Three months of juggling grew new brain matter

Researchers at the University of Regensburg in Germany taught a group of non-jugglers a basic three-ball juggling routine, scanning their brains before training, after about three months of practice, and again after three more months of not practicing at all.

Grey matter increased measurably in a visual motion-processing area of the brain after three months of practicing the skill, compared with a control group that learned nothing new, and the increase then partly reversed after three months without further juggling practice.

The rise and partial fall showed the change tracked active practice rather than any fixed trait of the people studied, since the same brains lost some of what they had gained once practice stopped. The scans measured grey matter volume, not cell counts directly, so exactly what changed inside that tissue was a question the imaging alone could not answer.

Grey matter, grown and then let go.