Document Detail

Size scaling compensates for sensitivity loss produced by a simulated central scotoma in a shape-from-texture task.
MedLine Citation:
PMID:  21047750     Owner:  NLM     Status:  MEDLINE    
Studies of eccentricity-dependent sensitivity loss typically require participants to maintain fixation while making judgments about stimuli presented at a range of sizes and eccentricities. However, training participants to fixate can prove difficult, and as stimulus size increases, they become poorly localized and may even encroach on the fovea. In the present experiment, we controlled eccentricity of stimulus presentation using a simulated central scotoma of variable size. Participants were asked to perform a 27-alternative forced-choice shape-from-texture task in the presence of a simulated scotoma, with stimulus size and scotoma radius as the independent variables. The resulting psychometric functions for each simulated scotoma were shifted versions of each other on a log size axis. Therefore, stimulus magnification was sufficient to equate sensitivity to shape from texture for all scotoma radii. Increasing scotoma radius also disrupts eye movements, producing increases in fixation frequency and duration, as well as saccade length.
Aaron Johnson; Rick Gurnsey
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-10-01
Journal Detail:
Title:  Journal of vision     Volume:  10     ISSN:  1534-7362     ISO Abbreviation:  J Vis     Publication Date:  2010  
Date Detail:
Created Date:  2010-11-04     Completed Date:  2011-02-24     Revised Date:  2012-09-19    
Medline Journal Info:
Nlm Unique ID:  101147197     Medline TA:  J Vis     Country:  United States    
Other Details:
Languages:  eng     Pagination:  18     Citation Subset:  IM    
Department of Psychology, Concordia University, Montreal, Quebec, Canada.
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MeSH Terms
Fixation, Ocular / physiology
Form Perception / physiology*
Fovea Centralis / physiology
Macular Degeneration / physiopathology*
Middle Aged
Models, Neurological
Night Vision / physiology*
Pattern Recognition, Visual / physiology*
Photic Stimulation / methods
Saccades / physiology
Scotoma / physiopathology*
Young Adult
Grant Support
//Canadian Institutes of Health Research

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