title: Brain connectivity in body dysmorphic disorder compared with controls: a diffusion tensor imaging study.
abstract: BACKGROUND
  Several neuroimaging studies have investigated brain grey matter in people with body dysmorphic disorder (BDD), showing possible abnormalities in the limbic system, orbitofrontal cortex, caudate nuclei and temporal lobes. This study takes these findings forward by investigating white matter properties in BDD compared with controls using diffusion tensor imaging. It was hypothesized that the BDD sample would have widespread significantly reduced white matter connectivity as characterized by fractional anisotropy (FA).
  
  
  METHODS
  A total of 20 participants with BDD and 20 healthy controls matched on age, gender and handedness underwent diffusion tensor imaging. FA, a measure of water diffusion within a voxel, was compared between groups on a voxel-by-voxel basis across the brain using tract-based spatial statistics within the FSL package.
  
  
  RESULTS
  Results showed that, compared with healthy controls, BDD patients demonstrated significantly lower FA (p < 0.05) in most major white matter tracts throughout the brain, including in the superior longitudinal fasciculus, inferior fronto-occipital fasciculus and corpus callosum. Lower FA levels could be accounted for by increased radial diffusivity as characterized by eigenvalues 2 and 3. No area of higher FA was found in BDD.
  
  
  CONCLUSIONS
  This study provided the first evidence of compromised white matter integrity within BDD patients. This suggests that there are inefficient connections between different brain areas, which may explain the cognitive and emotion regulation deficits within BDD patients.
authors.affiliation: Monash Alfred Psychiatry Research Centre, School of Psychology and Psychiatry, Faculty of Medicine, Nursing and Health Sciences, Monash University and The Alfred Hospital, Melbourne, Australia.
authors.forename: B G
authors.initials: BG
authors.lastname: Buchanan
authors.forename: S L
authors.initials: SL
authors.lastname: Rossell
authors.forename: J J
authors.initials: JJ
authors.lastname: Maller
authors.forename: W L
authors.initials: WL
authors.lastname: Toh
authors.forename: S
authors.initials: S
authors.lastname: Brennan
authors.forename: D J
authors.initials: DJ
authors.lastname: Castle
mesh_terms: D000328:Adult; D016880:Anisotropy; D057215:Body Dysmorphic Disorders / Q000503:physiopathology*; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D056324:Diffusion Tensor Imaging / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D056784:Leukoencephalopathies / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology*