May 09, 2008

Know the lifesaving facts about stroke detection:

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.

—Vaughan.

May 01, 2008

A rattle around Harvard's baby brain lab:

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.

—Vaughan.

April 25, 2008

My mind on my money and my money on my mind:

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.

Link to PubMed entry for article.

—Vaughan.

April 24, 2008

I'm on the drug that killed Paul Erdős:

In the wake of the Nature survey 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.

—Vaughan.

April 23, 2008

Neuroscience of meditation and attention:

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 short courses 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.

Link to abstract of article.
pdf of full-text.

—Vaughan.

April 15, 2008

The yin and yang of cannabis and psychosis:

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.

Link to abstract of scientific study.

—Vaughan.

April 09, 2008

Releasing creativity in a decaying brain:

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 two websites 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.

—Vaughan.

March 21, 2008

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.

Link to Boston Globe article 'Fatal flaw'.

—Vaughan.

March 13, 2008

Following deep brain stimulation:

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'.

—Vaughan.

March 11, 2008

The way to a man's hiccups...:

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.

Link to PubMed entry for case study.

—Vaughan.

March 10, 2008

Could you endure such pain, at any hand but hers?:

I finally got round to having a look at the New York Times migraine 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?

Link to NYT's Migraine Blog (via Neurophilosophy).

—Vaughan.

March 01, 2008

Maths and the numbers game in the brain:

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.

Link to New Yorker article 'Numbers Guy'.

—Vaughan.

February 27, 2008

The metaphysics of a Jazz Thing:

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.

—Vaughan.

February 25, 2008

Psychosis and the coming glutamate revolution:

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 heavily linked 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'.

—Vaughan.

February 14, 2008

Neurology podcasts - the shocking truth:

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 Psychiatry podcasts (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's podcasts 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's NeuroPod seems to be missing in action again.

Mind Hacks. The Perez Hilton of academic neuroscience podcast gossip.

—Vaughan.

The operation of the skulls: a trepanation video:

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.

—Vaughan.

February 12, 2008

Better living through caffeine:

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 Wikipedia page 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.

—Vaughan.

January 31, 2008

Haunted by Dracula's Teeth Syndrome:

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.

Link to abstract of scientific study.

—Vaughan.

January 30, 2008

The highs and lows of brain doping:

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.

Link to 'brain doping' correspondence in Nature

—Vaughan.

January 29, 2008

My first book of hallucinogenic drugs:

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'.

—Vaughan.

January 28, 2008

New super low-power brain scans:

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.

—Vaughan.

January 26, 2008

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.

—Vaughan.

January 24, 2008

So long, and thanks for all the fish, suckers:

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.

Link to 'Are Whales Smarter Than We Are?'.

—Vaughan.

January 21, 2008

Test your corpus callosum:

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!).

—Vaughan.

January 16, 2008

Artistic assault:

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.

Link to Pubmed abstract.

—Vaughan.

January 08, 2008

Buy your own brain surgery tools, online:

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.

—Vaughan.

January 03, 2008

Would you vaccinate your child against cocaine?:

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.

—Vaughan.

December 28, 2007

Sex, prodrugs and rock and roll:

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.

Link to BBC News on the rise of GBL use.

—Vaughan.

December 18, 2007

The problem of believing in belief:

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.

—Vaughan.

December 17, 2007

Experiment with a virtual neuron:

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.

Yay!

Link to virtual neuron.

—Vaughan.

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.

Link to abstract on PubMed.

—Vaughan.

December 13, 2007

Scanning psychopaths:

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'.

pdf of Nature article 'Scanning Psychopaths'.

—Vaughan.

December 06, 2007

Which brain hemisphere falls asleep first?:

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.

Link to abstract of scientific paper.

—Vaughan.

December 04, 2007

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.

There's a trailer available online.

Link to article 'Harnessing the Brain's Power to Adapt After Injury'.
Link to Sharp Brains on PBS neuroplasticity programme.

—Vaughan.

December 03, 2007

No eye deer - an amazing brain injury:

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 Neurophilosophy article.

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.

—Vaughan.

November 27, 2007

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.

—Vaughan.

November 23, 2007

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 markedly poorer 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'.

—Vaughan.

November 16, 2007

A pain in the neck, mind, brain and society:

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.

—Vaughan.

November 07, 2007

Sonata in epilepsy: