title: Limbic white matter microstructure plasticity reflects recovery from depression.
abstract: BACKGROUND
  White matter microstructure alterations of limbic and reward pathways have been reported repeatedly for depressive episodes in major depressive disorder (MDD) and bipolar disorder (BD). However, findings during remission are equivocal. It was the aim of this study to investigate if white matter microstructure changes during the time course of clinical remission.
  
  
  METHODS
  Fifteen depressed patients (11 MDD, 4 BD) underwent diffusion-weighted MRI both during depression, and during remission following successful antidepressive treatment (average time interval between scans = 6 months). Fractional anisotropy (FA) was sampled along reconstructions of the supero-lateral medial forebrain bundle (slMFB), the cingulum bundle (CB), the uncinate fasciculus (UF), the parahippocampal cingulum (PHC) and the fornix. Repeated measures ANCOVAs controlling for the effect of age were calculated for each tract.
  
  
  RESULTS
  There was a significant main effect of time (inter-scan interval) for mean-FA for the right CB and for the left PHC. For both pathways there was a significant time × age interaction. In the right CB, FA increased in younger patients, while FA decreased in older patients. In the left PHC, a reverse pattern was seen. FA changes in the right CB correlated positively with symptom reductions. Mean-FA of UF, slMFB and fornix did not change between the two time points.
  
  
  CONCLUSIONS
  All patients were medicated, sample size, and lack of control group.
  
  
  CONCLUSIONS
  Right CB and left PHC undergo age-dependent plastic changes during the course of remission and may serve as a state marker in depression. UF, slMFB and FO microstructure remains stable.
authors.affiliation: Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, United Kingdom; University Hospital of Psychiatry, University of Bern, Bern, Switzerland. Electronic address: brachtt@cardiff.ac.uk.
authors.forename: Tobias
authors.initials: T
authors.lastname: Bracht
authors.affiliation: Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, United Kingdom.
authors.forename: Derek K
authors.initials: DK
authors.lastname: Jones
authors.affiliation: University Hospital of Psychiatry, University of Bern, Bern, Switzerland.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Müller
authors.affiliation: Institute of Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Roland
authors.initials: R
authors.lastname: Wiest
authors.affiliation: University Hospital of Psychiatry, University of Bern, Bern, Switzerland.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Walther
mesh_terms: D000328:Adult; D000375:Aging / Q000502:physiology; D016880:Anisotropy; D001714:Bipolar Disorder / Q000473:pathology / Q000523:psychology; D003866:Depressive Disorder / Q000473:pathology* / Q000523:psychology; D003865:Major Depressive Disorder / Q000473:pathology* / Q000523:psychology; D038524:Diffusion Magnetic Resonance Imaging; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008032:Limbic System / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000502:physiology*; D011569:Psychiatric Status Rating Scales; D020127:Recovery of Function; D012201:Reward; D066127:White Matter / Q000473:pathology*
keywords: Bipolar disorder; Diffusion tensor imaging; Major depressive disorder; Neuroplasticity; Remission; Reward system