Document Detail

The selective impairment of the perception of first-order motion by unilateral cortical brain damage.
MedLine Citation:
PMID:  9605533     Owner:  NLM     Status:  MEDLINE    
First-order (Fourier) motion consists of stable spatiotemporal luminance variations. Second-order (non-Fourier) motion consists instead of spatiotemporal modulation of contrast, flicker, or spatial frequency. In spite of extensive psychophysical and computational analysis of the nature and relationship of these two types of motion, it remains unclear whether they are detected by the same mechanism or whether separate mechanisms are involved. Here we report the selective impairment of first-order motion, on a range of local and global motion tasks, in the contralateral visual hemifield of a patient with unilateral brain damage centered on putative visual areas V2 and V3 in the medial part of the occipital lobe. His perception of second-order motion was unimpaired. As his disorder is the obverse of that reported after damage in the vicinity of human visual area MT (V5), the results support models of motion processing in which first- and second-order motion are, at least in part, computed separately at the extrastriate cortical level.
L M Vaina; N Makris; D Kennedy; A Cowey
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Publication Detail:
Type:  Case Reports; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Visual neuroscience     Volume:  15     ISSN:  0952-5238     ISO Abbreviation:  Vis. Neurosci.     Publication Date:    1998 Mar-Apr
Date Detail:
Created Date:  1998-07-27     Completed Date:  1998-07-27     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8809466     Medline TA:  Vis Neurosci     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  333-48     Citation Subset:  IM    
Boston University, Department of Biomedical Engineering, MA 02215, USA.
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MeSH Terms
Brain Damage, Chronic / complications*,  diagnosis
Discrimination (Psychology) / physiology
Fourier Analysis
Magnetic Resonance Imaging
Motion Perception / physiology*
Orientation / physiology
Perceptual Disorders / etiology*,  physiopathology
Photic Stimulation / methods
Space Perception / physiology
Time Perception / physiology
Visual Perception / physiology*
Grant Support

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