| Global-motion perception: interaction of chromatic and luminance signals. | |
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MedLine Citation:
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PMID: 8917805 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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A global dot-motion stimulus was employed in order to investigate the interaction between luminance and chromatic signals in motion processing. Thresholds are determined by measuring the minimum number of dots which need to move in a coherent fashion in a field of randomly moving dots in order for the observers to be able to determine the direction of coherent motion. We found that: (1) observers could not track an achromatic signal-dot which changes its luminance polarity between frame transitions. The addition of a consistent chromatic signal allowed observers to track such a dot when the dot contained low- (8%) luminance contrast but this ability was impaired as the luminance contrast was increased; (2) the addition of chromatic contrast to a dot which contained consistent low-luminance contrast could result in threshold elevation. For fixed contrast chromatic and luminance signals, the presence and degree of threshold elevation depended upon the spatiotemporal properties of the dot motion; (3) the ability of observers to extract a global-motion signal carried by a group of dots of one colour was impaired by the addition of a number of additional-noise dots of a different colour. These results are interpreted as indicating that: (1) the motion-selective cells that are sensitive to chromatic signals are also sensitive to luminance signals; (2) the combined chromatic and luminance and purely luminance motion cells are pooled to form a single pathway prior to global-motion extraction; and (3) the negative interaction observed between the chromatic and luminance signals is likely to be due to the differences in the processing speeds of the combined luminance and chromatic and the purely luminance sensitive motion cells. |
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Authors:
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M Edwards; D R Badcock |
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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 Aug |
Date Detail:
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Created Date: 1996-12-11 Completed Date: 1996-12-11 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: 2423-31 Citation Subset: IM; S |
Affiliation:
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Department of Psychology, School of Behavioural Science, University of Melbourne, Parkville, Victoria, Australia. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Color* Contrast Sensitivity / physiology Cues Humans Light* Male Motion Perception / physiology* Pattern Recognition, Visual / physiology Sensory Thresholds / physiology |
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