Temporal Properties of Color-Opponent Ganglion Cells

Abstract

The data presented so far were obtained with flashes of relatively long duration (200 ms) and low frequency (~1 c/s) so that the cell’s responses to each flash could be studied individually. Under physiological conditions, as for instance in a freely moving eye, a picture rapidly moves over the retina; consequently, a cell is usually stimulated by a series of different light stimuli of brief duration, occurring in rapid succession. In order to understand the action of retinal neurons under these physiological conditions, it is necessary to study the cell’s responses to simple consecutive stimuli such as flicker, and to flashes of various duration. Since spectrally and thus functionally different receptors forming the center and surround of the receptive field are influencing the responses of opponent ganglion cells, one cannot exclude temporal interferences of the center and the surround mechanism, caused by repetitive stimulation; the stimulus duration, which determines the on- and offset of light is expected to influence the interaction between cone mechanisms, since excitation of center and surround occurs at light on- or offset, respectively. One can also imagine that cells respond quite differently to repetitive stimulation, depending whether center and surround are acting in a spectrally antagonistic or synergistic manner. The experiments outlined in Section 5.1 provide some answers to such questions.