The FMRI Study Of Brain Inhibitory Control Function On The Former Heroin Users Receiving Methadone Maintenance Treatment

ObjectiveInhibitory control function deficit were observed in heroin dependent patients, methadonemaintenance treatment was the main method for the treatment of heroin dependence, whichhave the significant efforts on alleviating heroin withdrawal symptoms and reducing craving,however, methadone can also cause the impairment of working memory, decision making,attention and other cognitive function. What is the effects do methadone did on inhibitorycontrol function of heroin dependent patients was still being debated, meanwhile, the higherrate of relapse under MMT was the main difficulty in heroin dependence treatment，whether the inhibitory control function was associate with relapse was still need furtherresearch. The aim of this study was explore the effect of methadone on inhibitory controlfunction and the relationship between the inhibitory function and relapse by functionalmagnetic resonance imaging techniques, and the go-nogo task was emploied.Methods1、Thirty-seven Heroin-dependent patients under MMT were divided into short-term MMT（SMMT） group （n=19, duration of MMT〈2years） and long-term MMT （LMMT） group （n=18, duration of MMT≥2years） according to the duration of MMT. fMRI wasperformed in all patients while they were executing an event-related go/nogo task. ThefMRI data were analyzed using statistical parametric mapping (SPM)8software, get allthe participants brain activation map and the groups of brain activation map under thecondition of success nogo> go. with the highest t value as the center of a circle,draw aspherical region of interest for the significant differences in brain regional activity,radius2mm. Extracting subjects the signal intensity of ROI activation, partial correlation analysiswith Methadone related variables.2、Continuous follow-up of6months for the experimental one subjects，according towhether relapse was divided into abstinence group (AB,12subjects) and relapse group(RE,17subjects). fMRI was performed in all patients while they were executing anevent-related go/nogo task. The fMRI data were analyzed using statistical parametricmapping (SPM)8software, get all the participants brain activation map and the groups ofbrain activation map under the condition of success nogo> go. with the highest t value asthe center of a circle,draw a spherical region of interest for the significant differences inbrain regional activity,radius2mm. Extracting subjects the signal intensity of ROIactivation, partial correlation analysis with methadone and heroin related variables.Results1、Compared with LMMT group, stronger activation in the dorsal anterior cingulate cortex（dACC） in response inhibition condition was demonstrated in SMMT group.Meanwhile, the activation of dACC was negatively associated with the total dose ofmethadone used （r=-0.58, P=0.001）.2、Compared with RE group, the abstinence demonstrated stronger activation in the leftpre-supplementary motor area, thalamus, right middle cingulate cortex and cerebellum.There was no correlation between these activations in brain areas associated with heroinand methadone variables.Conclusion1、This study compare the short and long-term MMT patients, we found that long-termMMT can injure the inhibitory control of former Heroin dependents, which may be one ofthe relevant factors related to high relapse rate in patients receiving MMT. 2、This study compare the abstinence and relapse heroin addicts, we found that theinhibitory function was better in abstinence, and which may be used as the neurobiologicalfactors in relapse prediction.