Know blood, know the brain

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).