Document Detail

Processing time of contour integration: the role of colour, contrast, and curvature.
MedLine Citation:
PMID:  11515956     Owner:  NLM     Status:  MEDLINE    
We investigated the temporal properties of the red - green, blue-yellow, and luminance mechanisms in a contour-integration task which required the linking of orientation across space to detect a 'path'. Reaction times were obtained for simple detection of the stimulus regardless of the presence of a path, and for path detection measured by a yes/no procedure with path and no-path stimuli randomly presented. Additional processing times for contour integration were calculated as the difference between reaction times for simple stimulus detection and path detection, and were measured as a function of stimulus contrast for straight and curved paths. We found that processing time shows effects not apparent in choice reaction-time measurements. (i) Processing time for curved paths is longer than for straight paths. (ii) For straight paths, the achromatic mechanism is faster than the two chromatic ones, with no difference between the red-green and blue-yellow mechanisms. For curved paths there is no difference in processing time between mechanisms. (iii) The extra processing time required to detect curved compared to straight paths is longest for the achromatic mechanism, and similar for the red - green and blue-yellow mechanisms. (iv) Detection of the absence of a path requires at least 50 ms of additional time independently of chromaticity, contrast, and path curvature. The significance of these differences and similarities between postreceptoral mechanisms is discussed.
W H Beaudot; K T Mullen
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Perception     Volume:  30     ISSN:  0301-0066     ISO Abbreviation:  Perception     Publication Date:  2001  
Date Detail:
Created Date:  2001-08-22     Completed Date:  2001-08-30     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0372307     Medline TA:  Perception     Country:  England    
Other Details:
Languages:  eng     Pagination:  833-53     Citation Subset:  IM    
Department of Ophthalmology, McGill University, Montréal, Québec, Canada.
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MeSH Terms
Analysis of Variance
Color Perception / physiology*
Contrast Sensitivity / physiology*
Discrimination (Psychology) / physiology
Form Perception / physiology*
Orientation / physiology
Reaction Time / physiology*
Visual Pathways / physiology

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

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