Cervico-ocular reflex in the normal adult.

(1) The cervico-ocular reflex (COR) in humans was measured while the subjects (n = 10) stood on a rotatable platform in a dark room with the head fixed by a stationary biteplate. Eye movements were measured in response to active and passive rotations about a vertical axis. (2) The COR gain (i.e., horizontal eye movement/amplitude of body rotation) was as great as 22% at low frequency of body rotation (0.025 Hz). With increasing frequency (e.g., at 0.4 Hz) the gain decreased to about 2%. (3) The phase angle of the eye movement ranged generally between -80 and -240 degrees with an average response around -180 degrees. (4) During active rotation, the COR response was similar to the responses measured during passive body rotation. (5) The principal conclusion drawn is that in normal adult humans the COR does not aid in stabilization of the image on the retina during passive or active body rotations. A theoretical function for the COR is presented and discussed.