Functional reorganization of adult raccoon somatosensory cerebral cortex following neonatal digit amputation.

Amputation of a forepaw digit in raccoons 2-8 weeks of age produced dramatic changes in the functional organization of somatosensory cortex examined electrophysiologically 9-12 months later. The cortical region normally representing the digit that was amputated received widely overlapping input from the entire forepaw, with local disruption of somatotopic organization. Compared with normal animals, the receptive fields of cortical neurons in amputated animals were larger, often included both glabrous and hairy skin, sometimes involved discontinuous skin regions, and were much more variable in peripheral location as a function of recording distance across the cortex and of depth within the cortex.