Document Detail

Specializations for chromatic and temporal signals in human visual cortex.
MedLine Citation:
PMID:  15800201     Owner:  NLM     Status:  MEDLINE    
Neurological case studies and qualitative measurements suggest that regions within human extrastriate cortex are specialized for different perceptual functions, including color. However, there are few quantitative measurements of human extrastriate color specializations. We studied the chromatic and temporal responses in several different clusters of human visual field maps using functional magnetic resonance imaging. Contrast response functions were measured for luminance [(L + M)-cone], red-green [(L - M)-cone] and blue-yellow (S-cone) modulations at various temporal frequencies. In primary visual cortex (V1), temporal responsivities to luminance and red-green modulations are approximately constant up to 10 Hz, but responsivities to blue-yellow modulations decrease significantly. In ventral occipital cortex (VO), all colors elicit strong responses, and, for each color, low temporal frequency modulations are more effective than high temporal frequency modulations. Hence, VO represents the full range of color information but does not respond well to rapid modulations. Conversely, in human motion-selective cortex (MT+) and V3A, blue-yellow modulations elicit very weak responses, whereas luminance and red-green high temporal frequency modulations are equally or more effective than low temporal frequency modulations. Hence, these dorsal occipital regions respond well to rapid modulations, but not all color information is represented. Similar to human motion perception, MT+ and V3A respond powerfully to all temporal frequencies but only to some colors. Similar to human color perception, VO responds powerfully to all colors but only to relatively low temporal frequencies.
Junjie Liu; Brian A Wandell
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of neuroscience : the official journal of the Society for Neuroscience     Volume:  25     ISSN:  1529-2401     ISO Abbreviation:  J. Neurosci.     Publication Date:  2005 Mar 
Date Detail:
Created Date:  2005-03-31     Completed Date:  2006-03-23     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8102140     Medline TA:  J Neurosci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3459-68     Citation Subset:  IM    
Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
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MeSH Terms
Brain Mapping
Color Perception / physiology*
Contrast Sensitivity / physiology*
Functional Laterality / physiology
Image Processing, Computer-Assisted / methods
Magnetic Resonance Imaging / methods
Oxygen / blood
Pattern Recognition, Visual / physiology
Photic Stimulation / methods
Sensory Thresholds / physiology
Time Factors
Visual Cortex / blood supply,  physiology*
Visual Fields / physiology*
Visual Pathways / physiology
Grant Support
Reg. No./Substance:

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

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