The dual-peak light response of ganglion cells in chicken retina.

In the present study, a particular temporal pattern of the ganglion cells' light response specified as "dual-peak" was observed. In the chicken retina (N=15), about 37.5% (174 out of 464) of the ganglion cells showed such special temporal property in response to the onset of light flash. These neurons responded to light stimulus with two successive components: a transient increase of firing rate which lasted for less than 100 ms, and another prolonged light response appeared in about 100 ms after the first transient response. Moreover, our data demonstrated a temporal adaptation process in the later phase of firing activities when repeated flashes were applied. Meanwhile, the earlier phase had a more stable latency in response to the stimulus. Application of picrotoxin could evoke the dual-peak responses in transient ganglion cells. These results suggest that the origination of the two response components might be distinct and the later one is likely related to GABAergic pathways.