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

Fellner, M.-C., Volberg, G., Mullinger, K.J., Goldhacker, M., Wimber, M. , Greenlee, M.W. and Hanslmayr, S. (2016) Spurious correlations in simultaneous EEG-fMRI driven by in-scanner movement. NeuroImage, 133, pp. 354-366. (doi: 10.1016/j.neuroimage.2016.03.031) (PMID:27012498)

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Abstract

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:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Hanslmayr, Professor Simon and Wimber, Dr Maria
Authors: Fellner, M.-C., Volberg, G., Mullinger, K.J., Goldhacker, M., Wimber, M., Greenlee, M.W., and Hanslmayr, S.
College/School:College of Medical Veterinary and Life Sciences > Institute of Neuroscience and Psychology
Journal Name:NeuroImage
Publisher:Elsevier
ISSN:1053-8119
ISSN (Online):1095-9572
Published Online:21 March 2016

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