[Spectral sensitivity of off-response in human VECP during selective chromatic adaptation (author's transl)]

The spectral sensitivity of the visual system of man during selective chromatic adaptation was determined. The criterion was an off-response of constant amplitude in the evoked cortical potential. Criterion of height of response differed among the subjects investigated. Generally, a pupillary radiant intensity between 0.4 and 1.0 lg unit above the sensory threshold was used. With stimulation of both the green- and the red-sensitive mechanism, the sensitivity of the off-response was low. It was high if either the green or the red mechanism were suppressed by selective chromatic adaptation. Demonstration of an opponent color mechanism in the visual system was easier with recording of the off-response in the VECP than with determination of the sensory threshold. The presence of the blue-sensitive mechanism as revealed by the VECP off-response was shown for light stimuli near the sensory threshold during adaptation which orange and red light for a late response of low amplitude.