Spurious correlations in simultaneous EEG-fMRI driven by in-scanner movement

Fellner, M.-C. and Volberg, G. and Mullinger, K.J. and Goldhacker, M. and Wimber, M. and Greenlee, M.W. and Hanslmayr, S. (2016) Spurious correlations in simultaneous EEG-fMRI driven by in-scanner movement. NeuroImage, 133 . pp. 354-366. ISSN 1053-8119

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Simultaneous EEG-fMRI provides an increasingly attractive research tool to investigate cognitive processes with high temporal and spatial resolution. However, artifacts in EEG data introduced by the MR-scanner still remain a major obstacle. This study employing commonly used artifact correction steps shows that head motion, one overlooked major source of artifacts in EEG-fMRI data, can cause plausible EEG effects and EEG-BOLD correlations. Specifically, low frequency EEG (<20 Hz) is strongly correlated with in-scanner movement. Accordingly, minor head motion (<0.2 mm) induces spurious effects in a twofold manner: Small differences in task-correlated motion elicit spurious low frequency effects, and, as motion concurrently influences fMRI data, EEG-BOLD correlations closely match motion-fMRI correlations. We demonstrate these effects in a memory encoding experiment showing that obtained theta power (~3-7 Hz) effects and channel-level theta-BOLD correlations reflect motion in the scanner. These findings highlight an important caveat that needs to be addressed by future EEG-fMRI studies.


Item Type: Article
Keywords: Brain oscillations, EEG-BOLD correlations, motion artifacts, simultaneous EEG-fMRI, theta oscillations
Schools/Departments: University of Nottingham UK Campus > Faculty of Science > School of Physics and Astronomy
Identification Number: https://doi.org/10.1016/j.neuroimage.2016.03.031
Depositing User: Mullinger, Dr Karen
Date Deposited: 18 Mar 2016 11:21
Last Modified: 17 Sep 2016 21:29
URI: http://eprints.nottingham.ac.uk/id/eprint/32369

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