Histology of the monkey lateral geniculate nucleus after unilateral lid closure and experimental strabismus: further observations.

The histology of binocularly and monocularly innervated portions of the lateral geniculate nucleus (LGN) was studied after unilateral lid closure and experimental esotropia and exotropia in the Macaca mulatta and the results were compared with behavioral and neurophysiological data. The most severe cell shrinkage occurred in two animals who had one eye sutured during the first week of life; all dorsal and ventral deprived LGN layers, including the monocular segment, were involved. Less severe anomalies and sparing of the monocular segment were encountered in esotropic amblyopic monkeys and the least severe changes were in exotropic animals without amblyopia. The severity of behavioral, neurophysiologic, and histologic changes following unilateral lid suture or experimental strabismus could be correlated in all animals studied. The data indicate that the order of susceptibility of the LGN to reduced or abnormal visual input early in life appears to be: dorsal laminae greater than ventral laminae greater than monocular segment.