Decrease in the number of synapses formed by subcortical inputs to the striate cortex of binocularly deprived cats.

Abstract

The density of synapses was determined from electronmicrographs taken from area 17 of cats binocularly deprived of pattern vision for 6 months and in normally reared litter mates. In each cat the optic radiation was transected on one side 4 days before sacrifice and the density of synapses of subcortical origin was estimated by comparing the density of normal synapses remaining on the lesioned side with the density of synapses on the unlesioned side. In normal animals 36% of the synapses were formed by subcortical afferents, but in the binocularly deprived animals this figure was reduced to only 17%. A decrease found in the total synaptic density in the deprived visual cortex was not statistically significant. Thus, binocular deprivation seems to selectively diminish the subcortical contribution to the synaptic density in the visual cortex.