title: The resting brain: unconstrained yet reliable.
abstract: Recent years have witnessed an upsurge in the usage of resting-state functional magnetic resonance imaging (fMRI) to examine functional connectivity (fcMRI), both in normal and pathological populations. Despite this increasing popularity, concerns about the psychologically unconstrained nature of the "resting-state" remain. Across studies, the patterns of functional connectivity detected are remarkably consistent. However, the test-retest reliability for measures of resting state fcMRI measures has not been determined. Here, we quantify the test-retest reliability, using resting scans from 26 participants at 3 different time points. Specifically, we assessed intersession (>5 months apart), intrasession (<1 h apart), and multiscan (across all 3 scans) reliability and consistency for both region-of-interest and voxel-wise analyses. For both approaches, we observed modest to high reliability across connections, dependent upon 3 predictive factors: 1) correlation significance (significantly nonzero > nonsignificant), 2) correlation valence (positive > negative), and 3) network membership (default mode > task positive network). Short- and long-term measures of the consistency of global connectivity patterns were highly robust. Finally, hierarchical clustering solutions were highly reproducible, both across participants and sessions. Our findings provide a solid foundation for continued examination of resting state fcMRI in typical and atypical populations.
authors.affiliation: Phyllis Green and Randolph Cowen Institute for Pediatric Neuroscience, NYU Child Study Center, New York, NY 10016, USA.
authors.forename: Zarrar
authors.initials: Z
authors.lastname: Shehzad
authors.forename: A M Clare
authors.initials: AM
authors.lastname: Kelly
authors.forename: Philip T
authors.initials: PT
authors.lastname: Reiss
authors.forename: Dylan G
authors.initials: DG
authors.lastname: Gee
authors.forename: Kristin
authors.initials: K
authors.lastname: Gotimer
authors.forename: Lucina Q
authors.initials: LQ
authors.lastname: Uddin
authors.forename: Sang Han
authors.initials: SH
authors.lastname: Lee
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Margulies
authors.forename: Amy Krain
authors.initials: AK
authors.lastname: Roy
authors.forename: Bharat B
authors.initials: BB
authors.lastname: Biswal
authors.forename: Eva
authors.initials: E
authors.lastname: Petkova
authors.forename: F Xavier
authors.initials: FX
authors.lastname: Castellanos
authors.forename: Michael P
authors.initials: MP
authors.lastname: Milham
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009415:Nerve Net / Q000502:physiology; D012044:Regression Analysis; D015203:Reproducibility of Results; D012146:Rest / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted