A pattern correlation model of vestibulo-ocular reflex habituation

Through the process of habituation, the response of the vestibulo-ocular reflex (VOR) is decreased by prolonged, sinusoidal stimulation at lower frequencies (< or =0.1 Hz). Research on goldfish has uncovered frequency-specific and nonlinear behaviors associated with habituation of the goldfish VOR, which include phenomena that cannot be explained using dynamic linear and static nonlinear models. The unexplained phenomena are abrupt decreases at peak response, gain decreases far in excess of linear predictions based on phase, and violation of superposition. Their existence was attributed to a hypothetical switch that closed in the appropriate context. The pattern correlation model provides a new perspective on the process of VOR habituation. Rather than treat the stimulus as a continuous sinusoid, the pattern correlation model breaks it up into a number of discontinuous patterns. The pattern most closely correlated with the current stimulus then decreases the VOR response by the amount of that correlation times a pre-assigned weight. The pattern correlation model explains how the frequency-specific and the nonlinear behaviors may be related, and how the apparent switching phenomena may occur.