Document Detail


Selective color constancy deficits after circumscribed unilateral brain lesions.
MedLine Citation:
PMID:  10191325     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The color of an object, when part of a complex scene, is determined not only by its spectral reflectance but also by the colors of all other objects in the scene (von Helmholtz, 1886; Ives, 1912; Land, 1959). By taking global color information into account, the visual system is able to maintain constancy of the color appearance of the object, despite large variations in the light incident on the retina arising from changes in the spectral content of the illuminating light (Hurlbert, 1998; Maloney, 1999). The neural basis of this color constancy is, however, poorly understood. Although there seems to be a prominent role for retinal, cone-specific adaptation mechanisms (von Kries, 1902; Pöppel, 1986; Foster and Nascimento, 1994), the contribution of cortical mechanisms to color constancy is still unclear (Land et al., 1983; D'Zmura and Lennie, 1986). We examined the color perception of 27 patients with defined unilateral lesions mainly located in the parieto-temporo-occipital and fronto-parieto-temporal cortex. With a battery of clinical and specially designed color vision tests we tried to detect and differentiate between possible deficits in central color processing. Our results show that color constancy can be selectively impaired after circumscribed unilateral lesions in parieto-temporal cortex of the left or right hemisphere. Five of 27 patients exhibited significant deficits in a color constancy task, but all of the 5 performed well in color discrimination or higher-level visual tasks, such as the association of colors with familiar objects. These results indicate that the computations underlying color constancy are mediated by specialized cortical circuitry, which is independent of the neural substrate for color discrimination and for assigning colors to objects.
Authors:
L Rüttiger; D I Braun; K R Gegenfurtner; D Petersen; P Schönle; L T Sharpe
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Publication Detail:
Type:  Clinical Trial; Controlled Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of neuroscience : the official journal of the Society for Neuroscience     Volume:  19     ISSN:  0270-6474     ISO Abbreviation:  J. Neurosci.     Publication Date:  1999 Apr 
Date Detail:
Created Date:  1999-04-27     Completed Date:  1999-04-27     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8102140     Medline TA:  J Neurosci     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  3094-106     Citation Subset:  IM    
Affiliation:
Forschungsstelle für Experimentelle Ophthalmologie, Universitätsaugenklinik Tübingen, 72076 Tübingen, Germany.
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological
Adult
Aged
Brain / physiology*
Color Perception Tests
Color Vision Defects / congenital,  physiopathology*
Contrast Sensitivity
Discrimination (Psychology) / physiology
Female
Functional Laterality / physiology*
Humans
Male
Middle Aged

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


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