Document Detail


Deficits and recovery of first- and second-order motion perception in patients with unilateral cortical lesions.
MedLine Citation:
PMID:  9753098     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Unilateral lesions in the posterior parietal cortex can degrade motion perception in the contralesional visual hemifield. Our aim was to investigate whether deficits caused by cortical lesions may be different for first- and second-order motion perception, and to study the time scale of any potential recovery. In nine patients with circumscribed lesions mainly in the parietal and fronto-parietal cortex, thresholds for direction discrimination were measured for stimuli presented peripherally in their ipsi- and contralesional hemifield. Subjects had to identify the direction of a vertically moving object embedded in a background of dynamic random dot noise. The object consisted of various proportions of signal and noise dots. Signal dots were either (a) coherently moving in the same direction as the object (first-order), (b) stationary (second-order: drift-balanced), or (c) coherently moving in the opposite direction (second-order: theta). Noise dots were flickering. Two patients showed significant threshold elevations for all three types of motion stimuli presented in their contralesional hemifield, while thresholds for ipsilesional targets were unaffected. Neither showed any selective deficit of first- versus second-order motion perception, but second-order motion was more impaired. Their lesions probably included the motion area V5-MT, which was spared in the other seven patients. One of the patients, who was retested several times during a 27-month postlesional period, showed complete recovery for first- and second-order motion direction discrimination, as well as for the detection of speed differences.
Authors:
D Braun; D Petersen; P Schönle; M Fahle
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The European journal of neuroscience     Volume:  10     ISSN:  0953-816X     ISO Abbreviation:  Eur. J. Neurosci.     Publication Date:  1998 Jun 
Date Detail:
Created Date:  1998-11-09     Completed Date:  1998-11-09     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8918110     Medline TA:  Eur J Neurosci     Country:  FRANCE    
Other Details:
Languages:  eng     Pagination:  2117-28     Citation Subset:  IM    
Affiliation:
Sektion Visuelle Sensorik, University Eye Clinic, Tübingen, Germany. doris.braun@uni-tuebingen.de
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MeSH Terms
Descriptor/Qualifier:
Adult
Brain Diseases / physiopathology
Cerebral Cortex / physiopathology*
Discrimination (Psychology) / physiology
Functional Laterality / physiology*
Humans
Male
Middle Aged
Motion Perception / physiology*
Photic Stimulation / methods
Psychophysics / methods
Time Factors
Visual Fields / physiology

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


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