Document Detail


Effects of a static textured background on motion integration.
MedLine Citation:
PMID:  7571466     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We studied how the visual system integrates locally ambiguous velocities into global unambiguous coherent motion in the presence or absence of a textured background. Line drawings of complex figures were presented through invisible (i.e. same luminance and hue as the background) circular apertures such that only straight line segments were visible. These figures were either presented against a uniform background or embedded in static textures made of similar line segments in such a way that figures cannot be detected if they remain static. Under our experimental conditions, the figures translated clockwise or counterclockwise along a circular path and observers were required to discriminate the global direction of motion. Because of the aperture problem, a single moving segment cannot disambiguate the global direction of the figures and integration across multiple line segments is therefore necessary to perform the task. We found that with figures at high contrast, the presence of a texture enhanced direction discrimination, while direction discrimination of figures at low contrast was impaired by the presence of the texture. These paradoxical effects of a static texture were further tested by manipulating the relative contrast between figures and texture, the motion onset asynchrony (the delay between stimulus onset and motion onset or MOA), the density, the orientation and the distribution of texture elements. The effects of the texture, either facilitation or suppression, increase with texture contrast. Accuracy improves with MOA and decreases with texture density. In general, at high figure contrast, accuracy is better whenever referents are present in the image. We suggest that facilitation by the texture at high figure contrast is accounted for by reduced salience of segmentation cues such as line terminators and increased accuracy of local velocity measurements. On the other hand, decreased performance at low figure contrast may reflect lateral suppression of the responses to motion signals by the texture.
Authors:
J Lorenceau; M Boucart
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Vision research     Volume:  35     ISSN:  0042-6989     ISO Abbreviation:  Vision Res.     Publication Date:  1995 Aug 
Date Detail:
Created Date:  1995-11-09     Completed Date:  1995-11-09     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0417402     Medline TA:  Vision Res     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  2303-14     Citation Subset:  IM; S    
Affiliation:
Laboratoire de Psychologie Expérimentale, Université Paris V, CNRS, Paris, France.
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MeSH Terms
Descriptor/Qualifier:
Contrast Sensitivity / physiology*
Discrimination (Psychology) / physiology
Female
Humans
Motion Perception / physiology*
Pattern Recognition, Visual / physiology*
Rotation
Time Factors
Visual Fields

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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