title: Impaired structural connectivity of socio-emotional circuits in autism spectrum disorders: a diffusion tensor imaging study.
abstract: BACKGROUND
  Abnormal white matter development may disrupt integration within neural circuits, causing particular impairments in higher-order behaviours. In autism spectrum disorders (ASDs), white matter alterations may contribute to characteristic deficits in complex socio-emotional and communication domains. Here, we used diffusion tensor imaging (DTI) and tract based spatial statistics (TBSS) to evaluate white matter microstructure in ASD.
  
  
  RESULTS
  DTI scans were acquired for 19 children and adolescents with ASD (∼8-18 years; mean 12.4±3.1) and 16 age and IQ matched controls (∼8-18 years; mean 12.3±3.6) on a 3T MRI system. DTI values for fractional anisotropy, mean diffusivity, radial diffusivity and axial diffusivity, were measured. Age by group interactions for global and voxel-wise white matter indices were examined. Voxel-wise analyses comparing ASD with controls in: (i) the full cohort (ii), children only (≤12 yrs.), and (iii) adolescents only (>12 yrs.) were performed, followed by tract-specific comparisons. Significant age-by-group interactions on global DTI indices were found for all three diffusivity measures, but not for fractional anisotropy. Voxel-wise analyses revealed prominent diffusion measure differences in ASD children but not adolescents, when compared to healthy controls. Widespread increases in mean and radial diffusivity in ASD children were prominent in frontal white matter voxels. Follow-up tract-specific analyses highlighted disruption to pathways integrating frontal, temporal, and occipital structures involved in socio-emotional processing.
  
  
  CONCLUSIONS
  Our findings highlight disruption of neural circuitry in ASD, particularly in those white matter tracts that integrate the complex socio-emotional processing that is impaired in this disorder.
authors: Department of Psychiatry, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors: Stephanie H
authors: SH
authors: Ameis
authors: Jin
authors: J
authors: Fan
authors: Conrad
authors: C
authors: Rockel
authors: Aristotle N
authors: AN
authors: Voineskos
authors: Nancy J
authors: NJ
authors: Lobaugh
authors: Latha
authors: L
authors: Soorya
authors: A Ting
authors: AT
authors: Wang
authors: Eric
authors: E
authors: Hollander
authors: Evdokia
authors: E
authors: Anagnostou
mesh_terms: D000293:Adolescent; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000503:physiopathology*; D002675:Child, Preschool; D003710:Demography; D056324:Diffusion Tensor Imaging / Q000379:methods*; D004644:Emotions / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009415:Nerve Net / Q000503:physiopathology*; D012919:Social Behavior