Ganglion Cell Receptive Field Organization at Different Levels of Light Adaptation

Retinal ganglion cells of the goldfish retina show color opponency at photopic levels of illumination. The spectral sensitivity curves fo the opposing excitatory and inhibitory responses indicate two underlying cone mechanisms. At scotopic levels, these same cells show a marked increase in over‐all sensitivity and a different spectral sensitivity curve with only one response type. The sign of the scotopic rod response was always the same as that produced by stimulating the long wavelength cone pigment in the center of the receptive field. The change in spectral sensitivity, the large increase in sensitivity, and the clearly demonstrable Purkinje shift in all of the ganglion cells studied indicated that even cells exquisitely tuned to color information have both rod and cone inputs.