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Title

The neural substrates and timing of top-down processes during coarse-to-fine categorization of visual scenes: a combined fMRI and ERP study

Authors
Peyrin, Carole
Seghier, Mohamed
Marendaz, Christian
Published in Journal of Cognitive Neuroscience. 2010, vol. 22, no. 12, p. 2768-2780
Abstract Spatial frequencies in an image influence visual analysis across a distributed, hierarchically organized brain network. Low spatial frequency (LSF) information may rapidly reach high-order areas to allow an initial coarse parsing of the visual scene, which could then be "retroinjected" through feedback into lower level visual areas to guide finer analysis on the basis of high spatial frequency (HSF). To test this "coarse-to-fine" processing scheme and to identify its neural substrates in the human brain, we presented sequences of two spatial-frequency-filtered scenes in rapid succession (LSF followed by HSF or vice versa) during fMRI and ERPs in the same participants. We show that for low-to-high sequences (but not for high-to-low sequences), LSF produces a first increase of activity in prefrontal and temporo-parietal areas, followed by enhanced responses to HSF in primary visual cortex. This pattern is consistent with retroactive influences on low-level areas that process HSF after initial activation of higher order areas by LSF.
Keywords AdultBrain/*physiologyBrain MappingConcept Formation/*physiologyElectroencephalographyEvoked Potentials/*physiologyHumansImage Processing, Computer-Assisted*Magnetic Resonance ImagingMalePhotic StimulationReaction Time/physiologyVisual Perception/*physiology
Identifiers
PMID: 20044901
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Structures
Research groups Organisation et plasticité des réseaux neuronaux cérébraux (148)
Mécanismes cérébraux du comportement et des fonctions cognitives (701)
Neuroimagerie du Sommeil et de la Cognition (832)
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PEYRIN, Carole et al. The neural substrates and timing of top-down processes during coarse-to-fine categorization of visual scenes: a combined fMRI and ERP study. In: Journal of Cognitive Neuroscience, 2010, vol. 22, n° 12, p. 2768-2780. doi: 10.1162/jocn.2010.21424 https://archive-ouverte.unige.ch/unige:21212

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Deposited on : 2012-05-23

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