This is a proposal to study some of the behavioral and the neurophysiological consequences of rotationally disparate binocular visual experience. The long-term goal of this work is to understand the function that feature-detecting neurons, particularly those of the visual cortex and superior colliculus, may play in visual perception. An important contribution of these studies is that behavioral and neurophysiological studies will be undertaken in the same animals. The focus of the proposed work is on binocular interactions in animals reared with surgical torsional rotation of one or both eyes, produced at the time of eye opening. In one series of experiments, depth perception will be studied behaviorally in these animals and in parallel neurophysiological studies, binocular interaction will be investigated for neurons of striate cortex and superior colliculus, concentrating on the issue of disparity selectivity. In a second series of experiments, we will pursue recent behavioral results which apparently indicate active suppression of a rotated eye by a normal eye under conditions of binocular exposure (but not during monocular exposure). The question is whether, when there is an orientation disparity between the two eyes, the cat's performance is based on input through only one eye. Or, does the cat sometimes act on one input and, at other times, on the other input? We propose to examine the extent to which changes in ocular dominance of cortical and collicular neurons correlate with the behavioral data, as has previously been proposed for cats with monocular paralysis. A secondary goal of this research is to determine the extent to which adaptation to rotation is similar in visually inexperienced kittens and in adult cats. In higher mammals, including humans, some examples of neural plasticity seem to occur only within some critical or sensitive period in infancy, while other instances of sensory rearrangement (including prism adaptation) seem to produce adaptive change in adults as well, thus raising the question of whether the processes of adaptation are in any way similar to changes which occur in young animals during development.
