Learning a complex task, such as juggling, which involves visual and movement processes results in changes in the connective white matter in the brain, reports a study published this week in Nature Neuroscience.
Grey matter in the brain mostly consists of the cell bodies of neurons, whereas white matter consists of the projections sent out by these cell bodies connecting neurons to each other. Although previous work had reported changes in the grey matter in brains of people learning to juggle, this study is the first demonstration of comparable changes in white matter connections.
To test the idea that practicing a new skill can actually cause changes in white matter, Jan Scholz and his colleagues scanned a group of subjects before and after six weeks of juggling training. They found changes in the parietal lobe of the brain, which has previously been linked to visual and movement functions.
Moreover, the authors found training-associated grey matter changes, some of which were localized to the same area as the white matter changes. This suggests that the training influenced the structure of both the neurons' cell bodies and their projections. Both these changes were still apparent when subjects were scanned again four weeks after they had last juggled, showing that the changes are quite long lasting. However, there was no correlation between the magnitude of the grey and white matter changes,?which led the team to propose that these may be relatively independent processes.