Motion perception of head or trunk modulates cervico-ocular reflex (COR).

In 15 sitting volunteers with eyes covered the vestibulo- and cervico-ocular reflexes were tested with sinusoidal movements around the vertical axis of the body, at frequencies of 0.05, 0.1 and 0.2 s-1 and a total amplitude of 40 degrees. When the trunk was moved against the fixed head, the subjects described mainly an illusionary head movement at 0.05 s-1, while, at 0.2 s-1 only the trunk movement was perceived. Subjects asked to imagine head motion during COR showed increased eye shifts and total saccadic amplitudes. With concentration on trunk movement perception these values decreased.