Responses to drifting gratings of varying aperture. A, Example PSTHs and aperture response curves for two K-on/off cells, an M cell, and a P cell. Example PSTHs are chosen relative to each cell's aperture of maximum response. The eccentricities of the cells are 3.1°, 5.0°, 6.5°, and 8.5°, respectively. Smooth curves show fitted difference-of-Gaussians functions as given by Equation 7. B, Distributions of SSI for spatial uniform modulation and drifting grating stimuli. Box plots show median, range, and interquartile range. Two K-on/off cells had only uniform or only grating data recorded; they are shown as open symbols on the relevant axis. K-on/off cells are more suppressed by large stimuli than P or M cells, and spatially uniform stimuli are more suppressive than drifting gratings. Temporal modulation frequency 5 Hz.