THE AVIAN ACCESSORY OPTIC SYSTEM: NEUROPHYSIOLOGY, DEVELOPMENT AND OCULOMOTOR FUNCTION (OPTOKINETIC NYSTAGMUS, ECTOMAMMILLARY).
Item
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Title
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THE AVIAN ACCESSORY OPTIC SYSTEM: NEUROPHYSIOLOGY, DEVELOPMENT AND OCULOMOTOR FUNCTION (OPTOKINETIC NYSTAGMUS, ECTOMAMMILLARY).
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Identifier
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AAI8515611
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identifier
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8515611
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Creator
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BURNS, SHEILA.
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Contributor
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Joshua Wallman
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Date
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1985
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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
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Abstract
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This is a study of the nucleus of the basal optic root (nBOR) of the avian accessory optic system. Single unit recordings in nBOR suggest that it has a role in vertical stabilizing eye movements. Cells in nBOR have unusually large receptive fields peripheral to the optic axis. They respond best to large, richly patterned stimuli moving slowly (2 to 4 deg./sec.) in vertical directions and they never respond to small stationary stimuli.;The functional organization of nBOR differs from the classical anatomical divisions of the nucleus. A partial retinotopic organization unrelated to the anatomical divisions, but closely related to the functional divisions was also found. The functional organization of nBOR is partially related to known efferent projections to the oculomotor nuclear complex. Only neurons detecting upward motion in the frontal visual field appear to project to oculomotor neurons which move the eye upward, while both neurons detecting upward and downward motion throughout the visual field may project to oculomotor neurons which move the eye downward.;Electrical stimulation of nBOR resulted in horizontal nystagmus. This suggests that nBOR may have a role in regulating horizontal stabilizing eye movements. This may occur via efferent pathways.;The properties of cells in nBOR in neonates differ substantially from those in older animals, indicating that there is an important postnatal component to the development of the accessory optic system. Directional selectivity, which is a property of cells in older birds, is present in some neurons in neonates, but absent in others. This indicates that some neurons develop directional selectivity postnatally and raises the possibility that visual experience may have a role in this development. The segregation of neurons responsive to upward and downward movement, which is present in older birds, is only partially present in neonates. This suggests that the functional organization of nBOR changes substantially during the postnatal period. These differences in the nBOR of neonates and older birds may account for the differences in stabilizing eye movements that have been shown to exist in the two age groups. (Abstract shortened with permission of author.).
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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.
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Program
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Biology
