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Event-related brain dynamics: Time-varying interdependence among cortical domains************************************************** Seminar Monday Dec 2, 2002, 14:00-15:00 Informatics and Mathematical Modelling DTU Building 321, Room 053. ************************************************** Scott Makeig Swartz Center for Computational Research Institute for Neural Computation University of California San Diego La Jolla CA 92093-0961 -- http://sccn.ucsd.edu Abstract: High-dimensional recordings from the human scalp contain rich information about human cortical event-related brain dynamics. Until recently, interpretation of theses data has been severely limited by the use of simple response averaging methods originally introduced for fitting simple 'bottom-up' models of sensory perceptual processing. Recent neurophysiological and EEG evidence suggests that brain field dynamics are intimately related to dynamic reallocation of attention, to memory-related processing, and to self-evaluation of the consequences of actions, all more 'top-down' than 'bottom-up' processes. A more adequate model of human EEG dynamics must involve, first, spatial unmixing of contributions from quasi-independent domains of synchrony, for which Independent Component Analysis (ICA) is proving useful, followed by modeling of dynamic interrelations between EEG domains, which may be approached using time/frequency analysis. First results of the combined approach suggest new conceptions of macroscopic brain dynamics supporting cognitive events. More adequate models and analysis methods should also permit closer integration of scalp field, local field and single-unit spike information, pointing toward the emergence of a more unified science of human brain dynamics. Host: Lars Kai Hansen |