Vestibular Habituation in Man and Monkey During Sinusoidal Rotation*

Habituation of the vestibular system by repeated steps of angular velocity leads to a shortening of nystagmus. These steps can be broken down into different frequency sinusoids. High-frequency sinusoidal rotation (above 0.1 Hz) generally was found to be ineffective, while low-frequency stimulation (0.0015-0.05 Hz) led to a dramatic shortening of time constants after only a few cycles of stimulation. In the alert monkey, time constants of vestibular nystagmus and single units, recorded from the vestibular nuclei, are always similar and covary together. Experiments in humans, with measurement of nystagmus and subjective velocity sensation, suggest similar processes for habituation.