The Neural Mechanism Study Of Craving And Automatic Drug-taking Behavior In Heroin Addicts

The craving and automatic drug-taking behaviors of heroin addicts are the basic reasons for the addiction and relapse.Previous studies suggest that the formation of craving and automatic drug-taking behaviors stems from the abnormal activities of four classical neural circuits,including reward circuit,motivation circuit,learning-memory circuit and cognitive control circuit.Previous studies think abnormalities of single neural circuits or brain area result in drug addiction.Later,researchers proposed that these classical neural circuits are not enough to explain complex addictive behavior and how drug related clues induce craving and habitual automatic drug-taking behaviors in heroin addicts.Therefore,this study uses meta-analysis and imaging technique to explore the neural basis of raving and automatic drug-taking behaviors.In Chapter two,this study uses meta-analysis of 19 articles about the resting-state functional connectivity in heroin addicts compared to normal human.The results showed that reward circuit,learning-memory circuit,cognitive control circuit and sensorimotor circuit have a strong functional connectivity with each other,but not motivation circuit.Motivation circuit only has a relationship with reward circuit,learning-memory circuit,cognitive control circuit and sensorimotor circuit when related brain area of motivation circuit is set as region of interests.Thus,this study suggests that the motivation circuit only show its functions in heroin addicts when heroin addicts' drug-taking behavior is blocked.In Chapter three,we use resting-state fMRI and choose bilateral dorsolateral striatum and bilateral Inferior parietal lobule as the region of interest to analyze the neural mechanism of craving and automatic drug-taking behaviors from the perspective of sensori-motor system.So the study recruited 27 heroin addicts and 27 normal healthy subjects to take part in the study.The result shows that the ROI 1(putamen)connected brain regions enhanced Cerebelum_Crus2_R,Occipital_Mid_R,Fusiform_R,Parietal_Sup_L,Parietal_Sup_R,Temporal_Mid_L,Frontal_Sup_Orb_L,Frontal_Inf_Orb_L,Postcentral_R,Frontal_Inf_Tri_L,Precuneus_L and decreased Frontal_Med_Orb_R,Anterior Cingulate_R,Inferior Frontal Gyrus_R,Temporal_Sup_L,Anterior Cingulate_L,Heschl_R,SupraMarginal_R,Cingulum_Mid_L,Frontal_Sup_R,Putamen_L,Frontal_Mid_Orb_R,Frontal_Sup_Medial_L,Frontal_Mid_L,Frontal_Mid_R in heron addicts,compare to normal healthy subjects.The ROI 2(Inferior parietal lobule)connected brain regions enhanced Inferior Frontal Gyrus_L,Temporal_Inf_L,Temporal_Inf_R,Frontal_Mid_R,Occipital_Mid_R,Occipital_Sup_L,Occipital_Inf_L,Postcentral_R,Precentral_L,Precentral_R,and decreased Amygdala_R,Temporal_Sup_R,Putamen_L,Putamen_R,Cingulum_Ant_L,Angular_R,Parietal_Inf_L,Parietal_Sup_R,Frontal_Sup_L,SupraMarginal_R in heron addicts,compare to normal healthy subjects.We conclude that that sensorimotor circuit and reward circuit,motivation circuit,learning-memory circuit,cognitive control circuit work together,and make craving and habitual automatic drug-taking behaviors happen in heroin addicts.