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Cereb Cortex. 2017 Oct 1;27(10):4719-4732. doi: 10.1093/cercor/bhw265.

On the Stability of BOLD fMRI Correlations.

Author information

1
Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA.
2
Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
3
VISN 17 Center of Excellence for Research on Returning War Veterans, Waco, TX 76711, USA.
4
Center for Vital Longevity, School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX 75235, USA.
5
Department of Psychological and Brain Sciences, Washington University in St. Louis, St. Louis, MO 63110, USA.
6
Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA.
7
Department of Mathematics, Washington University in St. Louis, St. Louis, MO 63130, USA.
8
Departmen of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA.
9
Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
10
Institute for Medical Psychology, Christian-Albrechts-Universitat zu Kiel, Kiel, Germany.
11
Department of Neurology, Brain Imaging Center, Goethe-Universitat Frankfurt am Main, Frankfurt, Germany.
12
Department of Neurology, Christian-Albrechts-Universitat zu Kiel, Kiel, Germany.

Abstract

Measurement of correlations between brain regions (functional connectivity) using blood oxygen level dependent (BOLD) fMRI has proven to be a powerful tool for studying the functional organization of the brain. Recently, dynamic functional connectivity has emerged as a major topic in the resting-state BOLD fMRI literature. Here, using simulations and multiple sets of empirical observations, we confirm that imposed task states can alter the correlation structure of BOLD activity. However, we find that observations of "dynamic" BOLD correlations during the resting state are largely explained by sampling variability. Beyond sampling variability, the largest part of observed "dynamics" during rest is attributable to head motion. An additional component of dynamic variability during rest is attributable to fluctuating sleep state. Thus, aside from the preceding explanatory factors, a single correlation structure-as opposed to a sequence of distinct correlation structures-may adequately describe the resting state as measured by BOLD fMRI. These results suggest that resting-state BOLD correlations do not primarily reflect moment-to-moment changes in cognitive content. Rather, resting-state BOLD correlations may predominantly reflect processes concerned with the maintenance of the long-term stability of the brain's functional organization.

KEYWORDS:

BOLD fMRI; dynamics; functional connectivity; nonstationarity; resting state

PMID:
27591147
PMCID:
PMC6248456
DOI:
10.1093/cercor/bhw265
[Indexed for MEDLINE]
Free PMC Article

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