The effects of remote retinal stimulation on the responses of cat retinal ganglion cells.

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Abstract
Action potentials were recorded from optic nerve fibers of lightly anesthetized cats while parts of the retina remote from the receptive field were stimulated by a shifting grating. Vigorous responses were obtained under these conditions, confirming McIlwain, Krueger and Fischer, and others. These shift responses were not caused by fluctuations of stray light because they could not be reduced by deliberately increasing or decreasing the light falling on the receptive field synchronously with the shifting grating; a steady adapting light applied to the receptive field did not raise the threshold for the responses, whereas adapting light on the peripheral retina does; and the threshold for the responses is elevated more following bleaching adaptation of the periphery than following bleaching adaptation of the center. Shift responses were strong, of short latency and brief in duration in brisk-transient (Y-type) neurons. With few exceptions they were weak but long-lasting in brisk-sustained (X-type) neurons. Shift responses were unlike responses from the main receptive field in having a distinct threshold; the magnitude of the response to weak gratings was not simply proportional to contrast, as is the case with weak stimuli applied to the receptive field. The excitatory pathway may involve amacrine cells, and this mechanism may be concerned with the detection of the shifts of the image that occur with saccadic eye movements.