. However, viewed as a decision to engage, consciousness can instead be studied in the same framework as other types of decision and the allocation of attention. Rather than a central executive, there seems to be a network of brain regions that organize the resting state and maintain overall orientation towards context. It is quite possible that they make decisions about whether or not to engage and in what way. They do what Sartre considered impossible: they choose whether to choose or not.
Link to Nature news story on the research (via Retrospectacle). Link to summary of scientific paper. Link to Nature commentary. mp3 of Nature podcast discussion (starts 19 minutes in). Link to write-up from ABC News.
My last place of work blocked huge swathes of the web, meaning I'm discovering I've missed some blog posts recently, including this wonderful Neurophilosophyarticle on the rise and fall of prefrontal lobotomy.
It's a fantastic tour through the history of how the procedure was developed, popularised and abandoned.
It aptly illustrates that medical history has been driven as much by personalities as by evidence, something which has only seriously been addressed in the last half-century by systematic trials and evidence reviews, largely due to the work of Archie Cochrane.
The article does have one quirk, where it equates early antipsychotic drug chlorpromazine with 'psychosurgery gone wrong'.
Despite some serious and unpleasant side-effects (including movement disorders, sedation, weight-gain and dizziness), there is a large amount of evidence for its effectiveness in schizophrenia, and, in fact, was the first effective treatment for psychosis.
Even ignoring the brutal nature of the procedure, lobotomy was not even proven to be a useful 'treatment' by anything that would be accepted as reliable evidence today.
It is, however, an important chapter in the history of neuroscience, not least for what it tells us about how individuals can have such an influence on mainstream practice.
Link to article 'The rise & fall of the prefrontal lobotomy'.
Nature's neurology journal has a freely available article on a technique that interferes with the translation of genetic information into proteins that may help prevent inherited brain diseases.
DNA has two main functions. The 'template function' of DNA is to pass on genes through generations and allow different traits to be inherited.
The 'transcriptional function' of DNA is to allow these genes to be expressed at appropriate times and places (and not expressed at others) to allow the cell to do its work.
'Expression' just means 'turned into a protein' and genes are just blueprints for proteins.
The blueprint gets turned into a protein by messenger RNA, which 'reads off' the information, then moves away to assemble the protein from a store of amino acid component parts.
As different cells in the body have different functions, and individual cells need to behave differently depending on what's happening, different proteins need to be created at different times.
Disorders like Huntington's disease result from genes that cause damaging proteins to be formed. These lead to the malfunction and death of brain areas that, in turn, leads to cognitive problems, movement difficulties, mental illness and eventual death.
Using a technique called RNA interference, researchers have found they can selectively interfere with the process where messenger RNA assembles proteins from the DNA's genetic information.
Essentially, small chunks of gene-specific RNA are introduced into the cell, these find the messenger RNA and destroy the information before it gets turned into a protein.
In other words, it prevents specific genes from being turned into proteins.
This has caused a great deal of excitement because it could lead to treatments for disorders like Huntingdon's by simply 'silencing' the rogue Huntingdon's gene.
While you might have a rogue gene, RNA interference could essentially gag it, meaning it would never have a knock-on effect in the brain.
This has been demonstrated in very limited lab tests, and the Nature article examines the prospects for it being developed into a widespread treatment.
There are still some difficulties to overcome, however. One of which is how to get the interfering RNA into the right cells in the brain, a difficulty with many treatments owing to the filtering effect of the blood-brain barrier.
Another is how to make sure that the technique affects only the disease process. Researchers talk about proteins being involved in 'chemical cascades', meaning that they are involved in huge and complex mechanisms in the body.
It's hard to predict exactly what effect silencing a gene will have, and whether your technique for doing so will also interfere with some other processes that use some of the same mechanisms, some of which we probably don't even know about at the present.
RNA interference is still an experimental process, but it holds great potential for treating inherited brain diseases. The Nature article is a fantastic guide to the cutting edge of the science in this area.
Link to Nature Clinical Practice Neurology article on RNA interference. Link to plain language guide to its use in Huntington's. Link to Wikipedia page on RNA interference.
Magnetic brain stimulation not proven to fight depression:
At a recent American Psychiatric Association meeting, commercial companies were showing off custom made magnetic brain stimulators as a treatment for depression. A review article in the latest Nature Reviews Neuroscience looks at the technology and finds there's still no convincing evidence that it's an effective treatment.
The technology is based on transcranial magnetic stimulation (TMS), essentially a large electromagnetic which is activated near the scalp.
As you might remember from high school physics, a magnetic field that moves over a conductor causes a current. As your brain is a conductor, a current is formed in the neurons which cause them to briefly activate.
After an area of brain is magnetically activated, there are a few hundred milliseconds of inactive 'silence', effectively switching the area off, albeit safely and temporarily.
Depending on how quickly these pulses are applied, over a short period of time (typically a few minutes), the overall level of activity in the targeted brain area can be increased, or decreased. A technique known as repetitive or rTMS.
It has been known for a while that patients with depression have reduced activity in the left frontal lobe.
Researchers thought that TMS could be used to increase activity in this area and treat the depression, and so a long series of controlled trials were started to see how effective it could be.
It turns out, TMS does seem to reliably increase activation in the left frontal lobe, but the evidence on whether it actually improves depression in mixed, so mixed in fact, it's not clear whether overall, it's an effective treatment at all.
One of the difficulties is that there are so many variables to test out.
TMS can be applied to anywhere on the cortex, at varying strengths, at varying frequencies, at varying angles, with different wave forms and with different shaped coils, just to name a few of the possibilities that don't include variation in the patients themselves.
Ridding and Rothwell, authors of the review paper, are not impressed with the results so far, but note some areas are promising but under-researched:
It is a sobering conclusion. A new treatment that might help some patients slightly more than placebo, but for which we do not know the most effective dose nor the best group of patients to target. Yet this is not the most worrying thing about the depression story. The main problem is that none of these trials has advanced our understanding of how rTMS may be having any action at all in depression. Trials currently underway are being conducted with almost the same rationale as the initial trials more than 10 years ago. The only changes are in variables such as the subset of patients being studied, or the intensity of the stimulus with respect to the distance of the patient's brain from the scalp surface. In effect, the science has stood still.
In retrospect, depression was probably a poor choice of condition in which to begin trials of rTMS. It is phenotypically diverse with difficult diagnostic criteria and a subjective clinical evaluation that makes it highly susceptible to any placebo effects of rTMS. Diagnostically simpler conditions that have been studied more recently, such as auditory hallucinations in schizophrenia and tinnitus may prove more tractable. In both cases, rTMS of areas of the parietal or temporal cortices, respectively, have reduced symptoms, in some cases for several weeks after treatment. However, the number of studies done so far is small, and any firm conclusions about efficacy await much larger controlled trials.
This hasn't stopped a number of companies producing 'off-the-shelf' TMS devices to make the technology more accessible to work-a-day psychiatrists, rather than clinical researchers.
There are currently some large scale trials being conducted to test further whether TMS for depression is a useful treatment, but so far, the evidence just isn't there.
However, one promising avenue might be using TMS as a treatment for stroke - brain damage caused by bleeds and blockages in blood flow.
A different, but perhaps equally effective approach has been driven by a model in which recovery after stroke is suppressed in some patients by input from an 'overactive' non-stroke hemisphere. Reduction of the excitability of this hemisphere by low-frequency rTMS has also been reported to increase function, in this instance in a group of chronic patients whose stroke had occurred at least 1 year previously
It's still early evidence, but it might be that using TMS to target specific symptoms and selective disorders may be more effective than trying to treat the diverse conditions that make up the common psychiatric diagnoses, such as depression, bipolar and schizophrenia.
Link to abstract of TMS review paper (sadly, not open-access).
The American College of Neuropsychopharmacology have made a huge text book freely available online that covers the cutting edge of pretty much everything we know about how drugs affect the mind and brain.
Psychopharmacology is the science of how drugs affect the mind. You can do this without a huge understanding of brain function. You can just see how different drugs affect people's mental state.
This was pretty much how many of the early drug treatments in psychiatry were discovered.
For example, the first antipsychotic, chlorpromazine, was developed in the 1950s as an antiemetic, a drug to prevent vomiting.
However, the French doctor Henri Laborit noticed that it induced a sort of 'indifference' to the world, and wondered whether it might help calm patients with mental illness who were agitated.
It was discovered that this drug was the first effective treatment for psychosis, and for several decades, psychopharmacology research simply tested various derivatives without a good understanding of how they were affecting the brain.
Neuropsychopharmacology adds neuroscience into the mix, and attempts to explain how drugs have their effect by studying how they interact with the biology of the brain.
It's an incredibly important science, not only for the purpose of developing new treatments, but also for understanding how any drug (be it aspirin, cocaine or caffeine) has its effect.
The online text book, entitled Neuropsychopharmacology: The Fifth Generation reviews a huge, and I mean HUGE, amount of research into this area.
It's an academic text, so is very in-depth, but is a fantastic resource to have freely available on the net.
Link to Neuropsychopharmacology: The Fifth Generation.
Open-access science journal PLoS Medicine published a recent study that suggests that infection with the herpes virus might cause temporal lobe epilepsy in some people.
The study found the virus in the brains of 11 out of 16 patients with temporal lobe epilepsy but not in those with other forms of epilepsy.
Studies that test brain tissue are often done post-mortem, on people who have died, because brain surgery is just too risky for the sake of removing samples for research.
This study is particularly impressive because it studied brain tissue from live patients.
In severe cases of epilepsy that don't respond to medication, one option is to find which bit of the brain triggers the seizures (the 'foci') and surgically remove it.
This is particularly effective in people with mesial temporal lobe epilepsy, a type in which the foci is deep within the temporal lobes (mesial means 'towards the midline'), usually stemming from disturbance in the hippocampus.
The team examined brain tissue removed in operations on 22 patients, and tested it for the presence of the human herpesvirus 6B (HHV-6B).
This type of herpes infection is incredibly common, more than 90% of the population have it. Normally, it's completely harmless and just lies dormant in the body.
We don't really know why, but in some people, it seems to reactivate, and is linked to neurological disorders like multiple sclerosis.
The researchers found that it was present in brain cells called astrocytes from 11 out of 16 patients with mesial temporal lobe epilepsy, but wasn't present at all in patients with other types of epilepsy.
The image on the right is of a herpes infected astrocyte, the infection is visible due to a green marker.
They also studied one patient in more detail. He had four operations in a row, each of which reduced his seizures, until the final one left him seizure-free.
They found that the herpes virus was present most strongly in the temporal lobe tissue from the first operation, was weakly present in later operations, and wasn't present in other brain areas.
They also found that infected brain tissue didn't produce very much of a chemical that transports the key neurotransmitter glutamate across the brain.
If it doesn't get transported properly, it 'hangs around', and because glutamate tends to make brain cells more active, too much could lead to overactivity and seizures.
To test the herpes - glutamate link, the team deliberately infected brain tissue taken from a patient without a previous infection.
In the lab, they discovered that herpes slowed the creation of the transporter chemical for glutamate, providing strong evidence for the link.
The evidence from the lab tests, the single case study, and the 22 patients, provides strong evidence that herpes infection could lead to temporal lobe epilepsy in some people.
This is an important finding because it suggests a cause for the disorder in some people, and provides a clear target which could lead to better treatments and prevention strategies.
What is still not clear is why this usually harmless infection might cause some people severe neurological problems, and remain dormant in others.
There's been quite a bit in the news recently about 'brain scan lie detection', but The New Yorker magazine have just published possibly the best article I've read so far on this intriguing but still-not-very-accurate technology.
It not only looks at the current technology, but also explores the dubious history of lie detection technology from times past.
The article is also remarkably well researched and level-headed, a balance that many stories about the technology sorely lack.
It points out some of the drawbacks of the technology, and some of frankly bizarre pitches being made by commercial companies.
One company recommends brain scans to help with "risk reduction in dating" and "trust issues in interpersonal relationships"!
Don't get me wrong, people with brain scanners are sexy, but as with many things in life, it's not what you have but what you do with it. Being shoved in a 'fMRI lie detector' by a potential lover would be a definite turn off.
The article is delightfully wide-ranging and talks to plenty of senior psychologists about their views on the technology and why we're so attracted to brain scan evidence despite its drawbacks.
Really, an excellent piece. Well done New Yorker.
Link to New Yorker article 'Duped: Can brain scans uncover lies?'.
A book called Best of the Brain from Scientific American (ISBN 1932594221) turned up unannounced the other day, and so far, I'm very impressed with it.
It's a collection of twenty one of the most notable mind and brain articles from past issues of SciAm collected in a single volume.
I feel a bit reticent about waxing lyrical about a free book I've been sent, but I have to admit, I quite a fan of SciAm and SciAmMind, not least because they always make two feature articles from every issue freely available online which allows you judge the quality for yourself.
In fact, several of the articles from the book have already been made available online:
Unfortunately, it doesn't seem if the book's a table of contents is online, as you could get a better idea of the diversity of topics that are covered.
Essentially, if you're a fan of SciAm psychology and neuroscience writing, you'll probably like this book. It's really a greatest hits collection.
As this is the first unsolicited book I've been sent, a couple of clarifications. Readers: I'll always say if a book I mention has been sent to me for free. Publishers: I won't mention your book just because you've sent it to me.
The hardest cut: Penfield and the fight for his sister:
In 1935, world renowned neurosurgeon Wilder Penfield published three remarkable case studies describing the psychological effects of frontal lobe surgery.
They remain a fascinating insight into the link between brain and behaviour, but one case was unlike anything Penfield had tackled before.
It described the fight to save the life of his only sister.
Penfield's sister, Ruth, had been experiencing splitting headaches since the age of fourteen. Suddenly, at the age of twenty, she experienced a Jacksonian seizure - a fleeting but distinctive type of neurological disturbance that can cause an almost eerie succession of involuntary movements.
Ruth's cortex was mercifully quiet for the next eight years, until she unexpectedly suffered a succession of seizures, in a pattern which would become increasingly common as she reached her early 40s.
By that time it became clear that she was suffering from a type of glioma, a particularly dangerous form of brain tumour caused by a cancer of the glial cells, the essential building blocks that support the very structure of the brain itself.
Penfield undoubtedly knew that her life was in grave danger. He had spent his adult life travelling the world training as a brain surgeon and had worked with some of the finest neuroscientists of his time.
He stepped in to undertake the operation himself and opted to remove almost the entire right frontal lobe, a radical form of brain surgery that had barely been tried before.
Then, as now, the majority of these operations are done while the patient is awake, so the surgeon can check that they're not unnecessarily removing any areas needed for speech, memory or other essential functions.
We can only imagine what was running through the mind of brother and sister as one began the attempt to save the other's life by moving surgically through the brain.
Throughout his professional life, Penfield often considered what the brain could tell us about the possible existence of the soul, and it would be hard not to speculate on whether this profound experience had any bearing on his quest.
If he was troubled by these existential issues at the time, he remained outwardly cool. The operation was a success.
Penfield's sister did worry during the operation, but not, seemingly, about her life. Penfield's colleague, Colin Russel had sat by Ruth throughout the operation, and afterwards noted that her main anxiety was a sisterly concern about embarrassing her younger brother at work.
Russel, neuroscientist to the last, noted "She said that she had felt so afraid of causing you distress by making an exhibition of herself... When I remarked that the only exhibition I had seen was one of the best exhibitions of courage that it had been my fortune to witness, she expressed her gratitude so nicely that one could not help wondering how much of the frontal lobe had to do with higher association processes".
Ruth recovered and returned to work as a valued wife and mother of six children. She found planning and organisation difficult, something that we would now call dysexecutive syndrome, but lost none of her eloquence and good humour.
Quite suddenly, after two years, her symptoms returned. The tumour had regrown and was successfully removed, this time by Penfield's mentor, Harvey Cushing, but this last-ditch attempt only bought her a few final months and, sadly, she died shortly after.
Nevertheless, her brother's operation had gained her two more valuable years with her family, but it was not enough to save her.
The experience had a profound impact on Penfield, who was inspired to found the Montreal Institute of Neurology, then, as now, one of the world's leading centres for brain treatment and research.
Penfield obviously struggled with the decision to publish a clinical case study on his sister's treatment, but eventually included it with two other cases in a 1935 article for the journal Brain, writing that "if she were alive, I am sure she would approve of such an analysis in the hope it would help others".
As an academic case study, it is almost unique, as it weaves the medical language of neurology with fragments of memories and heart-felt tributes.
As a historical document, we learn as much about Ruth Wilder as neurosurgery itself. As a piece of science, it remains a skilful description of a rarely performed operation and an insightful commentary on the link between the frontal lobes and psychological function.
Penfield became one of the most important neurosurgeons of his generation, advancing a type of medicine only just finding its feet while making some of the most significant advances in neuropsychology - the science of linking mind to brain.
Throughout his career, family was never far from his mind, and after his retirement, and shortly before his own death, Penfield wrote Man and His Family, stressing the need to nurture and encourage positive family life.
It's fitting that his legacy is not only a contribution to scientific knowledge, but also a hospital and institute that allows neuroscience to be applied where it is most needed - helping individuals affected by brain disorder. Truly, Penfield's speciality.
Link to more about Wilder Penfield. Link to Penfield's Brain paper, sadly not open-access.
Kidman new face of brain game, will it sharpen the mind?:
As a sure sign that cognitive improvement games have gone mainstream, Nicole Kidman has been announced as the new face of Nintendo's latest 'brain training' title.
The idea that mental training will actually help boost your mental skills is relatively new.
It was traditionally thought that the mind and brain just start losing their edge after young adulthood and your best hope was to learn to use your remaining resources more effectively as you age.
However, studies started to appear in the late 1990s suggesting that practicing certain tasks could act as a sort of 'mental workout', actually improving mental abilities directly in people with disorders like Alzheimer's disease and schizophrenia.
Most people weren't fully convinced of the benefits in healthy older people until a key study was published last year in the Journal of the American Medical Association that showed modest but reliable improvements, even after five years.
The effects were typically small (often too small to be picked up without standard tests), but interestingly, the training also had a knock-on effect on the participants' ability to look after themselves effectively on a day-to-day basis.
It seems that cognitive training may have a stronger effect in people with mental impairments. A recent review of 17 studies found a positive effect on mental abilities, everyday activities and mood in people with Alzheimer's.
However, as far as I know, no controlled trials have ever been published on any off-the-shelf 'brain training' game, including Nintendo's. You'd guess from the medical literature that they might have a similar effect, but it's yet to be shown for sure.
Link to BBC News article 'Kidman to be new face of Nintendo'. Link to JAMA article 'Long-term Effects of Cognitive Training...'
ABC Radio National's All in the Mind has just broadcast the first of a two-part series on using neuroscience to read the mind.
The first programme investigates whether neuroscience can tell us anything about criminality and violence, and what role brain-based evidence will play in the court room.
The programme talks to many of the delegates from last April's The Law and Ethics of Brain Scanning conference which was one of the first to consider the legal issues of brain scans in detail.
All of the conference talks have been put online as mp3 files so you can listen to the talks yourself if you want to hear more.
In the mean time, this edition of All in the Mind covers the key issues and next week's will investigate some more (as yet undisclosed) aspects of so-called 'mind-reading' technology.
Link to AITM on 'Mind Reading'. Link to The Law and Ethics of Brain Scanning conference audio.
A brain scanning study has found that naming emotions reduces the intensity of emotion processing in the brain, possibly outlining a brain network responsible for the old saying 'a problem shared is a problem halved'.
A team led by psychologist Dr Matthew Lieberman brain-scanned participants while they looked at pictures of faces that had different emotional expressions.
Earlier studies have found that naming an emotion seems to reduce its impact but this study went to particular lengths to make sure it was actually naming the emotion that helped, rather than just naming something, or identifying the emotion in other ways.
Participants were also scanned while having to name a face with a proper name, like Jane or Peter, or while matching the face to one with a similar emotional expression. This last task involved identifying the emotion but not naming it.
It turned out that when naming an emotion, and not for the other tasks, activity in a frontal lobe area called the the right ventrolateral prefrontal cortex (right VLPFC) significantly increased while activity in the amygdala decreased.
The amygdala is known to be heavily involved in processing emotions and seems to be regulated, at least in part, by the VLPFC.
These findings are consistent with this idea. The VLPFC increases its activity to dampen down the emotions triggered by the amygdala.
However, it's not clear whether this happens equally for both positive and negative emotions, as 80% of the faces in the study had expressions of anger or fear, while only 20% displayed happiness or surprise, so this data only really tells us about unpleasant feelings.
We know that observing emotion in others makes us more likely to feel the same thing ourselves, but it's not the same as experiencing an emotion 'first-hand', so we need to be a bit careful in assuming that this study fully represents the more everyday experience of talking about our emotions.
This experiment gives us a good understanding of the brain circuit involved reducing emotional impact via naming, but it doesn't tell us much about why this occurs.
This is one of the major drawbacks of neuroimaging studies. They often just redescribe an effect in terms of brain activity.
Of course, this is essential knowledge, but we need to do more than just have several types of description and it is why the results from brain scanning studies need to be integrated with behavioural, experimental, clinical and subjective reports to be fully informative.
Link to write-up from APA Monitor. Link to write-up from Scientific American. Link to abstract of scientific study.
Natalie Portman is best known for her roles in Hollywood movies like Star Wars, Cold Mountain and V for Vendetta. What is less known is that she was co-author of a scientific paper on the neuroscience of child development. This is about her research.
Portman, whose real name is Natalie Hershlag, left acting to pursue a psychology degree at Harvard during 2000.
While there she was employed as a research assistant in Prof Stephen Kosslyn's neuropsychology lab where she got involved in a study investigating the link between frontal lobe development and visual knowledge in infants.
The study investigated object permanence - the ability to understand that objects do not disappear from the world when they are out of sight, something that typically develops in the first year of life.
Researchers have argued that the frontal lobes are particularly important for this skill, but the trouble is, you can't put babies in conventional brain scanners to easily test the idea. They just wriggle about too much.
This technology relies on the fact that near-infrared light can penetrate the skull, and that blood carrying oxygen, and blood that has given up its oxygen, absorbs the light differently.
The idea is that the device beams light into the frontal lobes, and you can work out how hard this area is working from how much oxygen-rich blood there is.
The advantage is that this technology is safe for children, and can be worn as a sort of high-tech hat, meaning there's less of a problem if the child being tested moves about.
During the study, infants were shown a toy, which was then hidden under a cloth. Children who have object permanence - who know that it hasn't disappeared - look for it under the cloth.
Children without this skill just ignore the cloth and look for something else to do, because the memory of the toy is gone.
The study tested 20 infants, every four weeks, from the ages of 5-12 months. To see what changed in the brain as the ability emerged, the researchers compared infrared light absorption from a time when the kids first looked for the toy, to an earlier time, when they just forgot that it existed when it was out of sight.
The team discovered that the frontal lobes suddenly kicked in when children develop the knowledge that hidden objects still exist, providing an understanding of which brain areas are involved in this important mental function.
The study also demonstrated that near-infrared spectroscopy could be used successfully to study the brain development of very young children.
The paper was eventually published in the journal Neuroimage, under Natalie's real name, with the title 'Frontal lobe activation during object permanence: data from near-infrared spectroscopy'.
It has since been cited by at least 20 different studies that have built on its findings.
And if you want to read the study in full, it is available as a pdf file at the link below.
Open-access science journal PLoS Biology has a fascinating article on the latest developments in getting drugs across the blood-brain barrier - the body's strict border control that keeps the brain free of foreign substances.
The blood-brain barrier is a filtering system in the capillaries, the smallest blood vessels in the brain, to prevent molecules over a certain size reaching the brain itself (click image for larger version).
This makes good biological sense as it keeps the brain free of a whole range of potential poisons and infections but is a pain for drug designers.
There are many drugs which would have an effect but can't get from the blood into the brain because the molecules are too big.
For example, Parkinson's disease involves the death of dopamine neurons in the nigrostriatal pathway of the brain - a key circuit for movement - which is partly why the disease causes tremor and rigidity.
The obvious thing to do would be to give people dopamine to make up for the lost neurons, but it turns out that dopamine molecules are too big to cross the blood-brain barrier. If you swallow a dopamine pill, it won't reach the brain.
Eventually someone hit on the idea of giving people levodopa or L-DOPA - a molecule that the body eventually transforms into dopamine and is small enough to cross the barrier.
So, you swallow an L-DOPA pill, it crosses the barrier and is changed into dopamine inside the brain itself. Clever.
Substances given with the intention that the body will transform them into the desired drug are called prodrugs and finding prodrugs small enough to cross the blood-brain barrier is one method for getting round the delivery problem.
This is fine if what you're trying to deliver can be transformed into something useful but for many drugs this isn't possible, so other methods have to be found.
New techniques are being developed which take advantage of the fact that the blood-brain barrier makes special exceptions for certain essential proteins.
The idea is that a drug molecule will be 'wrapped up' in a familiar protein and so will be smuggled across the barrier, only to be released when it reaches the other side.
Other techniques involve a mechanical approach to the problem where a device is implanted to pump the drug straight into the brain. Needless to say this direct intervention approach is favoured by neurosurgeons (the armed wing of the neuroscience world).
The PLoS Biology article discusses these are other developments and looks at how this problem is now becoming a core focus of drug development as useful medicines have sometimes been invented only to be found to be unusable in practice.
Link to PLoS Biology article 'Bridging the Blood-Brain Barrier'.
Many thanks to Alex and the Neurophilosopher, who sent in the article I had no luck getting hold of in the previous post on trepanation - the surgical technique of putting a hole in the skull.
The brief article is from the 1923 edition of the anthropology journal Man and describes ninth century brain surgery on a 22-year-old man.
If you're wondering why it describes the operation as trephination, it's an alternative word for trepanation. Click on the image for a larger version.
A Trephined Irish Skull Man, Vol 23, (Nov 1923), p180
Thomas Walmsley
Cennfaelad, a young Irish chief, had his skull fractured by a sword-cut at the Battle of Moyrath AD 637. He was under treatment for a year afterwards at the celebrated school of Tomregan (now in Co. Cavan), where the injured part of his skull and a portion of his brain were removed. He recovered and afterwards became a great scholar and a great jurist. Such is one record of early Irish surgery.
The skull reproduced here (Fig. 1) is that of a young male about twenty-two years of age, which was obtained, along with a number of other skulls, from early Christian (ninth century) graves at Nendrum Monastery in Island Mahee, Strangford Lough. The other skulls, with a few more of the same period from another locality, I hope to describe at a later date, but this one is of sufficient interest to be described separately.
For on the left side, towards the anterior-inferior angle of the parietal bone and just within the temporal line, there is a trephined opening. The diameter of the opening is 8mm, but it originally must have been more, for the edges have healed all round; this can be seen better on the inner surface. Round the opening, on the outside of the skull, for a distance of 3mm, the bone is bevelled as if it had been scraped away. On the inside there is no such bevelling; rather the bone is slightly raised and tuberculated round the original margin of the opening.
There are no marks of injury on the skull, and there is no evidence of disease. The deficiency above the mastoid is due to the falling out of a sutural element.
Like a hole in the head: An illustrated history of trepanation:
Neurophilosopher has written an absolutely fantastic post on the history of trepanation - the surgical procedure that has been carried out since prehistoric times and involves drilling a hole in the head.
Neurophilosopher always has great articles but this is also wonderfully illustrated and has all the gory details of this fascinating procedure.
The trepanned skulls found at prehistoric European sites contained round holes, which varied in size from just a few centimetres in diameter to nearly half of the skull. They are most commonly found in the parietal bone, and also in the occipital and frontal bones, but rarely in the temporal bone. In the earliest European skulls, the holes were made by scraping the bone away with sharp stones such as flint or obsidian; later, primitive drilling tools were used to drill small holes arranged in circles, after which the piece of bone inside the circle was removed. The late Medieval period saw the introduction of mechanical drilling and sawing instruments, whose sophistication would continue to increase for several hundred years.
The article takes you through the prehistoric origns of the procedure, to how it developed around the world, to its modern uses for surgery and recreation (yes, recreation!).
The picture at the top is from a trepanned skull from the Hunterian museum in London that also showed signs of neurosyphilis infection. There's more about it in a previous post.
I also found a good example of a trepanned skull in the National Museum of Ireland but unfortunately they don't allow pictures and don't have images of it available.
However, this article has an interesting snippet about the various examples of the procedure discovered in the country:
From Ireland several interesting examples are available. A trepanned skull of a thirteen-year-old child, probably early Christian, was recovered from Collierstown in Co. Meath (Martin, 1935). Two further trepanations each of late Mediaeval date, one from Ballinlough (Co. Laois) and the other from Maganey Lower (Co. Kildare), were found during recent excavations.
A fourth specimen was discovered in a stone-lined grave at the Abbey of Nendrum on Mahee Island in Strangford Lough (Martin). The abbey was destroyed in 974 A.D. by fire. It is highly likely that in those days "major surgery" was performed in monastic institutions (Fleetwood, 1951). Legend has it that Cennfaeladh, whose skull was fractured by a blow from a sword during the battle of Moyrath in Co. Down (637 A.D. ), was operated upon by St. Bricin, the Abbot of Tuaim Drecain, an accomplished surgeon and scholar (Fleetwood).
And this page has an image of a 7th century gargoyle-esque carving of St Bricin with trepanning tools in one hand and a skull in the other.
Apparently, the treatment worked so well that Cennfaelad, an Irish chieftan, recovered his intellect and improved his memory so that on his recovery he became a great scholar, whose name 'Kennfaela the Learned' is known in Irish literature to this day.
There's more about this case, and about trepanning in Ireland, on this page, and, if you've got a subscription to JSTOR, which I don't have unfortunately, there's an academic article here. Do let me know if you can get hold of a copy!
Link to Neurophilospher on 'An Illustrated History of Trepanation'.
ScienceDailyreports that the first images from a new type of brain scanner that combines both magnetic and radiation-based imaging have been shown at a recent medical conference.
The new technology is called MR/PET because it allows magnetic resonance and positron emission tomography scans to be conducted at the same time.
MRI uses very strong magnets that align the spin of the atoms in your body. It then sends a radio pulse which knocks the atoms out of alignment.
After the knock, the atoms return to their previous alignment but the time taken will differ, depending on the body tissue. As they return, they send off their own pulse, and this can be picked up and turned into an MR image of the tissue by computer software.
PET involves adding a small amount of oxygen or glucose into the body that the brain uses to do its work. Crucially, the substance has been altered so it is slightly radioactive.
As the brain works, the areas that are most active will be slightly more radioactive, and this can be measured to generate a map of brain activity.
You can create similar maps using functional MRI, but one advantage of PET is that it is especially good at 'resting PET', meaning you're not asked to do any tasks. It just gives a general picture of which brain areas are most active.
This is particularly useful if the medical team think your brain might be structurally intact but may have areas which are under or overactive, or want to know the effects of structural damage in one area on function in the rest of the brain.
PET can also be used to track the effects of specific chemicals in the brain (by making them slightly radioactive and injecting them), which is something that fMRI currently can't do very well.
Previously, to combine the two scans, someone would have to go into a MR scanner to get a structural image, and then go into a PET scanner to get a measure of activity, and computer software would impose the PET image onto the MR image.
This causes problems because the two images aren't perfectly aligned and so information gets lost.
Imagine you are trying to fit a photo you took from an airplane onto a street map. You might need to stretch or edit the photo to make it fit properly, and in doing so, you might miss bits out or blur important details.
The reason the combined MR/PET will be useful is that the two scans are taken at exactly the same time, so no information is lost.
It also means patients with fragile brains won't need to be moved between scanners.
One of the difficulties with combining the types of scanning before is that PET normally uses photomultiplier tubes to detect the effects of radiation, which don't work in magnetic fields, but now new sensors have been developed which are MR safe.
Unfortunately, I can't seem to find any images of the new scans online (please let me know if you find or have any!).
However, if you want to know more, Radiology Today magazine has a more in-depth article and Siemens, the creator of the technology, has some information as a webpage and pdf.
Also there's an image of the scanner from a Cambridge University team also working on the technology.
Link to ScienceDaily on new MR/PET images. Link to Radiology Today article on the technology.
Bullets, bleeds and bangs - brain injury animations:
Brain injury resource site Neuroskills has a nifty page of brain animations, including a selection showing how various types of brain injury occur.
They're a bit clunky in places and the point of injury seems to be illustrated with a small science-fiction-like stellar explosion, but they're genuinely informative and quite fun to watch at times.
They include the effect of a bullet to the head, stroke, shaking injuries, animations highlighting the main anatomical areas, the functioning of healthy and damaged neurons and a few others thrown in for good measure.
Wired has a good break down of theory that says that nerve cells don't work on electricity as we assume, but instead transmit signals using pressure waves, and crucially, this might explain how anaesthetics work.
The idea that nerve cells send their signals as pressure waves is not brand new. Known as the Soliton model, it was first published in 2005 by Drs Andrew Jackson and Thomas Heimburg and was thought a bit of a curiosity.
It challenges the model of nerve cell functioning that was developed by Alan Hodgkin and Andrew Huxley, both of whom won the Nobel prize for their work.
Their discovery was that nerve cells can be understood as electrical circuits and that the transmission of nerve signals or action potentials can be described using a simple elegant mathematical formula.
This formula describes how nerve cells work remarkably well and is still the basis of much modern neuroscience.
So suggesting that the Hodgkin-Huxley model is wrong is likely to piss a lot of people off, and that's exactly what the Soliton model has done.
However, this new paper suggests it could explain how anaesthetics work, which is one of the mysteries of modern neuroscience.
It's a totally left-field idea, but if it works out, it would be a revolution in both neuroscience and medicine.
Link to Wired article on application of the Soliton model to anaesethics. Link to 2005 scientific paper on the Soliton model.
BBC Radio 4 science programme Frontiers just had a special edition on using brain scans to read the mind.
There's been variousreports in the media about research studies that have been able to identify subjective mental states or intentions from patterns on brain scans, mainly reported as a sort of 'mind reading' technology.
While these are genuinely interesting studies, they're really not at the stage of being able to 'read' anyone's thoughts.
The first thing to ask yourself when you hear this sort of claim is 'has the effect been shown to work on individuals, or only as an average over a group?'. The next is 'what task was the effect demonstrated on?' and finally think about how reliably the effect could be demonstrated.
For example, on a recent brain imaging study that attempted to predict intentions, the prediction was made for individuals, but only between one of two possible options and the best reliability was 71%.
In other words, this study found that for each individual, when looking back at the data, with a choice deliberately designed to be predictable, their choice could be worked out before they made it about two-thirds of the time.
It's hardly likely to concern anyone worried about the privacy of their thoughts.
It is a start though, and the implications of how the technology might be used as it becomes more accurate are certainly thought provoking.
The special edition of Frontiers talks to some of the researchers involved in this work and tackles the ethics of the technology.
The Journal of Cerebral Blood Flow and Metabolism publishes cutting edge scientific research on brain scanning and blood flow, and it's just put a collection of some of the key papers from the last few years online, for free.
It is particularly important that neuroscientists understand blood flow because this is what PET and fMRI, the two most popular forms of brain scanning, rely on to investigate brain activity.
Broadly speaking, both attempt to estimate which parts of the brain are most active by measuring which areas of the brain have the most blood going to them.
Despite the fact that brain scans look like a map of activity, the link between blood flow and the work done by neurons is still not fully understood.
For example, in fMRI, there seems to be a delay from when neuron activity occurs, to when the blood flow responds. A 2003 study [pdf] found that this delay was about two seconds long and was slower to return to normal the older you get.
While two seconds might seem a short amount of time, in brain time, it's an age, as scientists are usually trying to understand changes that occur on the millisecond level.
Also, it's not clear how closely the changes in blood flow reflect the quality and extent of neuron activity, because blood needs to move around the brain for many different reasons.
Therefore, an important goal in neuroscience is to try and solve these questions, to improve how we understand brain function from brain scans.
The online collection has articles that describe some of the most important research in this area from the last few years.
The papers are technical and in-depth, but even if you aren't a neuroscientist, click on a few and just get a feel for what's involved.
At the very least, the images can be truly beautiful.
Link to MRI and PET imaging collection (via BrainWaves).
Developing Intelligence has an interesting look at a brain-injured patient from the medical literature who can identify objects, but can't locate them.
RM suffered two strokes, damaging both sides of his occipito-parietal cortex (see the image above). This region of the brain is known to be important for spatial computations; this pattern of damage will often result in Balint's Syndrome, characterized by three primary problems: the inability to perceive more than one object at a time (simultagnosia), the inability to reach towards objects that are being focused on (optic apraxia), and severe problems in changing which object the eyes are focused on (optic ataxia). Such patients are essentially blind outside the focus of their attention, and cannot locate, reach for, or track the spatial movements even of items that are within their focus of attention. In some ways, this represents the complete dissolution of spatial awareness; Robertson quotes a description of Balint's "as if there is no there, there."
The article suggests that the brain damage may have a caused a problem in 'visual binding'.
The 'binding problem' is the question about how the brain can process different aspects of an experience in different parts, but we still get an impression of a single combined perception.
For example, we know that colour is largely processed in an area of the visual cortex called 'V4' and motion processed in an area called 'V5', yet unless we suffer brain damage, we just experience a moving coloured object as a single experience.
Somehow, these different processes are combined into our conscious experience. It's still a mystery, but patients like the one discussed in the Developing Intelligence article are giving us important insights into how the brain does the job, by seeing how it breaks down after injury.
The article also makes the interesting suggestion that while Balint's syndrome and similar disorders might be the visual binding system not working properly, synaesthesia, where the senses are combined, might be visual binding working too hard.
Chris goes on to explore this idea in more detail, in a further article that looks at the research on visual binding in people with synaesthesia.
Link to DevIntel article 'Dissolved Space: The Strange Case of Patient RM'. Link to DevIntel article 'Synthetic Space: Binding Errors In Synesthesia'.
The picture is a man with a knife blade embedded in his head. It's from a case report in the Croatian Medical Journal by a group of neurosurgeons who reported how it happened, and how they safely removed it.
The man was stabbed in the head by his daughter, who's ominously described only as a 'drug addict' in the case report.
The blade penetrated 8cms into his skull but he was conscious on admission to hospital, he remembered the event, and had not fainted during or after the assault.
The surgical team used a grinder to remove the handle from the knife and CT scanned the patient's head, and found the blade was at the very edge of the brain.
The neurosurgeons removed the knife, and the man recovered with no brain injury and no damage to the facial nerve.
A recently published study has found that females show greater brain activation to uncertain rewards during the most fertile stage of the menstrual cycle, perhaps explaining why women dress more attractively and have altered sexual preferences during this time.
The dopamine system is known to be involved in reward processing, and one of the current theories is that it is particularly involved in reward prediction - that is, it signals when we might expect to find something gratifying.
The key female sex hormone estrogen is known to alter dopamine function, so it was thought that females might show changes in how they experience rewards when estrogen levels fluctuate during the menstrual cycle.
The most direct dopamine-related rewards are drugs like cocaine and amphetamine, and studies have found that the same dose feelsstronger during the fertile follicular phase of the cycle.
Research, largely conducted with straight women, has found that females dress more attractively during this phase and have altered sexual preferences so that they experience more masculine looking, assertive males as more attractive.
This new study by Dr Jean-Claude Dreher and colleagues fMRI brain-scanned men and women during a gambling task, and looked at between-sex differences and within-cycle differences in brain activity.
They found that women have a greater response to rewards than men in the amygdala and hippocampus, both key emotion areas.
They also found that during the most fertile follicular phase of the menstrual cycle, women show more activity when predicting rewards, particularly in the amygdala and another key emotion and reward area, the orbitofrontal cortex.
When the reward was delivered (a win in the gambling task), women showed stronger response in a number of reward-related areas during the fertile phase, including the striatum, a dopamine-rich deep brain area.
