title: Decreased functional connectivity in the language regions in bipolar patients during depressive episodes but not remission.
abstract: BACKGROUND
  Retardation of thought is a crucial clinical feature in patients with bipolar depression, characterized by dysfunctional semantic processing and language communication. However, the underlying neuropathological mechanisms remain largely unknown. The objective of this study was to evaluate the disruption in resting-state functional connectivity in 90 different brain regions during the depressive episodes of bipolar disorder and during disease remission.
  
  
  METHODS
  Applying the whole brain and language regions of interest methods to the resting-state functional magnetic resonance imaging data, we explored the discrepancies in 90 brain regions' functional connectivity in 42 patients with bipolar disorder - 23 experiencing a depressive episode and 19 in remission - and 28 healthy controls matched for gender, age, and education.
  
  
  RESULTS
  Bipolar depressive patients had significantly reduced connectivity strength in the language regions relative to healthy controls. Specifically, the affected regions included the left triangular part of the inferior frontal gyrus, left opercular part of the inferior frontal gyrus, left middle temporal gyrus, and left angular gyrus. However, no significant differences in these regions were observed between bipolar patients in remission and healthy controls. Furthermore, the decreased connectivity strength between the left middle temporal gyrus and right lingual gyrus showed significant positive correlation with the scores on the Hamilton Depression Rating Scale.
  
  
  CONCLUSIONS
  Bipolar depressive patients received treatment of benzodiazepines, which may confound the findings.
  
  
  CONCLUSIONS
  Our results illustrated that connectivity disturbances in the language regions may change depending on the disease phase of bipolar disorder.
authors.affiliation: Institute of Mental Health, Second Xiangya Hospital of Central South University, Changsha, China; Institute of Mental Health, Inner Mongolia Autonomous Region, Hohhot, China.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Lv
authors.affiliation: School of Mathematics and Computational Science, Sun Yat-sen University, Guangzhou, China.
authors.forename: Wuhong
authors.initials: W
authors.lastname: Lin
authors.affiliation: Institute of Mental Health, Second Xiangya Hospital of Central South University, Changsha, China.
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Xue
authors.affiliation: Medical Psychological Institute, Second Xiangya Hospital, Central South University, Changsha, Hunan, China.
authors.forename: Weidan
authors.initials: W
authors.lastname: Pu
authors.affiliation: Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA.
authors.forename: Qing
authors.initials: Q
authors.lastname: Yang
authors.affiliation: Institute of Mental Health, Second Xiangya Hospital of Central South University, Changsha, China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Huang
authors.affiliation: Institute of Mental Health, Second Xiangya Hospital of Central South University, Changsha, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhou
authors.affiliation: School of Mathematics and Computational Science, Sun Yat-sen University, Guangzhou, China; Key Laboratory of Computational Science, Sun Yat-sen University, Guangzhou, China. Electronic address: mcsylh@mail.sysu.edu.cn.
authors.forename: Lihua
authors.initials: L
authors.lastname: Yang
authors.affiliation: Institute of Mental Health, Second Xiangya Hospital of Central South University, Changsha, China; State Key Laboratories of Medical Genetics, Central South University, Changsha, China. Electronic address: zningl@163.com.
authors.forename: Zhening
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000503:physiopathology* / Q000523:psychology; D065711:Broca Area / Q000503:physiopathology*; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000503:physiopathology; D003863:Depression / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged
keywords: Bipolar disorder; Functional connectivity; Language regions; Resting-state fMRI; Retardation of thought