Patterns of hemodynamic low-frequency oscillations in the brain are modulated by the nature of free thought during rest
NeuroImage. 2012-02-01; 59(4): 3194-3200
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1. Neuroimage. 2012 Feb 15;59(4):3194-200. doi: 10.1016/j.neuroimage.2011.11.059.
Epub 2011 Dec 1.
Patterns of hemodynamic low-frequency oscillations in the brain are modulated by
the nature of free thought during rest.
Doucet G(1), Naveau M, Petit L, Zago L, Crivello F, Jobard G, Delcroix N, Mellet
E, Tzourio-Mazoyer N, Mazoyer B, Joliot M.
(1)Univ Bordeaux, GIN, UMR 5296, F-33000 Bordeaux, France.
During conscious rest, the mind switches into a state of wandering. Although this
rich inner experience occupies a large portion of the time spent awake, how it
relates to brain activity has not been well explored. Here, we report the results
of a behavioral and functional magnetic resonance imaging (fMRI) study of the
continuous resting state in 307 healthy participants. The analysis focused on the
relationship between the nature of inner experience and the temporal correlations
computed between the low-frequency blood oxygen level-dependent (BOLD)
fluctuations (0.01-0.1 Hz) of five large-scale modules. The subjects’
self-reported time spontaneously spent on visual mental imagery and/or inner
language was used as the behavioral variable. Decreased temporal correlations
between modules were revealed when subjects reported more time spent thinking in
mental images and inner language. These changes segregated the three modules
supporting inner-oriented activities from those associated with sensory-related
and externally guided activities. Among the brain areas associated with
inner-oriented processing, the module including the lateral parietal and frontal
regions (commonly described as being engaged in the manipulation and maintenance
of internal information) was implicated in the majority of these effects. The
preponderance of segregation appears to be the signature of the spontaneous
sequence of thoughts during rest that are not constrained by logic, causality, or
even a rigorous temporal organization. In other words, though goal-directed tasks
have been demonstrated to rely on specific regional integration, mind wandering
can be characterized by widespread modular segregation. Overall, the present
study provides evidence that modulation of spontaneous low-frequency fluctuations
in the brain is at least partially explained by spontaneous conscious cognition
while at rest.
Copyright © 2011 Elsevier Inc. All rights reserved.
PMID: 22155378 [Indexed for MEDLINE]