University of Oulu

Kananen, J., Tuovinen, T., Ansakorpi, H., Rytky, S., Helakari, H., Huotari, N., Raitamaa, L., Raatikainen, V., Rasila, A., Borchardt, V., Korhonen, V., LeVan, P., Nedergaard, M., Kiviniemi, V. (2018) Altered physiological brain variation in drug-resistant epilepsy. Brain and behavior, 8 (9), e01090. doi:10.1002/brb3.1090

Altered physiological brain variation in drug‐resistant epilepsy

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Author: Kananen, Janne1,2; Tuovinen, Timo1,2; Ansakorpi, Hanna3,4;
Organizations: 1Department of Diagnostic Radiology, Medical Research Center, Oulu University Hospital
2Oulu Functional NeuroImaging-Group, Research Unit of Medical Imaging, Physics and Technology, University of Oulu
3Research Unit of Neuroscience, Neurology, University of Oulu
4Department of Neurology and Medical Research Center Oulu, Oulu University Hospital
5Department of Clinical Neurophysiology, Medical Research Center Oulu, Oulu University Hospital
6Faculty of Medicine, Department of Radiology – Medical Physics, University Medical Center Freiburg, University of Freiburg
7Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester
8Faculty of Health and Medical Sciences, Center for Basic and Translational Neuroscience, University of Copenhagen
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.6 MB)
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Language: English
Published: John Wiley & Sons, 2018
Publish Date: 2018-10-25


Introduction: Functional magnetic resonance imaging (fMRI) combined with simultaneous electroencephalography (EEG‐fMRI) has become a major tool in mapping epilepsy sources. In the absence of detectable epileptiform activity, the resting state fMRI may still detect changes in the blood oxygen level‐dependent signal, suggesting intrinsic alterations in the underlying brain physiology.

Methods: In this study, we used coefficient of variation (CV) of critically sampled 10 Hz ultra‐fast fMRI (magnetoencephalography, MREG) signal to compare physiological variance between healthy controls (n = 10) and patients (n = 10) with drug‐resistant epilepsy (DRE).

Results: We showed highly significant voxel‐level (p < 0.01, TFCE‐corrected) increase in the physiological variance in DRE patients. At individual level, the elevations range over three standard deviations (σ) above the control mean (μ) CVMREG values solely in DRE patients, enabling patient‐specific mapping of elevated physiological variance. The most apparent differences in group‐level analysis are found on white matter, brainstem, and cerebellum. Respiratory (0.12–0.4 Hz) and very‐low‐frequency (VLF = 0.009–0.1 Hz) signal variances were most affected.

Conclusions: The CVMREG increase was not explained by head motion or physiological cardiorespiratory activity, that is, it seems to be linked to intrinsic physiological pulsations. We suggest that intrinsic brain pulsations play a role in DRE and that critically sampled fMRI may provide a powerful tool for their identification.

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Series: Brain and behavior
ISSN: 2162-3279
ISSN-E: 2162-3279
ISSN-L: 2162-3279
Volume: 8
Issue: 9
Article number: e01090
DOI: 10.1002/brb3.1090
Type of Publication: A1 Journal article – refereed
Field of Science: 3126 Surgery, anesthesiology, intensive care, radiology
3124 Neurology and psychiatry
Funding: Funding information: Jane and Aatos Erkkos Foundation; Finnish Academy, Grant/Award Number: 275352 and 123772; Finnish Medical Foundation; Finnish Neurological Foundation; Oulu University Hospital; Epilepsy Research Foundation; Finnish Cultural Foundation, North Ostrobothnia Regional Fund; Orion Research Foundation; Tauno Tönning Foundation
Academy of Finland Grant Number: 275352
Detailed Information: 275352 (Academy of Finland Funding decision)
123772 (Academy of Finland Funding decision)
Copyright information: © 2018 The Authors. Brain and Behavior published by Wiley Periodicals, Inc. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.