title: The brain matures with stronger functional connectivity and decreased randomness of its network.
abstract: We investigated the development of the brain's functional connectivity throughout the life span (ages 5 through 71 years) by measuring EEG activity in a large population-based sample. Connectivity was established with Synchronization Likelihood. Relative randomness of the connectivity patterns was established with Watts and Strogatz' (1998) graph parameters C (local clustering) and L (global path length) for alpha (~10 Hz), beta (~20 Hz), and theta (~4 Hz) oscillation networks. From childhood to adolescence large increases in connectivity in alpha, theta and beta frequency bands were found that continued at a slower pace into adulthood (peaking at ~50 yrs). Connectivity changes were accompanied by increases in L and C reflecting decreases in network randomness or increased order (peak levels reached at ~18 yrs). Older age (55+) was associated with weakened connectivity. Semi-automatically segmented T1 weighted MRI images of 104 young adults revealed that connectivity was significantly correlated to cerebral white matter volume (alpha oscillations: r = 33, p<01; theta: r = 22, p<05), while path length was related to both white matter (alpha: max. r = 38, p<001) and gray matter (alpha: max. r = 36, p<001; theta: max. r = 36, p<001) volumes. In conclusion, EEG connectivity and graph theoretical network analysis may be used to trace structural and functional development of the brain.
authors.affiliation: Biological Psychology, VU University, Amsterdam, The Netherlands. d.j.a.smit@vu.nl
authors.forename: Dirk J A
authors.initials: DJ
authors.lastname: Smit
authors.forename: Maria
authors.initials: M
authors.lastname: Boersma
authors.forename: Hugo G
authors.initials: HG
authors.lastname: Schnack
authors.forename: Sifis
authors.initials: S
authors.lastname: Micheloyannis
authors.forename: Dorret I
authors.initials: DI
authors.lastname: Boomsma
authors.forename: Hilleke E
authors.initials: HE
authors.lastname: Hulshoff Pol
authors.forename: Cornelis J
authors.initials: CJ
authors.lastname: Stam
authors.forename: Eco J C
authors.initials: EJ
authors.lastname: de Geus
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D003344:Cortical Synchronization / Q000502:physiology; D004569:Electroencephalography / Q000379:methods; D005260:Female; D006801:Humans; D019369:Life; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult