title: Fibre tract analysis using diffusion tensor imaging reveals aberrant connectivity in a rat model of depression.
abstract: Abnormal brain connectivity has been described in depressive disorder. However, these studies are correlational or cross-sectional and their design does not examine causal relationships. We aimed to investigate structural connectivity in a genetic rat model of depression.
  
  
  
  Using diffusion tensor imaging (DTI), we reconstructed white matter tracts and analysed fractional anisotropy (FA) and diffusivity indices (mean, axial and radial) to investigate structural connectivity in fibre tracts implicated in major depression: the corpus callosum, fornix, cingulum and anterior commissures.
  
  
  
  Tractography-based analysis revealed that, compared to Wistar control rats, the Wistar-Kyoto strain (WKY) rat model of depression exhibited decreased connectivity, manifested by decreased FA in the corpus callosum, right and left anterior commissures. A statistical trend of decreased FA was observed in both the right and left cingulum. Increased diffusivity (mean diffusion) was detected in both the corpus callosum and the fornix of WKY rats compared to controls. Voxel-based analysis confirmed differences between WKY and controls in the regions investigated.
  
  
  
  Decreased connectivity in a genetic rat model of depression corroborates the findings in patients suffering from major depression suggesting that the vulnerability for developing depression is mainly polygenic and less likely to be due to childhood adversity per se.
authors.affiliation: a Child and Adolescent Division, Geha Mental Health Center and Sackler School of Medicine , Tel Aviv University , Tel Aviv , Israel.|b Division of Molecular Imaging and Neuropathology, Department of Psychiatry , Columbia University , New York , NY , USA.
authors.forename: Gil
authors.initials: G
authors.lastname: Zalsman
authors.affiliation: c Department of Psychology and the Gonda Brain Research Center , Bar-Ilan University , Ramat-Gan , Israel.
authors.forename: Aron
authors.initials: A
authors.lastname: Weller
authors.affiliation: c Department of Psychology and the Gonda Brain Research Center , Bar-Ilan University , Ramat-Gan , Israel.
authors.forename: Liat
authors.initials: L
authors.lastname: Shbiro
authors.affiliation: a Child and Adolescent Division, Geha Mental Health Center and Sackler School of Medicine , Tel Aviv University , Tel Aviv , Israel.
authors.forename: Ran
authors.initials: R
authors.lastname: Barzilay
authors.affiliation: c Department of Psychology and the Gonda Brain Research Center , Bar-Ilan University , Ramat-Gan , Israel.|d Department of Psychology , Tel Aviv University , Tel Aviv , Israel.
authors.forename: Avihay
authors.initials: A
authors.lastname: Gutman
authors.affiliation: e Research Unit, Geha Mental Health Center, Petah Tikva and Sackler School of Medicine , Tel Aviv University, Tel Aviv and Felsenstein Medical Research Center , Petah Tikva , Israel.
authors.forename: Abraham
authors.initials: A
authors.lastname: Weizman
authors.affiliation: b Division of Molecular Imaging and Neuropathology, Department of Psychiatry , Columbia University , New York , NY , USA.
authors.forename: J John
authors.initials: JJ
authors.lastname: Mann
authors.affiliation: f National Centre for Suicide Research and Prevention of Mental Ill-Health (NASP) , Karolinska Institute , Stockholm , Sweden.
authors.forename: Jerzy
authors.initials: J
authors.lastname: Wasserman
authors.affiliation: f National Centre for Suicide Research and Prevention of Mental Ill-Health (NASP) , Karolinska Institute , Stockholm , Sweden.
authors.forename: Danuta
authors.initials: D
authors.lastname: Wasserman
mesh_terms: D000818:Animals; D066240:Anterior Commissure, Brain / Q000000981:diagnostic imaging*; D003337:Corpus Callosum / Q000000981:diagnostic imaging*; D003865:Major Depressive Disorder / Q000000981:diagnostic imaging*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D004195:Disease Models, Animal; D009434:Neural Pathways / Q000000981:diagnostic imaging*; D051381:Rats; D011921:Rats, Inbred WKY; D066127:White Matter / Q000000981:diagnostic imaging*
keywords: Major depression; animal model; connectivity; diffusion tensor imaging; white matter