[Interactions between saccades and vestibulo-ocular reflex during double gaze shifts].
After fixating the center, human subjects were required to track two visual targets (T1, T2) presented in the horizontal plane in a dark room. When T2 was lit 200-600 msec after T1, T2 was given and also second saccadic eye movement unsolicited at various positions of eye and head during the course of gaze (eye position in the orbit plus head position) shift toward T1. Under all circumstances, the final gaze reached T2 without significant difference from the trials made by eye movement alone, suggesting head and eye positions are perfectly monitored to adjust the amplitude of gaze. As head velocity increased, gaze velocity increased and duration decreased with little change in eye velocity, contrary to the previous assumption that vestibulo-ocular reflex adjusts the time course of gaze shift to be constant.
Dept. of Ophthalmol., School of Med., Nihon Univ., Tokyo, Japan.
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Shinozuka
D000328:Adult; D005133:Eye Movements; D006257:Head; D006801:Humans; D010775:Photic Stimulation / Q000379:methods; D011187:Posture; D012027:Reflex, Vestibulo-Ocular; D012438:Saccades