Association of short-latent processes in the rabbit visual system with pre-excitation inhibition in the retina.

An electrographic correlate of short-latent processes in the visual system corresponding to the ERG a-wave was detected in chronic experiments on awake rabbits. The formation of an early negative potential (ENP), small in amplitude, that precedes the positive component of the primary responses (PR) to light and is thus the earliest signal concerning the arrival of information from the retina was detected during a special recording regimen in the optic tract, superior colliculi, outer geniculate body, and visual cortex. The shift in the latent periods with respect to the onset of the development of the ERG a-wave comprised 2-3 msec in all the above structures. The suppression of all ERG components except the a-wave by glycine injected into the vitreous body was accompanied in all structures by the suppression of all PR components except the very initial ENR. Since the pre-excitatory inhibition of ganglionic elements corresponds to the ERG a-wave at the exit from the retina, the role of this inhibition in the transmission of information concerning the very first instant of the visual signal both to subcortical centers and the visual region of the cerebral cortex should be recognized.