The influence of dark-adapted rods upon color vision.
Item
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Title
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The influence of dark-adapted rods upon color vision.
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Identifier
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AAI9732942
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identifier
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9732942
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Creator
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Lembessis, Elizabeth.
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Contributor
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Adviser: Thomas E. Frumkes
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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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Biology, Neuroscience | Psychology, Physiological | Biology, Animal Physiology | Health Sciences, Ophthalmology
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Abstract
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Monocular changes in color vision were examined for 25 minutes following a substantial bleach of photopigment in the right, left, or both eye(s). A test flash of 3{dollar}\sp\circ{dollar} diameter, 100 ms duration, and of 478, 511, 576, or 637 nm wavelength was presented 6{dollar}\sp\circ{dollar} in the right eye temporal field. In some experiments, the observer adjusted retinal illuminance of the stimulus until its hue could be identified (i.e., the specific threshold); alternatively, stimulus illuminance was fixed at 5 tds. and the observer evaluated hue and saturation using "4 + 1" scaling (Gordon et al., 1994).;Following monocular bleaching, specific thresholds for all wavelengths increased during the rod recovery stage of dark adaptation, as reported by Lie (1963). The time courses and magnitudes of threshold change were similar for stimuli that appeared predominantly blue (478 nm) and yellow (576 nm) in hue. The magnitudes of threshold change occurring with predominantly green (511 nm) and red (637 nm) hued stimuli were greater than the influences on 478 nm and 576 nm stimuli. In general, specific threshold changed more rapidly for 511 nm stimuli than for the other wavelengths.;After the first 5 minutes of dark adaptation following monocular bleaching, 5 td. stimuli became increasingly desaturated and shifted in hue; the shorter the wavelength, the greater the saturation change. In general, 637 nm stimuli appeared less red and more yellow. The appearances of the other stimuli changed in more varied ways.;The adapted state of the nonviewing eye exerted an influence upon color vision that varied with wavelength, response measure, and the observer. The most reliable interocular effect involved hue shifts for 637 nm stimuli, with similar time courses but smaller magnitudes than those observed monocularly.;Specific threshold and hue scaling data are most compatible with a chromatic suppressive rod-cone interaction model that posits a greater influence upon green/red than upon blue/yellow mechanisms. Saturation scaling data are most consistent with a luminosity channel summation model. The site(s) within the nervous system for rod-cone interaction remain ambiguous.
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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.
