| The integration of local chromatic motion signals is sensitive to contrast polarity. | |
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MedLine Citation:
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PMID: 21426617 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Global motion integration mechanisms can utilize signals defined by purely chromatic information. Is global motion integration sensitive to the polarity of such color signals? To answer this question, we employed isoluminant random dot kinematograms (RDKs) that contain a single chromatic contrast polarity or two different polarities. Single-polarity RDKs consisted of local motion signals with either a positive or a negative S or L-M component, while in the different-polarity RDKs, half the dots had a positive S or L-M component, and the other half had a negative S or L-M component. In all RDKs, the polarity and the motion direction of the local signals were uncorrelated. Observers discriminated between 50% coherent motion and random motion, and contrast thresholds were obtained for 81% correct responses. Contrast thresholds were obtained for three different dot densities (50, 100, and 200 dots). We report two main findings: (1) dependence on dot density is similar for both contrast polarities (+S vs. -S, +LM vs. -LM) but slightly steeper for S in comparison to LM and (2) thresholds for different-polarity RDKs are significantly higher than for single-polarity RDKs, which is inconsistent with a polarity-blind integration mechanism. We conclude that early motion integration mechanisms are sensitive to the polarity of the local motion signals and do not automatically integrate information across different polarities. |
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Authors:
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Sophie M Wuerger; Alexa Ruppertsberg; Stephanie Malek; Marco Bertamini; Jasna Martinovic |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-3-23 |
Journal Detail:
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Title: Visual neuroscience Volume: - ISSN: 1469-8714 ISO Abbreviation: - Publication Date: 2011 Mar |
Date Detail:
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Created Date: 2011-3-23 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8809466 Medline TA: Vis Neurosci Country: - |
Other Details:
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Languages: ENG Pagination: 1-8 Citation Subset: - |
Affiliation:
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School of Psychology, University of Liverpool, Liverpool, UK. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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