It seems that the hormone cycle makes brain areas related to the prediction and experience of rewards become more active when women are more fertile. This might explain why the menstrual cycle can alter women's sexual preferences and behaviour.
If you want more details of the study, the full paper is available at the link below.
Link to PubMed entry for the scientific paper. pdf of full-text scientific paper.
Simultanagnosia is where a person can't perceive more than one object at a time. They literally cannot see the wood for the trees. There are two main types that differ depending on the location of the brain injury which has caused the syndrome.
Damage to the dorsal stream can cause dorsal simultanagnosia, where the patient cannot see two or more objects at the same time.
Damage to the ventral stream can cause ventral simultanagnosia, where the patient can see multiple objects, but can only identify one at a time.
The following is from p61 of the 1970 book Brain Damage and the Mind (ISBN 0140801405) by Moyra Williams, who describes a gentleman with dorsal simultanagnosia:
A sixty-eight-year old patient studied by the author had difficulty finding his way around because "he couldn't see properly". It was found that if two objects (e.g. pencils) were held up in front of him at the same time, he could see only one of them, whether they were held side by side, one above the other, or one behind the other.
Further testing showed that single stimuli representing objects or faces could be could be identified correctly and even recognized when shown again, whether simple or complex... If the stimuli included more than one object, only one would be identified at one time, though the other would sometimes "come into focus" as the first one went out...
If long sentences were presented, only the rightmost word could be read... If a single word covered as large a visual area as a sentence which could not be read, the single word was read in its entirety... If the patient was shown a page of drawings, the contents of which overlapped (i.e. objects were drawn on top of one another), he tended to pick out one and deny that he could see any others.
Recent evidence has suggested that although the unseen objects may not be consciously available, carefully designed psychological tests can detect they have been registered at some unconscious level.
The book Visual Agnosia by Prof Martha Farah covers a number of curious object perception disorders that occur after brain injury, including simultanagnosia.
The book's webpage has a table of contents and some sample chapters freely available online.
In a study investigating how the brain generates paranormal experiences and psychotic states, researchers used strong electromagnets to alter brain function and found they could reduce the number of times healthy volunteers saw spontaneously experienced false perceptions.
The researchers altered the function of the temporal lobes with a method called transcranial magnetic stimulation or TMS while participants were asked to detect supposedly 'hidden' images in what were actually completely random dot patterns.
When compared to a control area at the top of the head, reducing left temporal lobe function significantly reduced the number of false perceptions.
During the procedure, participants were asked to look at a series of quickly presented dot patterns and told to indicate which had images 'hidden' within them.
Crucially, they were told not to guess and only to press a button when they genuinely detected a 'hidden' image. In actual fact, all the dot patterns were completely random and none contained 'hidden' images, so every 'detect' response was a false perception of meaningful information.
Just before each dot pattern was presented, the brain was stimulated with a pulse of TMS, either to the left or right temporal lobe, or a control spot at the top of the head known as the vertex.
TMS uses magnetic pulses to safely 'switch off' a small area of brain for a several hundred milliseconds.
When compared to the control area, temporarily 'switching off' an area on the left temporal lobe significantly reduced the number of false perceptions, suggesting that this brain area is likely to be involved in making meaningful connections, even when there's no meaning to be found.
Seeing meaningful information in random data is known as 'apophenia' and statistically is known as a false positive or a Type I error.
Previous research has shown that this tendency is known to be enhanced in people who report high levels of paranormal experience, and to a greater extent, in people who experience psychosis - the mental state involving delusions and / or hallucinations that is most commonly linked to schizophrenia.
Other evidence suggests that differences in temporal lobe function are common in people diagnosed with schizophrenia.
The paper is published in the May edition of Cortex, but a pre-print is available at the link below if you don't have access to the journal.
Neurophilosopher has a great article on a brain scanning study showing that people with synaesthesia have different patterns of brain connections compared to non-synaesthetes.
You read a lot of articles on the brain that use phrases like "wired differently", suggesting that the connections in the brain are altered.
As the connections in our brain are changing all the time at the dendrite level, often this is just a meaningless way of saying "there's a difference".
Perhaps these sort of phrases are best applied to white matter which is the nearest you'll find to genuine wires in the brain.
White matter fibres run in bundles, they carry electrical signals, and they are insulated by a fatty covering called myelin.
The connections of white matter have been quite hard to study in living people until the development of diffusion tensor imaging (DTI), a brain scanning technology that can specifically pick out the white matter fibres and create maps like the one in the picture.
Rarely when articles talk about "different brain wiring" do they actually mean detectable differences in white matter though.
In the DTI study covered by Neurophilosopher this is exactly what was studied, and it does indeed seem to be different in people who experience synaesthesia, a condition where some of the senses are crossed so, for example, numbers might be also experienced as colours.
DTI is a type of magnetic resonance imaging (fMRI) that measures the diffusion of water molecules. In the brain, water diffuses randomly, but tends to diffuse easier along the axons that are wrapped in myelin, the fatty protein that insulates nerve fibres. Diffusion tensor imaging can therefore be used to infer the size and direction of the bundles (or "fascicles") of white matter tracts that connect different regions of the brain (above).
The Dutch researchers show that synaesthetes have more connections between the two adjacent areas in the fusiform gyrus than non-synaesthetes. They report their findings in the June issue of Nature Neuroscience.
As well as showing these differences between synaesthetes and non-synaesthetes, the authors also show that there are also differences in connectivity between synaesthetes who differ in the intensity of their sense-mixing experiences.
In other words, the researchers found people with synaesthesia had white matter 'wiring' between sensory areas that others don't have, and that this wiring differed depending on how much synaesthesia the participants experience.
Just from the fantastically straight-forward explanation of DTI imaging given above, you can see that it's a wonderfully written article.
Have a look at the full piece for more on this fascinating study.
Link to Neurophilospher on 'Imaging of connectivity in the synaesthetic brain'. Link to abstract of scientific study.
The ANZ Journal of Surgery just published the summary of a conference paper describing 12 patients with head injuries caused by nail guns. It makes for some surprising reading.
You might think brain injuries from nail guns would be rare, but there are a startling number of case studies in the medical literature.
A recent review of suicide attempts by nail gun noted it was unusual, but this new case series suggests that many of this type of brain injury are caused in this way.
In fact, out of the 12 cases, three quarters were attempting to kill themselves.
Mostly, the cases concern a single nail, but one case was particularly extreme:
The other case involved a staggering 24 nails of 5cm length and represents the largest number of intra-cranial nails in a surviving patient.
This beats the previous record of 12 nails, held by a man reported in a case study from a neurosurgery team in Portland, Oregon.
The picture is the X-ray of Isidro Mejia, who survived a nail gun accident in 2004, where he was unfortunate enough to have four nails embedded in his skull and two in his neck.
Removal of a nail often involves a craniotomy, where the surgeons have to cut around the bit of skull where the nail is embedded, and remove it in one piece.
There are some images of this operation in an article from the Spanish language neurosurgery journal Neurocirugía which is available online as a pdf.
Link to abstract of nail gun head injury case series. pdf of Spanish language case report of neurosurgical nail removal.
These completely passed me by last year but are well worth checking out: BBC Radio 4 broadcast a couple of excellent radio programmes - one on the effects and treatment of mild brain injury and other other on the doomed historical attempt to link intelligence to skull size.
Mild traumatic brain injury doesn't necessarily mean that effects are minor.
For some people, fatigue, poor concentration, memory difficulties and irritability may continue when the immediate affects of the injury have subsided.
These symptoms can be quite dramatic, even after simple concussion, and there is now significant interest in this post-concussional syndrome as it is quite disabling for some people.
What is interesting, is that there is evidence that these symptoms can arise out of a combination of the original brain damage plus psychological distress and poor coping strategies.
In other words, it's not just the brain injury that causes the problems but also how people make sense of and deal with their experience.
The programme on skull size and intelligence looks at how early 20th century researchers tried to link intelligence to skull size in the futile attempt to prove that various races where biologically inferior.
A dodgy aim but an important chapter in the history of science gone wrong.
Link to documentary on mild brain injury. Link to documentary on intelligence and skull size.
If you roll your eyes every time you hear more media hype surrounding the pseudoscientific 'think your way to victory' film The Secret, Scientific American has a short, sharp, shock of a reply to its dodgy claims about the mind and brain.
A pantheon of shiny, happy people assures viewers that The Secret is grounded in science: "It has been proven scientifically that a positive thought is hundreds of times more powerful than a negative thought." No, it hasn't. "Our physiology creates disease to give us feedback, to let us know we have an imbalanced perspective, and we're not loving and we're not grateful." Those ungrateful cancer patients. "You've got enough power in your body to illuminate a whole city for nearly a week." Sure, if you convert your body's hydrogen into energy through nuclear fission. "Thoughts are sending out that magnetic signal that is drawing the parallel back to you." But in magnets, opposites attract--positive is attracted to negative. "Every thought has a frequency.... If you are thinking that thought over and over again you are emitting that frequency."
The brain does produce electrical activity from the ion currents flowing among neurons during synaptic transmission, and in accordance with Maxwell's equations any electric current produces a magnetic field. But as neuroscientist Russell A. Poldrack of the University of California, Los Angeles, explained to me, these fields are minuscule and can be measured only by using an extremely sensitive superconducting quantum interference device (SQUID) in a room heavily shielded against outside magnetic sources.
Actually, I'm all for anything that helps people to think more positively, but basing your advice on misinformation and empty promises is a recipe for disaster.
BBC Radio 4's weekly medical programme Case Notes just had a special on multiple sclerosis. The programme looks at what we know about the brain disorder and investigates the controversial use of cannabis as a treatment.
Some neurons in the brain have extended sections called axons that allow the neuron to transmit signals over distance.
The signals travel down the axon as electrical pulses, and as with electrical wires in the house, the signalling is more efficient when it is insulated from the outside world.
Axons are insulated by a layer of fatty covering called myelin.
In MS, the myelin starts to degrade and the neurons are eventually unable to send signals, becoming useless and withering.
It is not clear why this happens, but it might be because a problem with the immune system means the body starts attacking and destroying the myelin.
The destruction of myelin in the brain is not evenly spread out and doesn't continue at a steady rate, meaning that people with the disorder may have difficulties with a whole variety of different brain functions.
This pattern might differ from person to person, and might progress at a different rate.
Movement, memory, attention, mood, perception and speech can all be affected (to name but a few), and the person is at a much higher risk for mental illness as a result.
Currently, there is no cure for MS but several treatments are known to slow the disorder or help with the symptoms.
These can include drugs that regulate the immune system and steroids to limit the damage.
However, many patients report that cannabis significantly helps with the symptoms.
While cannabis treatment is illegal in most countries, researchers are trying to understand what is it about cannabis that helps, and are working on developing medications based on cannabinoids.
The programme looks at these treatments, as well as looking at the science of MS, and how is it managed by the clinical team.
Prozac is twenty and The Observer celebrates with an article noting 20 things you may not know about the drug that was supposed to make us 'better than well'.
Prozac is the brand name for the drug fluoxetine and was so successful that it has become a by-word for antidepressants and psychiatric drug treatment.
Its popularity was partly due to it being a safer alternative to the older tricyclic antidepressants, such as amitriptyline, and the addictive benzodiazepine drugs used to treat anxiety, such as Vallium.
Also, it came at a time when depression was becoming destigmatised and more widely recognised. Helped in no small part, of course, by Eli Lilly heavily funding a number 'public education' campaigns and depression support groups.
During the 1990s Prozac was truly considered a wonder drug.
Psychiatrist Peter Kramer's 1994 book Listening to Prozac (ISBN 0140266712) had case studies of people who's marriages were saved, porn addiction was cured (!) and generally became better, more thoughtful people after taking the drug.
Notably, several of the case studies were not people who were clinically depressed. Kramer wondered whether we would take such drugs to improve on normality rather than to treat pathology, and coined the term 'cosmetic pharmacology' for the former.
As the 90s drew to a close, clouds started to form and the sunshine started to fade.
The storm broke in 1998 as court cases focused on the negative effects of Prozac and related drugs and an influential paper was published suggesting the drug wasn't as effective as it was thought.
Drug company Smithkline was sued by the family of a man who killed himself and his family after taking the related drug paroxetine, also known as Paxil or Seroxat.
The court case involve psychiatrist Dr David Healy who had been investigating the possible role of Prozac in stirring up suicidal thoughts in some depressed patients.
Healy discovered that Eli Lilly had obscured the adverse effects of Prozac from their pre-release drug trials and was subsequently subjected to a dirty tricks campaign by the company.
This became a legal case in itself and he eventually settled for what are thought to be significant out-of-court damages.
Furthermore, an influential paper published by Irving Kirsh and Guy Sapirstein (wittily titled 'Listening to Prozac but hearing placebo'), analysed a series of antidepressant drug trials and reported that only 25% of the improvement in the patients was due to the drug, the rest, the data suggested, was placebo effect.
Researchers started to challenge the virtually evidence free message that 'low serotonin causes depression' on which the marketing campaigns for SSRI drugs relied.
More recently, worries have emerged about Prozac and related drugs increasing suicidal thoughts in some children (again with allegations about drug companies burying negative findings), with antidepressants now carrying a warning on the box to alert doctors and clinicians.
The pendulum has swung back a little since then, with recent studies indicating that while some children will have an increase in suicidal thinking, they are a small minority and, generally, the benefits outweigh the risks in most children.
Current evidence suggests that Prozac is an effective treatment for depression, although it's not without side-effects and, on balance, is about as effective as most other antidepressants.
Prozac is a useful treatment for depression and anxiety, but is no longer the 'wonder drug' it once was - and we're probably all better off for having a more balanced view.
The Observer article is a guide to the drug and its wide-ranging impact on society, covering everything from its neurochenical effects to its influence on the music scene.
ABC Radio National's All in the Mind has a compelling discussion about the development and dangers of weapons designed to target the brain and nervous system.
The guests on the programme are Prof Malcom Dando and Dr Mark Wheelis, who have recently written a paper for the International Red Cross entitled 'Neurobiology: A Case Study of the Imminent Militarization of Biology' [pdf].
The programme largely focuses on what we known about the secret development of nerve agents, based on the glimpses we see of them in action - for example, during the Moscow theatre siege of 2002, where Russian special forces used an opiate-based 'knock out gas' that resulted in the death of 129 hostages.
Interestingly, one of the guests notes that although these sorts of compounds are banned for use in war under international treaties, these regulations can have specific exemptions that allow them to be used in civilian 'crowd control' operations.
So while it would be illegal to use some drugs as weapons against soldiers, governments are, in some cases, allowed to use them on their own population.
It's fascinating and somewhat troubling coverage of a too-rarely discussed topic.
Link to AITM on 'Bioterrorism and Your Brain'. Link to full-text of 'Neurobiology: A case study of the imminent militarization of biology'.
The Scientist has an article on the latest developments in the world of fMRI lie detection, looking at how accurate and reliable the technology really is.
This is a particularly hot topic because a commercial company, No Lie MRI, are marketing a brain scan lie detection service.
This is despite the fact that neuroscientists and the legal system are still unconvinced that it is accurate enough to be useful.
Interestingly, the company was partly funded by the US Government, and you can bet that they'll be trying the system, even with the low accuracy rates, in case it proves useful for the secret services.
Probably the main advantage for most buyers is that is looks intimidating and high-tech.
Like with the polygraph test, many people put through the system will undoubtedly be more truthful because they believe that they will be caught if they lie.
In terms of its ability to catch genuine lies made by an individual, it's still fairly limited though.
Not least because most brain imaging research is done as group studies. The results are usually based on average brain activity across all participants, rather than on any one individual.
Also, the studies don't really resemble real-world conditions:
And in the real world, lying is verbal and carried out in defiance of instruction, and the stakes are incomparably higher. Rather than missing out on a $20 study reward, being caught in a lie could mean life in prison. Lying under these circumstances comes with an emotional component that is poorly elicited by a playing card, she argues.
"Applied fMRI studies of the kinds done so far have similar limitations to those of typical laboratory polygraph research," according to a 2003 National Academy of Sciences report. "Real deception in real life circumstances is almost impossible to explore experimentally. You can't randomly assign people to go do crimes. I do think that's an inherent limit," says Gabrieli, a professor of cognitive neuroscience. Others worry about the level of nuance that fMRI-posed questions can accommodate.
Still, researchers are hoping further studies will help improve the system, until, maybe, it will be the most accurate lie detection system in existence.
Until then, it's an interesting field, but I wouldn't bet your life on it.
Link to Scientist article 'Watching the Brain Lie'.
There's been a wonderful series of posts at neuroscience blog Neuroevolution which have charted the history of cognitive neuroscience from ancient Greece to the age of the brain scanner.
There's been 26 posts in all, each of them a beautifully illustrated snapshot of a groundbreaking discovery.
The series tells the story of how we've come to understand more and more about the workings of the mind and brain, with each discovery building on the lessons of history.
Highly recommended.
Link to "History’s Top Insights Into Brain Computation".
Open-access science journal PLoS Biology has another fantastic article that investigates what neuroscience tells about about the causes of antisocial behaviour and how damage to the brain can, in rare cases, lead someone to become violent.
The article looks at research on the neuropsychology of violent criminals, as well as 'forensic neurology' - the science of understanding how brain injury can remove the normal inhibitions for aggression.
Some striking case studies are covered as well as possible ways of understanding and managing criminality.
Criminality and violence is a difficult area, as personal motivations and influences are complex. The paper notes that:
To be clear, there is at present no reason to believe that all criminal behaviours, or indeed even all violent criminal behaviours, are the result of organically dysfunctional brains. However, there is ample evidence to suggest that some kinds of dysfunction are likely to increase the probability of some kinds of behaviours that society labels as criminal.
The discussion also covers how the legal system might make sense of these new brain discoveries, in light of neuroscience evidence being increasingly used in court cases as a way of determining if someone is telling the truth, and as a way of arguing for reduced responsibility for a criminal act.
Link to PLoS Biology article 'Law, Responsibility, and the Brain'.
Author Bruce Stutz writes about his experience of depression, stopping antidepressants and the science of SSRI withdrawal in an article for the New York Times.
Withdrawal from SSRI medication, a group which includes drugs such as Prozac, Seroxat and Zoloft, is known to cause considerable discomfort in about 1 in 5 people.
It's been spun as a 'discontinuation syndrome' by the drug companies, as 'withdrawal symptoms' sounds a bit too much like what drug addicts have.
Although SSRIs are not addictive in the sense that they don't cause a strong desire to take more, the brain does go through a significant period of readjustment when the drug leaves the body.
The NYT article examines Stutz's experience of treatment for depression, and how he coped with the withdrawal symptoms that he was unlucky enough to experience.
The piece also takes a look at the neuroscience of serotonin and mood, with a more critical analysis than is often found in some mainstream science articles.
Huge numbers of news sources are reporting on recent neuroscience studies that have linked the effect of cannabis on the brain to the development of psychosis.
The excitement is because the 2nd International Cannabis and Mental Health Conference is currently under way in London where scientists from around the world are presenting the latest research on the effects of cannabis.
Luckily, the conference programme and summaries for all the research presented are available online as a pdf file, so you can get a more accurate idea of what the studies have found.
It is now clear that cannabis increases the risk of psychosis in some people who have a family history of psychosis and / or certain versions of the COMT gene.
However, the main thrust of the news stories is that even a single dose of THC, the main ingredient in cannabis that causes the 'high', can trigger psychotic symptoms.
A study by Dr Cyril D'Souza noted that:
Δ-9-THC produced schizophrenia-like positive and negative symptoms, altered perception, increased anxiety, produced euphoria, disrupted immediate and delayed word recall, impaired performance on tests of attention and working memory without impairing orientation.
The difficulty is that just because something seems to cause similar effects to psychosis, it doesn't necessarily mean it is strongly linked to it.
