Searching for just a few words should be enough to get started. If you need to make more complex queries, use the tips below to guide you.
Article type: Research Article
Authors: Clément, Gillesa; | Wood, Scott J.b | Lathan, Corinna E.c | Peterka, Robert J.d | Reschke, Millard F.e
Affiliations: [a] Laboratoire de Physiologie de la Perception et de I'Action, CNRS/Collège de France, Paris, France | [b] Neurosciences Laboratory, Krug Life Sciences, Houston, Texas, USA | [c] Department of Mechanical Engineering, Catholic University of America, Washington, D.C., USA | [d] R.S. Dow Neurological Sciences Institute, Portland, Oregon, USA | [e] Life Sciences Research Laboratories, NASA Johnson Space Center, Houston, Texas, USA
Note: [*] Reprint address: Dr. Gilles Clément, Cerveau et Cognition, CNRS UMR 5549, Faculté de Médecine, Université Paul Sabatier, 133 Route de Narbonne, F-31062 Toulouse Cédex, France. Tel.: +33 5 62 1737 79; Fax: +33 5 62 1728 09
Abstract: Spatial transformations of the vestibular-optokinetic system must account for changes in head position with respect to gravity in order to produce compensatory oculomotor responses. The purpose of this experiment was to study the influence of gravity on the vestibulo-ocular reflex (VOR) in darkness and on visual-vestibular interaction in the pitch plane in human subjects using two different comparisons: (1) Earth-horizontal axis (EHA) rotation about an upright versus a supine body orientation, and (2) Earth-horizontal versus Earth-vertical (EVA) rotation axes. Visual-vestibular responses (VVR) were evaluated by measuring the slow phase velocity of nystagmus induced during sinusoidal motion of the body in the pitch plane (at 0.2 Hz and 0.8 Hz) combined with a constant-velocity vertical optokinetic stimulation (at ±36°/s). The results showed no significant effect on the gain or phase of the VOR in darkness or on the VVR responses at 0.8 Hz between EHA upright and EHA supine body orientations. However, there was a downward shift in the VOR bias in darkness in the supine orientation. There were systematic changes in VOR and VVR between EHA and EVA for 0.2 Hz, including a reduced modulation gain, increased phase lead, and decreased bias during EVA rotation. The same trend was also observed at 0.8 Hz, but at a lesser extent, presumably due to the effects of eccentric rotation in our EVA condition and/or to the different canal input across frequencies. The change in the bias at 0.2 Hz between rotation in darkness and rotation with an optokinetic stimulus was greater than the optokinetic responses without rotation. During EHA, changes in head position relative to gravity preserve graviceptor input to the VVR regardless of body orientation. However, the modifications in VVR gain and phase when the rotation axis is aligned with gravity indicate that this graviceptive information is important for providing compensatory eye movements during visual-vestibular interaction in the pitch plane.
Keywords: vestibulo-ocular reflex, optokinetic nystagmus, visual-vestibular interaction, otoliths
DOI: 10.3233/VES-1999-9101
Journal: Journal of Vestibular Research, vol. 9, no. 1, pp. 1-11, 1999
IOS Press, Inc.
6751 Tepper Drive
Clifton, VA 20124
USA
Tel: +1 703 830 6300
Fax: +1 703 830 2300
sales@iospress.com
For editorial issues, like the status of your submitted paper or proposals, write to editorial@iospress.nl
IOS Press
Nieuwe Hemweg 6B
1013 BG Amsterdam
The Netherlands
Tel: +31 20 688 3355
Fax: +31 20 687 0091
info@iospress.nl
For editorial issues, permissions, book requests, submissions and proceedings, contact the Amsterdam office info@iospress.nl
Inspirees International (China Office)
Ciyunsi Beili 207(CapitaLand), Bld 1, 7-901
100025, Beijing
China
Free service line: 400 661 8717
Fax: +86 10 8446 7947
china@iospress.cn
For editorial issues, like the status of your submitted paper or proposals, write to editorial@iospress.nl
如果您在出版方面需要帮助或有任何建, 件至: editorial@iospress.nl