Document Detail


Mechanisms of simple and choice reaction to changes in direction of visual motion.
MedLine Citation:
PMID:  10996608     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Experiments are presented in which a random dot pattern moved vertically upwards (velocity vector V(1)) and then abruptly changed its direction of motion by the angle alpha (velocity vector V(2)), either to the left or to the right, without changing the speed. Subjects performed simple reactions to the direction change, disregarding its sign. In another experiment choice reactions to the same stimuli were performed: the subjects pushed a left button when the direction change was to the left and a right button when the change was to the right. The simple reaction time decreased monotonically with alpha increasing from 11 degrees to 169 degrees, whereas, within the same range of angles, a U-shaped curve described the function of the choice reaction time versus alpha. Both types of reaction time increased with decreasing the base speed. Difficulties are outlined which occur when the angle of change alpha is considered as 'intensity' of the stimulus. Instead, the parameter mid R:V(2)-V(1)mid R:, the absolute value of the difference between the velocity vectors before and after the change, is shown to be a meaningful 'intensity' parameter for the simple reaction task. The parameter V(2N), the speed of the velocity component normal to the initial velocity vector V(1), is suggested as an 'intensity' parameter for the choice reaction task. It is shown that the simple and choice reactions to changes in direction of visual motion are performed by two distinct mechanisms which seem to work in parallel and may be nearly equally fast for small angles of change, when mid R:V(2)-V(1)mid R: approximately V(2N).
Authors:
B Genova; S Mateeff; C Bonnet; J Hohnsbein
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Vision research     Volume:  40     ISSN:  0042-6989     ISO Abbreviation:  Vision Res.     Publication Date:  2000  
Date Detail:
Created Date:  2000-11-09     Completed Date:  2000-11-09     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0417402     Medline TA:  Vision Res     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  3049-58     Citation Subset:  IM    
Affiliation:
Institute of Physiology, 1113, Sofia, Bulgaria.
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MeSH Terms
Descriptor/Qualifier:
Adult
Analysis of Variance
Choice Behavior / physiology*
Female
Humans
Male
Motion Perception / physiology*
Reaction Time
Space Perception / physiology*

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


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