title: Disrupted functional connectivity of the hippocampus in patients with hyperthyroidism: evidence from resting-state fMRI.
abstract: OBJECTIVE
  The hippocampus expresses high levels of thyroid hormone receptors, suggesting that hippocampal functions, including cognition and regulation of mood, can be disrupted by thyroid pathology. Indeed, structural and functional alterations within the hippocampus have been observed in hyperthyroid patients. In addition to internal circuitry, hippocampal processing is dependent on extensive connections with other limbic and neocortical structures, but the effects of hyperthyroidism on functional connectivity (FC) with these areas have not been studied. The purpose of this study was to investigate possible abnormalities in the FC between the hippocampus and other neural structures in hyperthyroid patients using resting-state fMRI.
  
  
  METHODS
  Seed-based correlation analysis was performed on resting-state fMRI data to reveal possible differences in hippocampal FC between hyperthyroid patients and healthy controls. Correlation analysis was used to investigate the relationships between the strength of FC in regions showing significant group differences and clinical variables.
  
  
  RESULTS
  Compared to controls, hyperthyroid patients showed weaker FC between the bilateral hippocampus and both the bilateral anterior cingulate cortex (ACC) and bilateral posterior cingulate cortex (PCC), as well as between the right hippocampus and right medial orbitofrontal cortex (mOFC). Disease duration was negatively correlated with FC strength between the bilateral hippocampus and bilateral ACC and PCC. Levels of depression and anxiety were negatively correlated with FC strength between the bilateral hippocampus and bilateral ACC.
  
  
  CONCLUSIONS
  Decreased functional connectivity between the hippocampus and bilateral ACC, PCC, and right mOFC may contribute to the emotional and cognitive dysfunction associated with hyperthyroidism.
authors.affiliation: Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China; Department of Radiology, Sichuan Provincial Corps Hospital, Chinese People's Armed Police Forces, Leshan 614000, China. Electronic address: will.zhang.1111@gmail.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Radiology, Sichuan Provincial Corps Hospital, Chinese People's Armed Police Forces, Leshan 614000, China. Electronic address: xianjun6.liu@gmail.com.
authors.forename: Xianjun
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Radiology, Sichuan Provincial Corps Hospital, Chinese People's Armed Police Forces, Leshan 614000, China. Electronic address: yi.zhang.0833@gmail.com.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China. Electronic address: songlh1023@hotmail.com.
authors.forename: Lingheng
authors.initials: L
authors.lastname: Song
authors.affiliation: Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China. Electronic address: jingminghou@hotmail.com.
authors.forename: Jingming
authors.initials: J
authors.lastname: Hou
authors.affiliation: Department of Endocrinology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China. Electronic address: chenbing3@medmail.com.cn.
authors.forename: Bing
authors.initials: B
authors.lastname: Chen
authors.affiliation: Department of Clinical Psychology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China. Electronic address: sunnusunny0105@gmail.com.
authors.forename: Mei
authors.initials: M
authors.lastname: He
authors.affiliation: Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China. Electronic address: pingc_ddd@sina.com.
authors.forename: Ping
authors.initials: P
authors.lastname: Cai
authors.affiliation: Department of Radiology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China. Electronic address: haitaolii023@gmail.com.
authors.forename: Haitao
authors.initials: H
authors.lastname: Lii
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D006980:Hyperthyroidism / Q000473:pathology*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011594:Psychometrics
keywords: Functional connectivity; Hippocampus; Hyperthyroidism; Magnetic resonance imaging; Resting-state