Brain activity at rest: a multiscale hierarchical functional organization

J Neurophysiol. 2011 Jun;105(6):2753-63. doi: 10.1152/jn.00895.2010. Epub 2011 Mar 23.

Abstract

Spontaneous brain activity was mapped with functional MRI (fMRI) in a sample of 180 subjects while in a conscious resting-state condition. With the use of independent component analysis (ICA) of each individual fMRI signal and classification of the ICA-defined components across subjects, a set of 23 resting-state networks (RNs) was identified. Functional connectivity between each pair of RNs was assessed using temporal correlation analyses in the 0.01- to 0.1-Hz frequency band, and the corresponding set of correlation coefficients was used to obtain a hierarchical clustering of the 23 RNs. At the highest hierarchical level, we found two anticorrelated systems in charge of intrinsic and extrinsic processing, respectively. At a lower level, the intrinsic system appears to be partitioned in three modules that subserve generation of spontaneous thoughts (M1a; default mode), inner maintenance and manipulation of information (M1b), and cognitive control and switching activity (M1c), respectively. The extrinsic system was found to be made of two distinct modules: one including primary somatosensory and auditory areas and the dorsal attentional network (M2a) and the other encompassing the visual areas (M2b). Functional connectivity analyses revealed that M1b played a central role in the functioning of the intrinsic system, whereas M1c seems to mediate exchange of information between the intrinsic and extrinsic systems.

MeSH terms

  • Adolescent
  • Adult
  • Algorithms
  • Brain / blood supply
  • Brain / physiology*
  • Brain Mapping*
  • Female
  • Humans
  • Image Processing, Computer-Assisted / methods
  • Magnetic Resonance Imaging / methods
  • Male
  • Middle Aged
  • Models, Neurological
  • Neural Pathways / physiology
  • Oxygen / blood
  • Principal Component Analysis
  • Rest / physiology*
  • Statistics as Topic
  • Young Adult

Substances

  • Oxygen