Compensatory gaze nystagmus: Visual, vestibular and somatosensory contributions to gaze stabilization during circular locomotion in the monkey.
Item
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Title
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Compensatory gaze nystagmus: Visual, vestibular and somatosensory contributions to gaze stabilization during circular locomotion in the monkey.
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Identifier
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AAI9108178
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identifier
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9108178
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Creator
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Solomon, David.
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Contributor
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Adviser: Bernard Cohen
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Date
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1990
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Neuroscience | Biology, Animal Physiology
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Abstract
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Head and eye movements of two monkeys were recorded during circular locomotion around the perimeter of a 1 meter platform. Only horizontal angular movements, i.e. rotation of the head on the body and the eye in the orbit about the vertical axis were considered. Angular body velocity relative to earth was also measured. The head and eye movements combined to generate what is here termed "compensatory gaze nystagmus," consisting of slow phases opposite in direction to body rotation (hence 'compensatory') and quick phases which direct gaze forward. In order to investigate the role of the visual, vestibular and somatosensory systems in the maintenance of stable gaze, the animals were observed running in light, in darkness and on a counter-rotating platform, respectively.;During running in light, the nature of the visual surround influenced the behavior both qualitatively and quantitatively. When fixating a presumed target of interest, an eye-head coordination strategy was utilized which preferentially utilized head movement, indicating strong visual control of neck muscles. Depending on the distance of the animal from the visual surround, the gain of the compensatory gaze nystagmus (eye + head slow phase velocity/body velocity) was altered to account for the rotational and translational components of the animal's trajectory.;In darkness, gaze compensation during constant velocity rotation was maintained for longer periods when the animals actively ran than when they were passively rotated around the same path. The duration of the response was associated with the time constant of the velocity storage integrator, an element in a model of the vestibular-ocular reflex (Raphan et al. 1979). This suggests that velocity storage may be generalizable to control of head movement via the vestibulo-collic reflex, and have physiological significance in maintaining an estimate of angular body velocity in space during locomotion. When running on a counter-rotating platform, body movement relative to the running surface (gait velocity) was faster than actual angular body velocity with reference to the earth. This increased afferent somatosensory activity resulted in higher compensatory gaze velocities. Signals associated with active limb movement enabled compensatory head movements and were important inputs into the velocity storage mechanism.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
