Response properties of cat striate neurons to simulated optic flow stimuli

Optic flow analysis has been extensively investigated in several extrastriate visual areas of the primate, but it remains unclear whether and how the striate cortex is involved in the processing. In the present study 156 striate neurons in anaesthetized cats were tested with simulated optic flow patterns. More than 80% of the cells responded to the stimuli, about 30% significantly preferred translation to radiation and rotation, but few, if any, displayed clear preference for radial or circular motion. Most responsive neurons had fairly good direction sensitivity for their optimal stimuli. Generally, the differences between simple and complex cells were small and insignificant. Although translation obviously prevailed over radiation and rotation in driving more cells and eliciting stronger responses, the responsivity to complex flow fields was not predictable with the direction preference to planar motion. These results suggest that the striate contribution to optic flow analysis may go beyond the direction selectivity to local translation and there might be some kind of specific mechanism to complex motion features.