BINOCULAR INTERACTIONS IN RAPID SACCADIC ADAPTATION

An adaptive mechanism controls the strength of innervation to the two eyes independently. However, under some circumstances an adjustment in strength of innervation to one eye is generalized to the other. The c oupling and uncoupling of the two eyes during saccadic motor learning was studied using the technique of intrasaccadic target displacements to provide a precise visual-motor error proportional to the commanded movement. Early adaptive changes (saccade plus fast vergence) were mea sured within the saccadic interval and late adaptive changes (vergence error) were measured after the saccadic interval, When one viewing ey e was retrained using intrasaccadic displacements, saccadic amplitude changes generalized to the other nonviewing eye. Thus, rapid adaptive changes trained monocularly were transferred to the nonviewing eye. Bu t when two eyes were viewing and an adaptive stimulus was provided to only one eye (binocular viewing-monocular training), adaptive changes also occurred in both eyes. Experiments described here suggest that th e recalibration of the saccade occurs quickly as a conjugate adjustmen t of gain which is used to balance innervation to the two eyes. Therea fter, disconjugate mechanisms provide a further recalibration to each eye independently.