title: Abnormal resting-state activities and functional connectivities of the anterior and the posterior cortexes in medication-naïve patients with obsessive-compulsive disorder.
abstract: BACKGROUND
  Obsessive-compulsive disorder (OCD) is a mental illness characterized by the loss of control. Because the cingulate cortex is believed to be important in executive functions, such as inhibition, we used functional magnetic resonance imaging (fMRI) techniques to examine whether and how activity and functional connectivity (FC) of the cingulate cortex were altered in drug-naïve OCD patients.
  
  
  METHODS
  Twenty-three medication-naïve OCD patients and 23 well-matched healthy controls received fMRI scans in a resting state. Functional connectivities of the anterior cingulate (ACC) and the posterior cingulate (PCC) to the whole brain were analyzed using correlation analyses based on regions of interest (ROI) identified by the fractional amplitude of low-frequency fluctuation (fALFF). Independent Component Analysis (ICA) was used to identify the resting-state sub-networks.
  
  
  RESULTS
  fALFF analysis found that regional activity was increased in the ACC and decreased in the PCC in OCD patients when compared to controls. FC of the ACC and the PCC also showed different patterns. The ACC and the PCC were found to belong to different resting-state sub-networks in ICA analysis and showed abnormal FC, as well as contrasting correlations with the severity of OCD symptoms.
  
  
  CONCLUSIONS
  Activity of the ACC and the PCC were increased and decreased, respectively, in the medication-naïve OCD patients compared to controls. Different patterns in FC were also found between the ACC and the PCC with respect to these two groups. These findings implied that the cardinal feature of OCD, the loss of control, may be attributed to abnormal activities and FC of the ACC and the PCC.
authors.affiliation: Department of Psychiatry, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, PRC.
authors.forename: Yuqi
authors.initials: Y
authors.lastname: Cheng
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
authors.forename: Binbin
authors.initials: B
authors.lastname: Nie
authors.forename: Chunrong
authors.initials: C
authors.lastname: Luo
authors.forename: Tao
authors.initials: T
authors.lastname: Yang
authors.forename: Haijun
authors.initials: H
authors.lastname: Li
authors.forename: Jin
authors.initials: J
authors.lastname: Lu
authors.forename: Lin
authors.initials: L
authors.lastname: Xu
authors.forename: Baoci
authors.initials: B
authors.lastname: Shan
authors.forename: Xiufeng
authors.initials: X
authors.lastname: Xu
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods; D002540:Cerebral Cortex / Q000503:physiopathology*; D005260:Female; D006179:Gyrus Cinguli / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009434:Neural Pathways / Q000503:physiopathology*; D009771:Obsessive-Compulsive Disorder / Q000503:physiopathology*