Oscillations and effective connectivity in human corticothalamic networks

Abstract

Event Abstract Back to Event Oscillations and effective connectivity in human corticothalamic networks Mario Rosanova1* and Massimini Marcello1 1 University of Milan, Italy Complex cognitive events, from sensory perception to dreams, are sustained by fast causal interactions -- effective connectivity -- among specialized cortical regions that are reflected in electroencephalogram (EEG) oscillations. We will demonstrate how combing EEG recordings with navigated transcranial magnetic stimulation (TMS/EEG) allows one to simultaneously measure evoked EEG rhythms and state-dependent cortical effective connectivity. This approach has revealed that each cortical region generates oscillations at a distinctive characteristic frequency (natural frequency), either when stimulated directly or when activated indirectly via TMS to another area. These high-frequency sustained TMS-evoked oscillations, together with long-range corticocortical interactions, are predictive of an individual’s level of awareness: they are systematically reduced during loss of consciousness in deep sleep, anesthesia, and coma. Further, they are recovered during REM sleep, when subjects experience dreams, and in acute brain injured patients before they can reestablish a reliable communication with the environment. They are also sensitive to psychiatric diagnosis: a decrease in TMS-evoked potentials in the gamma band (30-50 Hz) and a reduced spreading of activation is observed selectively in schizophrenia patients. In this way, TMS/EEG measurements suggest the existence of a causal link between TMS-evoked oscillations and corticocortical connectivity. Thus, whereas observations of the spontaneous EEG are limited to inferences based on temporal correlations (cortical functional connectivity), applying controlled TMS perturbations to different cortical areas affords causal investigation of the functions of cortical effective connectivity. Keywords: cortical oscillations, EEG, TMT Conference: XI International Conference on Cognitive Neuroscience (ICON XI), Palma, Mallorca, Spain, 25 Sep - 29 Sep, 2011. Presentation Type: Symposium: Oral Presentation Topic: Symposium 14: Probing Cortical Oscillations with Transcranial Stimulation Citation: Rosanova M and Marcello M (2011). Oscillations and effective connectivity in human corticothalamic networks. Conference Abstract: XI International Conference on Cognitive Neuroscience (ICON XI). doi: 10.3389/conf.fnhum.2011.207.00552 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 14 Nov 2011; Published Online: 28 Nov 2011. * Correspondence: Dr. Mario Rosanova, University of Milan, Milan, Italy, mario.rosanova@unimi.it Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Mario Rosanova Massimini Marcello Google Mario Rosanova Massimini Marcello Google Scholar Mario Rosanova Massimini Marcello PubMed Mario Rosanova Massimini Marcello Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.