Document Detail


No interaction of first- and second-order signals in the extraction of global-motion and optic-flow.
MedLine Citation:
PMID:  21130796     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
Edwards and Badcock (Vision Research 35, 2589, 1995) argued for independent first-order (FO) and second-order (SO) motion systems up to and including the global-motion level. That study used luminance (which they called FO) and contrast (SO) modulated dots. They found that SO noise dots did not mask signal extraction with luminance increment dots while luminance increment dots did mask SO signal extraction. However, they argued this asymmetry was not due to a combined FO-SO pathway, but rather due to the fact that the luminance-modulated dots, being also local variations in contrast, are both FO and SO stimuli. We test their claim of FO and SO independence by using a stimulus that can generate pure FO and SO signals, specifically one consisting of multiple Gabors (the global-Gabor stimulus) in which the Gaussian envelopes are static and the carriers drift. The carrier can either be luminance-modulated (FO) or contrast-modulated (SO) and motion signals from the randomly-oriented local Gabors must be combined to detect the global-motion vector. Results show no cross-masking of FO and SO signals, thus supporting the hypothesis of independent FO and SO systems up to and including the level extracting optic-flow.
Authors:
Carlos R Cassanello; Mark Edwards; David R Badcock; Shin'ya Nishida
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Publication Detail:
Type:  Journal Article     Date:  2010-12-03
Journal Detail:
Title:  Vision research     Volume:  51     ISSN:  1878-5646     ISO Abbreviation:  Vision Res.     Publication Date:  2011 Feb 
Date Detail:
Created Date:  2011-01-21     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0417402     Medline TA:  Vision Res     Country:  England    
Other Details:
Languages:  eng     Pagination:  352-61     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 Elsevier Ltd. All rights reserved.
Affiliation:
Department of Psychology, The Australian National University, Canberra, ACT, Australia; ARC Centre of Excellence in Vision Science, The Australian National University, Canberra, ACT, Australia.
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