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Abstract

The firing patterns from frog retina ganglion cells were investigated using microelectrode recordings from the retina and the optic nerve fiber endings. When the eye is stimulated under certain restricted conditions by flashes of light, a response pattern is observed showing an “apparent latency” or “delay time” which is unusually long. In some circumstances the response is not seen until 20 sec after stimulus application. The duration of this silent period before the response is influenced (as measured from theon-off cells) by three parameters; background illumination, degree of dark adaptation, and stimulus flash intensity. Delayed responses can also be elicited in the other three types of ganglion cells if these three parameters are kept within certain ranges. The experimental results suggest that the delayed response is caused by an interplay of long lasting excitatory and inhibitory processes in the retina.