Latency of horizontal cell response in the carp retina

The response latency of horizontal cells in the carp retina was investigated by means of the stimulus-response crosscorrelation using a randomly modulated light of various wavelengths. R/G type cells produced two response components with some difference in latency; short-latency hyperpolarising response to green light and long-latency depolarising one to red light. The latency difference could not be made smaller than 14 ms by increasing the intensity of test light. These results were reconciled with similar measurements under selective chromatic adaptation. The latency difference revealed here supports the current view of neural circuitry that accounts for spectral response characteristics of horizontal cell subtypes.