Transient desensitization of a red-green opponent site

Abstract

The threshold for detection of a 3°, 200 msec red test flash may rise immediately after a dim red or green adapting background has been turned off. The threshold falls, however, if the background is yellow; or if the red or green background is slowly flickered during adaptation (e.g. at 2 Hz); or if the test is small and brief (24′, 20 msec). The threshold rise may reflect transient desensitization of a flickersensitive red-green opponent site in the pathway that detects larger and or longer test flashes at low adaptation levels.