COMPARISON OF INTRARETINAL B-WAVE AND DC COMPONENT IN AREA CENTRALIS OF CAT RETINA

The local electroretinogram (LERG) was recorded with microelectrodes from the area centralis of cat retina. Evidence is presented that supports the separation of the d.c. component and b-wave based upon differences in their sensitivity to qualities of the stimulus. The d.c. component occurred at a lower threshold, survived light adaptation, and summated within a smaller retinal area when compared to the b-wave. Vitreal injections of xylocaine hydrochloride (2 per cent), near the microelectrode tip, differentially affected the -wave and d.c. component. It is suggested that the d.c. component probably originates in bipolar cells and that the b-wave requires the excitation of a more widely convergent input, to the same or different bipolar cells. © 1969.