title: Brain activity at rest: a multiscale hierarchical functional organization.
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.
authors: Univ. de Bordeaux, Bordeaux, France.
authors: Gaëlle
authors: G
authors: Doucet
authors: Mikaël
authors: M
authors: Naveau
authors: Laurent
authors: L
authors: Petit
authors: Nicolas
authors: N
authors: Delcroix
authors: Laure
authors: L
authors: Zago
authors: Fabrice
authors: F
authors: Crivello
authors: Gaël
authors: G
authors: Jobard
authors: Nathalie
authors: N
authors: Tzourio-Mazoyer
authors: Bernard
authors: B
authors: Mazoyer
authors: Emmanuel
authors: E
authors: Mellet
authors: Marc
authors: M
authors: Joliot
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D001921:Brain / Q000098:blood supply / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D009434:Neural Pathways / Q000502:physiology; D010100:Oxygen / Q000097:blood; D025341:Principal Component Analysis; D012146:Rest / Q000502:physiology*; D013223:Statistics as Topic; D055815:Young Adult
chemical_list: D010100:Oxygen