Document Detail


Directional tuning of human motion adaptation as reflected by the motion VEP.
MedLine Citation:
PMID:  11448711     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Motion onset evoked visual potentials are dominated by a negativity (N2) at occipital electrodes and a positivity (P2) at the vertex. The degree of true motion processing reflected by N2 and P2 was estimated from the direction specificity of motion adaptation. Adapting stimuli moved to the right and test stimuli (random dot patterns of 26 degrees diameter; 10% contrast; 10.5 degrees /s velocity) moved in one of eight directions, which differed by 45 degrees. VEPs were recorded from occipito/temporal and central sites in eight subjects. Two adaptation effects were observed for N2 (P<0.01): a global amplitude reduction by 47% and a direction-specific reduction by a further 28%. For P2, only the global effect (54%; P<0.01) was observed. The global adaptation effect could also be induced by pattern reversal and pattern-onset adaptation, i.e. stimuli containing ambiguous or very little motion energy, respectively. We conclude that at least 28% of the N2 amplitude reflects the activity of direction-specific elements, whereas P2 does not at all.
Authors:
M B Hoffmann; A S Unsöld; M Bach
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Vision research     Volume:  41     ISSN:  0042-6989     ISO Abbreviation:  Vision Res.     Publication Date:  2001 Aug 
Date Detail:
Created Date:  2001-07-12     Completed Date:  2001-08-16     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0417402     Medline TA:  Vision Res     Country:  England    
Other Details:
Languages:  eng     Pagination:  2187-94     Citation Subset:  IM    
Affiliation:
Elektrophysiologisches Labor, Universitäts-Augenklinik, Killianstr. 5, D-79106 Freiburg, Germany.
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological*
Electrooculography
Evoked Potentials, Visual / physiology*
Humans
Linear Models
Motion Perception / physiology*
Pattern Recognition, Visual / physiology

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