Figure 1. Three different adaptive fields in the retina.

(A) A single frame of the stimulus when a high contrast square was presented. (B) Temporal sequence of the binary stimulus in the different regions. High contrast was 100% Michelson contrast in a single region, indicated by the black box in (A). Low contrast was 5%. (C) Response of an On (left), fast Off adapting (middle), and fast Off sensitizing cell (right). PSTHs are shown with the high contrast region (square) located at two positions relative to the receptive field center (circle), and show the average response for > 60 stimulus sequences. Data binned at 0.5 s. Colored responses indicate when all regions were low contrast. Black indicates the time of the local high contrast. (D) Adaptive indices for all cells. The color of each point in the polar plot indicates the cell’s adaptive index when the adapting square was at that location. The origin indicates the cell’s receptive field center. Data comes from 9 On, 21 sensitizing, and 74 adapting Off cells. For sensitizing cells, adaptive fields are shown during L_early (top), and during L_{0 – 0.5}, 0 – 0.5 s after high contrast (bottom) (E) Average adaptive index for each cell type as a function of distance from the cell’s center. Results were averaged across angles in (D), and colors correspond to (C). Solid black lines are single or difference of Gaussian fits to the data with a standard deviation of 0.41 mm for sensitizing cells, 0.30 mm (larger) and 0.11 mm (smaller) for adapting Off cells, and 0.32 mm for On cells.