Brain maturation in adolescence: concurrent changes in neuroanatomy and neurophysiology.

Whitford TJ Rennie CJ, Grieve SM, Clark CR, Gordon E, Williams LM (2007). Brain maturation in adolescence: concurrent changes in neuroanatomy and neurophysiology, Human Brain Mapping, , 228-237.

adolescence maturation magnetic resonance imaging MRI electroencephalography EEG grey matter white matter slow wave power

Adolescence to early adulthood is a period of dramatic transformation in the healthy human brain, however the relationship between the concurrent structural and functional changes remains unclear. We investigated the impact of age on both neuroanatomy and neurophysiology in the same healthy subjects (n=138) aged 10 to 30 years, using magnetic resonance imaging (MRI) and resting electroencephalography (EEG) recordings. MRI data were segmented into grey and white matter images and parcellated into large-scale regions-of-interest. Absolute EEG power was quantified for each lobe for the slow-wave, alpha and beta frequency bands. Grey matter volume was found to decrease across the age bracket in the frontal and parietal cortices, with the greatest change occurring in adolescence. EEG activity, particularly in the slow-wave band, showed a similar curvilinear decline to GM volume in corresponding cortical regions. An inverse pattern of curvilinearly increasing white matter volume was observed in the parietal lobe. We suggest that the reduction in grey matter primarily reflects a reduction of neuropil, and that the corresponding elimination of active synapses is responsible for the observed reduction in EEG power. .