Hierarchical functional modularity in the resting-state human brain.
Functional magnetic resonance imaging (fMRI) studies have shown that anatomically distinct brain regions are functionally connected during the resting state. Basic topological properties in the brain functional connectivity (BFC) map have highlighted the BFC's small-world topology. Modularity, a more advanced topological property, has been hypothesized to be evolutionary advantageous, contributing to adaptive aspects of anatomical and functional brain connectivity. However, current definitions of modularity for complex networks focus on nonoverlapping clusters, and are seriously limited by disregarding inclusive relationships. Therefore, BFC's modularity has been mainly qualitatively investigated. Here, we introduce a new definition of modularity, based on a recently improved clustering measurement, which overcomes limitations of previous definitions, and apply it to the study of BFC in resting state fMRI of 53 healthy subjects. Results show hierarchical functional modularity in the brain.
Ferrarini
Luca
L
Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands. l.ferrarini@lumc.nl
Veer
Ilya M
IM
Baerends
Evelinda
E
van Tol
Marie-José
MJ
Renken
Remco J
RJ
van der Wee
Nic J A
NJ
Veltman
Dirk J
DJ
Aleman
André
A
Zitman
Frans G
FG
Penninx
Brenda W J H
BW
van Buchem
Mark A
MA
Reiber
Johan H C
JH
Rombouts
Serge A R B
SA
Milles
Julien
J
D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000502:physiology; D055815:Young Adult