title: Dissociation of glutamate and cortical thickness is restricted to regions subserving trait but not state markers in major depressive disorder.
abstract: BACKGROUND
  The anterior cingulate cortex (ACC) plays an important role in the neuropathology of major depressive disorder (MDD). So far, the effect of local cortical alteration on metabolites in multiple subdivisions of ACC has not been studied. We aimed to investigate structural and biochemical changes and their relationship in the pregenual ACC (pgACC), dorsal ACC (dACC) in MDD.
  
  
  METHODS
  We obtained magnetic resonance spectroscopy (MRS) in two investigated regions for 24 depressed patients and matched controls. In each region, cortical thickness (CTh) was calculated within a template mask based on its MRS voxel. We investigated neurotransmitter concentrations of Glx, N-acetyl aspartate (NAA), and myo-inositol (m-Ins) in two investigated regions, as well as their relationships with CTh in depressed individuals and healthy controls.
  
  
  RESULTS
  Patients showed significantly lower cortical thickness in dACC compared to controls. Glx in dACC significantly correlated with CTh in healthy controls but not MDD patients, while NAA and CTh in dACC significantly correlated in both groups. A marginal decrease of Glx in pgACC was found in the subgroup of more severely depressive patients, compared to the mildly depressed patients.
  
  
  CONCLUSIONS
  Modest sample size and lack of episodes of depression may limit the generalizability of our findings.
  
  
  CONCLUSIONS
  Our results indicate an abolished CTh-MRS relation in dACC-associated with structural decline-but not in pgACC, where acute MRS alterations prevailed. Our study provides the first evidence of a neurochemical basis explaining some of the inter-individual variability in CTh in MDD.
authors.affiliation: Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany.
authors.forename: Meng
authors.initials: M
authors.lastname: Li
authors.affiliation: Department of Psychiatry and Psychotherapy, Otto-von-Guericke University, Magdeburg, Germany; Leibniz Institute for Neurobiology, Magdeburg, Germany; Center of Behavioral Brain Sciences, Otto-von-Guericke University, Magdeburg, Germany.
authors.forename: Coraline D
authors.initials: CD
authors.lastname: Metzger
authors.affiliation: State Key Laboratory of Management and Control for Complex Systems, Institute of Automation, Chinese Academy of Sciences, Beijing, China; College of Electronic and Control Engineering, Beijing University of Technology, Beijing, China.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Psychology, Northwestern University, United States.
authors.forename: Adam
authors.initials: A
authors.lastname: Safron
authors.affiliation: Neuroimaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Marie-José
authors.initials: MJ
authors.lastname: van Tol
authors.affiliation: Leibniz Institute for Neurobiology, Magdeburg, Germany.
authors.forename: Anton
authors.initials: A
authors.lastname: Lord
authors.affiliation: Department of Psychiatry and Psychotherapy, Otto-von-Guericke University, Magdeburg, Germany.
authors.forename: Anna Linda
authors.initials: AL
authors.lastname: Krause
authors.affiliation: Leibniz Institute for Neurobiology, Magdeburg, Germany.
authors.forename: Viola
authors.initials: V
authors.lastname: Borchardt
authors.affiliation: Biomedical Magnetic Resonance, Otto-von-Guericke University, Magdeburg, Germany.
authors.forename: Weiqiang
authors.initials: W
authors.lastname: Dou
authors.affiliation: Department of Psychiatry and Psychotherapy, Otto-von-Guericke University, Magdeburg, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Genz
authors.affiliation: Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany; Center of Behavioral Brain Sciences, Otto-von-Guericke University, Magdeburg, Germany.
authors.forename: Hans-Jochen
authors.initials: HJ
authors.lastname: Heinze
authors.affiliation: State Key Laboratory of Management and Control for Complex Systems, Institute of Automation, Chinese Academy of Sciences, Beijing, China. Electronic address: huiguang.he@ia.ac.cn.
authors.forename: Huiguang
authors.initials: H
authors.lastname: He
authors.affiliation: Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany; Department of Psychiatry and Psychotherapy, Otto-von-Guericke University, Magdeburg, Germany; State Key Laboratory of Management and Control for Complex Systems, Institute of Automation, Chinese Academy of Sciences, Beijing, China; Leibniz Institute for Neurobiology, Magdeburg, Germany; Center of Behavioral Brain Sciences, Otto-von-Guericke University, Magdeburg, Germany. Electronic address: martin.walter@med.ovgu.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Walter
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D003866:Depressive Disorder / Q000378:metabolism; D003865:Major Depressive Disorder / Q000378:metabolism* / Q000473:pathology; D004213:Dissociative Disorders; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism*; D006179:Gyrus Cinguli / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018377:Neurotransmitter Agents / Q000378:metabolism; D009929:Organ Size; D055815:Young Adult
chemical_list: D015415:Biomarkers; D018377:Neurotransmitter Agents; D018698:Glutamic Acid
keywords: Cortical thickness; Glutamate; Major depressive disorder