Abstract

The first major stage of binocular integration in the visual pathways occurs at the level of striate cortex. Neurons here are thought to process stereoscopic depth information from incongruities in left and right eye receptive fields. This idea is hampered by serious theoretical constraints that prevent an integration of monocular form and binocular disparity encoding. We propose an alternative scheme that provides for this integration in a neurally parsimonious manner. In the alternative notion, disparity information is conveyed by differences in receptive field structure (phase) between left and right eyes. This requires that some first-order cortical neurons (simple cells) have a different receptive field structure for left and right eyes. Detailed tests of cells in the cat’s striate cortex confirm that this requirement holds. Furthermore, there is evidence of a specialization for horizontal disparities which is required for animals with laterally separated eyes. Additional tests of second-order cortical neurons (complex cells) demonstrate that a subset are specialized for the processing of disparity information provided by small groups of simple cells. Considered together, these experimental tests are consistent with the alternative notion of the neural basis of depth discrimination.

© 1991 Optical Society of America