Learning, plasticity, and recovery in the central nervous system.

Cerebral functions can be described by the interaction of different brain regions as parts of distributed networks. Learning is seen as a refinement of the connection between the various parts of these networks. Plastic changes, as illustrated in brain charting techniques, are the result of learning (or use) in normal brains or found as adaptation (active or passive) after peripheral or central lesions. The relation between brain reorganization and recovery of function is investigated by two recent studies relating the training-induced improvement of lost function to changes in the brain. Others search for the effects of passive stimulation and drug influences. Independently of the approach, however, the general idea is that recovery can be seen as a reconnection between the remaining parts of the disturbed network.