Abstract
Electrical stimulation of the retina causes discharges of ganglion cells. The responses may be divided into two classes on the basis of their latencies, that is, a short-latency response and a long-latency one. With an on-unit the short-latency response was evoked by a corneopositive current, but the long-latency one by a corneonegative current. With an off-unit a reversed relation was found between the latency and the direction of the current. All four kinds of responses were remarkably facilitated by steady focal illumination and their latencies shortened according to the increase of light strength except for a short latency of an off-unit which was prolonged with increasing intensity of light. In the present experiment the record was obtained from the optic tract of the cat. The dependence of electrical threshold and latency upon the wavelengths of monochromatic lights was determined, using steady focal illumination. The facilitatory effect of light upon the electrical threshold and the latency was found to be maximal in the neighborhood of 500 mμ, but some units showed exceptional behavior.
