title: Regional homogeneity changes in heroin-dependent individuals: resting-state functional MR imaging study.
abstract: OBJECTIVE
  To identify heroin-related modulations of neural activity in the resting state in heroin-dependent individuals (HDIs) by using resting-state functional magnetic resonance (MR) imaging and a regional homogeneity method and to investigate whether these changes of neural activity can be related to duration of heroin use and to decision-making deficits in HDIs.
  
  
  METHODS
  This prospective study was approved by the appropriate ethics committee, and written informed consent was obtained from each participant. Thirty-one HDIs receiving methadone-maintained treatment and 24 control subjects participated. Resting-state functional MR imaging was performed by using a gradient-echo echo-planar imaging sequence. Regional homogeneity was calculated by using software. Voxel-based analysis of the regional homogeneity maps between control and HDI groups was performed with two-sample t tests by using software. Statistical maps were set at P less than .05 and were corrected for multiple comparisons. The Iowa gambling task (IGT) was used to assess participant decision making during uncertainty. Abnormal clusters revealed by group comparison were extracted and correlated with behavioral performance at the IGT and with duration of heroin use.
  
  
  RESULTS
  Regional homogeneity was diminished in the bilateral medial orbitofrontal cortex (OFC), bilateral dorsal medial thalamus, bilateral cuneus, and lingual gyrus in HDIs compared with control subjects. There were negative correlations between mean regional homogeneity in the medial OFC, bilateral cuneus, and lingual gyrus and duration of heroin use. There was a positive correlation between mean regional homogeneity in the medial OFC and performance level at the IGT.
  
  
  CONCLUSIONS
  The present study reveals resting-state abnormalities in HDIs that may lead to further improvement of the understanding of the neural substrates of cognitive impairment in HDIs.
authors.affiliation: Medical Imaging Centre, Nanfang Hospital, Southern Medical University, 1838 Guangzhou Ave North, Guangzhou 510515, People's Republic of China.
authors.forename: Ying-Wei
authors.initials: YW
authors.lastname: Qiu
authors.forename: Lu-Jun
authors.initials: LJ
authors.lastname: Han
authors.forename: Xiao-Fei
authors.initials: XF
authors.lastname: Lv
authors.forename: Gui-Hua
authors.initials: GH
authors.lastname: Jiang
authors.forename: Jun-Zhang
authors.initials: JZ
authors.lastname: Tian
authors.forename: Fu-Zhen
authors.initials: FZ
authors.lastname: Zhuo
authors.forename: Huan-Huan
authors.initials: HH
authors.lastname: Su
authors.forename: Chu-Lan
authors.initials: CL
authors.lastname: Lin
authors.forename: Xue-Lin
authors.initials: XL
authors.lastname: Zhang
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping / Q000379:methods; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003657:Decision Making; D005260:Female; D006556:Heroin Dependence / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology*; D011446:Prospective Studies; D018709:Statistics, Nonparametric; D013647:Task Performance and Analysis