CENTRAL REORGANIZATION OF SENSORY PATHWAYS FOLLOWING PERIPHERAL-NERVEREGENERATION IN FETAL MONKEYS

TRANSECTION Of a sensory nerve in adults results in profound abnormali ties in sensory perception, even if the severed nerve is surgically re paired to facilitate accurate nerve regeneration, In marked contrast, fewer perceptual errors follow nerve transection and surgical repair i n children(1-3), The basis for this superior recovery in children was unknown. Here rye show that there is little or no topographic order in the median nerve to the hand after median nerve section and surgical repair in immature macaque monkeys, Remarkably, however, in the same a nimals the representation of the reinnervated hand in primary somatose nsory cortex (area 3b) is quite orderly, This indicates that there are mechanisms in the developing brain that can create cortical topograph y, despite disordered sensory inputs. Presumably the superior recovery of perceptual abilities after peripheral nerve transection in childre n depends on this restoration of somatotopy in the central sensory map s.