Topographic Organization in and near Human Visual Area V4

The existence and location of a human counterpart of macaque visual area V4 are disputed. To resolve this issue, we used functional magnetic resonance imaging to obtain topographic maps from human subjects, using visual stimuli and tasks designed to maximize accuracy of topographic maps of the fovea...

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Bibliographic Details
Published in:	The Journal of neuroscience Vol. 27; no. 44; pp. 11896 - 11911
Main Authors:	Hansen, Kathleen A, Kay, Kendrick N, Gallant, Jack L
Format:	Journal Article
Language:	English
Published:	United States Soc Neuroscience 31-10-2007 Society for Neuroscience
Subjects:	Brain Mapping Functional Laterality Humans Image Processing, Computer-Assisted Macaca Magnetic Resonance Imaging Oxygen - blood Photic Stimulation - methods Visual Cortex - anatomy & histology Visual Cortex - physiology Visual Fields - physiology Visual Pathways - anatomy & histology
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Summary:	The existence and location of a human counterpart of macaque visual area V4 are disputed. To resolve this issue, we used functional magnetic resonance imaging to obtain topographic maps from human subjects, using visual stimuli and tasks designed to maximize accuracy of topographic maps of the fovea and parafovea and to measure the effects of attention on topographic maps. We identified multiple topographic transitions, each clearly visible in > or = 75% of the maps, that we interpret as boundaries of distinct cortical regions. We call two of these regions dorsal V4 and ventral V4 (together comprising human area V4) because they share several defining characteristics with the macaque regions V4d and V4v (which together comprise macaque area V4). Ventral V4 is adjacent to V3v, and dorsal V4 is adjacent to parafoveal V3d. Ventral V4 and dorsal V4 meet in the foveal confluence shared by V1, V2, and V3. Ventral V4 and dorsal V4 represent complementary regions of the visual field, because ventral V4 represents the upper field and a subregion of the lower field, whereas dorsal V4 represents lower-field locations that are not represented by ventral V4. Finally, attentional modulation of spatial tuning is similar across dorsal and ventral V4, but attention has a smaller effect in V3d and V3v and a larger effect in a neighboring lateral occipital region.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 K. A. Hansen's present address: National Institute of Mental Health, National Institutes of Health, Building 10, Room 4C104, Bethesda, MD 20892.
ISSN:	0270-6474 1529-2401
DOI:	10.1523/JNEUROSCI.2991-07.2007