Central nervous system effects of limb amputation in man

WE report here the results of an electrophysiological study of the central effects of long-standing limb amputation in man. The findings are felt to have significance for an understanding of neurotrophic mechanisms. The results show that, after amputation, the impulse-conducting ability of a peripheral nerve is severely reduced and that this is accompanied by significant changes in the evoked cortical response; in contrast, function in certain reflex pathways is apparently well maintained. This type of study complements a number of early anatomical investigations1,2. In reviewing the early studies it is evident that much disagreement exists concerning the extent of the atrophy to be found in the cells of the anterior and posterior horns, and in the myelinated fibres of the anterior and posterior roots and of the ascending and descending tracts in the spinal cord. There is the added problem, common to all neuropathological studies, of deciding to what extent impulse conduction and synaptic transmission might have been interfered with. By using a functional approach our study has resolved some of these uncertainties.