title: Topographic electrophysiological signatures of FMRI Resting State Networks.
abstract: BACKGROUND
  fMRI Resting State Networks (RSNs) have gained importance in the present fMRI literature. Although their functional role is unquestioned and their physiological origin is nowadays widely accepted, little is known about their relationship to neuronal activity. The combined recording of EEG and fMRI allows the temporal correlation between fluctuations of the RSNs and the dynamics of EEG spectral amplitudes. So far, only relationships between several EEG frequency bands and some RSNs could be demonstrated, but no study accounted for the spatial distribution of frequency domain EEG.
  
  
  RESULTS
  In the present study we report on the topographic association of EEG spectral fluctuations and RSN dynamics using EEG covariance mapping. All RSNs displayed significant covariance maps across a broad EEG frequency range. Cluster analysis of the found covariance maps revealed the common standard EEG frequency bands. We found significant differences between covariance maps of the different RSNs and these differences depended on the frequency band.
  
  
  CONCLUSIONS
  Our data supports the physiological and neuronal origin of the RSNs and substantiates the assumption that the standard EEG frequency bands and their topographies can be seen as electrophysiological signatures of underlying distributed neuronal networks.
authors.affiliation: Department of Psychiatric Neurophysiology, University Hospital of Psychiatry and University of Bern, Bern, Switzerland. jann@puk.unibe.ch
authors.forename: Kay
authors.initials: K
authors.lastname: Jann
authors.forename: Mara
authors.initials: M
authors.lastname: Kottlow
authors.forename: Thomas
authors.initials: T
authors.lastname: Dierks
authors.forename: Chris
authors.initials: C
authors.lastname: Boesch
authors.forename: Thomas
authors.initials: T
authors.lastname: Koenig
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D055815:Young Adult