EFFECTS OF VISUAL DEPRIVATION AND ALTERATIONS IN BINOCULAR COMPETITION ON RESPONSES OF STRIATE CORTEX NEURONS IN CAT

Electrophysiological recordings were made from single neurons in striate cortex of normally reared kittens (group N), kittens raised with binocular lid-suture (group BD) and kittens raised with 1 eye lid-sutured and the other eye removed (group MD-E). The MD-E group represented a condition in which inputs from the deprived eye were placed at a competitive advantage over those from the other eye. In agreement with previous studies, fewer cells were responsive to visual stimulation in BD kittens than in N kittens. Among the responsive cells, fewer were direction selective, fewer were orientation selective and more had inconsistent or fast-adapting responses than in normals. The responsiveness and receptive field properties of striate cortex neurons in the MD-E kittens were less affected by the visual deprivation than in BD kittens; however, they still were abnormal in comparison to normal kittens. Comparison of the ocular dominance distributions for cells in N and BD kittens showed a marked reduction in binocularly driven cells in BD kittens. In BD kittens, a larger proportion of monocularly driven cells had orientation selective receptive fields than did binocularly driven cells. This difference was not found in normally reared kittens. Abnormal binocular interactions may contribute to the effects of visual deprivation following binocular lid-suture, probably due to asynchronous light-dark inputs through the closed lids. Removing the other eye and placing inputs from the deprived eye at a competitive advantage during development results in decreased effects on striate cortex neurons. Nevertheless, visual deprivation still produces abnormalities in striate cortex independent of asynchronous or uncorrelated visual stimulation of the 2 eyes.