Olivier J.M.D. Coenen
Terrence J. Sejnowski
Computational Neurobiology Laboratory
Howard Hughes Medical Institute
The Salk Institute for Biological Studies
10010 North Torrey Pines Road
La Jolla, CA 92037, U.S.A.
Departments of Biology and Physics
University of California, San Diego
La Jolla, CA 92093, U.S.A
The vestibulo-ocular reflex (VOR) stabilizes images on the retina during rapid head motions. The gain of the VOR (the ratio of eye to head rotation velocity) is typically around -1 when the eyes are focused on a distant target. However, to stabilize images accurately, the VOR gain must vary with context (eye position, eye vergence and head translation). We first describe a kinematic model of the VOR which relies solely on sensory information available from the semicircular canals (head rotation), the otoliths (head translation), and neural correlates of eye position and vergence angle. We then propose a dynamical model and compare it to the eye velocity responses measured in monkeys. The dynamical model reproduces the observed amplitude and time course of the modulation of the VOR and suggests one way to combine the required neural signals within the cerebellum and the brain stem. It also makes predictions for the responses of neurons to multiple inputs (head rotation and translation, eye position, etc.) in the oculomotor system.