Role of visual experience in human voluntary eye movement.
Item
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Title
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Role of visual experience in human voluntary eye movement.
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Identifier
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AAI9720096
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identifier
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9720096
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Creator
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Hall, Elaine C.
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Contributor
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Adviser: James Gordon
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Date
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1997
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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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Health Sciences, Ophthalmology | Psychology, Cognitive | Biology, Neuroscience | Psychology, Psychobiology
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Abstract
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This research tested the proposition that childhood and/or ongoing visual experience affects voluntary production of eye movements in adults. Computer-generated verbal instructions were used to elicit voluntary eye movements in the dark (without visual stimuli, vision, and/or a mental visual frame of reference) from three groups of adults (N = 49) whose visual experience differed. Visual experience of groups: Congenitally blind--{dollar}\leq{dollar}12 years; adventitiously blind--{dollar}\geq{dollar}13 years; sighted--normal vision. Requests were to move the eyes to the extremes of the vertical and horizontal oculomotor range, halfway toward these extremes, and, repeatedly, "straight ahead." Eye movements were videotaped under infrared illumination. Videotapes were digitized using an eye tracker targeting the pupil. Entire responses (not individual saccades and fixations) were evaluated graphically and statistically. Clear group differences emerged despite the lack of within-group uniformity in visual experience of adventitiously versus congenitally blind participants, and the wide time window associated with the "congenitally blind" classification criterion. Voluntary oculomotor control increased with years of visual experience until reaching mature, relatively stable, levels, indicating that vision experienced during approximately the first eight-ten years of childhood is most salient for subsequent voluntary oculomotor control (although data were not available from participants with four, five, six or seven years of visual experience). After long-term adventitious blindness a small amount of degradation of human voluntary oculomotor control was revealed. Measures including response amplitude and direction of vertical and horizontal responses, and variability within- and across-trial of requests to "look straight ahead" were profoundly attenuated in cases of little or no visual experience (except midposition scaling accuracy, which yielded questionable results). This study contributes to knowledge of the nature and extent of the neural plasticity inherent to the relationship between visual experience and voluntary oculomotor control. It supports the idea that voluntary oculomotor control retains a degree of plasticity well into childhood. Theoretically and perhaps clinically, this research indicates that oculomotor control adequate to subserve vision might be anticipated in individuals with even a short period of prior visual experience, were it possible to restore function to the other components of the visual system.
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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.
