Vestibular Contributions to Gaze Stability During Transient Forward and Backward Motion

• Published in: Journal of neurophysiology Vol. 90; no. 3; pp. 1996 - 2004
• Main Authors: Hess, Bernhard J. M, Angelaki, Dora E
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01.09.2003
• Subjects: Animals; Eye Movements - physiology; Head Movements - physiology; Macaca mulatta; Motion Perception - physiology; Photic Stimulation - methods; Vestibule, Labyrinth - physiology
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.00302.2003

Department of Neurology, University Hospital Zurich, CH-8091 Zurich, Switzerland; and Department of Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63130 Submitted 28 March 2003; accepted in final form 13 May 2003 The accuracy with which the vestibular system anticipates and compensates for the visual consequences of translation during forward and backward movements was investigated with transient motion profiles in rhesus monkeys trained to fixate targets on an isovergence screen. Early during motion when visuomotor reflexes remain relatively ineffective and vestibular-driven mechanisms have an important role for controlling the movement of the eyes, a large asymmetry was observed for forward and backward heading directions. During forward motion, ocular velocity gains increased steeply and reached near unity gains as early as 40–50 ms after motion onset. In addition, instantaneous directional errors also remained <10° for forward headings. In contrast, backward motion was characterized by smaller vestibular gains and larger directional errors during the first 70 ms of the movement. To evaluate the accumulated retinal slip and vergence errors during the early epochs of motion when vestibular-driven mechanisms dominate gaze stability, the movement of a virtual fixation point defined by the intersection of the two gaze lines was quantitatively compared with the respective movement of the extinguished target in head coordinates. Both conjugate retinal slip and vergence errors were <0.2° during the first 70 ms of the movement, with forward motion conjugate errors typically being smaller as compared with backward motion directions. Thus vestibularly driven gaze stabilization mechanisms can effectively minimize conjugate retinal slip errors as well as keep binocular disparity errors low during the open loop interval of head movement. Address for reprint requests: B.J.M. Hess, Neurology Dept, University Hospital Zurich, Frauenklinikstrasse 26, CH-8091 Zurich (E-mail: bhess{at}neurol.unizh.ch ).