POSTLESIONAL PLASTICITY OF THE HUMAN CERE BRAL-CORTEX .1. LESION EFFECTS

The mechanisms of functional recovery and rehabilitation in brain lesi ons are poorly understood. We studied regression from hemiparesis in n eurological patients using clinical evaluation, neurophysiological rec ordings, and neuroimaging methods. Our results show that the extent of a neurological deficit was determined by the lesion volume of its spe cific cortical representation area or its projection system both in th e acute and chronic stage of disease. in addition to the lesion, also alterations of the cortico-cortical and cortico-subcortical projection tracts affecting distant brain areas contribute to the clinical defic it. in mirror-like correspondence, clinical recovery was found to be d etermined primarily by the topography of the residual brain lesion in adults. Morphometric MR image analysis, evoked potentials and measurem ents of the regional cerebral blood flow revealed that within-system r ecovery was inversely related to the lesion volume.