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Activity in the Visual Cortex is Modulated by Top-Down Attention Locked to Reaction Time

Moradi, Farshad and Hipp, Constanze and Koch, Christof (2007) Activity in the Visual Cortex is Modulated by Top-Down Attention Locked to Reaction Time. Journal of Cognitive Neuroscience, 19 (2). pp. 331-340. ISSN 0898-929X.

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We studied the correlation between perception and hemodynamic activity in the visual cortex in a change detection task. Whenever the observer perceived the location of a change, rightly or wrongly, the blood oxygenation level-dependent signal increased in the primary visual cortex and the nearby extrastriate areas above the baseline activity caused by the visual stimulation. This non-sensory-evoked activity was localized and corresponded to the perceived location of the change. When a change was missed, or when observers attended to a different task, the change failed to evoke such a response. The latency of the nonsensory component increased linearly with subjects' reaction time, with a slope of one, and its amplitude was independent of contrast. Control experiments are compatible with the hypothesis that the nonsensory hemodynamic signal is mediated by top-down spatial attention, linked to (but separate from) awareness of the change.

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Additional Information:© 2007 The MIT Press. We thank S. Flaherty and M. Tyszka for assisting in the MR imaging, A. Movshon and J. Hipp for discussion of the experiments. F.M. was supported by a fellowship from Caltech, C.H. was supported by a fellowship from the Neuroscience Center Zürich. The research was supported by NSF, the Moore Foundation, and a Tom Slick Research Award of the Mind Science Foundation.
Group:Koch Laboratory, KLAB
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Moore FoundationUNSPECIFIED
Tom Slick Research Award of the Mind Science FoundationUNSPECIFIED
Record Number:CaltechAUTHORS:MORjcn07
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ID Code:7705
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Deposited On:24 Mar 2007
Last Modified:23 Sep 2013 19:24

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