Stop writing your grant and take a ride for an hour

Dave Munger at Cognitive Daily comments briefly on a recent NY Times on the positive effects of exercise on brain function. [Update 8/22/07: Jake at Pure Pedantry waxes pedantic about the Morris Water Maze and data interpretation thereof, jeez.]  The Times starts off with the findings from Rusty Gage’s lab at the Salk Institute which focus mostly on evidence of improved neurogenesis, decreased cell death and improved cognition in spatial memory tasks in mice and rats. The pubs started with van Praag et al. 1999 , got a particularly big splash with a finding of improved learning in aged mice (van Praag et al. 2005) and the most recent is van Praag et al. 2007 showing beneficial effects of a plant-derived flavinol in combination with exercise.

[As a sidebar for regular readers of DM, I should point out that San Diego is not only cycling paradise but biomedical research paradise as well. We’re home to the University of California, San Diego, the Salk Institute for Biological Studies, The Scripps Research Institute, The Burnham Institute, The La Jolla Institute of Allergy and Immunology, San Diego State University (not only perennial Playboy top party school but the “top small research institute”), and bunch of smaller or less-well-known institutes. Of course, you knew that already… BM Disclosure: Yes, I work for one of these places. It is no accident that DM and I talk science on occasion.]

Getting back to the exercise-hippocampal neurogenesis-spatial learning stuff, the new finding is a report (Pereira et al, 2007) using MRI to evaluate how much blood was rushing (Cerebral Blood Volume; CBV) through the hippocampi of humans before and after a 3 mo aerobic exercise regimen. Findings were that CBV was increased in dentate gyrus after exercise, the increase was correlated with individual changes in VO2max (a good proxy for the physiological benefit of the exercise program; measured on cycling ergometer, heh!) and, importantly

a correlation between CBV and VO2max was not observed for any other hippocampal subregion, including the entorhinal cortex Fig. 4b), confirming that exercise has a selective effect on dentate
gyrus CBV.

better yet:

we found that changes in VO2max correlated exclusively with postexercise trial 1 learning… Additional analyses showed that the orrelatcion between changes in VO2max and cognition was selective to trial 1 learning (Fig. 4b), thereby confirming that, despite apparent increases in other cognitive measures (i.e., delayed recognition, as shown in Fig. 4a), this particular measure was selectively influenced by exercise.

The rest of the paper is laden with similar and more-invasive mouse findings similar to the Gage studies, in fact Gage is a co-author on this study.

Pretty cool. It starts to put to rest the suspicions of old-time Experimental Psychologists that rodents studies were confounded by the old “impoverished/enriched environment” deal. Basically, the complaint is that normal lab housed rats are not likely to be getting a normal amount of sensory stimulation and thus the “control” group is the abnormal one. Not a huge deal until you want to apply it to humans since there may be ceiling effects. This study tends to confirm the effects in a relatively normal human sample.

BikeMonkey has a question though:

Eleven subjects (mean age, 33 ranging from 21–45 years; 2
males and 9 females) who fulfilled the American Heart Association
criteria for below-average aerobic fitness (VO2max, <43 for men
and <37 for women) were recruited (51). The 11 enrolled subjects
engaged in an exercise training protocol for 12 weeks at Columbia
University Fitness Center at a frequency of four times a week. Each
exercise session lasted ~1hr: 5 min of low-intensity warm-up on a
treadmill or stationary bicycle, 5 min of stretching, 40 min of aerobic
training, and 10 min for cool down and stretching. During the 40
min of aerobic activity, subjects were permitted to select from
cycling on a stationary ergometer, running on a treadmill, climbing
on a StairMaster, or using an elliptical trainer.

So how many chose the bike and who got the best V02max improvement???!!!!