For example, a dose of alcohol can 'produce' similar symptoms to Alzheimer's disease - loss of memory, disorientation, mood swings, aggression and so on - but that isn't a good basis to say that the alcohol is doing the same thing in the short-term as the degenerative brain disorder does in the long-term.
More convincing are the results from the cognitive tests: impairment in immediate and delayed recall, attention and working memory without impairing orientation.
This is because the subjective effects of both cannabis and psychosis are, well subjective, but the cognitive effects are measurable with controlled neuropsychological tests.
One particularly interesting study from Dr Cecile Henquet found that when compared to controls, patients experienced a greater increase in psychotic experience after taking THC, but also had a greater improvement in their mood.
This might explain why people with psychosis will often continue smoking cannabis even when they know it causes their mental state to deteriorate.
Another fascinating finding, is that as well as containing the possibly psychosis increasing THC, cannabis also seems to contain an antipsychotic called cannabidiol or CBD.
One study presented by Prof Markus Leweke found that purified CBD had a beneficial effect equal to amisulpride, a widely used pharmaceutical antipsychotic medication.
If you're interested in finding out more about the cutting-edge of cannabis research the surprisingly readable conference programme is well worth checking out.
Link to conference programme and research summaries.
Online psychedelic drug archive Erowid has scanned in a copy of a classic guide to hallucinogenic plants of the world and how they are used by native peoples.
The Golden Guide to Hallucinogenic Plants is by pioneering ethnobotanist, Richard E. Schultes.
Ethnobotany is the study of how people make use of plants, and hallucinogenic plants are obviously of keen interest owing to their important place in ritual and religion throughout the world.
The book is sadly out of print and and second hand copies are now collectors items. However, the full version has been scanned in full colour, so you can read it online or download it as one single zip file.
Link to Golden Guide to Hallucinogenic Plants (via BB).
ABC Radio National's All in the Mind just broadcast some essential listening with a programme that takes a critical look at the reporting of brain scanning studies and discusses what brain scans actually tell us about human nature.
The panel discussion also covers how cognitive and neuroscience discoveries get translated from lab work to public awareness, and how the core messages might get warped along the way.
ABC Radio National's All in the Mind recently broadcast an incredibly moving account of a young woman's fight with a life threatening brain tumour that eventually resulted in her death.
The woman in question was the Australian writer Julie Deakin (pictured left), who wrote the most touching and elegant prose about her experiences of diagnosis and treatment, and the impact of her declining health on her loved ones.
The programme weaves Deakin's writing with her mother's recollection of the time, making for a powerful programme.
I was listening to it while walking to work this morning and it stopped me in my tracks on a couple of occasions.
Link to information and transcript. mp3 of programme audio.
Independent artificial intelligence researcher Jeff Hawkins has an article in this month's IEEE Spectrum magazine asking the question 'why can't a computer be more like a brain?'.
Hawkins argues that while we hope that machines will be able to simulate human intelligence, we ignore the thing that makes us so - the brain.
He suggests that we need to create artificial intelligence systems that closely match the architecture of the brain to achieve this task.
Hawkins has outlined his arguments, and his own theories of simulated brain architecture, in his book On Intelligence, but if you want a whistle-stop tour of his theories, this article is a great summary.
Researchers from the University of Calgary have released the first version of NeuroArm - a surgeon-controlled robot for conducting brain surgery.
The key feature of the robot is that it is designed to work inside an MRI brain scanner.
MRI scans currently provide the most accurate structural image of the brain and therefore provide important information for planning operations.
Neurosurgeons also use MRI scans completed before surgery to guide the operation while it's happening, using a method called stereotactic neurosurgery.
This allows surgical instruments to be guided to an exact spot in the brain by tracking their position in real time, in relation to the 3D scan completed earlier.
One disadvantage is that the brain scan can't be updated as the brain is altered during the operation.
Being able to scan people while they're having surgery might sound a simple idea, but MRI scans involve the patient being inside a tube surrounded by hugely powerful magnets, meaning the environment isn't accommodating to surgeons who need free space and surgical steel.
NeuroArm has been designed to fit inside the tube, and crucially, is not made of any magnetic materials that will affect and be affected by the MRI machine.
This means the surgeon can update the brain scan and complete the operation by controlling the robot remotely.
He or she can do this by using a specially designed surgical workstation that provides a virtual interface to the robot arms, including force feedback on the tools, so the surgeon does not have to give up his 'surgical touch'.
While the current set-up seems to involve the surgeon being located in the same building as the patient, it is interesting to speculate that, in the future, operations could be directed from hundreds or even thousands of miles away.
The combination of the accurate brain scan and the robot controlled tools also means that the surgeon should be able to attempt microsurgery on very fine brain structures.
You may be surprised to learn that robot-assisted neurosurgery isn't particularly new and was introduced in the 1980s.
Brown University has a fantastic history of the technology and procedures if you want some background.
Link to Project neuroArm page. Link to more info on Project neuroArm. Link to write-up from New Scientist. Link to history of robotic neurosurgery page.
In 1955, after seven years of trying, John and Mary's first child was born. The birth of Casey Holter turned John Holter's life upside-down and changed the course of medical history.
Agonisingly, Casey had spina bifida, a condition where the spine doesn't fully form and may be dangerously misshapen.
The condition was also causing hydrocephalus, a life-threatening build-up of fluid in the brain.
The fluid that surrounds the brain is called cerebrospinal fluid or CSF and acts as a fluid 'bath' which cushions and protects the delicate organ.
It is produced by a structure in the brain stem called the choroid plexus and circulates around the brain before being drained into the blood supply.
If the drainage system is blocked, however, it can lead to a dangerous build-up that can pressure, distort and eventually damage the brain beyond repair. If left untreated, it can be deadly.
In 1955, the only thing keeping Casey Holter alive was a twice daily procedure where a needle was inserted into the fontanelle, the soft spot on a baby's head, and the excess fluid was removed with a syringe to reduce the pressure.
Eventually, Casey was given an operation by the neurosurgeon Eugene Spitz to insert a ball and spring valve that would, in principle, allow the fluid to drain into the blood supply, without letting anything dangerous from the blood wash back into the CSF.
Unfortunately, the valve was clumsy technology, and when inserted, it irritated Casey's heart to the point where the young child had a heart attack and suffered permanent brain damage.
John Holter, then working as a technician in a hydraulics factory, asked Eugene Spitz about the details of the procedure. He was surprised that the problem, which seemed to him like a simple hydraulics issue, had not been solved.
He had noticed that when nurses inserted needles into certain types of medical tubing, leaks didn't occur because the gap was water-tight under low pressure conditions.
But, like a teat on a baby's bottle, when the pressure was high enough the gap opened and the fluid forced its way through. A perfect valve for releasing built-up CSF and preventing backwash.
Holter went home, sat in his workshop, and constructed the first version that very evening. It was a rough-and-ready rubber-tubing and condom prototype, but it worked.
While the principle was sound, Spitz noted that that the valve must made of a material that wouldn't irritate the body, as this might cause the same problem that had brain-damaged his son.
Holter contacted Dow Chemical and was advised to use silicone, at the time, a newly developed material.
Holter had created a usable version within months. So quickly, in fact, that his son was still too weak from the last operation to have it installed.
It was first and successfully installed in another child, and then in March 1956, Eugene Spitz installed John Holter's valve into Casey, successfully treating his hydrocephalus.
Sadly, Casey never fully recovered from his brain damage from the initial operation, and died during an epileptic seizure five years later.
Fittingly, Casey's legacy is that Holter's invention, now called the Spitz-Holter shunt, is still in use today.
Holter spent the rest of his life developing valves for medical use and passed away in 2003, having saved the lives of thousands children affected by the same condition as his son.
It is estimated that 15,000 valves based on Holter's design are installed every year in the United States alone.
John Holter's remarkable story was retold in a 2001 paper published in the Journal of the American College of Surgeons upon which this article was based.
Link to PubMed entry for Journal of the American College of Surgeons paper.
ABC Radio National's All in the Mind recently had a two programme special (part 1, part 2) on the neuroscience of blindness, focusing on how blindness affects the development of the brain and how electronic neural implants and being developed to restore lost vision.
One of the most remarkable parts is the interview with psychologist Zoltan Torey, who became blind as a student in an industrial accident.
He has written The Crucible of Consciousness (ISBN 0195508726), a remarkable and highly regarded book on the conscious mind.
In the 1st part of the series, he describes how he constructs a a 'visual' representation of the world and how his blindness has informed his study of consciousness:
But what is new of course is just the way in which I am able to combine things in my brain without the interference of vision. Normally when people want to think they close their eyes because the flood of visual impressions that comes at you is a distraction. I have the privilege of not having to cope with that, of thinking without...I'm a sort of 'thinkaholic', if I might use this expression. This is the way I did my research work about psychology and the consciousness. Not being troubled with vision itself, it was possible for me to imagine complex internal systems, and so I have this marvellous opportunity to run an internal show like a movie director.
Researchers studying neuroplasticity (how the brain changes its structure and function) are now focusing on the brains of blind people, as it has become clear that, for example, the area of the brain normally functioning as the visual cortex in sighted people seems to be active during touch-based reading, which is something that doesn't occur in sighted people.
The second programme looks at the latest research on 'bionic' retina implants, that aim to process light and, through implanted electrodes, stimulate the optic nerve to act as an artificial retina replacement.
Link to The Blind Brain: Part 1 of 2. Link to The Blind Brain: Part 2 of 2 - The bionic eye.
Psychology Today has an interesting article on anthropologist Helen Fisher's theory that SSRI drugs (commonly used as antidepressants) interfere with love and attraction.
SSRI stands for 'Selective Serotonin Reuptake Inhibitor' and the group includes drugs such as Prozac (fluoxetine), Seroxat (paroxetine) and Zoloft (sertraline) which all increase the availability of the neurotransmitter serotonin in the synapse - the chemical junction between neurons.
Despite the (somewhat misleading) use of the word 'selective' in the title, these drugs also affect many other types of neurotransmitters to varying degrees - of which dopamine is one.
Fisher maintains that as attraction, desire and sexual pleasure are known to involve dopamine circuits in the brain, these drugs interfere with relationship formation.
This dopamine deficit affects people in a variety of ways, according to Fisher and her research partner, Virginia-based psychiatrist J. Andrew Thomson, Jr. Singles using antidepressants may have a harder time meeting people, because their natural sexual response is dampened. Some researchers believe desire was designed to help people select mates who are genetically suited to them. The spark that ignites on meeting someone new is telling you something: This might be your match. When you miss those signals, your odds of finding an appropriate mate decrease.
Fisher outlines her theory in a paper published with psychiatrist J. Anderson Thomson in the recent bookEvolutionary Cognitive Neuroscience.
Luckily, the paper is also available online as a pdf file if you want to see their argument in full.
As an aside, the Psychology Today article is by science writer Orli Van Mourik, who you may know from Neurontic blog.
Link to Psychology Today article 'Sex, love and SSRIs'. pdf of scientific paper (warning: big download!).
Neurophilosopher has a great review of a recent study on how short naps help improve memory, and how this is supported by the brain.
Participants were asked to learn an action task and were split into two groups. One group was allowed to have an afternoon nap, while the others remained awake.
Afterwards, those who had slept during the afternoon could perform the task better than those who hadn't.
EEG recordings of the brain suggested how the learning boost occurred:
This study confirms that the consolidation of motor memories is associated with a particluar stage of sleep (NREM), and that this in turn is correlated with electrical activity in an anatomically discrete region of the brain (the motor cortex).
One interpretation of the findings is that power naps trigger accelerated memory consolidation. An alternative hypothesis is that a good night's sleep consists of multiple stages which are devoted to the consolidation of memories encoded during waking hours; thus, a full night's sleep may not be necessary for this consolidation to take place; as long as a sleep episode - be it a a short night's sleep or an afternoon power nap - includes the corresponding stages (NREM), newly-encoded memories will be consolidated.
For more details and link to the full paper, check out the article over at the Neurophilosophy Blog.
Link to Neurophilosophy article 'Power naps enhance memory consolidation'.
The Washington Post has just published an article on the worrying amount of brain damage suffered by US troops in Iraq because of shockwave injuries from roadside bombs known as improvised explosive devices or IEDs.
These sorts of injuries tend not to damage the skull, but can cause significant injury as the brain rapidly accelerates and decelerates inside the skull, and impacts on the inside of the bone casing.
These types of injury are known as 'closed head injuries' as nothing penetrates the skull.
It's a common misconception that a skull fracture always leads to a worse brain injury.
In fact, in some cases, if the skull breaks, it can allow some of the force of the impact to be dispersed (this is why bicycle and motorcycle helmets are designed to break).
If the skull doesn't break, sometimes this can lead to the energy of the impact being more fully absorbed by the brain, often leading to shearing and tearing of the white matter pathways as the brain 'bounces around' inside.
The Washington Post article outlines why IEDs are likely to have this effect:
Here's why IEDS carry such hidden danger. The detonation of any powerful explosive generates a blast wave of high pressure that spreads out at 1,600 feet per second from the point of explosion and travels hundreds of yards. The lethal blast wave is a two-part assault that rattles the brain against the skull. The initial shock wave of very high pressure is followed closely by the "secondary wind": a huge volume of displaced air flooding back into the area, again under high pressure. No helmet or armor can defend against such a massive wave front.
It is these sudden and extreme differences in pressures -- routinely 1,000 times greater than atmospheric pressure -- that lead to significant neurological injury. Blast waves cause severe concussions, resulting in loss of consciousness and obvious neurological deficits such as blindness, deafness and mental retardation. Blast waves causing TBIs can leave a 19-year-old private who could easily run a six-minute mile unable to stand or even to think.
The article notes that the military have not had to deal with these sorts of injuries in such large numbers before, as IEDs have rarely been used on this scale.
Apparently, the military are currently poorly equipped to deal with these injuries, which is causing problems both for treatment in the field and for longer-term rehabilitation programmes.
The article also contains an interesting factual error: "Iraq has brought back one of the worst afflictions of World War I trench warfare: shell shock. The brain of a soldier exposed to a roadside bomb is shocked, truly."
'Shell shock' was given this name during World War I because it was originally thought to be due to the blasts of shells affecting the brain.
It was later discovered that the cause of the condition was combat trauma (i.e. emotional stress) rather than brain injury, so it doesn't actually describe any type of closed head injury.
Link to Washington Post article 'A Shock Wave of Brain Injuries'.
This week's international edition of Newsweek has several articles on how researchers have found that physical exercise can sharpen the mind and boost brain function.
The first article looks at how scientists came to discover that exercise improves brain function, increases learning and can delay the onset of Alzheimer's disease.
In terms of understanding why this occurs, it seems one factor is that exercise causes the release of brain-derived neurotrophic factor or BDNF, a key substance for promoting neural growth and development.
The second main article looks at the effect of exercise on mood.
It is now known that light exercise seems to be an effective treatment for mild to moderate depression, and, at least in the UK, is being recommended by mental health clinicians as a useful non-drug treatment.
The key, it seems, both for the beneficial effects on mood and mental sharpness, is not the intensity of the workout but whether it occurs regularly or not.
The pieces suggests that regular light exercise seems to be enough to keep the mind and brain trim, so you don't have to wear yourself out to see the benefit.
The special issue has been put together with the help of Harvard Medical School, who roll out several experts to give advice in addition to a range of researchers interviewed for the main pieces.
Also look out for the embedded audio of an interview with two Harvard clinicians on the topic.
Link to article 'Stronger, Faster, Smarter'. Link to article 'Exercise is a State of Mind'.
Nina and the Neurons is a BBC TV series aimed at children aged six and under that looks at the psychology and neuroscience of the senses.
It's presented by the bubbly and attractive Nina who, with the help of a collection of animated neurons, explores and explains the senses and gives various sensory demonstrations.
The programme is shown on BBC Children's channel CBeebies, but there's some episodes kicking around internet bittorrent trackers and they're well worth checking out either if you know children who might enjoy them, or if you're interested in how neuroscience could be taught to young children.
Nina typically fields questions from children and then goes to meet their family and runs experiments with them to test out the ideas.
The programme is based at the Glasgow Science Centre which has earned a reputation for new and interesting ways of engaging the public in science education.
As well as the programme information page, there's also a website of Nina's Lab where children can match sensations to the senses.
Link to programme information. Link to Nina's Lab.
The BPS Research Digest has picked up on a curious case study of a brain injured man whose identity appears dependent on the environment he is in, owing to severe memory problems.
The case was published in the neurological journal Neurocase by psychologist Giovannina Conchiglia and colleagues.
The patient was investigated by the team after he suffered left-focused damage to the frontal and temporal lobes after the oxygen supply to the brain was cut off during a heart attack.
Unfortunately, the full paper isn't available online, but it's well worth reading if you do have access to the journal.
The researchers put the patient, named AD, in various environments, such as a bar or kitchen, where he assumed the identity of a barmen and chef.
Interestingly, this didn't happen in all cases:
During the first two experiments A.D was attracted by social and environmental stimuli, and did not in fact hesitate after a short while to interpret the role expected of him, and to "take on" the personality of the barman and chef, respectively. It is to be emphasised that in none of the experiments proposed did A.D. imitate the characters interpreted by the actors/experimenters, but rather assumed his own role in keeping with the context. In the last experiment, however, the patient manifested a different form of behaviour, in that he did not assume any role, as he considered that specific context inadequate...
His refusal to take on the role of laundryman in Experiment 3 is relevant since it is unlikely to be suited to him. The roles he adopts, therefore, must in some way correspond to certain traits of his personality structure or his social prerogatives, however versatile these may be.
There is now a growing recognition that symptoms caused by brain injury might be influenced not only by physical damage, but also by the wishes and desires of the patient.
Recent research has looked at this effect in both confabulations and delusions and found a strong interaction between unusual neurological conditions and the motivations of the patient.
This suggests that symptoms are influenced as much by the remaining intact brain areas, as the damaged ones.
Link to BPSRD article 'Brain damage turns man into human chameleon'. Link to abstract of Neurocase paper.
The New York Times has a fantastic article and video documentary on people who have decided to find out whether they carry the gene for the degenerative brain disorder Huntingdon's disease, even before it's started to causes any symptoms.
The disorder is caused by a single gene which, if inherited, causes a progressive deterioration in areas of the basal ganglia and frontal lobe which are eventually lethal.
The symptoms usually only appear in middle age and include, most visibly, uncontrolled movements of the body.
However, cognitive problems (such as impairments in memory, concentration, perception and strategic thinking), and the development of mood disorders and psychosis are also possible.
Because the disorder only takes hold in later years, many people with parents or grandparents with the disorder have to decide whether to get tested, and discover whether they have the gene and are fated to develop Huntingdon's later in life.
The NYT article reports on how one young woman, who has taken the test and found out that she will develop the disorder, deals with the knowledge of her neurological fate.
Ms. Moser is still part of a distinct minority. But some researchers say her attitude is increasingly common among young people who know they may develop Huntington's.
More informed about the genetics of the disease than any previous generation, they are convinced that they would rather know how many healthy years they have left than wake up one day to find the illness upon them. They are confident that new reproductive technologies can allow them to have children without transmitting the disease and are eager to be first in line should a treatment become available.
"We're seeing a shift," said Dr. Michael Hayden, a professor of human genetics at the University of British Columbia in Vancouver who has been providing various tests for Huntington's for 20 years. "Younger people are coming for testing now, people in their 20s and early 30s; before, that was very rare. I've counseled some of them. They feel it is part of their heritage and that it is possible to lead a life that's not defined by this gene."
As well as showing some of the striking and distinctive movements associated with the disorder, the videos also relate some insightful reflections from Katie Moser, the subject of the article.
It's common for there to be no cure for neurological illness, but usually there are some treatments which can slow down the symptoms.
Unlike some other disorders, there are remarkably few of these treatments for Huntingdon's disease, although research is currently being undertaken to try and improve the situation.
Link to NYT article 'Facing Life With a Lethal Gene'. Link to Wikipedia page on Huntingdon's.
Nobel prize-winning neuroscientist Eric Kandel has been asked to describe four advances in neuroscience from the past year that inspire optimism in an article for Edge.
