This study addresses the extent of divergence in the ascending somatosensory pathways of primates. Diver- gence of inputs from a particular body part at each successive synaptic step in these pathways results in a potential magni- fication of the representation of that body part in the somato- sensory cortex, so that the representation can be expanded when peripheral input from other parts is lost, as in nerve lesions or amputations. Lesions of increasing size were placed in the representation of a finger in the ventral posterior thalamic nucleus (VPL) of macaque monkeys. After a survival period of 1-5 weeks, area 3b of the somatosensory cortex ipsilateral to the lesion was mapped physiologically, and the extent of the representation of the affected and adjacent fingers was determined.
展开▼
