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The selective impairment of the perception of first-order motion by unilateral cortical brain damage

Published online by Cambridge University Press:  01 February 1998

LUCIA M. VAINA ,
NIKOS MAKRIS ,
DAVID KENNEDY  and
ALAN COWEY
LUCIA M. VAINA
Affiliation:
Boston University, Departments of Biomedical Engineering and Neurology, Brain and Vision Research Laboratory, Boston Harvard Medical School, Department of Neurology, Brigham and Women's Hospital, Boston
NIKOS MAKRIS
Affiliation:
Center for Morphometric Analysis, Massachusetts General Hospital, Charlestown
DAVID KENNEDY
Affiliation:
Boston University, Departments of Biomedical Engineering and Neurology, Brain and Vision Research Laboratory, Boston Harvard Medical School, Department of Neurology, Brigham and Women's Hospital, Boston Center for Morphometric Analysis, Massachusetts General Hospital, Charlestown
ALAN COWEY
Affiliation:
University of Oxford, Department of Experimental Psychology, Oxford, U.K.
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Abstract

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.

Keywords

First-order motionSecond-order motionVisual cortexPsychophysicsNeuroimaging

Information

Type
Research Article
Information
Visual Neuroscience , Volume 15 , Issue 2 , February 1998 , pp. 333 - 348
Copyright
1998 Cambridge University Press

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