Gain control mechanisms in X- and Y-type retinal ganglion cells of the cat.
A change in responsiveness caused by a spot of light (conditioning spot, CS; 3 sec in duration) presented within a central region of the receptive field of X- and Y-type retinal ganglion cells of the cat was investigated by measuring the magnitude of responses to another spot of light (test spot, TS; 50 msec in duration) which was juxtaposed with the CS within the same receptive field's central region. Responses to the TS were suppressed steadily during the on-phase of the CS as if it were divided by a certain value. This fact indicates that the gain of the center mechanism was changed by the CS presentation. The setting of the gain to a new level was rapid (within 100 msec after the onset or the cessation of the CS), and the magnitude of a gain change was not affected by the surround antagonism. These characteristics of the gain control were common to X- and Y-cells under both mesopic and scotopic levels of light adaptation.
D000200:Action Potentials; D000221:Adaptation, Ocular; D000818:Animals; D002415:Cats; D010775:Photic Stimulation; D012160:Retina / Q000502:physiology*; D012165:Retinal Ganglion Cells / Q000502:physiology*; D013997:Time Factors