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Abstract #2245

Inter-Subject Variability in the Amplitude of the Resting-State fMRI Global Signal Reflects Differences in EEG Vigilance

Chi Wah Wong1, Valur Olafsson1, Omer Tal1, Thomas Liu1

1Center for Functional MRI, University of California San Diego, La Jolla, CA, United States

The global signal is often considered a confound in resting-state fMRI. However, a recent primate study has shown that the global signal may contain significant contributions from neural sources. In this study, we used simultaneous EEG-fMRI to examine the sources of inter-subject variability in the amplitude of the global signal in humans. We found that the global signal amplitude is negatively correlated with an EEG-based vigilance measure.