Rehabilitation following brain damage: some neurophysiological mechanisms. Determinants of recovery

General theories of recovery are outlined. The effect of a partial lesion in the central nervous system (CNS) is described with the emphasis on the reaction of the intact and undamaged CNS. The reaction of the CNS includes sprouting of new terminals and the unmasking of synapses. The role of neuroglia is discussed in relation to the dynamic changes following partial damage and consequent reorganization of the CNS. The effect of this reaction, sprouting and unmasking of synapses, is to produce an altered nervous system and it is this altered nervous system, as well as the lesion responsible, which produces the clinical picture in human chronic neurological damage. Although much remains unanswered, the known facts of CNS reorganization (and possible regeneration?) in the experimental animal have definite implications for management of neurological deficit in man; in particular, that the adult nervous system is capable of considerable reorganization and therapeutic procedures may be based on active environmental and artificial stimulation.