Figure 2.

Dendritic fields and receptive field centers of brisk-transient ganglion cells overlap. A, Dendritic fields of an OFF/OFF pair typically overlapped by ∼40%. To compute overlap, we measured the dendritic field area of each cell from a polygon drawn around the dendritic tips of a cell. We then divided the shared dendritic field area by the average dendritic field area of the two cells. B, For each recorded pair, temporal filter characteristics (left; spike-triggered average of the white-noise response) were strongly similar. Spatial response profiles (right) fitted with difference-of-Gaussians functions (RMSE, 0.080 ± 0.01; mean ± SEM; n = 52) show that neighboring ganglion cell receptive fields overlap substantially. The example cell spacings shown here, 2.1σ (ON/ON) and 1.7σ (OFF/OFF), are representative for our sample and correspond, respectively, to receptive field coverage factors of 4.1 and 6.1.