The effect of unilateral deprivation on visual centers in rats

The effect of unilateral visual deprivation by lid suture on visual centers was studied in rats. In animals with previous visual experience this caused a decrease in volume of the dorsal nucleus of the lateral geniculate body and nucleus lateralis pars posterior of 10% and 8% respectively, a decrease in the thickness of layers II to IV of the visual cortex of 8% and an increase in cell density in cortical layers III and IV of 12% and 10% respectively. These changes were of the same magnitude as in rats which had no previous visual experience. Quantitative changes in deprived visual centers were detectable ten days after lid suture; the process reached its maximum after 30 days. The number of spines on the apical dendrites of pyramidal cells of layer V, observed in layer IV, was reduced by 17% after ten days of visual deprivation and by 28% after 30 days. Reopening of the eye for 10 and 30 days following two months of lid closure caused no recovery in the deprived visual centers.