Dynamics of adaptive change in vestibulo-ocular reflex direction. I. Rotations in the horizontal plane.

Horizontal and vertical vestibulo-ocular reflex (VOR) eye movements were recorded in alert cats before and after adaptation to vertical optokinetic motion coupled with horizontal rotation at 0.05, 0.25 or 1.0 Hz. Within 15-30 min, the VOR measured in darkness acquired a vertical component; the maximal directional change in the VOR occurred at the frequency of the adapting stimulus. At other frequencies the gain was less and there were phase leads or lags for higher or lower frequencies, respectively. Adaptive VOR was stable for at least 14 h in unrestrained animals with no visual input and decayed within 30 min during rotation in a stationary visual world.