His choices demonstrate an eclectic interest in modern mind and brain science.
The first is the discovery that MicroRNA is involved in synaptic connections and the second is advances in the understanding of how the hippocampus might store spatial information.
Kandel's third choice is the discovery that single genes might lead to quite profound changes in social behaviour.
Perhaps his fourth choice is the most interesting, however. He cites neuroscientific evidence for the effectiveness of psychotherapy in treating mental illness, particularly for a type of therapy called cognitive behavioural therapy or CBT.
CBT is the most comprehensively researched of all the psychotherapies.
It has been shown to be as effective, if not more effective, than medication for anxiety and depressive disorders in randomised controlled trials, although best results are usually reported when both medication and CBT are combined, particularly in moderate or severe cases.
Recently, researchers have started to use brain scanning techniques to see how the function of the brain changes after CBT treatment.
Link to Kandel's article 'A Neuroscience Sampling' from Edge.
Neurologist Prof Kevin Nelson and colleagues have just published a study in the journal Neurology showing that out-of-body experiences and near death experiences are more likely to occur in people who have unusual experiences when falling asleep or waking.
They found that an out-of-body experience is statistically as likely to occur during a near death experience as it is to occur during the transition between wakefulness and sleep. Nelson suggests that phenomena in the brain's arousal system, which regulates different states of consciousness including REM sleep and wakefulness, may be the cause for these types of out-of-body displays.
Hallucinations and free-form ideas are very common in the period of entering sleep (called the hypnagogic state) and the period of waking (called the hypnopompic state).
Artists and visionaries throughout history have found inspiration from these unusual sleep-related experiences, as recounted in a recent Fortean Timesarticle.
Link to coverage from Science Daily. Link to coverage from the Daily Telegraph. Link to PubMed entry for scientific paper.
Wired magazine has a fascinating feature article about an operation to implant deep brain stimulation electrodes in a patient with Parkinson's disease. Crucially, the article is written the patient himself.
Deep brain stimulation involves inserting permanent electrodes into the brain to pump tiny pulses of electricity into key areas.
It's most commonly used as a treatment for Parkinson's disease which causes problems with the 'motor loop' - a network of brain areas that control movement (actually there are two main ones, the direct and indirect).
This is why patients with Parkinson's disease have trouble moving and have a visible tremor.
The loops consist of a series of areas that might boost activity or reduce activity in subsequent parts of the loop.
Damage to any of these areas might mean that the following area might not get enough activation (like with a faulty accelerator), or might be too active because it is not being damped down correctly (like with a faulty brake).
Neurosurgeons can try and restore balance in this loop by either damping down an area by surgery (e.g. a pallidotomy) or by increasing activation at an area by deep brain stimulation.
This is exactly the treatment that Steven Guile, the author of the Wired article, describes.
I'll be kept awake for the entire procedure. During the surgery I will talk and move my limbs on command, which helps Team Hubris know which part of my brain is being poked.
Unfortunately, this also means I'm conscious when [neurosurgeon] Henderson produces what looks like a hand drill and uses it to burr two dime-sized holes into the top of my skull. It doesn't hurt, but it's loud.
Team Hubris is installing a deep brain stimulator, essentially a neurological pacemaker, in my head. This involves threading two sets of stiff wires in through my scalp, through my cerebrum — most of my brain — and into my subthalamic nucleus, a target the size of a lima bean, located near the brain stem. Each wire is a little thinner than a small, unfolded paper clip, with four electrodes at one end. The electrodes will eventually deliver small shocks to my STN. How did I get into this mess? Well, I have Parkinson's disease. If the surgery works, these wires will continually stimulate my brain in an attempt to relieve my symptoms.
The article is a wonderful tale of neurosurgery from the inside and a great guide to some of the science and medicine of the condition.
There's also a fantastic a video segment where Gulie narrates and explains the operation.
BBC Radio 4 recently broadcast a documentary on the long-term effects of ecstasy (MDMA) now that the 'E Generation' are in their 40s.
The documentary looks at the evidence for long-term effects of ecstasy and dispels some of the myths that were promoted in anti-ecstasy campaigns of the early 90s (for example, the famously flawed brain scans presented to suggest that ecstasy leaves functional 'holes' in the brain).
It is clear that such scare stories about the drug's damaging effects were greatly exaggerated.
The evidence does suggest, however, that heavy and / or long-term ecstasy use does lead to mild to moderate cognitive impairment in some people (memory seems particularly sensitive to change).
There is still a need for much more systematic research in this area, particularly as the evidence on whether these long-term impairments get better is quite mixed.
The programme is presented by Dr John Marsden who has researched the impact and neuroscience of ecstasy and talks to a number of people who were heavy ecstasy users in the past.
ABC Radio's Science Show just had a special edition on the evolution of the brain and the development of social intelligence.
The programme talks to some of the leading researchers in social intelligence whose research interests range from comparing the behaviours of animals across species, to neuroimaging humans, to building robots to mimic social interaction.
In particular, the programme tackles the 'social intelligence hypothesis' that suggests that our increase in brain size during evolution has been driven by the need to work in groups and make sense of complex relationships.
There seems to be two key figures of brain expansion, and I think this is where the social intelligence hypothesis becomes very interesting. The first was around two million years ago, and at that time brains expanded perhaps about 50%. So we went from brain size of around 450cc to a brain size of around 1,000cc by 1.8 million years ago. What's interesting during that time is that we don't see dramatic changes in human behaviour as represented by the archaeological remains....
So archaeologists asked; why are brains getting larger and what is it providing? Brains wouldn't get larger just for any reasons because brain tissue is metabolically very expensive, so it's got to be serving a really important purpose. I think the social intelligence hypothesis suggests to us that that expansion of brain size around two million years ago was because people were living in larger groups, more complex groups, having to keep track of different people, a larger number of social relationships which we simply required a larger brain to do.
Link to Science Show special on 'The social intelligence hypothesis'.
An excerpt from the entry for the psychedelic drug 4-TASB from the book Phenethylamines I Have Known And Loved (otherwise known as PiHKAL).
The drug was one of many developed by chemist and psychedelics researcher Alexander Shulgin. As with hundreds of other compounds, the chemical structure and effects of this new drug are described in the book.
From the experiences of testing this compound, it seems 4-TASB was not a success:
Music was lovely during the experiment, but pictures were not particularly exciting. I had feelings that my nerve-endings were raw and active. There was water retention. There was heartbeat wrongness, and respiration wrongness. During my attempts to sleep, my eyes-closed fantasies became extremely negative. I could actually feel the continuous electrical impulses travelling between my nerve endings. Disturbing. There was continuous erotic arousability, and this seemed to be part of the same over-sensitivity of the nervous system; orgasm didn't soothe or smooth out the feeling of vulnerability. This is a very threatening material. DO NOT REPEAT.
Below is an excerpt from a review, published in this week's Nature, of the bookThe Science of Orgasm (ISBN 9780801884900).
The review is by Prof Tim Spector whose work we've featured previously on Mind Hacks.
Spector published the results of a study in 2005 on the genetics of female orgasm which generated a range of critical commentaries.
His review tackles a new book which aims to cover the latest research on orgasm from a number of perspectives, but also gives a glimpse into the neuroscience of orgasm itself.
In my view, the best part of the book is the neurochemistry of the orgasm. Studies of paraplegic women clearly show the importance in female orgasm of multiple complex neural pathways such as the vagus nerve.
Functional brain imaging is an exciting area for study and (despite poor-quality pictures) the authors present the latest findings of multiple areas of brain activity during orgasm — which make any simplistic dopamine (stimulatory) – serotonin (inhibitory) mode of action unlikely.
They postulate a central role for areas such as the cingulate cortex, which is also where pain is perceived — linking pain and orgasm as related sensory processes. Orgasms apparently alter pain perception and increase pain thresholds, and this link may explain bizarre reports of women having orgasms during childbirth.
However, just when I was ready for the truth — a clear definition of orgasm and where it arises in the brain — I was told it was not a reflex, only a perception of neural activity and, even worse, probably a form of diffuse consciousness in an as yet undiscovered fifth dimension.
After such a careful, slow build-up of teasing and tantalizing data, I was definitely left frustrated — and wanting more.
Link to Spectors' review (not freely available unfortunately). Link to info on the book from the publishers.
The fruit pictured on the right is called a soursop - a reportedly delicious fruit from the French West Indies that contains very small amounts of a substance that kills dopamine neurons.
Two research studies have looked at the substance - annonacin - and found it to kill off dopamine neurons in test tube trials.
Annonacin is only present in small quantities so occasionally eating soursop should be safe.
However, it is thought that the high rates of treatment resistant Parkinson's disease in the French West Indies may be linked to high levels of soursop consumption.
Parkinson's disease is caused by the death of dopamine neurons in the nigrostriatal pathway of the brain.
Link to neurotoxicity study on soursop. Link to study on link with Parkinson's disease.
As a perfect follow-up to recent news that damage to an area of the brain called the insula makes it easier to kick an addiction, The New York Times has an article looking more generally at the function of this fascinating neural structure.
The article is by science writer Sandra Blakeslee who has a history of teaming up with cognitive scientists to make their work accessible to a wider audience.
Two of her most notable books have included the strikingly original On Intelligence with Jeff Hawkins, and Phantoms in the Brain with V.S. Ramachandran.
[There's a wonderful typo on Blakeslee's site where she's listed him as 'VR Ramachandran', which makes me think that in the future, everyone will have own virtual Ramanchandran's to pose neuroscience questions to]
The NYT article looks at what is known about the insula, and why it seems to have been relatively neglected by cognitive neuroscientists until recently.
According to neuroscientists who study it, the insula is a long-neglected brain region that has emerged as crucial to understanding what it feels like to be human.
They say it is the wellspring of social emotions, things like lust and disgust, pride and humiliation, guilt and atonement. It helps give rise to moral intuition, empathy and the capacity to respond emotionally to music.
Its anatomy and evolution shed light on the profound differences between humans and other animals.
The insula also reads body states like hunger and craving and helps push people into reaching for the next sandwich, cigarette or line of cocaine. So insula research offers new ways to think about treating drug addiction, alcoholism, anxiety and eating disorders.
Of course, so much about the brain remains to be discovered that the insula's role may be a minor character in the play of the human mind. It is just now coming on stage.
Link to NYT article 'A Small Part of the Brain, and Its Profound Effects'.
The hippocampus is thought to be essential for navigation. Surprisingly, a paper published last year reported that a London Taxi driver, who suffered hippocampus damage on both sides of the brain, could successfully navigate around much of London.
London black cab drivers must pass 'The Knowledge' to get a license.
It involves memorising London streets and being able to work out, from memory, the best route between any two places in the city.
In 2003, neuroscientist Dr Eleanor Maguire and her team won the Ig Nobel Prize (a humorous award for discoveries "that cannot, or should not, be reproduced") for a study that found that the hippocampi of London Taxi drivers were larger than average, possibly because the drivers are constantly exercising their spatial memory.
Despite winning the Ig Nobel, this paper has been very important in understanding both spatial memory and how the brain grows during adult life.
The same team of researchers published a paper last year, looking at the navigation skills of a London taxi driver who suffered selective damage to both his hippocampi after a brain infection.
If the hippocampi were essential for navigation, it would be thought that such a person would have lost 'The Knowledge' or would be unable to use it in practice.
They tested the driver in a complete computer simulation of London (pictured left) and discovered, to their surprise, that he was surprisingly good at orienting himself in the city and navigating the main roads.
He often became lost, however, when he moved away from the main roads and had to rely on smaller roads for navigation.
This suggests that the hippocampus is necessary for the fine-grained knowledge of locations rather than navigation in total.
The researchers suggest that as roads become more familiar, they may become more like 'semantic knowledge' (facts like 'Paris is the capital of France') that you can remember without bringing to mind the context in which you learnt it, or last encountered it.
They note that the main roads may have become more familiar over time and so have acquired a more semantic-like status.
As this occurs, the information would become independent of the hippocampus, allowing the brain-injured taxi driver to keep some of his hard-won Knowledge.
Slate has an article on the use of MDMA ('Ecstasy') in the treatment of people with post-traumatic stress disorder or PTSD.
Limited licenses have been granted to research the use of MDMA to assist in psychotherapy, particularly for trials in people with trauma-related stress.
It will shortly be trialled to see if it can help relieve anxiety and pain in terminal cancer patients.
The Slate article looks at these recent developments, and discusses how they might be practically applied in clinical treatment plans considering some of unwanted effects that might occur.
Link to article 'What a Long Strange Trip It's Been' (via Dev Intel).
Sound Medicine has a fascinating podcast interview with Dr Jill Bolte Taylor a neuroanatomist who experienced a stroke that damaged her brain and fundamentally changed her perception of the world.
A stroke is when the blood supply to the brain get interrupted, often because an artery gets blocked, it swells, or bursts.
Taylor notes that she didn't 'suffer' a stroke, but 'experienced' one, as despite the significant impairment, she found the whole experience an amazing insight into how her brain degraded and repaired after damage.
In the interview, her sense of wonder at the effect of this sudden change in brain function is quite infectious.
Taylor has written a book about her experiences called My Stroke of Insight (ISBN 1430300612) which recounts how the stroke affected her life and mind.
If you're interested in how mind and brain scientists make sense of their own personal experiences of neurological disorder, there's a wonderful book called Injured Brains of Medical Minds which is a collection of writing on the topic.
If you want to know how to detect the signs of a stroke and want to know what life-saving action you could take, there's a fantastic information page here.
Link to podcast webpage. mp3 of podcast interview. Link to 'What You Need to Know About Stroke' infomation.
Wired has a report and video on a research project by Spanish researchers to develop a wheelchair which can be controlled by a brain-computer interface.
Brain-computer interfaces are big news at the moment, although most of the excitement is focused on the sci-fi-like interfaces that implant directly into the brain.
These systems are all lab-based prototypes at the moment so it's interesting to see the Spanish team, led by Dr Javier Minguez, use off the shelf parts to attempt to make something that could be widely available.
The system will read and process from brain signals via EEG to determine the intended direction, but also use an electronic collision avoidance system to help the wheelchair make fine-grained adjustments.
While most the media attention focuses on direct brain implants, it is this sort of remarkably practical approach that will most quickly produce a potentially life-enhancing and relatively low-cost solution for severely paralysed people.
Link to Wired article 'A Wheelchair That Reads Your Mind' (with video). Link to Javier Minguez's webpage with more info.
BBC News has a report on a recent conference presentation by Prof Vivette Glover suggesting that mother's stress can affect the brain development of an unborn child.
If you are pregnant, don't panic, the effect has only been found for quite intense stresses, but these do seem to increase the chances of the child developing behavioural problems later in life.
Actually, the idea that motherly stress could affect the unborn child's chance of developing mental illness is not new.
One of the earliest reports on this was a paper from 1978 who looked at mothers affected by the Soviet invasion of Finland in 1939, later to become known as the Winter War.
Researchers tracked down mothers who were pregnant when their partners were killed in the conflict, and compared them to mothers who were also pregnant at the time of the war, but whose partners were not killed in the fighting.
They found that children born to mothers whose partners were killed were more likely to develop schizophrenia later in life than the children born to mothers with partners who survived, suggesting that the stress of grief affected the child's neurodevelopment.
This is thought to be due, at least in part, to the effect of stress-related hormone cortisol from the mother affecting the development of the foetus' nervous system.
Interestingly, a similar increase in cases has also been found for children born to women who lived through physically and psychologically stressful famines - one in China and one in Holland.
It is well known that birth complications can lead to a slight increase risk for schizophrenia later in life, probably because of the effect on the brain.
It is fascinating to think that the mother's experiences can influence the development of the unborn child's brain, however indirectly it might occur.
Link to BBC News story on conference presentation.
A study published in today's edition of Sciencereports that nicotine addicted patients who acquired damage to the insula - an area just behind the temporal lobes - reported that the urge to smoke reduced after their brain damage occurred.
The insula is coloured red in the diagram on the right and has been heavily linked to emotional responses, particularly the perception and experience of disgust.
However, this new study, led by Nasir Naqvi, suggests that the insula is also heavily involved in addiction-related cravings.
Studying patients with brain damage is one of the most powerful methods in cognitive neuroscience.
While brain scans can tell you which areas of the brain might be associated with a particular experience or behaviour, they can't tell you whether that area is necessary or not.
If you think a brain area might be crucial for a certain process, finding someone who has damage to that area should confirm whether your idea is correct or not by seeing whether they still have the ability or experience you think is linked to the area.
In Bechara and colleagues' study, they included a series of patients who had insula damage, either after suffering a stroke, or after having it deliberately removed as part of brain surgery to treat epilepsy or brain cancer.
Because this sort of damage is rarely precise and causes damage to a number of areas in addition to the insula, a series of patients was studied.
While other damage was present, the patients only had insula damage in common.
This means when group results are analysed, the strongest overall effect should be related to insula damage, whereas effects from damage to other areas wouldn't be as apparent, because it's not common to all patients.
The researchers compared the group with insula damage to other smokers who had suffered non-insula brain damage by measuring who quit smoking, how strong the cravings were and how easy it was to give up.
Insula-damaged patients were much more likely to have quit smoking than the other patients, to experience less cravings, and to have found it easier to give up.
The researchers start their paper by noting that "cigarette smoking [is] the most common preventable cause of morbidity and mortality in the developed world".
You can bet this study will cause massive interest in the pharmaceutical industry who will be attempting to work out the neurochemistry of the insula to try and create drugs which will make treating addiction easier.
Undoubtedly, education and prevention will be much cheaper, but it's hard to make money out of people who don't become addicted.
That's progress for you.
Link to ScienceNow write-up of study. Link to study abstract.
Brain Ethics has a fantastic post by neuroscientist Thomas Ramsøy who describes the discovery of a worrying brain pathology in a volunteer who took part in one of his brain imaging studies.
A 1999 study found that 18% of healthy participants have brain scans that might suggest some form of abnormality, although only a minority of these abnormalities were considered serious enough to require a referral for further medical assessment.
As more and more healthy people are being scanned for neuroscience studies, researchers are now starting to develop protocols and procedures for dealing with situations where previously undiscovered medical problems are discovered, as described by a 2006 Sciencearticle.
In his own work, Ramsøy notes a useful technique he's picked up for detecting brain abnormalities and what he discovered in one of his participants.
One of our radiologists told me to "scroll through the brain quickly and look for flashes", just as a first approximation to detecting brain pathology. So I've done that ever since. Just that simple trick has actually been helpful, this case being the prime example. Above, you can see how the lesions pop out as white sparks in the brain.
For my subject, it means that we have detected a stenosis in both arteries supporting the brain. If untreated, they would eventually have blocked the bloodstream to the brain and caused widespread neuronal damage, maybe even be life threatening.
It's rare researchers talk about instances when this happens, so Ramsøy's post is an enlightening look into a worrying situation that thankfully turned out well in the end.
Link to Brain Ethics article 'Scroll through and look for fireworks'. Link to Science article 'Incidental Findings in Brain Imaging Research'.
It seems the latest edition of Time Magazine is a special on the brain, and there's another full-length neuroscience feature article available online that discusses how the brain reorganises and 'rewires' itself.
This is known as 'plasticity' and neuroscientists often talk about the brain being 'plastic'.
This doesn't refer to the material, although does refer to the fact that the structure of the brain isn't fixed and can change in response to learning or physical stresses.
For decades, the prevailing dogma in neuroscience was that the adult human brain is essentially immutable, hardwired, fixed in form and function, so that by the time we reach adulthood we are pretty much stuck with what we have....
But research in the past few years has overthrown the dogma. In its place has come the realization that the adult brain retains impressive powers of "neuroplasticity" - the ability to change its structure and function in response to experience. These aren't minor tweaks either. Something as basic as the function of the visual or auditory cortex can change as a result of a person's experience of becoming deaf or blind at a young age. Even when the brain suffers a trauma late in life, it can rezone itself like a city in a frenzy of urban renewal. If a stroke knocks out, say, the neighborhood of motor cortex that moves the right arm, a new technique called constraint-induced movement therapy can coax next-door regions to take over the function of the damaged area. The brain can be rewired.
