title: Hearing voices: a role of interhemispheric auditory connectivity?
abstract: OBJECTIVE
  Auditory verbal hallucinations (AVH) are among the most common symptoms in schizophrenia. Earlier studies suggest changes in the structural connectivity of auditory areas involved in the pathophysiology of auditory hallucinations. Combining diffusion tensor imaging (DTI) and fibre tractography provides a unique opportunity to visualize and quantify entire fibre bundles.
  
  
  METHODS
  Fibre tracts connecting homotopic auditory areas via the corpus callosum were identified with DTI in ten first episode paranoid schizophrenia patients and ten healthy controls. Regions of interest were drawn manually, to guide tractography, and fractional anisotropy (FA) - a measure of fibre integrity - was calculated and averaged over the entire tract for each subject.
  
  
  RESULTS
  There was no difference in the FA of the interhemispheric auditory fibres between schizophrenic patients and healthy controls. However, the subgroup of patients hearing conversing voices showed increased FA relative to patients without these symptoms (P = 0.047) and trendwise increased FA relative to healthy controls (P = 0.066). In addition, a trendwise correlation between FA values and AVH symptoms (P = 0.089) was found.
  
  
  CONCLUSIONS
  Our findings suggest that in addition to local deficits in the left auditory cortex and disturbed fronto-temporal connectivity, the interhemispheric auditory pathway might be involved in the pathogenesis of AVH.
authors.affiliation: Department of Psychiatry, Psychiatry Neuroimaging Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA. c.mulert@uke.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Mulert
authors.forename: Valerie
authors.initials: V
authors.lastname: Kirsch
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Whitford
authors.forename: Jorge
authors.initials: J
authors.lastname: Alvarado
authors.forename: Paula
authors.initials: P
authors.lastname: Pelavin
authors.forename: Robert W
authors.initials: RW
authors.lastname: McCarley
authors.forename: Marek
authors.initials: M
authors.lastname: Kubicki
authors.forename: Dean F
authors.initials: DF
authors.lastname: Salisbury
authors.forename: Martha E
authors.initials: ME
authors.lastname: Shenton
mesh_terms: D000328:Adult; D016880:Anisotropy; D001931:Brain Mapping; D003337:Corpus Callosum / Q000503:physiopathology*; D038524:Diffusion Magnetic Resonance Imaging; D056324:Diffusion Tensor Imaging; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006212:Hallucinations / Q000503:physiopathology*; D006801:Humans; D008297:Male; D011569:Psychiatric Status Rating Scales; D012563:Schizophrenia, Paranoid / Q000503:physiopathology*; D013702:Temporal Lobe / Q000503:physiopathology*