Fig. 2.

Consistency of retinal model with the receptive-field center dynamics of cat alpha ganglion cells. Illustration: A representative model ganglion cell was stimulated with a small square that activated the receptive field center out to a distance of one σ [Gaussian radius, see eqn. (5)]. Panels: Peristimulus-time histograms (PSTHs) recorded over a four-fold range of stimulus intensities ( $\frac{1}{16}-\frac{1}{2}$). The stimulus intensity (log₂ units) is indicated to the upper right of each PSTH. Local inhibition from nonspiking amacrine cells produced a form of contrast gain control that caused ganglion cell responses to become more transient as the stimulus intensity was increased (40 trials, 10-ms bin width). Model PSTHs were similar to those recorded from cat ganglion cells (Creutzfeldt et al., 1970).