The special edition of Time also has shorter article on the new map of the brain, how the brain deals with time, and an article on six lessons for handling stress.
There's also an interactive timeline of discoveries in psychology and neuroscience.
Link to Time article 'How The Brain Rewires Itself'.
The Sixth International Conference on Neuroaesthetics will take place on January 20th and will focus on the neurobiology of love.
The talks include everything from "Brain Activity During Male and Female Orgasms" from Prof Gert Holstege to "The Biological Concepts of Unity-in-Love and Annihilation-in-Love" by Prof Semir Zeki.
This is a bit of a departure for the International Conference on Neuroaesthetics which has previously focused on the neuroscience of art and aesthetic appreciation.
Link to 6th International Conference on Neuroaesthetics (via BrainWaves).
Science and Consciousness Review has a new feature article on how the brain allows us to revisit past times or predict the future, and how this sense can break down after brain injury.
The article is by new SCR staffer, Alice Kim, who works in the lab of pioneering memory researcher Endel Tulving.
Tulving developed the concept of autonoetic consciousness, a 'feeling of remembering' that allows us to distinguish when information is coming from memory compared to when it is coming from the senses.
Kim has written an article looking at how autonoetic consciousness helps memory, and how it is damaged in a patient with 'chronesthesia', a condition where the awareness of personal past and future is lost, despite a sense of the present being intact.
As well writing for SCR, Kim has also created a wonderful online archive of every Tulving publication, from 1959 (wow!) to the present.
As an aside, Science and Consciousness Review has now fully relaunched after a period of rebuilding since a nasty database crash last year.
Everything seems in perfect working order, so head on over if you want to keep tabs on all things consciousness related.
Link to 'Which brain regions enable us to remember our past and anticipate our future?'. Link to SCR front page.
Brain Maps is an online database of high resolution brain images that you can examine on the web or view with a point-and-zoom desktop application called StackVis.
The team behind Brain Maps has uploaded brain images from a number of species, including humans, so you can point click, zoom and scroll your way across the cortical landscape.
Link to Brain Maps. Link to Brain Maps StackVis download.
Wired has a brief guide to one of the most recently developed and exciting brain imaging technologies - magnetoencephalography or MEG.
The first thing you'll notice about MEG machines is that they live in carefully shielded sealed rooms. The second you'll notice is that they look like giant hair dryers.
MEG works by picking up the magnetic field generated by the brain. You might remember from high school physics that every current produces a magnetic field, meaning neurons produce a magnetic field every time they are active.
However, because even groups of active neurons only have a small current, the associated magnetic field is very weak.
So weak, in fact, that a car passing in a nearby street, and even the earth itself, produces a much stronger magnetic field. This is why the shielded room is needed.
Even with the shielding, to pick up such a weak magnetic field MEG uses ultra sensitive Superconducting Quantum Interference Devices or SQUIDs.
Because they rely on superconductors, they need to be supercooled to work. To achieve this, they're bathed in a pool of liquid helium held in a large container above the head - this is why MEG machines look like giant hairdryers.
An advantage of MEG over EEG is that unlike electrical fields, magnetic fields travel virtually unaltered across the skull, meaning it's possible to more accurately measure where activity comes from.
An advantage over fMRI is that MEG can measure brain changes on a millisecond by millisecond basis, meaning it's much quicker than the typical fMRI 1 second time frame.
Also, MEG is measuring brain activity directly, rather than inferring it from changes in blood flow as fMRI and PET do.
However, as MEG only measures activity on the surface of the brain and can't distinguish activity from small areas, it doesn't give the full depth or spatial resolution of fMRI.
As the Wired article notes, MEG is going to become an increasingly important player in our quest to understand psychology and neuroscience, so keep a lookout for an increasing number of important findings based on MEG scans.
Link to Wired article 'MEG Scanners Are Mega Powerful'.
We have the impression that our free will is supreme, but modern neuroscience is starting to challenge the idea that we are the masters of our fate and captains of our soul.
A recent article in The New York Times looked at some of the philosophical aspects of free will from the perspective of physics and neuroscience.
Newtonian physics suggests that interactions in the physical world are deterministic, that is, the outcome is predictable.
As physical objects, a crucial question is how can we have free will in a universe where every outcome is determined by what went before.
Some people have suggested that the 'fuzzy' nature of quantum physics might provide an answer to this, but there have been no convincing accounts of how this might work.
In neuroscience, free will is more to do with whether we have conscious control over our actions.
Two main threads of research have suggested that our experience of having complete conscious control over our actions may be an illusion.
The first is from experiments like those originally completed by Benjamin Libet. He asked people simply to move their hand whenever they felt like it and note the time when they first felt the urge to move.
While they performed this voluntary action, he recorded electrical activity from areas in the brain known to be involved in generating actions.
His experiments, and many subsequent replications, suggest that the brain's movement areas are active about 200 milliseconds before we feel the urge to move.
In other words, we only become conscious of the intention to move after the brain has initiated the action.
The second source of doubts about our sense of free will is from patients who have suffered brain injury and discover that they have lost conscious control over their actions.
One of the most striking examples is anarchic hand syndrome, linked to frontal lobe damage, where patients find their hand has a 'mind of its own' and often have to prevent it from carrying out actions they don't consciously intend.
An article in The Economist questions whether such findings are eroding the concept of legal responsibility.
This is particularly in light of court cases where evidence of neurological disturbance has been used in an attempt to persuade the jury that the person wasn't responsible for their actions, and, therefore, not guilty of the crime in question.
Link to NYT article "Free Will: Now You Have It, Now You Don't". Link to Economist article 'Free to choose?' (both via 3Q).
There's a great piece in The New York Times on Prof Daniel Levitin and the rapidly developing research field tackling the cognitive neuroscience of music.
We've covered material related to Levitin's recently-released bookThis is Your Brain on Music (ISBN 0525949690) before, but the NYT article goes into a little more detail into some of the scientific findings than previous articles.
Letivin is an ex-rock producer who eventually became disillusioned with the music industry but maintained his love of music through his work as a neuropsychologist.
For his first experiment he came up with an elegant concept: He stopped people on the street and asked them to sing, entirely from memory, one of their favorite hit songs. The results were astonishingly accurate. Most people could hit the tempo of the original song within a four-percent margin of error, and two-thirds sang within a semitone of the original pitch, a level of accuracy that wouldn't embarrass a pro.
"When you played the recording of them singing alongside the actual recording of the original song, it sounded like they were singing along," Dr. Levitin said.
It was a remarkable feat. Most memories degrade and distort with time; why would pop music memories be so sharply encoded? Perhaps because music triggers the reward centers in our brains. In a study published last year [pdf] Dr. Levitin and group of neuroscientists mapped out precisely how.
Observing 13 subjects who listened to classical music while in an M.R.I. machine, the scientists found a cascade of brain-chemical activity. First the music triggered the forebrain, as it analyzed the structure and meaning of the tune. Then the nucleus accumbens and ventral tegmental area activated to release dopamine, a chemical that triggers the brain's sense of reward.
His book got a glowing review from Salon, although I've yet to find any reviews in the academic literature.
However, Levitin's website has a huge amount of information on it, including the audio of interviews he's done and the full text of all his papers, so is well worth a visit if you're interested in checking out the area.
UPDATE: Dr Levitin emailed to say the book has indeed been reviewed in the academic literature. A review that appeared in the journal Cerebrum is available online as a pdf. Enjoy!
Link to NYT article 'Music of the Hemispheres' (via BrainWaves). Link to Salon review of 'This is Your Brain on Music'. Link to Levitin's website.
The always excellent ABC Radio All in the Mind has just had a particularly compelling edition where they covered a neurosurgery operation to fix a particularly dangerous type of problem - an arteriovenous malformation or AVM - in a young woman named Kia.
An AVM is a tangle of veins and arteries meaning that the usually separate arterial (oxygen rich) and venous (oxygen depleted) blood can become mixed or doesn't flow properly.
The problem is usually present from birth owing to a problem in development, and when intact, might not cause any noticeable symptoms.
However, AVMs are known to be fragile and there is a high risk that the AVM might bleed or cause an aneurysm - potentially causing death or serious brain injury.
Therefore, if treatable (and some are so big, complex or fragile that they can't be treated) surgeons will often opt to risk an operation to remove the AVM to prevent any catastrophes in the future.
You'd think that radio wouldn't be a good medium to cover a surgical procedure but the programme makes for compelling listening as the neurosurgeon, Professor Jeffrey Rosenfeld, narrates each stage as the operation progresses.
The patient and other staff also describe their hopes and fears, as well as their role in the treatment.
One of the most striking things is the sound of the drill as it cuts into the skull.
Link to AITM on 'Brain Surgery - Live on the Wireless!'
I've stumbled across a wonderful collection of mind and brain artwork, collected by the author of the Italian website PsicoCafé.
Unfortunately, my Italian isn't what it should be but the site's blog is updated daily, has a podcast and video section, and, not surprisingly, looks beautiful.
If your language doesn't hold out, however, the image gallery is well worth a browse as it's quite a stunning collection.
Link to PsicoCafé image gallery. Link to PsicoCafé.
A new Scientific American Mind has arrived and two of the feature articles are available online - one of which is on the neuroscience of violence.
The article makes a fantastic complement to the Science News article on psychopaths we featured previously.
It touches on psychopathy, but is more focused on the wider issues of non-psychopathic violence that could be triggered in anyone in the population.
Some people in the population engage in more violent acts than others and much research has focused on what are the social and biological risk factors that distinguish high from low-violence individuals.
The frontal lobes seems important as neural circuits here seem to be involved in preventing impulsive acts.
People who experience an abusive or impoverished childhood are also known to be at higher risk for violence, and it is possible that these experiences shape the function of the relevant circuits in the brain as it develops.
Genetics also plays a part, and recent findings that a version of a gene known as MAOA is linked to violence suggests that we may partly inherit a 'violence threshold'. Brain Ethics has a fantastic article on this research if you want to know more.
The article also talks about the Dunedin project, an important and long-running study on development and psychopathology that has provided a huge amount of data in this, and many other areas.
The December edition of SciAmMind also has articles on the military applications of neuroscience, which we featured previously on Mind Hacks, and a number of articles only available to subscribers or in the print edition.
These include articles on migraine, hearing voices, cooperation, crying, brain-scan lie detecting and whether the teen brain is too rational.
UPDATE: I've just noticed that there's a great article on Cognitive Daily examining a recent study on the interaction between guns, aggression and testosterone.
Cutting-edge cognitive science blog Developing Intelligence has a fantastic article on pupil dilation and its likely link to mental processing and arousal.
The eyes are fascinating for neuroscientists as they show the only part of the central nervous system visible from outside the body - namely, the retina.
Areas of the frontal lobes, called the frontal eye fields are specifically involved in eye movements (often called 'saccades') and eye movements are known to reflect a range of cognitive abilities.
Hence, eye movements are studied as a way of trying to understand what might be going on in the brain, particularly in people experiencing mental illness.
According to the new research, however, pupil dilation may also be an important measure of brain function.
One study has shown that it could be directly related to the amount of information held in memory:
In the most compelling finding from this literature, pupil diameter has been observed to increase with each successive item maintained in memory, up until each subject's working memory capacity - and then to contract incrementally as each item is reported back to the experimenter.
As always, there's a wonderfully thorough analysis over at Developing Intelligence so head over there if you want some more startling details of this developing field.
Link to article 'Eyes, Window to the Soul - and to Dopamine Levels?'
A recent brain imaging study has suggested that criminal psychopaths do not show the normal neurological reaction to seeing fear in other people's faces.
Contrary to the media depiction, a diagnosis of clinical psychopathy does not necessarily describe someone who enjoys sadistic violence, but instead describes an aggressive or antisocial person who also seems to have shallow emotions, manipulates others, and has a lack of guilt and empathy for victims.
These traits are usually measured by the use of a diagnostic checklist called the PCL-R.
One of the theories of psychopathy suggests that we learn to avoid treating others badly because their negative emotional reaction is also unpleasant for us.
Psychopaths, so the theory goes, lack the ability to perceive distress in others, and so have less reason to avoid treating others badly if it serves their needs.
A group of researchers, led by Dr Quinton Deeley, tested this theory by brain-scanning 15 psychopaths and 9 healthy controls while they viewed happy, sad and neutral faces.
The participants were asked to indicate whether the faces were male or female as a way of focusing participants on the faces and testing whether they could identify faces adequately, but the real comparison was for their reaction to different emotional expressions.
The researchers found that people with psychopathy show reduced activation in brain areas linked to vision and face perception in response to fearful faces, and surprisingly, also to happy faces.
They also showed less activation to fearful faces compared to neutral faces, which was the reverse of the pattern found in control participants.
These results suggest that psychopathy may involve a problem with identifying others' emotional reaction that is particularly apparent for fearful faces.
However, a previous study with psychopaths reported that they do not show the same fearful response to mild pain when compared to controls, suggesting that the effect may not be specific to faces but a more general problem with fear-based learning.
Whether the problem with identifying fear in other people's faces is a part of this, or an additional problem, remains to be seen.
It is known that both genetics and early life experiences, such as coming from a broken home, experiencing physical punishment and anti-social parenting, can contribute to psychopathy.
What remains to be answered is how much of the differences in brain function are due to inherited traits, and how much are the result of the brain developing in response to early experiences.
UPDATE: Dr Quinton Deeley discusses emotion recognition and psychopaths in the December Royal College of Psychiatristspodcast. The interview starts 27 mins 35 secs in.
Link to abstract of scientific study. Link to write-up from BBC News.
Scientific American has an article on military research programmes that are attempting to optimise the brain for the next generation 'warfighter' - the US army's jargon for the modern solider.
The article is by Dr Jonathan Moreno and is largely made up of excerpts from his new book Mind Wars (ISBN 1932594167) which we featured previously on Mind Hacks.
The SciAm article covers some of the technologies that might reduce the need for sleep, improve mental performance, and get rid of those pesky emotional reactions that crop up when faced with imminent slaughter.
If DNA testing for a fear gene is both scientifically and ethically dicey, what about setting out to create people who lack that characteristic? Would breeding humans without stathmin or other genes associated with fear reactions engender more courageous fighters? Would parents sign on for such meddling if they harbored ambitions for a child capable of a glorious military career or just didn't want to give birth to a "sissy"? One problem, however, is that fear or its functional equivalent is one of those ancient properties exhibited by just about every animal. It surely has tremendous survival value. Removing it would be deeply counterevolutionary and would almost certainly generate numerous unintended and undesirable consequences for the individual, let alone thrust humans headlong into a fierce debate about whether enhancing ourselves has gone too far.
Proponents of such artificial enhancements argue that the changes may not be artificial at all. Is there even a valid distinction, they ask, between artificial and "natural" enhancements such as exercise and discipline? Aren't we just trying to gain whatever advantages we can, as we have always tried to do, or are these techniques cheating nature? Can we manage the consequences, or are the risks for the individual and for humanity too great?
The Neurophilosopher has found an amazing video of a neurosurgical procedure to remove one hemisphere of the brain in a child - a treatment for otherwise untreatable epilepsy.
The procedure is known as a hemispherectomy and remarkably, not only can children survive this operation, but in some cases, can graduate high school and university when they are older.
This is a testament to the brain's ability to grow and adapt during childhood - something often called 'plasticity' in the scientific literature.
There's some more information and links about this remarkable operation in a previous post on Mind Hacks.
The surgical case in the video is from Le Bonheur Children's Medical Center and involves a 6 year-old girl who suffered brain damage before she was born.
In her case, a problem with the middle cerebral artery meant that part of the brain didn't get a proper blood supply. This caused one hemisphere to develop abnormally (see the brain scan on the right).
Damaged or malformed brain tissue can lead to epilepsy in both children and adults, and this is exactly what happened in this case.
If seizures can't be controlled by anti-epileptic medication one option is to surgically remove or isolate the source of the seizures in the brain.
Frequent seizures can lead to problems with day-to-day living, cognitive impairment, further brain damage and increase the chances of sudden unexpected death, which is a rare but tragic.
Therefore, surgery is often a life-saving procedure at best, or at the least, can make the patient a great deal safer.
Notably, before the surgery, the girl in the video wears a helmet. These are often given to children who have frequent seizures to prevent head injury when they fall.
The video explains some of the background to the case, and the surgeons narrate and explain the procedure as they go.
The Timescovers research published in the journal Paediatrics indicating that head size at one year old predicts intelligence in later childhood.
A research team led by Dr Catherine Gale measured the head circumference of 633 children at birth, and regularly afterwards.
The kept in contact with the families and assessed the children at 4 and 8 years for mental performance.
The team found that intelligence was positively related both to head size at birth, and to head growth during childhood.
Interestingly, the same team did a study looking back at older people's medical records and compared their head size at birth and in adulthood, to their IQ measured in their 60s and 70s.
They found no relationship between birth head size and current IQ, but did find a relationship between adult head size and IQ.
This may suggest that their are complex life-long factors affecting brain development that affect intelligence differently as we age.
This is one I missed a couple of months ago: Wired had an article on a novel technique that might help rouse people from coma - applying electrical currents to spinal nerves to stimulate the brain.
The surgeon mentioned in the story, Edwin Cooper, has published a number of studies on the technique, which involves applying an electrical current to the right median nerve which connects directly to the spine.
A Japanese team is attempting to do something similar, but uses electrodes implanted directly in the spine itself to stimulate the dorsal column.
The idea behind the treatment is that the electrical current travels up the spinal nerves and boosts the reticular activating system, a part of the brain stem known to be involved in arousal and motivation.
This in turn should boost the activity of higher brain centres, including the thalamus and then the cortex.
More recently, Japanese researchers have attempted to use electrodes implanted directly in the brain to increase arousal, with some success in early trials.
As an aside, Edwin Cooper is a member of the Lifeboat Foundation, a futurist organisation that aims to develop technology to save the planet from cataclysmic events such as global pandemics or holocaust.
This includes "self-sustaining space colonies in case the other defensive strategies fail".
Discover magazine has an excellent article on the neuroscience of religious or spiritual experience, an area sometimes known as neurotheology.
Although researchers vary in their own spiritual beliefs, it is possible to be an atheist and still study spiritual experience.
Just as a complete understanding of the visual system wouldn't disprove the existence of any particular object you see (after all, it could be a true perception, or it could be an illusion), studying the experience of God, doesn't really tell us anything about whether God exists or not.
One of the most established researchers in this area is Dr Michael Persinger who has stimulated the temporal lobes with weak but shifting magnetic fields (using a modified helmet, pictured) and claims to have induced the experience of a 'sensed presence' in naïve volunteers.
Persinger notes that minor temporal lobe disturbances are common throughout the population, and are more common in people with high numbers of paranormal beliefs.
Supposedly, a form is the helmet is available for sale over the internet, although as the tag-line of the website is "Neurotheology, Magnetic Brain Stimulation, Deja Vu, Death, God, Sex, Love, and more" it sounds more like a track-listing from a Hawkwind album than a serious piece of research equipment.
The article covers most of the major neurotheology research groups, and gives an overview of their main aims.
Neurofuture's Sandra Kiume, who seems to have a knack for discovering striking neuroart projects, has picked up on some pieces by Laura Splan, who has produced detailed neuroanatomy images drawn with her own blood.
Thought Patterns is a series of images inspired by neuroanatomical structures. Each drawing was created using blood taken from my fingertips as the primary medium. The series explores the relationship between the images being depicted and the source of the medium with which they are drawn. I was drawn to these images as a formal exploration of the elements of our body that tell us we sense pain or pleasure.
Wow. There's more at the links below.
Link to Neurofuture post. Link to Laura Splan's website.
BBC Radio 4 science programme Frontiers just started a new series, and the first programme was an in-depth investigation of the science and tricky moral and clinical problems thrown up by patients in a persistent vegetative state or PVS.
