It has been suggested that the visual system of cats reared without patterned-light visual experience (i.e. binocular deprivation) resembles that of the neonatal kitten. The object of the proposed research is to test this hypothesis by studying the functional properties of single units in the striate cortices of binocularly deprived cats and neonatal kittens. We aim to collect quantitative data on the orientation and direction selectivity and velocity selectivity of single units of such cats. We plan, as well, to study the receptive field structure (including inhibitory portions of receptive field) of striate neurons in binocularly deprived cats and neonatal kittens.