title: Fiber geometry in the corpus callosum in schizophrenia: evidence for transcallosal misconnection.
abstract: BACKGROUND
  Structural abnormalities in the callosal fibers connecting the heteromodal association areas of the prefrontal and temporoparietal cortices bilaterally have been suggested to play a role in the etiology of schizophrenia.
  
  
  OBJECTIVE
  To investigate for geometric abnormalities in these callosal fibers in schizophrenia patients by using a novel Diffusion-Tensor Imaging (DTI) metric of fiber geometry named Shape-Normalized Dispersion (SHD).
  
  
  METHODS
  DTIs (3T, 51 gradient directions, 1.7mm isotropic voxels) were acquired from 26 schizophrenia patients and 23 matched healthy controls. The prefrontal and temporoparietal fibers of the corpus callosum were extracted by means of whole-brain tractography, and their mean SHD calculated.
  
  
  RESULTS
  The schizophrenia patients exhibited subnormal levels of SHD in the prefrontal callosal fibers when controlling for between-group differences in Fractional Anisotropy. Reduced SHD could reflect either irregularly turbulent or inhomogeneously distributed fiber trajectories in the corpus callosum.
  
  
  CONCLUSIONS
  The results suggest that the transcallosal misconnectivity thought to be associated with schizophrenia could reflect abnormalities in fiber geometry. These abnormalities in fiber geometry could potentially be underpinned by neurodevelopmental irregularities.
authors.affiliation: Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA. whitford@bwh.harvard.edu
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Whitford
authors.forename: Peter
authors.initials: P
authors.lastname: Savadjiev
authors.forename: Marek
authors.initials: M
authors.lastname: Kubicki
authors.forename: Lauren J
authors.initials: LJ
authors.lastname: O'Donnell
authors.forename: Douglas P
authors.initials: DP
authors.lastname: Terry
authors.forename: Sylvain
authors.initials: S
authors.lastname: Bouix
authors.forename: Carl-Fredrik
authors.initials: CF
authors.lastname: Westin
authors.forename: Jason S
authors.initials: JS
authors.lastname: Schneiderman
authors.forename: Laurel
authors.initials: L
authors.lastname: Bobrow
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Rausch
authors.forename: Margaret
authors.initials: M
authors.lastname: Niznikiewicz
authors.forename: Paul G
authors.initials: PG
authors.lastname: Nestor
authors.forename: Christos
authors.initials: C
authors.lastname: Pantelis
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Wood
authors.forename: Robert W
authors.initials: RW
authors.lastname: McCarley
authors.forename: Martha E
authors.initials: ME
authors.lastname: Shenton
mesh_terms: D000328:Adult; D001931:Brain Mapping; D016022:Case-Control Studies; D003337:Corpus Callosum / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D009434:Neural Pathways / Q000503:physiopathology; D012559:Schizophrenia / Q000473:pathology*; D055815:Young Adult