COLOR SENSITIVE RESPONSES IN THE HUMAN FLICKER-ERG.

Abstract

Studies which have attempted to measure selective chromatic adaptation in the human ERG have demonstrated that although it is relatively simple to selectively depress either the photopic or the scotopic component, selective effects within the photopic system are very slight. The study to be described confirms these findings. The human photopic ERG was elicited by rapidly flickering monochromatic stimuli which were presented while the eye was exposed to steady monochromatic adapting fields. Computer averaging was employed to measure the resulting weak responses. Chromatic adaptation was found to depress responses to stimuli of all wavelengths about equally, although slight but reproducible selective effects occurred. These selective effects consisted of a greater depression in the amplitude of responses elicited by stimuli of wavelengths close to that of the adapting field. These selective effects were very small, and were equivalent to the decrease in response amplitude which could be produced by lowering stimulus intensity by a few hundredths of a log unit.