Document Detail


Do rotation coordinates provide the substrate for a mental protractor?
MedLine Citation:
PMID:  16355742     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In previous studies, we have found that the accuracy in judging collinearity of lines or dots varies considerably from one subject to another as a function of the relative angle of the stimulus elements. A model of errors generally shows large excursions across several subranges of angular position. These do not appear to be motor errors, at least not ones that are well separated from perceptual mechanisms. The errors are most likely generated at primary visual cortex, or beyond. We examined and modeled accuracy in judging collinearity of dot pairs, varying the angular position of the dots through 360 degrees, the distance between the dots (stimulus span), and the distance at which the subject was required to respond (response span). Subjects manifested idiosyncratic profiles of error across angular positions, as reported previously. But across the tested range of spans, from 4 to 8 deg, the errors tended to be the same, irrespective of stimulus or response span. This suggests that the judgments are based on a radial (angular) measure of spatial position. We discuss these results in the context of proposals that the brain maps spatial position using rotation coordinates. These new data are consistent with the hypothesis that subjects use the z-axis coordinates as a mental protractor for judging angular position and collinearity.
Authors:
Ernest Greene; William Frawley
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Perception     Volume:  34     ISSN:  0301-0066     ISO Abbreviation:  -     Publication Date:  2005  
Date Detail:
Created Date:  2005-12-16     Completed Date:  2006-02-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0372307     Medline TA:  Perception     Country:  England    
Other Details:
Languages:  eng     Pagination:  1339-52     Citation Subset:  IM    
Affiliation:
Department of Psychology, University of Southern California, Los Angeles, CA 90089-1061, USA. egreene@usc.edu
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MeSH Terms
Descriptor/Qualifier:
Humans
Judgment
Optical Rotation
Pattern Recognition, Visual / physiology
Perceptual Distortion
Psychological Tests
Space Perception / physiology*

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


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