Neurophysiology of Binocular Single Vision and Stereopsis

Abstract

In the last few years observations made from single cells in the striate cortex have revealed neural mechanisms which doubtless underlie many of the phenomena of binocular vision. These new observations will be reviewed and a neurophysiological theory of binocular single vision and depth discrimination, already outlined elsewhere (Barlow, Blakemoke, and Pettigrew, 1967; Nikara, Bishop, and Pettigrew, 1968; Pettigrew, Nikara, and Bishop, 1968 a and b; Joshua and Bishop, 1969) will be further elaborated below. Before proceeding with this task, it will be instructive to make brief reference to some of the evolutionary aspects of binocular vision and, prompted by our neurophysiological observations, to suggest new interpretations of some features of the evolution of single vision and depth discrimination. In addition it will be necessary to consider the psychophysics of binocular vision since it is the goal of the sensory physiologist to interpret psychophysics in neurological terms. In sharp contrast to form perception and pattern recognition, there is available in relation to binocular vision a well- structured, relatively coherent and widely-accepted body of psychophysical observation and theory, suggesting at once that the problems concerned are more tractable and perhaps less complex than those for form perception. A further matter to be considered is the role of eye movements and their co-ordination in the binocular process since vision is pre-eminently a sensorimotor activity.