Spatial frequency characteristics of brisk and sluggish ganglion cells of the cat's retina.

Receptive fields of cat retinal ganglion cells were stimulated by a drifting sinusoidal luminance pattern of fixed (50%) contrast and the amplitude of the fundamental frequency component of response was determined as a function of spatial frequency. Frequency response functions for most cells were unimodal and skewed towards zero frequency when plotted on linear scales. At a fixed retinal location, cells of different classes had different frequency response functions. Heterogeneity within some of the classes could be largely removed by normalizing the axes, thus, revealing a common shape of function for the class. At a fixed retinal location, the maximum response obtained at each spatial frequency was always obtained from a cell of the brisk, rather than sluggish, classes. Spatial frequency resolution was highest for brisk-sustained cells and usually lowest for brisk transient cells.