title: Sex differences in adolescent white matter architecture.
abstract: BACKGROUND
  Sex-specific trajectories in white matter development during adolescence may help explain cognitive and behavioral divergences between males and females. Knowledge of sex differences in typically developing adolescents can provide a basis for interpreting sexual dimorphisms in abilities and actions.
  
  
  METHODS
  We examined 58 healthy adolescents (12-14years of age) with diffusion tensor imaging (DTI). Diffusion parameters fractional anisotropy (FA), and mean (MD), radial (RD), and axial diffusivities (AD) were subjected to whole-brain voxel-wise group comparisons using tract-based spatial statistics. Sex differences in white matter microstructure were examined in relation to pubertal development.
  
  
  RESULTS
  Early adolescent females (n=29) evidenced higher FA in the right superior corona radiata, higher FA and AD in bilateral corticospinal tracts (≥164μl, p<.01), and lower MD in the right inferior longitudinal fasciculus (ILF) and left forceps major (≥164μl, p<.01) than age-matched males (n=29). Males did not show any areas of higher FA or lower MD than females, but had higher AD in the right superior longitudinal fasciculus, ILF, and forceps minor (≥ 164μl, p<.01). Pubertal stage did not account for sex disparities.
  
  
  CONCLUSIONS
  In early adolescence, females' motor tracts may reflect widespread changes, while males may undergo relatively more microstructural change in projection and association fibers.
authors.affiliation: VA San Diego Healthcare System, Psychology Service (116B), 3350 La Jolla Village Drive, San Diego, CA 92126, USA.
authors.forename: Sunita
authors.initials: S
authors.lastname: Bava
authors.forename: Veronique
authors.initials: V
authors.lastname: Boucquey
authors.forename: Diane
authors.initials: D
authors.lastname: Goldenberg
authors.forename: Rachel E
authors.initials: RE
authors.lastname: Thayer
authors.forename: Megan
authors.initials: M
authors.lastname: Ward
authors.forename: Joanna
authors.initials: J
authors.lastname: Jacobus
authors.forename: Susan F
authors.initials: SF
authors.lastname: Tapert
mesh_terms: D000293:Adolescent; D000375:Aging / Q000502:physiology; D001921:Brain / Q000033:anatomy & histology* / Q000254:growth & development; D002648:Child; D003627:Data Interpretation, Statistical; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008297:Male; D008603:Mental Health; D009483:Neuropsychological Tests; D011627:Puberty / Q000502:physiology; D011712:Pyramidal Tracts / Q000033:anatomy & histology / Q000254:growth & development; D012727:Sex Characteristics