The neurobiology of sports performance

Now that we’re almost through the 2010 Winter Olympics in Vancouver, we have witnessed several examples of athletes excelling and underperforming. How an athlete responds to a high pressure situation could give interesting clues into the underlying neurobiology and evolutionary history of the brain. The brain has to operate under trade-offs. There is what Stephen Grossberg calls the plasticity-stability trade-off, where a system that learns must decide when to learn and when not to learn since learning involves overwriting previously learned patterns.   There is also the question of how much cognitive control should be exercised.  People talk about just letting their “muscle memory” takeover and go on “instinct” but what does that really mean neurobiologically?  Recent research has shown that a movement resulting from a reaction is faster than one from an intention.  These experiments found that people could hit buttons faster when they reacted to someone rather than when they initiated which  shows that more cognitive control can make you slower.

I think it is quite clear that some athletes rise to the occasion under high pressure situations while others wilt.  The question is why is there such variability.   Naively, it would seem that always performing under pressure should be a good thing.  The answer must be that rising to the occasion is not always optimal in an evolutionary sense.  Let’s imagine in paleolithic times that you’re in a stressful situation where you’re trying to catch your dinner or are running away from something that wants you for dinner.  That would be an analogous situation to a high pressure athletic event.  I think that there is not always an optimal strategy.  In some instances, you would want to simply run as fast as you can and being able to reach top performance would be helpful.  In other instances, it may be better to hesitate and come up with a plan before acting.

Synthetic biology

This Sunday’s New York Times magazine has a rather whimsical and quixotic piece on synthetic biology. I was actually around at the beginning of this whole game as a postdoc in Jim Collin’s lab at Boston University in the mid-nineties.  Back then Jim’s lab was mostly focused on posture control and stochastic resonance and I was transitioning into computational neuroscience with Nancy Kopell.  One day in 1997 I think, Charles Cantor called a meeting with Jim, David Christini, who was a graduate student in Jim’s lab, and myself about using engineering methods to design bacteria.  His example idea was to design a bacteria that could eat oil and then die.   Jim, who was always open to new ideas, jumped right on it.  I think the premise of the meeting was to present this  proposal for a site visit by the Whitaker Foundation. This was when oil spills still dominated the news.  I think we quickly cobbled something together and Jim presented the ideas.  However, Dave was finishing up his thesis and heading off to Cornell in NYC and I was trying to learn about the hippocampus so the idea kind of sat idly for awhile.

Shortly afterwards, Jim recruited Tim Gardner, a first year grad student in biomedical engineering at BU, to work on the project.  Jim got some lab space in Cantor’s lab and we started to talk about what we could do.  At that time, I started reading about neural networks and noticed that the equations for a neural network looks remarkably like that for a gene regulatory network.  My idea was to build a gene Hopfield network associative memory.  I showed Tim how to use XPPAUT, a differential equation solver written by Bard Ermentrout, taught him a little about dynamical systems, and we started to write down equations.  This was 1998.

Increase in myopia

A recent study in the Archives of Ophthalmology confirms what we’ve all probably suspected, which is that the prevalence of near sightedness or myopia is on the rise.  The study headed by Susan Vitale of the National Eye Institute examined National Health and Nutrition Examination (NHANES) population data from 1971-1972 and compared it to the NHANES data from 1999-2004.  This is the same data set that we examined to compare the increase of obesity and food supply to conclude that the obesity epidemic is due to a push effect of too much food (see here).  The prevalence of  myopia increased from 25% to 41.6%.  The greatest increase in myopia was for African Americans, who doubled their prevalence.  Whites increased by about 30%.

The conventional wisdom is that the increase in near activities such as reading, surfing the web, texting and watching TV are the cause for this dramatic rise in myopia.  However, a group in Australia have been arguing that it is the lack of outdoor activities during childhood that may be the most to blame.  Papers in Opthalmology in 2008 for Australian children (age 6 and 12) and in 2010 in the British Journal of Opthalmology for Singaporean children (ages 11-20)  show that the number of hours spent outdoors was significantly correlated with less myopia.  To control for genetic factors, they also just looked at children of Chinese descent in Australia and Singapore.  Both studies found a protective role for outdoor activities and a further protective role for outdoor sports such as soccer, softball and baseball for the older children but only for 6 year old  boys.  They also found that it wasn’t a threshold effect – the more you play outside the less likely to have myopia. Interestingly, playing sports indoors did not have a protective effect so some combination of being outside and playing sports (and perhaps visually oriented sports) seems to help. The effect is also independent of the amount of time spent reading.  It would be interesting to repeat this study in the northern hemisphere where it is cold and dark for half the year to see if that plays a role.

I think there may also be a business opportunity to develop displays that put the point of focus at infinity (as well as mimicking being outside).  Although, it is still not known why being outdoors helps (it could be exposure to higher light intensities including UV light for example), I still believe that focusing at infinity rather than at 18 inches must help even if it is only to alleviate eye strain.  The display would essentially be a simplified 3D viewer where the experience of editing a document would change from staring at letters directly in front of you to looking at a supersized billboard sitting on a mountain top in the distance.

Addendum 2010-2-10:  You would also need to apply ray tracing software to the image to mimic the effect of a converging lens to put the image at infinity, in effect blurring the image unless you focused at infinity.

Paper now in print

M.A. Buice, J.D. Cowan, and C.C. Chow, Systematic Fluctuation Expansion for Neural Network Activity Equations, Neural Comp. 22:377-426 (2010) is now in print.  The summary of the paper is here and a PDF can be obtained here.