  The functional significance of resting state networks and their abnormal
manifestations in psychiatric disorders are firmly established, as is the
importance of the cortical rhythms in mediating these networks. Resting state
networks are known to undergo substantial reorganization from childhood to
adulthood, but whether distinct cortical rhythms, which are generated by
separable neural mechanisms and are often manifested abnormally in psychiatric
conditions, mediate maturation differentially, remains unknown. Using
magnetoencephalography (MEG) to map frequency band specific maturation of
resting state networks from age 7 to 29 in 162 participants (31 independent),
we found significant changes with age in networks mediated by the beta
(13-30Hz) and gamma (31-80Hz) bands. More specifically, gamma band mediated
networks followed an expected asymptotic trajectory, but beta band mediated
networks followed a linear trajectory. Network integration increased with age
in gamma band mediated networks, while local segregation increased with age in
beta band mediated networks. Spatially, the hubs that changed in importance
with age in the beta band mediated networks had relatively little overlap with
those that showed the greatest changes in the gamma band mediated networks.
These findings are relevant for our understanding of the neural mechanisms of
cortical maturation, in both typical and atypical development.
