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)

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, Professor 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 > School of Psychology & Neuroscience
• Journal Name: NeuroImage
• Publisher: Elsevier
• ISSN: 1053-8119
• ISSN (Online): 1095-9572
• Published Online: 21 March 2016