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Frederic Benmussa, Jean-Gabriel Dornbierer, Stephane Buffat, Anne-Lise Paradis, Jean Lorenceau; Looking for the LOC with MEG using frequency-tagged natural objects. Journal of Vision 2012;12(9):511. doi: 10.1167/12.9.511.
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© ARVO (1962-2015); The Authors (2016-present)
Previous fMRI studies found that Lateral Occipital Complex (LOC) is preferentially activated by visual objects. Here, we used frequency-tagged 3D dot scans of natural objects, and their scrambled counterparts to localize with sources reconstruction in MEG cortical regions subtending object perception as the LOC, and characterize the dynamics of their sustained MEG responses. Object tagging, consisting of Rapid Sequential Visual Presentation (RSVP) of Objects, Scrambles or mix of Objects and Scramble at 2.5hz rate was compared to feature tagging -dot renewal- with a single object at the same frequency. Localizer-defined ROIs from fMRI were also compared to, and used for, Magnetic Source Imaging. Results indicate that multiple object tagging reveals stronger activations in the temporal lobe than tagging with single object presentations. Contrasting responses to Objects and Scrambles revealed cortical sources activated between 150 and 350ms in regions comparable to those usually found with fMRI using the same –Object/Scramble- contrast. Contrasting mixture of Object and Scramble to Object or Scramble alone conditions revealed enhanced object-related activity for the mixed condition emerging around 150ms after each new stimulus onset. Cortical sources localized in the anterior temporal pole known to be involved in semantic processing were also activated. Altogether, the results indicate that frequency-tagging with MEG is well suited to uncover the localization and dynamics of perceptual processes underlying object processing.
Meeting abstract presented at VSS 2012
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