Document Detail

Color opponent neurons in V1: a review and model reconciling results from imaging and single-unit recording.
MedLine Citation:
PMID:  12678646     Owner:  NLM     Status:  MEDLINE    
The signals in visual cortex that ultimately give rise to color perception remain poorly understood. Controversy has particularly surrounded one aspect of color's encoding in the visual system-opponent processing in primary visual cortex. Early single-unit studies suggested that V1 contains relatively few color-opponent neurons. Neuroimaging measurements, however, have suggested that such neurons might be relatively numerous. Here, we reconcile these apparently discrepant results and conclude that V1 contains relatively large numbers of color-opponent neurons. We first review results from each method and find that most neuroimaging studies provide evidence of substantial color opponency in V1, and that despite apparent controversy, most single-unit studies agree that relatively large numbers of V1 neurons show some sort of color opponency. To reconcile the results from different techniques more formally, we used electrophysiological data to predict the outcomes of neuroimaging experiments. We simulated the expected fMRI response in V1 to spatial patterns of different color, based on the neurons' properties, as reported in Johnson, Hawken, and Shapley, (2001). The simulated responses to stimuli used in Engel, Zhang, and Wandell, (1997) agree well with the actually observed fMRI results. The model identifies several factors that led to the apparent discrepancy between techniques, and makes testable predictions about how these factors influence the magnitude of color-opponent signals. fMRI and single-unit data converge to show that large numbers of color-opponent neurons exist in V1.
Denis Schluppeck; Stephen A Engel
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.; Review    
Journal Detail:
Title:  Journal of vision     Volume:  2     ISSN:  1534-7362     ISO Abbreviation:  J Vis     Publication Date:  2002  
Date Detail:
Created Date:  2003-04-07     Completed Date:  2003-04-23     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  101147197     Medline TA:  J Vis     Country:  United States    
Other Details:
Languages:  eng     Pagination:  480-92     Citation Subset:  IM    
UCLA Department of Psychology, Los Angeles, CA, USA.
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MeSH Terms
Color Perception / physiology*
Computer Simulation
Magnetic Resonance Imaging
Neurons / physiology*
Retinal Cone Photoreceptor Cells / physiology
Visual Cortex / cytology,  physiology*
Grant Support

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