Purpose: Reports of the relationship between the default mode network (DMN) and alpha power are conflicting. Our goal was to assess this relationship by analyzing concurrently obtained EEG/functional MRI data using hypothesis-independent methods.
Methods: We collected functional MRI and EEG data during eyes-closed rest in 20 participants aged 19 to 37 (10 females) and performed independent component analysis on the functional MRI data and a Hamming-windowed fast Fourier transform on the EEG data. We correlated functional MRI fluctuations in the DMN with alpha power.
Results: Of the six independent components found to have significant relationships with alpha, four contained DMN-associated regions: One independent component was positively correlated with alpha power, whereas all others were negatively correlated. Furthermore, two independent components with opposite relationships with alpha had overlapping voxels in the medial prefrontal cortex and posterior cingulate cortex, suggesting that subpopulations of neurons within these classic nodes within the DMN may have different relationships to alpha power.
Conclusions: Different parts of the DMN exhibit divergent relationships to alpha power. Our results highlight the relationship between DMN activity and alpha power, indicating that networks, such as the DMN, may have subcomponents that exhibit different behaviors.
Departments of *Biomedical Engineering,
§Vision Sciences, University of Alabama at Birmingham, Birmingham, Alabama, U.S.A.;
‖Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, U.S.A.; and
¶Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama, U.S.A.
Address correspondence and reprint requests to Anthony D. Bowman, University of Alabama at Birmingham Epilepsy Center, 312 Civitan International Research Center, 1719 6th Avenue South, Birmingham, AL 35294-0021, U.S.A.; e-mail: firstname.lastname@example.org.
The authors have no funding or conflicts of interest to disclose.
All work pertaining to this study was performed at the University of Alabama at Birmingham, Birmingham, AL, U.S.A.
This work was part of the first author's Master's Thesis in the Department of Biomedical Engineering at the University of Alabama at Birmingham, Birmingham, AL, U.S.A.
This work was supported through the UAB Epilepsy Center funds.
Presented in part at the 2015 Annual Meeting of the American Academy of Neurology held at the Walter E. Washington Convention Center in Washington, DC from April 18 to 25, 2015.