Interactions Between Evoked And Intrinsic Brain Activity. Electrophysiology, Hemodynamics, Behavioral Consequences.

This project brings together an international and interdisciplinary team of recognized researchers with a common interest in how human behavior is influenced by intrinsic fluctuations of electrohysiologic and hemodynamic brian activity. Intrinsic activity has only recently been recognized as a relevant source of information in fMRI (5-7), most previous research has disregarded this variability as noise and only modeled the deterministic evoked response to stimulation (11). The exploration of interactions between intrinsic and evoked activity on single trial level with EEG and EEG-fMRI provides a unique window into the adaptive brain dynamics (12-15), and yields novel insights about the functional roles of large-scale networks (1-4). The present project w ill investigate a visual task requiring rapid responses which probes stimulus processing, response conflict, error monitoring, and adaptation. The applicants have recently found a set of brain regions in which hemodynamic activation patterns predicted the accuracy of behavioral performance at least six seconds ahead in time, with trends starting as early as 30 seconds before an erroneous response (1), consistent with results from other labs (2-4). Small sample studies, however, have only limited sensitivi ty and will not pick up features that have a higher degree of inter-individual variability. Therefore, in order to fully explore the impact of intrinsic activity on evoked responses and behaviour, respectively, the applicants suggest to fund a large-sampl e data collection of the Eriksen-Flanker experiment, in which event-related EEG data will be collected from 100 participants in Bergen to identify features of interest. Hereafter, 50 EEG-fMRI datasets will be collected in Albuquerque from a new sample of subjects. The data and methods will be made freely available to the imaging community to spur further inquiry into this and other data. A workshop will be organized in Bergen at the end of the project.