Allow a laboratory mouse to run as much as it likes, and its
brainpower improves. Force it to run harder than it otherwise
might, and its thinking improves even more. This is the finding
of an experiment led by researchers at National Cheng Kung
University in Taiwan and placed online in May. In the study,
scientists had two groups of mice swim a water maze and in a
separate trial had them endure an unpleasant stimulus to see how
quickly they would learn to move away from it. For the next four
weeks they allowed one group of mice to run inside their rodent
wheels, an activity most mice enjoy, while requiring the other
group to push harder on minitreadmills at a speed and duration
controlled by the scientists. They then tested both groups again
to track their learning skills and memory. Both groups of mice
performed admirably in the water maze, bettering their
performances from the earlier trial. But only the treadmill
runners were better in the avoidance task, a skill that,
according to brain scientists, deman