Labyrinthine control of the vestibulo-ocular reflex in three dimensions.
Item
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Title
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Labyrinthine control of the vestibulo-ocular reflex in three dimensions.
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Identifier
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AAI9618120
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identifier
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9618120
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Creator
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Yakushin, Sergei Borisovich.
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Contributor
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Adviser: Theodore Raphan
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Date
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1996
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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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Psychology, Experimental | Biology, Neuroscience
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Abstract
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This study determined the contribution of individual semicircular canals to the generation of horizontal and roll components of angular vestibulo-ocular reflex (aVOR). Animals were tilted forward or backward 0{dollar}\sp\circ{dollar} to {dollar}{lcub}\pm{rcub}90\sp\circ{dollar} around an interaural axis from upright, and rotated with sinusoids of 0.2-4.0 Hz around a vertical axis. At 0.2 Hz the gain of the horizontal aVOR was maximal at 11{dollar}\sp\circ{dollar} tilt forward and decreased as animals were pitched forward or backward. Torsional gain was maximal at 90{dollar}\sp\circ{dollar} tilt forward. After plugging of all vertical canals, the gains were zero at about {dollar}-60\sp\circ{dollar} backward tilt. After both lateral canals were plugged, peak gains were shifted from the normal data, reaching a peak at approximately {dollar}-56\sp\circ{dollar} tilted back. The same was true for the animals with an anterior and corresponding contralateral posterior canal intact.;The data were compared to predictions of a model based on the geometric organization of the canals and their relation to a head coordinate frame. The model used the normal to the canal planes to form a non-orthogonal coordinate basis for representing eye velocity. An analysis of variance was used to define the goodness of fit of model predictions to the data. Model predictions and experimental data agreed closely for both normal animals, and after canal lesions. This implies that there was no adaptation of the response planes of the individual canals after plugging. When the operated animals were tested in light, vision compensated for the lack of spatial adaptation of the response planes after plugging at 0.2 Hz.;There was also an approximate linear rise of horizontal and roll aVOR gain with regard to frequency in the all canal plugged animals up to 4 Hz. Thus, the changes in gain and phase as a function of frequency is likely due to the frequency response of the plugged canal and not to adaptation.;These results indicate that both the vertical and lateral canals contribute to the horizontal and roll component of the aVOR in the monkey, there is little or no central adaptation when canals are inactivated, and canal plugging may change the frequency characteristics of the canal response without abolishing its response to rotation.
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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.
