A model of quick phase generation in the vestibuloocular reflex

The vestibuloocular reflex of the cat was studied during step and sinusoidal head velocity stimuli. A model is presented which simulates the observed slow phase and quick phase behavior. The model is constructed to be compatible with neurophysiological observations of the behavior of neurons in the pons. Emphasis is placed on the amplitude and timing of quick phases which are active orienting movements that drive the eyes into the direction of turning. It is proposed that quick phases, like saccades, are generated by a local feedback loop in the pons which rapidly drives the eyes to a point in the orbit specified by a vestibular signal. It is suggested that two internal signals specify the eye positions at which quick phases start and end. The statistics of the fluctuations of these signals was measured and correlation between them was discovered and incorporated in the model.