Document Detail


Global-motion detection with transparent-motion signals.
MedLine Citation:
PMID:  10343805     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A number of experiments were conducted to compare the ability of observers to extract unidirectional and bidirectional (transparent) global-motion signals. In the unidirectional condition, the noise signal consisted of purely randomly-moving dots while in the bidirectional condition, a number of the randomly moving dots were replaced by the same number of dots moving in a specific (secondary-signal) direction. The threshold measure was the minimum number of signal dots required to determine the global-motion direction. For the bidirectional condition, parameters varied were the angular separation between the global-motion and secondary-signal directions and the strength of the secondary signal. Thresholds for unidirectional and bidirectional conditions were the same when the angular difference between global-motion and secondary-signal directions were 90 degrees or greater, i.e. the ability of observers to extract a transparent signal was the same as their ability to extract a unidirectional one. Similarly, with motion-in-depth signals, thresholds for extracting a centripetal signal were not elevated by replacing a number of the randomly-moving noise dots with the same number centrifugally-moving dots. The results are interpreted as indicating that motion signals moving between 90 and 180 degrees to the global-motion direction provide uniform masking of the global-motion signal. For angular separations less than 90 degrees, a suprathreshold secondary signal resulted in threshold elevation. This result could be due, to stronger inhibition from motion units tuned to similar (< 90 degrees) directions, broad directional-tuning of the underlying motion units (changing the task from signal detection to a signal discrimination) or a combination of the two.
Authors:
M Edwards; S Nishida
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Vision research     Volume:  39     ISSN:  0042-6989     ISO Abbreviation:  Vision Res.     Publication Date:  1999 Jun 
Date Detail:
Created Date:  1999-06-14     Completed Date:  1999-06-14     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  0417402     Medline TA:  Vision Res     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  2239-49     Citation Subset:  IM; S    
Affiliation:
NTT Basic Research Laboratories, Information Science Research Laboratory, Kanagawa, Japan. mark@hering.berkeley.edu
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MeSH Terms
Descriptor/Qualifier:
Depth Perception / physiology
Humans
Male
Motion Perception / physiology*
Pattern Recognition, Visual / physiology
Psychophysics
Sensory Thresholds / physiology

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


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