Abstract

For the most part, the modeling of visual cortical neurons has preceded complete measurement of their response characteristics. However our recent measurement of the phase transfer of striate neurons provides us the most complete description of their response to date. Our purpose in this paper is to enumerate the differences between striate cell responses and current models of these visual mechanisms. Further we describe the significance of these differences to further visual processing. Our laboratory has recently quantified striate cell response phase to drifting sinusoidal gratings. Within the linear systems framework, these measurements allow us to uniquely determine the response of cells to arbitrary visual stimuli in space and time. The phase transfer of striate cells differs from most theoretical work in two ways. First, response phase increases as a function of velocity but remains constant as a function of spatial frequency. Second, the absolute phase transfer varies from cell to cell and does not always land at the canonical phase positions often modeled in the literature. The consequences of these differences will be more fully detailed in the paper. Finally, although current theoretical work often models a Gaussian shaped response to linear increases in spatial frequency, our work indicates that the frequency response of striate cells is much better described by a Gaussian in log spatial frequency. The consequences of this have heretofore been unexplained.

© 1985 Optical Society of America