Response of the cortically blind hemifields to a moving visual scene.

Viewing a rotating field induces a counter-rotating tilt of the subjective vertical in normal subjects. A similar, though smaller, effect is observed when only one hemifield is stimulated. This technique was used with 7 hemianopic patients having retrogenicular lesions. It was hypothesized that the stimulation of a moving scene in the blind field produces an additional tilting effect to that produced by the stimulation of the normal hemifield alone. The visual rotation within only the blind field is expected to have a systematic tilting effect. Both predictions were confirmed in all 7 patients having either right or left hemianopic disorders.