The resting brain: Unconstrained yet reliable

Zarrar Shehzad, A. M.Clare Kelly, Philip T. Reiss, Dylan G. Gee, Kristin Gotimer, Lucina Q. Uddin, Sang Han Lee, Daniel S. Margulies, Amy Krain Roy, Bharat B. Biswal, Eva Petkova, F. Xavier Castellanos, Michael P. Milham

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Pages (from-to)2209-2229
Number of pages21
JournalCerebral Cortex
Issue number10
StatePublished - Oct 2009
Externally publishedYes

Bibliographical note

Funding Information:
Stavros S. Niarchos Foundation, the Leon Lowenstein Foundation, NARSAD (The Mental Health Research Association) grants to F.X.C.; and Linda and Richard Schaps, Jill and Bob Smith, and the Taubman Foundation gifts to F.X.C.


  • FMRI
  • Intraclass correlations
  • Reliability
  • Resting-state functional connectivity
  • Test-retest

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience
  • Cognitive Neuroscience


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