Document Detail


Amplitudes and directions of individual saccades can be adjusted by corollary discharge.
MedLine Citation:
PMID:  20462323     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
There is strong evidence that the brain can use an internally generated copy of motor commands, a corollary discharge, to guide rapid sequential saccades. Much of this evidence comes from the double-step paradigm: after two briefly flashed visual targets have disappeared, the subject makes two sequential saccades to the targets. Recent studies on the monkey revealed that amplitude variations of the first saccade led to compensation by the second saccade, mediated by a corollary discharge. Here, we investigated whether such saccade-by-saccade compensation occurs in humans, and we made three new observations. First, we replicated previous findings from the monkey: following first saccade amplitude variations, the direction of the second saccade compensated for the error. Second, the change in direction of the second saccade followed variations in vertical as well as horizontal first saccades although the compensation following horizontal saccades was significantly more accurate. Third, by examining oblique saccades, we are able to show that first saccade variations are compensated by adjustment in saccade amplitude in addition to direction. Together, our results demonstrate that it is likely that a corollary discharge in humans can be used to adjust both saccade direction and amplitude following variations in individual saccades.
Authors:
Wilsaan M Joiner; Edmond J Fitzgibbon; Robert H Wurtz
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Intramural     Date:  2010-02-23
Journal Detail:
Title:  Journal of vision     Volume:  10     ISSN:  1534-7362     ISO Abbreviation:  J Vis     Publication Date:  2010  
Date Detail:
Created Date:  2010-05-13     Completed Date:  2010-08-13     Revised Date:  2010-09-07    
Medline Journal Info:
Nlm Unique ID:  101147197     Medline TA:  J Vis     Country:  United States    
Other Details:
Languages:  eng     Pagination:  22.1-12     Citation Subset:  IM    
Affiliation:
Laboratory of Sensorimotor Research, National Eye Institute, National Institutes of Health, Bethesda, MD, USA. joinerw@nei.nih.gov
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological / physiology
Adult
Animals
Fixation, Ocular / physiology
Haplorhini
Humans
Middle Aged
Photic Stimulation / methods*
Reaction Time / physiology
Saccades / physiology*
Grant Support
ID/Acronym/Agency:
ZIA EY000109-29/EY/NEI NIH HHS

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


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