When people spend three months learning to juggle, according to a paper published in Nature, parts of their brains grow. “Researchers in Germany split 24 students into two groups, one of which was given three months to learn a classic three-ball cascade juggling routine. Brain scans were then carried out on both sets of volunteers.” (The Scotsman, 22 January 2004). The brains of the jugglers and non-jugglers were scanned before and after the three-month learning period.
According to BBC News Online (22 January 2004), “Jugglers had more grey matter — which consists largely of the nerve cells — in the mid-temporal area and the left posterior intraparietal sulcus, which both process visual motion information.”
Arne May, of the University of Regensburg, Germany, led the group that carried out the research. May said, “Our results challenge our view of the human central nervous system. Human brains probably must be viewed as dynamic, changing with development and normal learning.” (CNN, 22 January 2004).
When the same groups were scanned again after another three months, the increase in grey matter had reduced. Talking to BBC News Online, Vanessa Sluming of the University of Liverpool, UK said, “It would be interesting to know at what point this acquired grey matter can be retained. Does it mean you need to continuously practise the acquired skill to retain it, or at some point have you done enough to retain it?”