Document Detail

Exogenous attention enhances 2nd-order contrast sensitivity.
MedLine Citation:
PMID:  21356228     Owner:  NLM     Status:  MEDLINE    
Natural scenes contain a rich variety of contours that the visual system extracts to segregate the retinal image into perceptually coherent regions. Covert spatial attention helps extract contours by enhancing contrast sensitivity for 1st-order, luminance-defined patterns at attended locations, while reducing sensitivity at unattended locations, relative to neutral attention allocation. However, humans are also sensitive to 2nd-order patterns such as spatial variations of texture, which are predominant in natural scenes and cannot be detected by linear mechanisms. We assess whether and how exogenous attention--the involuntary and transient capture of spatial attention--affects the contrast sensitivity of channels sensitive to 2nd-order, texture-defined patterns. Using 2nd-order, texture-defined stimuli, we demonstrate that exogenous attention increases 2nd-order contrast sensitivity at the attended location, while decreasing it at unattended locations, relative to a neutral condition. By manipulating both 1st- and 2nd-order spatial frequency, we find that the effects of attention depend both on 2nd-order spatial frequency of the stimulus and the observer's 2nd-order spatial resolution at the target location. At parafoveal locations, attention enhances 2nd-order contrast sensitivity to high, but not to low 2nd-order spatial frequencies; at peripheral locations attention also enhances sensitivity to low 2nd-order spatial frequencies. Control experiments rule out the possibility that these effects might be due to an increase in contrast sensitivity at the 1st-order stage of visual processing. Thus, exogenous attention affects 2nd-order contrast sensitivity at both attended and unattended locations.
Antoine Barbot; Michael S Landy; Marisa Carrasco
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2011-02-26
Journal Detail:
Title:  Vision research     Volume:  51     ISSN:  1878-5646     ISO Abbreviation:  Vision Res.     Publication Date:  2011 May 
Date Detail:
Created Date:  2011-04-28     Completed Date:  2011-08-12     Revised Date:  2014-09-15    
Medline Journal Info:
Nlm Unique ID:  0417402     Medline TA:  Vision Res     Country:  England    
Other Details:
Languages:  eng     Pagination:  1086-98     Citation Subset:  IM    
Copyright Information:
Copyright © 2011 Elsevier Ltd. All rights reserved.
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MeSH Terms
Analysis of Variance
Attention / physiology*
Contrast Sensitivity / physiology*
Discrimination (Psychology) / physiology
Pattern Recognition, Visual / physiology*
Visual Fields / physiology
Grant Support
R01 EY016165/EY/NEI NIH HHS; R01 EY016165-04/EY/NEI NIH HHS; R01 EY016200/EY/NEI NIH HHS; R01 EY016200-03/EY/NEI NIH HHS; R01 EY016200-04/EY/NEI NIH HHS; R01-EY016200/EY/NEI NIH HHS; R01-EY16165/EY/NEI NIH HHS

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