Figure 2.

Response properties of a typical oriented, linear unit. A, Spike rasters in response to drifting bars in 16 directions. B, Orientation tuning curve from rasters in A demonstrates sharp tuning. Dashed curve is fit to a sum of Gaussians. C, Spike rasters in response to drifting gratings of 12 directions and six spatial frequencies. Periodic response is indicative of a linear response type. D, Orientation tuning curve from rasters in C. E, Spatial frequency tuning curve shows bandpass selectivity. Dashed curve is fit to difference of Gaussians.