title: Demonstration of decreased gray matter concentration in the midbrain encompassing the dorsal raphe nucleus and the limbic subcortical regions in major depressive disorder: an optimized voxel-based morphometry study.
abstract: BACKGROUND
  Previous neuroimaging studies in patients with major depressive disorder (MDD) have reported changes in several brain areas, such as the medial and dorsolateral orbital cortex, amygdala, hippocampus, and basal ganglia. However, the results of these studies are inconsistent, and relatively few studies have been conducted using voxel-based morphometry (VBM) to detect gray matter concentration (GMC) abnormalities in patients with MDD.
  
  
  METHODS
  We examined 47 MDD patients and 51 healthy controls to investigate structural abnormalities using a 1.5 T magnetic resonance imaging system, which was normalized to a customized T1 template and segmented with optimized VBM. Analysis of covariance with age and gender as covariates was adopted for the VBM statistics; the level of statistical significance was set at P<0.05 for the corrected false discovery rate.
  
  
  RESULTS
  Decreased GMC was found in MDD patients in the bilateral amygdalae, hippocampi, fusiform gyri, lingual gyri, insular gyri, middle-superior temporal gyri, thalami, cingulate gyri, the central lobule of the cerebellum, and the midbrain encompassing the dorsal raphe nuclei (DRN).
  
  
  CONCLUSIONS
  Half of our study subjects were taking antidepressants. This may have been a potential confounding factor if any of the medications affected cortical volume.
  
  
  CONCLUSIONS
  The results suggest that the GMC of several regions associated with emotion regulation was lower in MDD patients. In particular, we found decreased GMC in the DRN. These findings may provide a better understanding of the anatomical properties of the neural mechanisms underlying the etiology of MDD.
authors.affiliation: Department of Psychiatry, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Hwa-Young
authors.initials: HY
authors.lastname: Lee
authors.forename: Woo Suk
authors.initials: WS
authors.lastname: Tae
authors.forename: Ho-Kyoung
authors.initials: HK
authors.lastname: Yoon
authors.forename: Byeong-Taek
authors.initials: BT
authors.lastname: Lee
authors.forename: Jong-Woo
authors.initials: JW
authors.lastname: Paik
authors.forename: Kyu-Ri
authors.initials: KR
authors.lastname: Son
authors.forename: Yu-Whan
authors.initials: YW
authors.lastname: Oh
authors.forename: Min-Soo
authors.initials: MS
authors.lastname: Lee
authors.forename: Byung-Joo
authors.initials: BJ
authors.lastname: Ham
mesh_terms: D000328:Adult; D001921:Brain; D002540:Cerebral Cortex / Q000473:pathology*; D003866:Depressive Disorder; D003865:Major Depressive Disorder / Q000473:pathology* / Q000503:physiopathology; D004644:Emotions; D005260:Female; D005625:Frontal Lobe; D006179:Gyrus Cinguli / Q000473:pathology*; D006624:Hippocampus; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data; D008279:Magnetic Resonance Imaging; D008297:Male; D008636:Mesencephalon; D008875:Middle Aged; D011903:Raphe Nuclei; D013788:Thalamus