| Luminance and chromatic contributions to a hyperacuity task: Isolation by contrast polarity and target separation. | |
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MedLine Citation:
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PMID: 22306680 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Vernier thresholds are known to be elevated when a target pair has opposite contrast polarity. Polarity reversal is used to assess the role of luminance and chromatic pathways in hyperacuity performance. Psychophysical hyperacuity thresholds were measured for pairs of gratings of various combinations of luminance (Lum) and chromatic (Chr) contrast polarities, at different ratios of luminance to chromatic contrast. With two red-green gratings of matched luminance and chromatic polarity (+Lum+Chr), there was an elevation of threshold at isoluminance. When both luminance and chromatic polarity were mismatched (-Lum-Chr), thresholds were substantially elevated under all conditions. With the same luminance contrast polarity and opposite chromatic polarity (+Lum-Chr) thresholds were only elevated close to isoluminance; in the reverse condition (-Lum+Chr), thresholds were elevated as in the -Lum-Chr condition except close to equiluminance. Similar data were obtained for gratings isolating the short-wavelength cone mechanism. Further psychophysical measurements assessed the role of target separation with matched or mismatched contrast polarity; similar results were found for luminance and chromatic gratings. Comparison physiological data were collected from parafoveal ganglion cells of the macaque retina. Positional precision of ganglion cell signals was assessed under conditions related to the psychophysical measurements. On the basis of these combined observations, it is argued that both magnocellular, parvocellular, and koniocellular pathways have access to cortical positional mechanisms associated with vernier acuity. |
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Authors:
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Hao Sun; Bonnie Cooper; Barry B Lee |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-1-27 |
Journal Detail:
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Title: Vision research Volume: - ISSN: 1878-5646 ISO Abbreviation: - Publication Date: 2012 Jan |
Date Detail:
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Created Date: 2012-2-6 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0417402 Medline TA: Vision Res Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Copyright Information:
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Copyright © 2012 Elsevier Ltd. All rights reserved. |
Affiliation:
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State University of New York, State College of Optometry, NY, USA. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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