Learning to juggle is a neat trick for the brain as well as the hands. Two neural areas involved in perceiving and remembering visual motion became 3 percent to 4 percent larger during the 3 months it took volunteers to master a basic three-ball juggling routine, say Arne May of the University of Regensburg in Germany and his coworkers.
Over the next 3 months, the same brain structures then shrank in volume by 1 percent to 2 percent if the jugglers stopped practicing their newfound skill, the scientists report in the Jan. 22 Nature.
Brain changes that result from learning are thought to occur primarily at the synapses where brain cells communicate with one another. However, learning a skill and forgetting one occur on a larger neural scale, summing into discernible volume changes in substantial pieces of brain tissue, May's team theorizes.
The researchers used magnetic resonance imaging to measure brain-region volumes in 24 adults who did not know how to juggle. Over the next 3 months, half of them learned to juggle three balls for at least 1 minute. The rest did no juggling. At the end of the period, the researchers administered another round of brain scans. That's when the increased volumes in the visual areas of the jugglers' brains showed up.
To finish up the experiments, the researchers asked the jugglers to stop practicing. A third set of scans 3 months later showed that the enlarged brain areas of the neophyte jugglers had shrunk back down. Nonjugglers showed no change in brain volumes throughout the study.--B.B.