Document Detail


Global shape processing: which parts form the whole?
MedLine Citation:
PMID:  20884565     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Research suggests that detection of low-frequency radial frequency (RF) patterns involves global shape processing and that points of maximum curvature (corners) contribute more than points of minimum curvature (sides). However, this has only been tested with stimuli presented at the threshold of discriminability from a circle. We used RF pattern adaptation to (a) examine whether a supra-threshold RF pattern is processed as a global shape and (b) determine what the critical features are for representing its shape. We measured the perceived amplitude shift of an RF test pattern after prolonged exposure either to a higher amplitude pattern or to various combinations of its parts (concave maxima, convex maxima, inflections). We found greater shifts in perceived amplitude after adaptation to a "whole" pattern than after adaptation to its component parts, which alternated to produce equal net contrast. Furthermore, when adapting to specific parts of the shape in isolation, we found that each part generated a similar magnitude aftereffect. Although the whole is clearly greater than the sum of the parts, we find that concave maxima, convex maxima, and inflections contribute equally to global shape processing, a fact that is only apparent when using a supra-threshold appearance-based task.
Authors:
Jason Bell; Sarah Hancock; Frederick A A Kingdom; Jonathan W Peirce
Related Documents :
8810585 - Effects of task instructions and oscillation frequency on bimanual coordination.
11523815 - The development and evolution of the pharyngeal arches.
19965385 - Reproducibility distinguishes conscious from nonconscious neural representations.
19588985 - Nanopen: dynamic, low-power, and light-actuated patterning of nanoparticles.
22082025 - Nir light triggered dissociation of block copolymer micelles using upconverting nanopar...
1565435 - Light filters to improve vision.
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-06-01
Journal Detail:
Title:  Journal of vision     Volume:  10     ISSN:  1534-7362     ISO Abbreviation:  J Vis     Publication Date:  2010  
Date Detail:
Created Date:  2010-10-04     Completed Date:  2011-03-17     Revised Date:  2012-01-04    
Medline Journal Info:
Nlm Unique ID:  101147197     Medline TA:  J Vis     Country:  United States    
Other Details:
Languages:  eng     Pagination:  16     Citation Subset:  IM    
Affiliation:
McGill Vision Research, Department of Ophthalmology, McGill University, Montreal, Quebec, Canada.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological / physiology*
Figural Aftereffect / physiology*
Form Perception / physiology*
Humans
Pattern Recognition, Visual / physiology*
Photic Stimulation
Sensory Thresholds
Visual Pathways / physiology
Grant Support
ID/Acronym/Agency:
085444//Wellcome Trust; 085444/Z/08/Z//Wellcome Trust

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


Previous Document:  The chromatic selectivity of visual crowding.
Next Document:  Object form discontinuity facilitates displacement discrimination across saccades.