title: Longitudinal characterization of white matter maturation during adolescence.
abstract: BACKGROUND
  Late adolescence is comprised of considerable developmental transitions, though brain maturational changes during this period are subtle and difficult to quantitatively evaluate from standard brain imaging acquisitions. To date, primarily cross-sectional studies have characterized typical developmental changes during adolescence, but these processes need further description within a longitudinal framework.
  
  
  METHODS
  To assess the developmental trajectory of typical white matter development, we examined 22 healthy adolescents with serial diffusion tensor images (DTI) collected at a mean age of 17.8 years and 16-months later. Diffusion parameters fractional anisotropy, and mean, radial, and axial diffusivity were subjected to whole-brain voxelwise time point comparisons using tract-based spatial statistics.
  
  
  RESULTS
  At follow-up, adolescents showed a significant change (>or=153 contiguous voxels each at p<0.01) in diffusion properties, including in bilateral superior longitudinal fasciculi, superior corona radiata, anterior thalamic radiations, and posterior limb of the internal capsule. Overall, correlations with cognitive performances suggested behavioral improvement corresponding with white matter changes.
  
  
  CONCLUSIONS
  These longitudinal DTI findings support continued microstructural change in white matter during late adolescence, and suggest ongoing refinement of projection and association fibers into early adulthood.
authors.affiliation: University of California, San Diego, Department of Psychiatry, 9500 Gilman Drive # 151B, La Jolla, CA 92093-151B, USA.
authors.forename: Sunita
authors.initials: S
authors.lastname: Bava
authors.forename: Rachel
authors.initials: R
authors.lastname: Thayer
authors.forename: Joanna
authors.initials: J
authors.lastname: Jacobus
authors.forename: Megan
authors.initials: M
authors.lastname: Ward
authors.forename: Terry L
authors.initials: TL
authors.lastname: Jernigan
authors.forename: Susan F
authors.initials: SF
authors.lastname: Tapert
mesh_terms: D000293:Adolescent; D016880:Anisotropy; D001921:Brain / Q000033:anatomy & histology* / Q000254:growth & development*; D001931:Brain Mapping; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D055815:Young Adult