title: Brain development during adolescence: A mixed-longitudinal investigation of cortical thickness, surface area, and volume.
abstract: What we know about cortical development during adolescence largely stems from analyses of cross-sectional or cohort-sequential samples, with few studies investigating brain development using a longitudinal design. Further, cortical volume is a product of two evolutionarily and genetically distinct features of the cortex - thickness and surface area, and few studies have investigated development of these three characteristics within the same sample. The current study examined maturation of cortical thickness, surface area and volume during adolescence, as well as sex differences in development, using a mixed longitudinal design. 192 MRI scans were obtained from 90 healthy (i.e., free from lifetime psychopathology) adolescents (11-20 years) at three time points (with different MRI scanners used at time 1 compared to 2 and 3). Developmental trajectories were estimated using linear mixed models. Non-linear increases were present across most of the cortex for surface area. In comparison, thickness and volume were both characterised by a combination of non-linear decreasing and increasing trajectories. While sex differences in volume and surface area were observed across time, no differences in thickness were identified. Furthermore, few regions exhibited sex differences in the cortical development. Our findings clearly illustrate that volume is a product of surface area and thickness, with each exhibiting differential patterns of development during adolescence, particularly in regions known to contribute to the development of social-cognition and behavioral regulation. These findings suggest that thickness and surface area may be driven by different underlying mechanisms, with each measure potentially providing independent information about brain development. Hum Brain Mapp 37:2027-2038, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Psychology, University of Oregon, Eugene, Oregon.
authors.forename: Nandita
authors.initials: N
authors.lastname: Vijayakumar
authors.affiliation: Department of Psychology, University of Oregon, Eugene, Oregon.|Melbourne School of Psychological Sciences, University of Melbourne, Melbourne, Victoria, Australia.|Orygen Youth Health Research Centre, Centre for Youth Mental Health, University of Melbourne, Melbourne, Australia.
authors.forename: Nicholas B
authors.initials: NB
authors.lastname: Allen
authors.affiliation: Centre for Social and Early Emotional Development, School of Psychology, Deakin University, Melbourne, Australia.
authors.forename: George
authors.initials: G
authors.lastname: Youssef
authors.affiliation: Department of Psychology, University of Washington, Seattle.
authors.forename: Meg
authors.initials: M
authors.lastname: Dennison
authors.affiliation: Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, Melbourne, Australia.|Monash Clinical and Imaging Neuroscience, School of Psychological Sciences and Monash Biomedical Imaging Facility, Monash University, Melbourne, Australia.
authors.forename: Murat
authors.initials: M
authors.lastname: Yücel
authors.affiliation: Department of Psychology, University of Oregon, Eugene, Oregon.|Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, Melbourne, Australia.
authors.forename: Julian G
authors.initials: JG
authors.lastname: Simmons
authors.affiliation: Department of Psychology, University of Oregon, Eugene, Oregon.|Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, Melbourne, Australia.
authors.forename: Sarah
authors.initials: S
authors.lastname: Whittle
mesh_terms: D000293:Adolescent; D041923:Adolescent Development; D002540:Cerebral Cortex / Q000000981:diagnostic imaging* / Q000254:growth & development*; D002648:Child; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size; D015203:Reproducibility of Results; D012727:Sex Characteristics; D055815:Young Adult
keywords: FreeSurfer; brain structure; cortical development; neurodevelopment; sex differences