Chromatic properties of bipolar cells in the carp retina

Abstract

AbstractIn order to analyze the receptive‐field arrangement of color‐opponent bipolar cells, the intracellular responses to monochromatic light spots of different sizes and shapes were recorded from the isolated retina of the carp (Cyprinus carpio) under photopic conditions. Out of 72 bipolar cells identified, 39 color‐opponent cells were classified into three types: the spatially segregated color‐opponent type, the surround color‐opponent type, and the center coloropponent type. The spectral responses of the second type in the surround receptive field were similar to those of their chromatic counterparts in the horizontal cells, suggesting a close relationship to the horizontal‐cell feedback mechanism. The third type was characterized by a small center area of less than 100 μm in diameter. For each type, the mirror images of the spectral response curves were obtained from on and off bipolar cells. This fact strongly suggests that the four basic color channels originate in the bipolar cells.