Brain Building

I’ve been sitting here for the whole evening building a set of slides for my talk here at the Cambridge conference (that I still have not got around to telling you about because I’ve been, well, attending it). My talk is at the start of the Wednesday session and so I’m starting early (yeah, I know) so as to build up all the introductory slides with the fancier graphics to lull the viewer into that comfort zone before bombarding them with technical results. You may well know the sort I mean. (image above right: click-to-enlarge-able “scan” of Homer Simpson’s brain, which I got from here.)

Anyway, I was sitting here thinking that what I could really do with right now (what with the jetlag, the sitting through five one hour talks – all great) is a rapid hike up to the top of Runyon Canyon or up to the top of Mount Hollywood in Griffith Park – two of my favourite pick-me-ups (or is it picks-me-up…?). This would get the blood flowing and give me that jolt I need to stay smart and alert for a few more slides before packing in for the night (and then panicking tomorrow that I did not do enough). All of this was running through my head when an email arrived* with this article about how exercise can boost mental function – actually promote the growth of new neurons. The studies being reported on all started out with some strikingly clever (and fit) mice:

In the late 1990s, one group of mice at the Salk Institute for Biological Studies, near San Diego, blew away the others in the Morris maze. The difference between the smart mice and those that floundered? Exercise. The brainy mice had running wheels in their cages, and the others didn’t.

(this concerns the work of the neuroscientist Fred H. Gage (Salk) and his colleagues)

Gage’s mice proved otherwise. Before being euthanized, the animals had been injected with a chemical compound that incorporates itself into actively dividing cells. During autopsy, those cells could be identified by using a dye. Gage and his team presumed they wouldn’t find such cells in the mice’s brain tissue, but to their astonishment, they did. Up until the point of death, the mice were creating fresh neurons. Their brains were regenerating themselves.

All of the mice showed this vivid proof of what’s known as “neurogenesis,” or the creation of new neurons. But the brains of the athletic mice in particular showed many more. These mice, the ones that scampered on running wheels, were producing two to three times as many new neurons as the mice that didn’t exercise.

And these findings have been extended to human studies too, using mostly functional MRI (you’ll be relieved to learn):

The human brain is extremely difficult to study, especially when a person is still alive. Without euthanizing their subjects, the closest that researchers can get to seeing what goes on in there is through a functional M.R.I. machine, which measures the size and shape of the brain and, unlike a standard M.R.I. machine, tracks blood flow and electrical activity.

So there’s been a new study published by scientists at Columbia University which confirms increased activity in the area in the brain responsible for neurogenesis in people who have been increasing their fitness levels through exercise:

The Columbia study suggests that shrinkage to parts of the hippocampus can be slowed via exercise. The subjects showed significant improvements in memory, as measured by a word-recall test. Those with the biggest increases in VO2 max had the best scores of all.

“It’s reasonable to infer, though we’re not yet certain, that neurogenesis was happening in the people’s hippocampi,” says Scott A. Small, an associate professor of neurology at Columbia and the senior author of the study, “and that working out was driving the neurogenesis.”

(“VO2 max” is a measure of how much oxygen a person is taking in while exercising.) The article (by the New York Times’ Gretchen Reynolds) also reports on other studies supporting the findings, such as some at University of Illinois at Urbana- Champaign. There’s also discussion of the possible mechanisms why this this process occurs, and some rather splendid news about results on the positive effects that might be had from consuming certain substances such as chocolate (hurrah!) and some other interesting ones.

It’s all remarkably good news, but you know what? I ought to get back to writing my talk and leave you to read the article in full. But I think I’m going out for a midnight walk around a little bit of Cambridge first, to get some blood flowing in the hippocampus and so forth… Then it’ll be time for that rather tasty-looking dark chocolate I bought from Marks and Spencer’s yesterday.

Enjoy!

-cvj

(*Thanks Nick W!)