The programme talks to the researchers behind the recent study that used brain scanning to infer that a patient thought to be in PVS was actually conscious.
Doctors on the programme discuss the difficulty in diagnosing the condition, and whether functional brain scans should be used as part of the standard diagnostic checks.
Also involved in the discussion is Martin Coleman from Cambridge University's Impaired Consciousness Group who are researching whether brain-computer interfaces could help people incapacitated by brain-injury.
Link to Frontiers webpage on Vegetative State edition. realaudio of programme audio.
Today's Nature has a special supplement on chemical sensing, including a freely accessible article on smell and the flavour system that is full of surprising facts about one of the most neglected senses.
For me, one of the most surprising aspects of the article, was discovery that there are two distinct brain networks for smell.
One is the orthonasal system which deals with odours 'sniffed in' to the nose, and the other is the retronasal smell system (image on the right, click for larger version of both) which is involved in sensing odours when we breath out.
The retronasal system is particularly linked to the flavour system, because it is most commonly activated when we eat food.
The traditional view in the literature on eating behaviour in human culture is that the flavour of prepared foods is humanity's greatest universal shared behaviour, experienced by individuals of all ages in the course of daily life. Flavour is also among the most complex and powerful of all human sensations. It engages almost all of the sensory modalities. It also engages the complex facial, swallowing and respiratory motor systems. Flavour is therefore an active sensation — we use 'active taste' to palpate our food with our tongue as we use 'active touch' to palpate an object we are examining with our fingers. Some of these systems are indicated in the diagram [above]. Above these sensory and motor systems are the cognitive systems for memory, emotion, abstract thinking and language. The importance of retronasal smell images is illustrated by the massive extent to which they interact with these brain systems compared with orthonasal smell images
The article also discusses the how smells are transformed into spatial odour patterns in the brain depending on which sensors the odour activates, and notes that smell-related genes are the largest group in the genome.
All in all, it's a really eye-opening article if, like me, you're not familiar with the surprising and complex nature of our sense of smell.
Link to article 'Smell images and the flavour system in the human brain'.
The International Herald Tribune has a fascinating article on the work of neuroscientist Prof Sandra Witelson.
Witelson is notable for collating the world's largest 'brain bank' of non-diseased human brains.
She is particularly interested in examining how brain structure relates to mental function, and particularly in sex differences between men and women.
Her research has turned up some intriguing differences between the structures of male and female brains, usually not obviously visible on brain scans, as they are at the cellular level and only in specific areas.
Witelson also got the chance to study a particularly exceptional brain:
It was Witelson's 1999 study of Albert Einstein's brain that made headlines by revealing some remarkable features overlooked by other neuroscientists: the parietal lobe, the region responsible for visual thinking and spatial reasoning, was 15 percent larger than average, and it was structured as one distinct compartment, instead of the usual two compartments separated by the Sylvian fissure.
Witelson is continuing her analysis of Einstein's brain, but with a histological study, probing features of the cellular geography in the parietal lobe, like the packing density of his neurons.
These specimens of Einstein's brain came to Witelson via Dr. Thomas Harvey, the pathologist at the Princeton hospital where Einstein died in 1955. Shortly thereafter Harvey stole away with the great man's gray matter (and lost his job as a result).
Now 94, Harvey has received requests for Einstein's brain from many neuroscientists and turned most of them down. But hearing of Witelson's extensive brain bank, he sent her a handwritten note by fax in 1995 asking simply, "Do you want to study the brain of Albert Einstein?"
She sent a fax back: "Yes."
Link to 'A neuroscientist's life's work: Analyzing brains to study structure and cognition'.
Haynes, the maker of the well-known manuals on car mechanics, have released a Haynes Brain Manual (ISBN 1844253716) that gives tips and advice on keeping your mind and brain running smoothly.
Covering everything from exercise and nutrition for optimal brain function, to dealing with stress, to getting help with mental or neurological health problems, the manual seems to be fun and informative guide to possible solutions and resources available.
It not only gives personal advice but also includes a guide to dealing with professional services and tracking down the right sort of help when you need it.
It's mainly targeted at men, and probably fills a gap in the market which is often missed by most blokes' magazines.
The website has a selection of pages from the book available as PDF files if you want to have a look inside.
America's National Library of Medicine have put scans of beautiful old medical texts online including Jospeh Vimont's wonderfully illustrated 1832 anatomy book entitled Traité de phrénologie humaine et comparée that compares the skull and brain of humans and animals.
Despite the French title, it's annotated in both English and French and contains some fantastic illustrations of both normal and abnormal neuroanatomy.
Apparently, it was an attempt to investigate the links between brain structure and the 'science' of phrenology which claimed that bumps on the head indicated personality because they suggested how the brain was developing underneath.
Although phrenology has been discounted as rubbish, it is credited with sparking some of the first ideas on whether specific brain areas could be involved in specific mental abilities, an idea that is now central to modern cognitive neuroscience.
People who take this idea too far, by suggesting that there is a 'brain centre' for some particular complex behaviour are often accused of being 'modern day phrenologists' (usually with an accompanying look of disdain or a loud tut).
Unfortunately, the media loves stories that go something like "'Dream centre' of the brain found" (a real headline) which encourages reporters to distort the usually ambiguous findings of research studies, and scientists to over-simplify their conclusions.
In contrast, Vimont's book is a form of innocent and sincere phrenology and, perhaps, should be enjoyed as such.
Link to Traité de phrénologie humaine et comparée (via BB).
The New York Times has covered a recently published brain-scanning study of five individuals who 'speak in tongues' - an experience also known as glossolalia - where someone appears to be speaking in an incomprehensible language over which they seem to have no control.
This is usually linked to religious and spiritual worship, particularly for Christians in the charismatic tradition (there's some footage on YouTube).
A team of researchers, led by Dr Andrew Newberg, used a type of brain-imaging called SPECT to compare blood flow differences in the brain between when participants were singing hymns and when they were speaking in tongues.
The main findings were that when participants were speaking in tongues compared to when they were singing, there was a decrease in activity in the prefrontal cortex, the tip of the left temporal lobe and a deep brain structure called the caudate nucleus (see image on right).
Although brain areas are known to have multiple functions, the prefrontal cortex is known to be involved in cognitive control, while the left temporal pole is associated with naming and the caudate nucleus has been associated with the ability to switch between multiple languages.
The authors suggest that these findings may indicate a loosening of control over language functions in the brain, potentially leading to the production of apparently unstructured language that the participants experience as outside their control.
Notably, there were also relative increases in activity in the left parietal lobe (linked to our sense of body and spatial awareness) and the amygdala - an area known to be heavily involved in emotion.
These findings were a lot harder to explain, however, although the parietal lobe in particular has been linked to meditation, although a previous study found the area showed decreased, not increased activity, as was the case in this instance.
However, this is not the first time that neuroscientists have studied speaking in tongues.
Dr Michael Persinger reported a case in 1984 where he used EEG recordings to look at the electrical activity in the brain of a 20 year-old female who experienced the same phenomenon.
The graph on the left shows EEG recordings taken from the temporal lobes during a period of speaking in tongues that show increased 'spike events'.
This indicates that, like the more recent Newberg study, changes in temporal lobe function may be an important part of the experience.
Interestingly, people with temporal lobe epilepsy are known to be more likely to have religious or mystical experiences during seizures.
One of my favourite case studies is of 25 year-old female patient with temporal lobe epilepsy who had "seizures characterized by repetition of certain religious statements and a rather compulsive kissing behavior".
Well, they do say God moves in mysterious ways.
Link to NYT article 'A Neuroscientific Look at Speaking in Tongues'. Link to abstract of SPECT study on speaking in tongues.
The Washington Post investigates the neuroscience of lying in a recent article on whether new brain-scanning technologies will be able to separate facts from falsehoods.
This technology is of particular interest to governments interested in whether neuroscience can get more reliable information from suspects, and to companies willing to pay to 'interrogate' clients about their truthfulness.
The article mentions a company called No Lie MRI Ltd which claims to use "the first and only direct measure of truth verification and lie detection in human history", which surely must violate any number of laws regarding truthfulness in product advertising - considering that the recent research on fMRI lie detection suggests a poor reliability with current methods.
Presumably, they took their own lie detection test and convinced themselves they were telling the truth.
This is not to say that this technology will develop in the future to be more reliable, though.
This prospect has sparked concern about the potential legal (pdf) and ethical issues of this technology and spurred the American Civil Liberties Union to submit a freedom of information request to the US Government earlier this year to see if they are already using fMRI 'lie detection' on terrorist suspects.
Some of the hype around brain-scan lie detection harks back to similar claims that were made for the polygraph tests in the past, despite evidence of their poor reliability and high levels of false positives.
Whether fMRI based lie detection turns out to be anything other than a similarly unreliable detection method (but with prettier pictures) remains to be seen.
Nevertheless, one method which does seem to be generating a lot of interest is the Guilty Knowledge Test (pdf), which relies on the fact that the brain tends to produce reliably different automatic responses for items that are recognised compared to items that aren't.
The idea behind this is that you could show items to suspects that were taken from the 'crime scene' and look for the traces of successful recognition measured from the brain.
This technique is now reliable enough that it is starting to be admissible in court. The success of this technique has given researchers hope that successful lie detection may be possible for more than simple recognition situations.
Nevertheless, as every good conman knows, the best lies have a kernel of truth and it's not clear how well these techniques will detect economies of truth when compared to outright whoppers.
Link to article 'Brain on Fire' from The Washington Post.
I went to the exhibition I posted about yesterday on visual cognition in painting and surgery at the Royal College of Surgeons and was a bit under-whelmed to be honest.
It was interesting, but was really just some colourful information boards about the study and research project.
However, the Hunterian Museum is always excellent, and I happened across this exhibit of a skull with three trepanation holes in it, and evidence of syphilitic caries (cavities in the skull caused by infection).
There's no other information about it, except it is pre-1831.
It isn't known whether the hole-drilling operation was an attempt to 'treat' the infection by syphilis, but it is likely, owing to the fact that syphilis often leads to neurosyphilis.
Neurosyphilis is known to cause a number of neurological and psychiatric consequences - psychosis being the most well-known.
Some say that Dracula author Bram Stoker, was suffering from neurosyphilis when he wrote his final, and frankly weird, last novel The Lair of the White Worm.
The Hunterian Museum has an online catalogue, called SurgiCat that allows you to search the museum records and indexes.
A search for 'trephining' (an alternative name for trepanation) brings up a number of surgical kits used for the purpose and various bits of skull and brain-covering that show evidence of hole-drilling.
There's a short but fascinating piece in the New York Times on how the work of artist William Utermohlen was affected by the progression of Alzheimer's disease.
Utermohlen produced some striking pieces during his career and continued to paint after being diagnosed with the degenerative brain disorder.
The impact of the disorder on his creativity can be seen in a web slide show created to accompany the article.
It's particularly interesting that the impact of the paintings don't always seem to diminish with his reduction in technical skill, with some of the later paintings (particularly the one from 1998) remaining both vivid and haunting.
Link to NYT article 'Self-Portraits Chronicle a Descent Into Alzheimer’s'. Link to William Utermohlen gallery. Link to information on Alzheimer's disease.
Seed Magazinediscusses how researchers are exploring the neuropsychology of hypnosis to understand this curious state of mind.
Hypnosis fell out of favour in psychological circles as it got taken up by 'stage hypnotists', and researchers found out that, contrary to the movie stereotypes, hypnosis actually increases the number of false memories recalled, rather than making remembering more accurate.
Furthermore, 'hypnotherapy' seems not to be hugely effective on the current evidence. For example, trials of hypnosis for pain relief when giving birth and smoking cessation have shown mixed results, although it is known to be difficult to design effective trials because hypnotisable individuals are known to be psychologically different from others.
What is a reliable finding, however, is that in particularly susceptible individuals, hypnosis can be used to cause unusual experiences.
Particularly, it is being used as a model of what is alternatively called 'conversion hysteria' or 'conversion disorder', where a person might show physical symptoms, such as paralysis, but where they arise from a psychological cause.
Recent experiments have used hypnosis as a way of causing a temporary and reversible paralysis. Participants are then put in a brain scanner to determine which parts of the brain are active, and compared to people with diagnosed conversion disorder.
It turns out that hysterical paralysis may involve similar brain areas to hypnotic paralysis, but shows different patterns of activation to people asked to 'fake' a paralysis.
These are interesting findings and may provide an insight into the operation of how the unconscious influences our conscious life.
Nevertheless, thorough investigations into the neuroscience of hypnotic states will still need to be conducted, and Seed Magazine tackles some of the latest research in this area.
Link to article 'Science finally tackles hypnosis'.
The Times has a concise piece on a recent study published in Science magazine suggesting that performance on an economic bargaining task could be changed by altering the function of the brain with magnets.
Neuroscientist Dr Daria Knoch and her colleagues asked participants to pay the ultimatum game while, at certain points, the function of their right dorsolateral prefrontal cortex (DLPFC) was disrupted by magnetic pulses.
The team found that when this brain area was disrupted, participants were more likely to accept lower offers of money in the game.
The Times article is a good description of both the game (which is now a widely-used research task) and the results of the study, as well as some commentary on the growing recognition of neuroeconomics as a research field.
George Loewenstein, Professor of Economics and Psychology at Carnegie Mellon University, in Pittsburgh, and one of the pioneers of neuro-economics, said: "The new science of neuro-economics is lending support to a very ancient view of human behaviour. That is the idea that there is a conflict and interaction between passion, and reason and self-interest.
"The now standard view of people as rational maximisers of self-interest is a very recent view. Neuroscience is telling us that that was a bit of a diversion. The rational side is a process that sometimes overrides the dominant interest on human behaviour, which is the passionate side."
Link to Times story 'Why say no to free money? It's neuro-economics, stupid'. Link to abstract of original research study in Science.
Brain Ethics has a fantastic primer on neuroaesthetics for those wanting a concise introduction to the field that attempts to use neuroscience to understand art and aesthetic behaviour.
This is currently an exciting but fragmented field and Martin Skov gives an excellent account of the current state of understanding, as well as a guide to the best books available if you want to continue investigating yourself.
Neuroaesthetics can be thought of as a part of a more general study of art and aesthetics as a biological phenomenon. I will follow other proponents of this view (such as Tecumseh Fitch) in calling this broader approach bioaesthetics. The overall goal of bioaesthetics is to answer the three basic biological questions – what?, how?, why? – in regard to aesthetic behaviour in humans: what is art and aesthetics?; how does art and aesthetics spring from the brain?; and why did this cognitive ability evolve in humans?
Link to 'A short bibliographic guide to the emerging field of bioaesthetics'.
The previous post on the neurological and psychological benefits of breastfeeding made me wonder if being breastfed is associated with a lower risk of developing mental illness later in life.
Perhaps, those who have greater cognitive ability and stress resilience because they were breastfed are at less of a risk of being diagnosed with a serious mental illness later in life.
There seems to be evidence to support this idea.
According to one study published last year, being breastfed is associated with a significantly decreased risk of developing schizophrenia.
One other study found no difference in risk for previously breastfed and non-breastfed adults, but found evidence that early breastfeeding pushed back the time at which those with schizophrenia developed symptoms, suggesting breast milk might postpone the onset of the condition many years later.
Science Newsreports on research that suggests that breastfed babies show measurable benefits in terms of action control and coordination.
The coordination of movement relies heavily on good general brain function. If you ever visit a neurologist for a neurological examination, you'll notice the majority of tests are to do with balance, muscle tone, movement and reflexes.
Hence, the examination of these functions can give a clue to how well the brain is developing.
A research team led by Dr Amanda Sacker set out to use these sort of tests to compare how breastfed and non-breastfed babies were developing.
To the researchers' surprise, [research collaborator] Kelly notes, children "were about 50 percent less likely to have a [developmental] delay if they had prolonged, exclusive breastfeeding when compared to those who were never breastfed." They defined breastfeeding as prolonged when it had lasted at least 4 months. Even babies receiving mother's milk for a short while—2 months or less—were 30 percent less likely to have a developmental delay than those who received solely infant formula, beginning right after birth.
The same team also recently reported results from another study that suggested that breastfeeding is linked to resilience in the face of psychological stress.
The New York Times has an article on the scientific investigation of 'hysteria', the condition now typically called conversion disorder, where physical symptoms such as paralysis, seizures or even blindness seem to be caused by mental disorder rather than any detectable physical problems.
The diagnosis is controversial for many reasons, not least because it is largely Freudian in origin.
Actually, Freud was not the first to investigate the disorder. The French neurologist Jean-Martin Charcot made it popular with his dramatic case demonstrations using hypnotism and especially theatrical patients.
That's Charcot in the picture above, with a patient in a 'hysterical fit'. This painting hung above Freud's consulting couch, and can still be seen there in his London home, now the Freud Museum.
Freud's contribution was to provide a popular theory of why this occurs.
He argued that physical disorder could result from inner psychological turmoil as a result of unresolved conflict. He described a case of 'hysterical paralysis' in one of his most famous case studies, that of 'Anna O'.
Notably, there was little hard evidence for his theories, and critics have argued that his explanation is just used a fig leaf to hide the fact that doctors don't know what is actually wrong with such a patient.
However, similar cases turn up regularly in neuropsychiatry clinics, and in recent years a growing body of research has tackled the issue.
'Psychogenic non-epileptic seizures', where people seem to have epileptic seizures but without any detectable brain disturbance, have probably received the most research attention to date (see twoprevious articles on Mind Hacks).
More recently, brain scanning studies have attempted to make sense of what's going on - with some success.
In a 1997 paper published in the journal Cognition, Dr. Halligan, of Cardiff, and John C. Marshall and their colleagues analyzed the brain function of a woman who was paralyzed on the left side of her body. First they spent large amounts of money on tests to ensure that she had no identifiable organic lesion.
When the woman tried to move her "paralyzed leg," her primary motor cortex was not activated as it should have been; instead her right orbitofrontal and right anterior cingulate cortex, parts of the brain that have been associated with action and emotion, were activated. They reasoned that these emotional areas of the brain were responsible for suppressing movement in her paralyzed leg.
Otherstudies have looked at paralysis induced by hypnosis as a comparison, and interestingly found that similar brain areas are involved in some cases.
Conversion disorder is still poorly understood, but it seems as if these patients are not 'faking it' and may have problems that are not caused by permanent damage, but are outside their conscious control.
The New York Times article looks at some of the most recent research in this area, and charts the growing acceptance of a diagnosis which has been dismissed by some people as nonsense.
Link to NYT article 'Is hysteria real? Brain Images Say Yes'. Link to BMJ editorial 'New approaches to conversion hysteria'.
The latest edition of the Canadian Journal of Psychiatry has a comprehensive review of the evidence on whether cannabis contributes to causing psychotic mental illness - the best known being schizophrenia.
It has been known for a long time that there is a link between cannabis use and psychosis, but it was not known whether cannabis contributed to the development of psychosis, or whether people with psychosis were just more likely to smoke cannabis because it helps dispell some of the unpleasant emotions and feelings associated with the condition.
There is now good evidence that cannabis can contribute to the cause of psychosis, particularly during adolescence and early adulthood.
At a population level, this effect is detectable but small.
At the individual level, the effect seems to be quite variable. Recent research has suggested that the risk of developing psychosis when using cannabis is heavily influenced by what version of the COMT gene a person has.
The main conclusions of the Canadian Journal of Psychiatry review are summarised in an editorial, but for those wanting the in-depth lowdown, the full paper is also available online.
Link to August 2006 Canadian Journal of Psychiatry.
Inducing the shadow-self by stimulating the brain:
Yesterday's Nature contains an intriguing short report of how stimulating part of the brain during neurosurgery induced the feeling that a shadowy version of the patient's body had appeared and was mirroring the patient's movements.
The patient was undergoing routine neurosurgery to examine the brain, prior to more serious neurosurgery to treat otherwise untreatable epilepsy.
It is not uncommon for patients to volunteer to take part in simple neuroscience experiments during these procedures.
Patients have to be awake for part of the neurosurgery anyway because the surgeons probe the brain to make sure they avoid removing any areas essential for language, memory and so on.
The experience of feeling or seeing a double or your own body is called autoscopy or heautoscopy.
In this case, a team of researchers led by neuroscientist Shahar Arzy managed to induce this experience by stimulating an area of the brain called the left temporoparietal junction.
This is the area on the left side of the brain where the temporal lobe and parietal lobe meet (see the pink arrow in the image on the left).
This is not the first case of this kind. The Nature report is from the lab of Olaf Blanke which has reported a number of cases of this condition, either owing to brain injury, epilepsy, or induced by brain stimulation.
In a 2004 paper published in Brain, Blanke's team reported on a number of patients who experienced this phenomenon, including one who said "I see myself lying in bed, from above, but I only see my legs" when her brain was also stimulated in the left temperoparietal junction.
In a further recent paper published in Cortex, Peter Brugger and colleagues reviewed 14 cases of 'polyopic heautoscopy', where patients experience multiple doubles of their own body.
(NB: This paper is available on Cortex'swebsite but because their site is such as mess, you can't link to it directly and you have to use Explorer to navigate. Isn't progress great?)
The temporoparietal junction might be significant as it is thought to process and hold representations of the body and its relationship to external space.
One interesting aspect of the Nature paper is that the patient reported that her double was unpleasant and seemed to have somewhat malign intentions:
Further stimulations (11.0 mA; n=2) were applied while the seated patient performed a naming (language-testing) task using a card held in her right hand: she again reported the presence of the sitting "person", this time displaced behind her to her right and attempting to interfere with the execution of her task ("He wants to take the card"; "He doesn’t want me to read").
The authors suggest they may have found evidence for the mechanism behind 'delusions of control' or 'passivity symptoms' usually linked to schizophrenia.
These are experiences or beliefs that the body and / or mind is being controlled by external forces.
However, not all patients with autoscopy report their experiences as malign, and it may be that the effect of the anaesthetics (known to induce paranoia in some), epilepsy (also linked to risk for psychosis) or the stress of the operation, may have given an unpleasant or malign twist to the experience which might not be directly linked to the disruption of the proposed brain mechanism itself.
The paper is also discussed on Nature's news service.
Link to abstract of Nature study. Link to Nature News write-up. Link to full-text of 2004 Brain paper. Link to full-text of Journal of Neuroscience paper on tempororparietal junction, body image and self .
The University of Wisconsin Medical School have an online video series that shows a dissection of a human body, including special sections on the brain and spinal cord, all expertly narrated by the professors in the department.
There is no better way of learning anatomy than seeing a dissection for yourself (I have fond memories of passing round a freshly removed circle of Willis with my fellow MSc students) and the online video series is an excellent introduction.
The first thing you notice is how some parts of the dissection process are so undelicate. The body is very strong, and it can take quite some force to remove certain parts.
In the brain dissection, the anatomist has to use some significant leverage (and a surgical chisel) to separate the skull from the dura mater - the tough plasticy sheet covering the brain.
The dissection itself is quite medical, in that it tends to focus on the gross (large scale) anatomy of veins, arteries and cavities, rather than on the sort of areas of most interest to cognitive neuroscientists - mainly the internal structure of the cortex.
Nevertheless, if you want a good 'rough guide' to the brain, this is as good a place to start as any.
Link to University of Wisconsin dissection videos (via Omni Brain).
There's a useful article in this month's Scientific American that poses the question 'what is synesthesia?' in the 'ask the experts' section.
The question is answered by neuroscientists and synaesthesia researchers Thomas Palmeri, Randolph Blake and René Marois, who give a concise description of what its like to have synaesthesia as well as explaining some of the science behind this intriguing condition.
Until 5 years ago, syneasthesia was largely ignored and thought to be a rare and relatively uninteresting oddity.
It is now being investigated after surveys found it far more common than previously thought.
It is thought that researching synaesthesia will also give an insight into the structure and function of perception in the brain, in both those with and those without the condition.
The Washington Post has a review and the first chapter of neuropsychiatrist Dr Louann Brizendine's book 'The Female Brain' (ISBN 0767920090).
Brizendine is founder of the Women's and Teen Girls' Mood and Hormone Clinic in San Francisco and her book tackles how biological sex differences have a significant impact on thought and behaviour.
However, the psycholinguists over at Language Log were a bit suspicious about the book repeating a common claim that 'a woman uses about 20,000 words per day while a man uses about 7,000'.
In a series of posts [one, two, three] Mark Liberman looked for the relevant scientific studies and found that, on average, men use slightly more words per day than women.
Link to Washington Post review of 'The Female Brain'. One, two, three links to Language Log analysis (thanks Mageriane!).
The ever-excellent Developing Intelligence has just posted about research that suggests that certain types of brain pathology may selectively improve mental performance.
The first article reports on research that suggests that children with a history of febrile seizures (seizures or 'fits' caused by fever) tend to do better in school than their peers.
This is initially surprising, as seizures are traditionally associated with mental impairment if they occur frequently. As the Developing Intelligence article mentions, it is worth waiting until further evidence is gathered to be sure that this is a reliable finding, as the study uses some non-standard tests.
It does suggest the idea, however, that the brain maintains a "delicate balancing act" and that some things that may confer an advantage may also confer a risk of brain disturbances.
The second article reports that deaf people have enhanced motion sensitivity in that they can detect motion over a wider area than control participants.
Motion sensitivity is known to involve the magnocellular parts of the visual pathway. Motion sensitivity and magnocellular brain function are also known to be particularly sensitive to impairment in certain developmental conditions (such as dyslexia and autism).
The authors of the study thought that this area might, therefore, be most likely to show better performance where sensory problems (i.e. deafness) meant that vision was used to a much greater degree.
They found exactly this pattern of performance, and note that this is likely further evidence for the brain's 'plasticity' - where the brain reorganises through experience.
Link to article 'Working Memory and Convulsions'. Link to article 'Perceptual Enhancement Among the Deaf'.
The debate about male-female differences has always been controversial owing to the link with social and political issues. Where science has previously feared to tread, researchers are now beginning to untangle the differences and similarities.
The Economist has an in-depth article where they summarise and discuss many of the most reliable male-female differences in psychology and dispel some of the myths about men and women being fundamentally different in the way they think.
The article also tackles differences in the structures of male and female brains, noting that male brains are, on average, 9% bigger than female brains, but that female brains tend to be more densely packed with grey matter - the cell bodies and dendrites of neurons where most of the cognitive 'work' is supposedly done.
The San Francisco Chronicle continues in this vein by discussing the work of Dr Louann Brizendine a neuropsychiatrist who has been researching male-female brain differences and has recently published a book on her findings.
She's obviously trying to do a bit of PR for the book ("...talking activates the pleasure centers in a girl's brain. We're not talking about a small amount of pleasure. This is huge. It's a major dopamine and oxytocin rush, which is the biggest, fattest neurological reward you can get outside of an orgasm") but otherwise discusses some of the latest and most interesting developments in the field.
One of her particular interests is the role of hormones in brain function, both during the development of the fetus, and during childhood and adult life. This is becoming an increasing focus in neuroscience research.
A good place to start if you want a grounding in the scientific literature, is a recent article by Larry Cahill in Nature Reviews Neuroscience entitled 'Why sex matters for neuroscience'.
Link to Economist article 'The mismeasure of woman'. Link to SF Chronicle article 'Femme Mentale'. Link to 'Why sex matters for neuroscience'.
Could a wide-spread brain infection account for differences in cultures across the world? Possibly, is the surprising answer from a new research paper published in the Proceedings of the Royal Society of London.
If cognitive parasitology isn't your thing (and it may not be, as I just made that up) the research is expertly discussed by Carl Zimmer.
The disease caused by the parasite Toxoplasma gondii is called toxoplasmosis and has been linked to 'personality' changes in rats and mice.
Although controversial, some suggest that this infection may also be linked to personality changes in humans, suggesting that different rates of infections in different countries may lead to differences in 'national character'.
You're best going to Zimmer's write-up for a concise take on the major implications, but I'll leave you with an intriguing point he finishes on:
"[This] raises another interesting question: what about other parasites? Do viruses, intestinal worms, and other pathogens that can linger in the body for decades have their own influence on human personality?"
Link to Zimmer's article 'A Nation of Neurotics? Blame the Puppet Masters?'.
OR-Live is a website that carries videos of surgical procedures, including a section where you can watch neurosurgery in action.
A brain clipping and coiling procedure to repair an aneurysm will be broadcast live today, and if that doesn't take your fancy, there's plenty more in the archive.
One of my favorites is a temporal lobectomy (removal of part of the temporal lobe) that was completed to remove the source of untreatable epileptic seizures.
It has a winning combination of a fascinating surgical procedure and a slightly uncomfortable professor of neurosurgery looking a bit awkward in front of the camera.
The site is a little confusing in that you need to use the 'Watch Live Webcast' link to launch an archive recording as well as see a live broadcast.
There's a thought-provoking piece in the latest issue of open-access medical journal PLoS Medicine on whether antidepressants 'correct' a problem in the brain, or just create an altered state that may be useful fo
Author Roald Dahl was particularly well known for darkly humorous children's books that form a riotous part of almost every childhood in Britain. Less well known is that he also made some significant contributions to neurology, as detailed in a brief article for Advances in Clinical Neuroscience and Rehabilitation.
A brain scanning technology called MEG is being used to track the function of unborn babies' brains as they grow inside the womb until after they've been born.
Neuroskeptic 
This morning's 
The March edition of The Psychologist has just appeared online and has two freely available articles: one 
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The researchers found that the non-skull signals were richer, were less subject to interference, were more closely tied to specific tasks and could be better linked to specific brain areas.
The New York Daily News 
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A veterinary deworming drug called 
Discover Magazine has an excellent Carl Zimmer 
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Electrical readings from seven patients who died in hospital suggest that the brain undergoes a surge of activity at the moment of death, according to a 
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Your gut has its own neural network. Called the 
The Wellcome Trust is putting its archive of medical films online which includes some fascinating 
Today's Nature has a fantastic 
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A selection of objects described in the medical literature that have ended up in the brain via the nose:
The Boston Globe has a short but interesting 
According to 
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Newsweek has a short but smart 
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In the long history of outrageous drinking stories, this has got to be one of the best.
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It's now well known that high altitude mountain climbing 
The New Yorker has a fantastic in-depth 
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I am pleased to see a 
For the first time, the brain structure of male-to-female transsexuals has been investigated in living individuals using MRI brain scans, helping to fuel the debate over the possible neural basis of gender identity.
New Scientist has an excellent 
Advances in the History of Psychology has just 
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A surgical team from Italy have just 
Discover Magazine has an excellent 
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This week's Nature has an interesting 
I've just found this remarkable CT scan in a 1997 
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Stanford University have put a series of engaging TED style 10 minute 
Neuroscience textbooks often suggest that the ability to image the structure of the brain in living patients started in the 1970s with the introduction of the CT scanner. What they tend to forget is that brain surgeon 
The great British neurologist 
The British Medical Journal has just published one of the greatest and funniest research articles ever to grace the pages of the medical literature with a 
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The annual Society for Neuroscience conference is 
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Surely this must be the greatest headline for a BBC News 
A list of things that deep brain stimulation has been used to treat. 
This is quite a remarkable 
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A 48-year-old woman with a stimulating electrode implanted in her right ventral thalamus started to compulsively self-stimulate when she discovered that it could produce erotic sensations.
ABC Radio National's All in the Mind recently broadcast a gripping 
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The BBC has just begun broadcasting a fantastic series called Blood and Guts on the history of surgery with the first episode on neurosurgery. If you live in the UK you can watch it again on the BBC iPlayer for a 
Wired Science 
Cannabalism gave Western medicine its first understanding of 
Jonah Lehrer has written an excellent 
Neurology journal Brain has just 
A new 
Scientific American has an 
Today's Nature has an excellent feature 
Wired has 
In 1941, brain specialist 
This meant the researchers could identify areas of the cortex that are the most highly connected and highly important, forming a structural core of the human brain.
This week's ABC Radio National's All in the Mind 
New York Magazine has a wonderful 
Magnetic resonance imaging is the most popular method for scanning the brain both for research and for clinical investigations. I've just found a wonderfully written 
In light of research showing that an ingredient in cannabis, cannabidiol, seems to actually reduce the risk of psychosis, I speculated 
Neurophilosophy has 
What makes a man a genius? Russian neuroscientists were pondering this exactly this question in the early 1900s and did exactly what seemed sensible at the time - they collected and dissected the brains of some of the greatest cultural figures in a huge collection called 'The Pantheon of Brains'.
I've just noticed this review 
Wired magazine has just published a must-read 
Science News has an 
Neurophilosophy has a fascinating 
The Telegraph has an 
This is an excerpt from quite possibly the geekiest forensic pathology 
In the wake of the Nature 
This month's Trends in Cognitive Sciences has a fantastic review 
It is now quite widely known that cannabis use is linked to a small but significant 
The New York Times has a fantastic 
The Boston Globe has an interesting 
Wired Science have got a great short film that follows a two people who have deep brain stimulation devices implanted in their brains to treat tremors. 
A 
I finally got round to having a look at the New York Times 
Frontal Cortex has 
A fantastic 
Dopamine has been the big player in understanding schizophrenia since antipsychotic drugs were discovered. All current 
The American Academy of Neurology are now doing fortnightly super-geeky 
Neurophilosophy has found a gory but completely astonishing 
Developing Intelligence has a 
This case report from a 2001 
Today's edition of Nature has some 
Memoirs of a Postgrad has got a great 
Bad Science has a fantastic 
SciAm's Mind Matters blog has a completely 
I've just discovered a wonderfully simple finger touch procedure that can test the function of your 
This is a completely amazing 
I've just found a page with some beautiful 
Treatment Online has an interesting 
The Children's Hospital Boston have created a fantastic '
I just found this jaw-dropping 
Today's Nature has a great article [
The abstract of a fascinating 1995 review 
The online Dana magazine Cerebrum has a great 
Retrospectacle has found an 
One of the reporters for Wired took part in an 
Technology Review has an 
The August edition of medical journal Epilepsy and Behaviour has an interesting 
Artist Lee Pirozzi 
Neurophilosophy has just published another wonderfully illustrated 
I love the way this completely startling fact is dropped into a sentence about one of the pioneers of German neurology:
I've just discovered a fantastic short article on the curious neurological syndromes that appear in Alice's Adventures in Wonderland. It was published a couple of years ago in a clinical neuroscience journal and is freely available online as a 
Believer Magazine 
The New Scientist Invention blog has a short 
There's an interesting and in-depth 
The Spanish Journal of Psychology has an interesting English language article [
Nature Reviews Neuroscience has a fascinating 
Salon have just announced the start of a regular series of neuroscience articles with the 
Musicogenic epilepsy is a neurological disorder where epileptic seizures are uncontrollably triggered by music. Gloria Estefan's 
The Financial Times has a slightly 
YouTube hosts a classic 
A funny 
An 
It's often said that politicians need their head examined, but contrary to 
The Plymouth Marine Laboratory brings us footage of experiments on the giant axons of the squid --- the work that brought us the action potential. Quoting:
Discover magazine has an 
A 
This week's Nature has an intriguing 
My last place of work blocked huge swathes of the web, meaning I'm discovering I've missed some blog posts recently, including this wonderful Neurophilosophy 
Nature's neurology journal has a freely available 
At a recent American Psychiatric Association meeting, commercial companies were 
The American College of Neuropsychopharmacology have made a huge 
There's been quite a bit in the news recently about 'brain scan lie detection', but The New Yorker magazine have just published possibly the best 
A 
In 1935, world renowned neurosurgeon 
Then, as now, the majority of these operations are done while the patient is awake, so the surgeon can check that they're not unnecessarily removing any areas needed for speech, memory or other essential functions.
Nevertheless, her brother's operation had gained her two more valuable years with her family, but it was not enough to save her.
As a sure sign that cognitive improvement games have gone mainstream, Nicole Kidman has been 
ABC Radio National's All in the Mind has just 
A brain scanning 
Neurophilosopher has written an absolutely 
ScienceDaily 
Brain injury resource site Neuroskills has a nifty page of brain 
Wired has a good 
BBC Radio 4 science programme Frontiers just had a 
The picture is a man with a knife blade embedded in his head. It's from a 
Simultanagnosia is where a person can't perceive more than one object at a time. They literally cannot see the wood for the trees. There are two main types that differ depending on the location of the brain injury which has caused the syndrome.
In a study investigating how the brain generates paranormal experiences and psychotic states, researchers used strong electromagnets to alter brain function and found they could reduce the number of times healthy volunteers saw spontaneously experienced false perceptions.
Neurophilosopher has a 
These completely passed me by last year but are well worth checking out: BBC Radio 4 broadcast a couple of excellent radio programmes - one on the effects and treatment of 
If you roll your eyes every time you hear more media hype surrounding the pseudoscientific 'think your way to victory' film 
Prozac is twenty and The Observer celebrates with an 
There's been a wonderful 
Open-access science journal PLoS Biology has another 
Author 
Huge numbers of news sources are 
Online psychedelic drug archive Erowid has scanned in a copy of a 
ABC Radio National's All in the Mind just broadcast some essential listening with a 
ABC Radio National's All in the Mind recently broadcast an incredibly 
Independent artificial intelligence researcher Jeff Hawkins has an 
Researchers from the University of Calgary have released the first version of 
In 1955, after seven years of trying, John and Mary's first child was born. The birth of Casey Holter turned John Holter's life upside-down and changed the course of medical history.
ABC Radio National's All in the Mind recently had a two programme special (
Neurophilosopher has a 
The Washington Post has just published an 
This week's international edition of Newsweek has several articles on how researchers have found that physical exercise can sharpen the mind and boost brain function.
The BPS Research Digest has picked up on a curious 
The New York Times has a fantastic 
Nobel prize-winning neuroscientist 
Neurologist 
Wired magazine has a fascinating 
BBC Radio 4 recently broadcast a 
ABC Radio's Science Show just had a 
An excerpt from the entry for the psychedelic drug 
Below is an excerpt from a review, 
The fruit pictured on the right is called a 
As a perfect follow-up to 
The 
Slate has an 
Sound Medicine has a fascinating podcast 
Wired has a 
BBC News has a 
A study published in today's edition of Science 
Brain Ethics has a 
It seems the latest edition of Time Magazine is a special on the brain, and there's another full-length neuroscience feature 
The Sixth International Conference on Neuroaesthetics will 
Science and Consciousness Review has a new 
Wired has a 
We have the impression that our free will is supreme, but modern neuroscience is starting to challenge the idea that we are the masters of our fate and captains of our soul.
There's a great 
The always excellent ABC Radio All in the Mind has just had a particularly 
I've stumbled across a 
A new Scientific American Mind has arrived and two of the feature articles are available online - one of which is on the neuroscience of 
Cutting-edge cognitive science blog Developing Intelligence has a 
A recent brain imaging 
Scientific American has an 
The Neurophilosopher has found an 
The Times 
This is one I missed a couple of months ago: Wired had an 
Discover magazine has an excellent 
Neurofuture's Sandra Kiume, who seems to have a knack for discovering striking neuroart projects, has picked up on some pieces by 
The 
BBC Radio 4 science programme Frontiers just started a new series, and the 
The International Herald Tribune has a fascinating 
America's National Library of Medicine have put scans of beautiful old medical texts online including 
The New York Times has 
The graph on the left shows EEG recordings taken from the temporal lobes during a period of speaking in tongues that show increased 'spike events'.
The Washington Post investigates the neuroscience of lying in a recent 
Seed Magazine 
The Times has a 
Brain Ethics has a fantastic 
The 
Science News 
Yesterday's Nature contains an intriguing 
The University of Wisconsin Medical School have an online 
There's a useful 
The ever-excellent 
The debate about male-female differences has always been controversial owing to the link with social and political issues. Where science has previously feared to tread, researchers are now beginning to untangle the differences and similarities.
OR-Live is a website that carries videos of surgical procedures, including a section where you can 
There's a 
