Response of Visual Cortical Neurons of the cat to moving sinusoidal gratings: response-contrast functions and spatiotemporal interactions

Abstract

Recordings were obtained from 108 cells near the border of areas 17 and 18 in anesthetized, paralyzed cats. Emphasis was placed on analyzing responses to moving sinusoidal gratings, whose spatial frequency, velocity, and contrast were varied systematically. In the presence of drifting gratings, .apprx. 30% of the cells responded with a periodic discharge at virtually all effective spatial and temporal frequencies. These neurons tended to be simple, to have very low levels of spontaneous activity, and to have the narrowest spatial- and temporal-frequency response functions. Another 30% of the cells responded aperiodically at all but the lowest spatial and temporal frequencies. These cells tended to be complex and to have the broadest tuning curves. The remaining cells responded periodically over part of the range of effective frequencies, and could be simple, complex, or intermediate and difficult to classify.