title: Brain maturation in adolescence and young adulthood: regional age-related changes in cortical thickness and white matter volume and microstructure.
abstract: The development of cortical gray matter, white matter (WM) volume, and WM microstructure in adolescence is beginning to be fairly well characterized by structural magnetic resonance imaging (sMRI) and diffusion tensor imaging (DTI) studies. However, these aspects of brain development have rarely been investigated concurrently in the same sample and hence the relations between them are not understood. We delineated the age-related changes in cortical thickness, regional WM volume, and diffusion characteristics and investigated the relationships between these properties of brain development. One hundred and sixty-eight healthy participants aged 8-30 years underwent sMRI and DTI. The results showed regional age-related cortical thinning, WM volume increases, and changes in diffusion parameters. Cortical thickness was the most strongly age-related parameter. All classes of measures showed unique associations with age. The results indicate that cortical thinning in adolescence cannot be explained by WM maturation in underlying regions as measured by volumetry or DTI. Moderate associations between cortical thickness and both volume and diffusion parameters in underlying WM regions were also found, although the relationships were not strong. It is concluded that none of the measures are redundant and that the integration of the 3 will yield a more complete understanding of brain maturation.
authors.affiliation: Center for the Study of Human Cognition, Department of Psychology, University of Oslo, 0317 Oslo, Norway.
authors.forename: Christian K
authors.initials: CK
authors.lastname: Tamnes
authors.forename: Ylva
authors.initials: Y
authors.lastname: Ostby
authors.forename: Anders M
authors.initials: AM
authors.lastname: Fjell
authors.forename: Lars T
authors.initials: LT
authors.lastname: Westlye
authors.forename: Paulina
authors.initials: P
authors.lastname: Due-Tønnessen
authors.forename: Kristine B
authors.initials: KB
authors.lastname: Walhovd
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000254:growth & development*; D002648:Child; D002657:Child Development / Q000502:physiology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008137:Longitudinal Studies; D008297:Male; D009413:Nerve Fibers, Myelinated; D055815:Young Adult