Effects of chlorpromazine and promazine on the visual aftereffects of tilt and movement.

The effects of chlorpromazine (CPZ) and promazine on the visual aftereffects of tilt and motion were measured. CPZ markedly reduced the strength of both aftereffects, while promazine produced a smaller and not always significant reduction. Control experiments suggested that the effects were produced in the central visual system rather than by several possible peripheral artefacts or by drowsiness. The effects are discussed with reference to the pharmacological activity of the drugs and their influence on the strength of inhibition in the visual cortex, both in normal subjects and in schizophrenic illness.