Document Detail

Motion integration deficits are independent of magnocellular impairment in Parkinson's disease.
MedLine Citation:
PMID:  18822307     Owner:  NLM     Status:  MEDLINE    
Motion processing involves multiple hierarchical steps, from the magnocellular pathway, sensitive to high temporal frequency modulations, to subsequent motion integration within the visual cortical dorsal stream. We have tested whether motion integration deficits in mild Parkinson disease (PD) can be explained by visual deficits in earlier processing nodes. Contrast sensitivity deficits in the magnocellular pathway, were compared with speed discrimination of local dots moving in random directions, speed and direction discrimination of moving surfaces and motion integration as measured by 2D coherence thresholds (n=27). We have found that low-level magnocellular impairment in PD does not explain deficits in subsequent steps in motion processing. High-level performance was abnormal in particular for tasks requiring perception of coherently moving surfaces. Motion coherence deficits were predictive of visuomotor impairment, corroborating a previous magnetic stimulation study in normal subjects. We conclude that dorsal stream deficits in PD have a high-level visual cortical basis independent of low-level magnocellular damage.
Miguel Castelo-Branco; Mafalda Mendes; Fatima Silva; João Massano; Gustavo Januário; Cristina Januário; António Freire
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-09-07
Journal Detail:
Title:  Neuropsychologia     Volume:  47     ISSN:  0028-3932     ISO Abbreviation:  Neuropsychologia     Publication Date:  2009 Jan 
Date Detail:
Created Date:  2009-02-04     Completed Date:  2009-04-13     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0020713     Medline TA:  Neuropsychologia     Country:  England    
Other Details:
Languages:  eng     Pagination:  314-20     Citation Subset:  IM    
Visual Neuroscience Laboratory, IBILI, Faculty of Medicine, 3000-458 Coimbra, Portugal.
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MeSH Terms
Basal Nucleus of Meynert / pathology*
Cognition Disorders / etiology,  physiopathology*,  psychology*
Contrast Sensitivity / physiology
Data Interpretation, Statistical
Middle Aged
Motion Perception / physiology*
Parkinson Disease / complications,  pathology,  psychology*
Photic Stimulation
Psychomotor Performance / physiology
Sensory Thresholds / physiology
Visual Pathways / physiopathology

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

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