title: Sexual Dimorphism in White Matter Developmental Trajectories Using Tract-Based Spatial Statistics.
abstract: Increasing evidence is emerging for sexual dimorphism in the trajectory of white matter development in children assessed using volumetric magnetic resonance imaging (MRI) and more recently diffusion MRI. Recent studies using diffusion MRI have examined cohorts with a wide age range (typically between 5 and 30 years) showing focal regions of differential diffusivity and fractional anisotropy (FA) and have implicated puberty as a possible contributory factor. To further investigate possible dimorphic trajectories in a young cohort, presumably closer to the expected onset of puberty, we used tract-based spatial statistics to investigate diffusion metrics. The cohort consisted of 23 males and 30 females between the ages of 8 and 16 years. Differences in diffusion metrics were corrected for age, total brain volume, and full scale IQ. In contrast to previous studies showing focal differences between males and females, widespread sexually dimorphic trajectories in structural white matter development were observed. These differences were characterized by more advanced development in females compared to males indicated by lower mean diffusivity, radial and axial diffusivity, and higher FA in females. This difference appeared to be larger at lower ages (8-9 years) with diffusion measures from males and females tending to converge between 10 and 14 years of age. Males showed a steeper slope for age-diffusion metric correlations compared to females, who either did not correlate with age or correlated in fewer regions. Further studies are now warranted to determine the role of hormones on the observed differences, particularly in 8-9-year-old children.
authors.affiliation: 1 UCL Institute of Child Health , London, United Kingdom .
authors.forename: Kiran K
authors.initials: KK
authors.lastname: Seunarine
authors.affiliation: 1 UCL Institute of Child Health , London, United Kingdom .
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Clayden
authors.affiliation: 1 UCL Institute of Child Health , London, United Kingdom .|2 Cluster "Languages of Emotion", Freie Universität Berlin , Berlin, Germany .
authors.forename: Sebastian
authors.initials: S
authors.lastname: Jentschke
authors.affiliation: 1 UCL Institute of Child Health , London, United Kingdom .|3 School of Medicine, University of Castilla-La Mancha , Albacete, Spain .
authors.forename: Monica
authors.initials: M
authors.lastname: Muñoz
authors.affiliation: 1 UCL Institute of Child Health , London, United Kingdom .|4 Child Neuropsychology, Murdoch Childrens Research Institute , Melbourne, Australia .
authors.forename: Janine M
authors.initials: JM
authors.lastname: Cooper
authors.affiliation: 1 UCL Institute of Child Health , London, United Kingdom .|5 Division of Psychology and Language Sciences, Research Department of Cognitive, Perceptual, and Brain Sciences, Institute of Behavioral Neuroscience, University College London , London, United Kingdom .
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Chadwick
authors.affiliation: 6 Great Ormond Street Hospital for Children , London, United Kingdom .
authors.forename: Tina
authors.initials: T
authors.lastname: Banks
authors.affiliation: 1 UCL Institute of Child Health , London, United Kingdom .
authors.forename: Faraneh
authors.initials: F
authors.lastname: Vargha-Khadem
authors.affiliation: 1 UCL Institute of Child Health , London, United Kingdom .
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Clark
mesh_terms: D000293:Adolescent; D016880:Anisotropy; D002648:Child; D056324:Diffusion Tensor Imaging / Q000379:methods; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000378:metabolism*; D009415:Nerve Net / Q000254:growth & development*; D012727:Sex Characteristics; D046468:Sexual Development; D066127:White Matter / Q000254:growth & development*
keywords: brain development; diffusion tensor imaging; gender differences; puberty; tract-based spatial statistics; white matter