Evidence for a cooperative learning mechanism in the vestibulo-ocular reflex.

The vestibulo-ocular reflex (VOR) stabilizes vision by producing eye rotations that counterbalance head rotations. It receives input from a pair of vestibular receptors, and becomes unbalanced when input from one side is removed, producing spontaneous eye rotation in the absence of head rotation (SVOR). SVOR can be eliminated by the process of vestibular compensation. In mammals, SVOR elimination occurs over a period of days, and follows an exponential time course. We show that SVOR elimination in goldfish occurs in a matter of minutes, and its time course is not exponential but is characterized by a sigmoid function suggesting a cooperative mechanism. This time course is reproduced in a stochastic neural network model that has nonspecific reinforcement related to the level of VOR imbalance.