INNER RETINAL CONTRIBUTIONS TO THE PRIMATE PHOTOPIC FAST FLICKER ELECTRORETINOGRAM

The primate electroretinogram (ERG) recorded at the cornea in response to fast flickering light is thought to reflect primarily the cone pho toreceptor potential. We investigated the origin of the photopic 33-Hz corneal flicker ERG to square-wave and photostrobe flashes by recordi ng in the monkey before and after blocking postsynaptic responses with intravitreal injections of 2-amino-4-phosphonobutyric acid and/or cis -2, 3-piperidiendicarboxylic acid or sodium aspartate. Blocking postsy napic ON or OFF responses produced effects on the timing and the wavef orm of the 33-Hz flicker ERG similar to changes in the b and the d wav es in the corneal single-flash ERG. When all the ERG waves of postsyna ptic origin in the flash ERG were abolished the flicker response was g reatly suppressed, suggesting that postsynaptic cells producing the b and the d waves make major contributions to the photopic fast flicker ERG. (C) 1996 Optical Society of America