Document Detail


Global motion perception: interaction of the ON and OFF pathways.
MedLine Citation:
PMID:  7975320     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A number of experiments were conducted to investigate the interaction of the ON and OFF pathways in the processing of global-motion signals. The stimulus employed was a variant of that used by Newsome and Pare [(1988) Journal of Neuroscience, 8, 2201-2211] in which a small subset of dots move in a common (global-motion) direction in a field of randomly moving dots. The threshold measure was the number of dots required to move in the global-motion direction for that direction to be detected. We found that: (1) the extraction of a global-motion signal carried by light dots (luminance above the background) was impaired by the addition of dark dots (luminance below the background) which did not carry the signal (noise dots); (2) sub-threshold summation occurs for global-motion signals carried by light and dark dots; and (3) a signal dot which changed luminance polarity (went from light to dark) did not result in a motion signal--either in the global-motion direction or in the opposite direction (reverse apparent motion). From these findings we conclude that the inputs to the motion sensitive cells have matched spatial opponency (the ON and OFF pathways remain separate at this level) but that they then combine to form a single pathway prior to the extraction of the global-motion signal. These findings are contrary to those predicted by models which advocate squaring or full-wave rectification prior to global motion processing.
Authors:
M Edwards; D R Badcock
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Vision research     Volume:  34     ISSN:  0042-6989     ISO Abbreviation:  Vision Res.     Publication Date:  1994 Nov 
Date Detail:
Created Date:  1994-12-29     Completed Date:  1994-12-29     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0417402     Medline TA:  Vision Res     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  2849-58     Citation Subset:  IM; S    
Affiliation:
Department of Psychology, School of Behavioural Science, University of Melbourne, Parkville, Victoria, Australia.
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MeSH Terms
Descriptor/Qualifier:
Contrast Sensitivity / physiology
Electrophysiology
Female
Humans
Male
Motion Perception / physiology*
Optical Illusions / physiology
Pattern Recognition, Visual / physiology
Sensory Thresholds / physiology

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