title: Normalized cut group clustering of resting-state FMRI data.
abstract: BACKGROUND
  Functional brain imaging studies have indicated that distinct anatomical brain regions can show coherent spontaneous neuronal activity during rest. Regions that show such correlated behavior are said to form resting-state networks (RSNs). RSNs have been investigated using seed-dependent functional connectivity maps and by using a number of model-free methods. However, examining RSNs across a group of subjects is still a complex task and often involves human input in selecting meaningful networks.
  
  
  RESULTS
  We report on a voxel based model-free normalized cut graph clustering approach with whole brain coverage for group analysis of resting-state data, in which the number of RSNs is computed as an optimal clustering fit of the data. Inter-voxel correlations of time-series are grouped at the individual level and the consistency of the resulting networks across subjects is clustered at the group level, defining the group RSNs. We scanned a group of 26 subjects at rest with a fast BOLD sensitive fMRI scanning protocol on a 3 Tesla MR scanner.
  
  
  CONCLUSIONS
  An optimal group clustering fit revealed 7 RSNs. The 7 RSNs included motor/visual, auditory and attention networks and the frequently reported default mode network. The found RSNs showed large overlap with recently reported resting-state results and support the idea of the formation of spatially distinct RSNs during rest in the human brain.
authors.affiliation: Rudolf Magnus Institute of Neuroscience, Department of Psychiatry, University Medical Center Utrecht, Utrecht, The Netherlands. M.P.vandenheuvel@umcutrecht.nl
authors.forename: Martijn
authors.initials: M
authors.lastname: van den Heuvel
authors.forename: Rene
authors.initials: R
authors.lastname: Mandl
authors.forename: Hilleke
authors.initials: H
authors.lastname: Hulshoff Pol
mesh_terms: D000328:Adult; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012146:Rest / Q000502:physiology*