The Journal of Neuroscience, December 26, 2007, 27(52):14424-14433; doi:10.1523/JNEUROSCI.3759-07.2007
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Behavioral/Systems/Cognitive
Asymmetry of Anticipatory Activity in Visual Cortex Predicts the Locus of Attention and Perception
Chad M. Sylvester,1
Gordon L. Shulman,2
Anthony I. Jack,4 and
Maurizio Corbetta1,2,3
Departments of 1Radiology, 2Neurology, and 3Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63110, and 4Department of Cognitive Science, Case Western Reserve University, Cleveland, Ohio 44106
Correspondence should be addressed to Maurizio Corbetta, Department of Radiology, Washington University School of Medicine, 4525 Scott Avenue, Campus Box 8225, St. Louis, MO 63110. Email: mau{at}npg.wustl.edu
Humans can use advance information to direct spatial attention before stimulus presentation and respond more accurately to stimuli at the attended location compared with unattended locations. Likewise, spatially directed attention is associated with anticipatory activity in the portion of visual cortex representing the attended location. It is unknown, however, whether and how anticipatory signals predict the locus of spatial attention and perception. Here, we show that prestimulus, preparatory activity is highly correlated across regions representing attended and unattended locations. Comparing activity representing attended versus unattended locations, rather than measuring activity for only one location, dramatically improves the accuracy with which preparatory signals predict the locus of attention, largely by removing this positive correlation common across locations. In V3A, moreover, only the difference in activity between attended and unattended locations predicts whether upcoming visual stimuli will be accurately perceived. These results suggest that the locus of attention is coded in visual cortex by an asymmetry of anticipatory activity between attended and unattended locations and that this asymmetry predicts the accuracy of perception. This coding strategy may bias activity in downstream brain regions to represent the stimulus at the attended location.
Key words: attention; visual cortex; fMRI; behavior; spatial orientation; correlated noise
Received Aug. 17, 2007;
revised Oct. 23, 2007;
accepted Oct. 25, 2007.
Correspondence should be addressed to Maurizio Corbetta, Department of Radiology, Washington University School of Medicine, 4525 Scott Avenue, Campus Box 8225, St. Louis, MO 63110. Email: mau{at}npg.wustl.edu
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