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The Journal of Neuroscience, October 17, 2007, 27(42):11271-11278; doi:10.1523/JNEUROSCI.0599-07.2007
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Behavioral/Systems/Cognitive
Bihemispheric Leftward Bias in a Visuospatial Attention-Related Network
Tali Siman-Tov,1 Avi Mendelsohn,1 Tom Schonberg,1 Galia Avidan,1,2 Ilana Podlipsky,1 Luiz Pessoa,3,4 Natan Gadoth,5,6 Leslie G. Ungerleider,3 andTalma Hendler1,5 1Functional Brain Imaging Unit, Wohl Institute for Advanced Imaging, Tel Aviv Sourasky Medical Center, Tel Aviv 64239, Israel, 2Department of Behavioral Sciences, Ben Gurion University of the Negev, Be'er Sheva 84105, Israel, 3Laboratory of Brain and Cognition, National Institute of Mental Health, Bethesda, Maryland 20892, 4Department of Psychological and Brain Sciences, University of Indiana, Bloomington, Indiana 47405, 5Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel, and 6Department of Neurology, Ma'ayanei HaYeshua Medical Center, Bnei Brak 51544, Israel
Correspondence should be addressed to Dr. Talma Hendler, Functional Brain Imaging Unit, Wohl Institute for Advanced Imaging, Tel Aviv Sourasky Medical Center, 6 Weizmann Street, Tel Aviv 64239, Israel. Email: talma{at}tasmc.health.gov.il
Asymmetry of spatial attention has long been described in both disease (hemispatial neglect) and healthy (pseudoneglect) states. Although right-hemisphere specialization for spatial attention has been suggested, the exact neural mechanisms of asymmetry have not been deciphered yet. A recent functional magnetic resonance imaging study from our laboratory serendipitously revealed bihemispheric left-hemifield superiority in activation of a visuospatial attention-related network. Nineteen right-handed healthy adult females participated in two experiments of visual half-field presentation. Either facial expressions (experiment 1) or house images (experiment 2) were presented unilaterally and parafoveally for 150 ms while subjects were engaging a central fixation task. Brain regions previously associated with a visuospatial attention network, in both hemispheres, were found to be more robustly activated by left visual field stimuli. The consistency of this finding with manifestations of attention lateralization is discussed, and a revised model based on neural connectivity asymmetry is proposed. Support for the revised model is given by a dynamic causal modeling analysis. Unraveling the basis for attention asymmetry may lead to better understanding of the pathogenesis of attention disorders, followed by improved diagnosis and treatment. Additionally, the proposed model for asymmetry of visuospatial attention might provide important insights into the mechanisms underlying functional brain lateralization in general.
Key words: attention; DCM; fMRI; intraparietal sulcus; lateralization; neglect
Received Feb. 11, 2007; revised June 11, 2007; accepted June 18, 2007.
Correspondence should be addressed to Dr. Talma Hendler, Functional Brain Imaging Unit, Wohl Institute for Advanced Imaging, Tel Aviv Sourasky Medical Center, 6 Weizmann Street, Tel Aviv 64239, Israel. Email: talma{at}tasmc.health.gov.il
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[Abstract] [Full Text] [PDF]
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