| Responses to opposed directions of motion: continuum or independent mechanisms? | |
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MedLine Citation:
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PMID: 8759432 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Opponency between opposite directions of motion is a characteristic of many models of movement detection and is commonly invoked in explanations of the motion after-effect. If detection of opposite directions is mediated by a single mechanism, then a single, smooth psychometric function for the discrimination of global direction in random-dot kinematograms should be found as a function of the percent of directional coherence of dots in the display, ranging from 100% coherence leftwards through 0% coherence to 100% coherence rightwards. Moreover, after rightward motion adaptation, a single psychometric function should still be observed if adaptation affects the perceptual system prior to opponent interactions. If, however, leftward and rightward detectors operate independently, then the slopes of the leftward and rightward halves of the function may differ, particularly after unidirectional adaptation. We measured the probability of a "rightward" direction response for nine values of motion coherence for five observers with and without prior rightward motion adaptation. Although a smooth psychometric function was found without motion adaptation, after adaptation, the rightward half of the psychometric function was flattened whereas the leftward half remained unchanged. Such results indicate that movement direction analysers operate in a non-opponent manner. |
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Authors:
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J Raymond; O Braddick |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Vision research Volume: 36 ISSN: 0042-6989 ISO Abbreviation: Vision Res. Publication Date: 1996 Jul |
Date Detail:
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Created Date: 1996-10-03 Completed Date: 1996-10-03 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0417402 Medline TA: Vision Res Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 1931-7 Citation Subset: IM; S |
Affiliation:
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School of Psychology, University of Wales, Bangor, Gwynedd, U.K. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adaptation, Ocular Adult Afterimage Female Humans Male Motion Perception / physiology* Pattern Recognition, Visual / physiology Psychometrics Psychophysics Sensory Thresholds / physiology |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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