title: Aberrant default-mode functional and structural connectivity in heroin-dependent individuals.
abstract: BACKGROUND
  Little is known about connectivity within the default mode network (DMN) in heroin-dependent individuals (HDIs). In the current study, diffusion-tensor imaging (DTI) and resting-state functional MRI (rs-fMRI) were combined to investigate both structural and functional connectivity within the DMN in HDIs.
  
  
  METHODS
  Fourteen HDIs and 14 controls participated in the study. Structural (path length, tracts count, (fractional anisotropy) FA and (mean diffusivity) MD derived from DTI tractography)and functional (temporal correlation coefficient derived from rs-fMRI) DMN connectivity changes were examined in HDIs. Pearson correlation analysis was performed to compare the structural/functional indices and duration of heroin use/Iowa gambling task(IGT) performance in HDIs.
  
  
  RESULTS
  HDIs had lower FA and higher MD in the tract connecting the posterior cingulate cortex/precuneus (PCC/PCUN) to right parahippocampal gyrus (PHG), compared to the controls. HDIs also had decreased FA and track count in the tract connecting the PCC/PCUN and medial prefrontal cortex (MPFC), as well as decreased functional connectivity between the PCC/PCUN and bilateral PHG and MPFC, compared to controls. FA values for the tract connecting PCC/PCUN to the right PHG and connecting PCC/PCUN to the MPFC were negatively correlated to the duration of heroin use. The temporal correlation coefficients between the PCC/PCUN and the MPFC, and the FA values for the tract connecting the PCC/PCUN to the MPFC were positively correlated to IGT performance in HDIs.
  
  
  CONCLUSIONS
  Structural and functional connectivity within the DMN are both disturbed in HDIs. This disturbance progresses as duration of heroin use increases and is related to deficits in decision making in HDIs.
authors: Department of Medical Imaging Center, Nanfang Hospital, Southern Medial University, Guangzhou, PR China.
authors: Xiaofen
authors: X
authors: Ma
authors: Department of Medical Imaging, Guangdong No. 2 Provincial People's Hospital, Guangzhou, PR China.
authors: Yingwei
authors: Y
authors: Qiu
authors: Department of Medical Imaging, Guangdong No. 2 Provincial People's Hospital, Guangzhou, PR China.
authors: Junzhang
authors: J
authors: Tian
authors: Center for Cognition and Brain Disorders, Hangzhou Normal University, Hangzhou, PR China; Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Hangzhou, PR China.
authors: Jinhui
authors: J
authors: Wang
authors: Department of Medical Imaging, Guangdong No. 2 Provincial People's Hospital, Guangzhou, PR China.
authors: Shumei
authors: S
authors: Li
authors: Department of Medical Imaging, Guangdong No. 2 Provincial People's Hospital, Guangzhou, PR China.
authors: Wenfeng
authors: W
authors: Zhan
authors: Department of Medical Imaging Center, Nanfang Hospital, Southern Medial University, Guangzhou, PR China; Department of Medical Imaging, Guangdong No. 2 Provincial People's Hospital, Guangzhou, PR China.
authors: Tianyue
authors: T
authors: Wang
authors: Department of Medical Imaging, Guangdong No. 2 Provincial People's Hospital, Guangzhou, PR China.
authors: Shaoqing
authors: S
authors: Zeng
authors: Department of Medical Imaging, Guangdong No. 2 Provincial People's Hospital, Guangzhou, PR China.
authors: Guihua
authors: G
authors: Jiang
authors: Department of Medical Imaging Center, Nanfang Hospital, Southern Medial University, Guangzhou, PR China.
authors: Yikai
authors: Y
authors: Xu
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology / Q000502:physiology; D001931:Brain Mapping; D016022:Case-Control Studies; D056324:Diffusion Tensor Imaging; D006179:Gyrus Cinguli / Q000000981:diagnostic imaging / Q000473:pathology / Q000502:physiology; D003932:Heroin / Q000009:adverse effects* / Q000652:urine; D006556:Heroin Dependence / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020534:Parahippocampal Gyrus / Q000000981:diagnostic imaging / Q000473:pathology / Q000502:physiology; D011859:Radiography
chemical_list: D003932:Heroin