ON-OFF retinal ganglion cells temporally encode OFF/ON sequence

While the functions of ON and OFF retinal ganglion cells have been intensiv ely investigated, that of ON-OFF cells has not. In the present study, the t emporal properties of spike trains emitted from ON-OFF cells in response to randomly flickering or multiphase ramp stimuli were examined in the Japane se quail. The results indicate that the firing of ON-spikes was influenced by the recent firing of OFF-spikes, and vice versa. As a result of this int eraction, OFF/ON sequence of light intensity change was encoded with a spik e pair with an interval of 20 ms, indicating that temporal coding is utiliz ed in the vertebrate visual system as early as the retina. Thus, the presen t results suggest that retinal neuronal circuits may detect specific sequen tial features of stimuli. (C) 2001 Elsevier Science Ltd. All rights reserve d.