The brain matures with stronger functional connectivity and decreased randomness of its network

From roughly 5 years of age until adulthood, theta, alpha, and beta oscillation networks exhibit concurrent increases in clustering coefficient and strength of long-range anterior-posterior and interhemispheric connections.

“From roughly 5 years of age until adulthood, theta (~4Hz), alpha (~10Hz), and beta (~20Hz) oscillation networks exhibit concurrent increases in clustering coefficient (Boersma et al., 2011; Smit et al., 2012) and strength of long-range anterior-posterior and interhemispheric connections (Barry et al., 2004; Miskovic et al., 2015; Smit et al., 2012; Srinivasan, 1999).”

These coincident trajectories support the hypothesis that developmental changes in baseline electrophysiological signatures may primarily be subserved by reduction of neuropil and progressive synapse elimination.

“These coincident trajectories have provided key support for the hypothesis that developmental changes in baseline electrophysiological signatures may primarily be subserved by reduction of neuropil and progressive synapse elimination (Buchmann et al., 2011; Smit et al., 2012; Whitford et al., 2007).”

There is a progressive shift in peak amplitude towards higher frequency activity.

“There is also a progressive shift in peak amplitude towards higher frequency activity (Miskovic et al., 2015; Rodriguez-Martinez et al., 2015; Smit et al., 2012; Whitford et al., 2007).”

Spectral power decreases continually from 5-30 years of age across most frequency bands, particularly in the slow-wave (0.5-7Hz).

“One of the classical and well-reproduced findings is that spectral power (i.e. amplitude of activity within different temporal frequency bands) decreases continually from 5–30 years of age across most frequency bands, but particularly in the slow-wave (0.5–7Hz) (Miskovic et al., 2015; Rodriguez-Martinez et al., 2015; Smit et al., 2012; Whitford et al., 2007).”

Network structure becomes increasingly non-random across this timespan.

“There is also consensus that network structure becomes increasingly non-random across this timespan (Boersma et al., 2011; Miskovic et al., 2015; Smit et al., 2012).”

Two reports found path length increases with age, while more recent work demonstrates age-related reductions.

“Somewhat unexpectedly, two reports found path length to also increase with age (Boersma et al., 2011; Smit et al., 2012), although more recent work demonstrates age-related reductions (Miskovic et al., 2015).”

Frontal and parietal cortical gray matter volume decreases across 5-30 years and exhibits curvilinear trajectories closely correlated with loss of slow-wave power in the same areas.

“Interestingly, frontal and parietal cortical gray matter (but not white matter) volume decreases across this same age bracket, and exhibits curvilinear trajectories that are closely correlated to the loss of slow-wave power in these same areas (Buchmann et al., 2011; Smit et al., 2012; Whitford et al., 2007).”