Functional MRI Study Of Abnormal Cerebral Functional Connectivity In Heroin Addicts

The technology of functional MRI (fMRI) developed rapidly in recent years, it has been widely applied in neuroscience research . Unlike fMRI wtih task had risen early,fMRI in resting state flourished just until recent five years,and became the hotest method in the brain function study.There is two aspects of brain function study:function segment and function integration.The former is to locate brain function,the latter focuses on the functional connectivity in the brain. The resting-state fMRI is the primary way to study functional connectivity of brain,and very befitting in the cilinical study,due to it’s task-free,noninvasion,repeatablity.The resting-state fMRI has been widely applied in the research about neurological and psychiatric diseases.Brain imaging study on drug addiction mostly adopted task or stimulus activating way in the past.The neural mechanism of drug addiction is involved with the abnormity of functional connectivity in the complex brain networks.The study of drug ddiction with resting-state fMRI just began two yaears ago,present study performed resting-state fMRI in the early-abstinent heroin addicts,with the optimization of subjects selection and data analysis.In the analysis of study data, different regions of interest were used for two aims,the mesolimbic system and the subregions of the basal ganglia-striatum, to explore the abnormity of cerebral functional connectivity in heroin addicts.Additionally,present study used another index,amplitude of low frequency fluctuation(ALFF),to explore the abnormity of resting-state cerebral function in heroin addicts.Lastly,to compare wtih resting-state fMRI data,present study analysed the data form fMRI with drug-related cue stimulation in the early-abstinent heroin addicts,using similar analysis way.The results of present stuy showed,in the heroin addicts,the functional connectivity was increased between ventral tegmental area,striatum in charge of reward and reinforcement, and orbitofrontal cortex,anterior cingulate gyrus in charge of motivation and control.The functional connectivity was decreased between anterior cingulate gyrus in charge of control and orbitofrontal cortex in charge of motivation in the heroin addicts.Different with obsessive-compulsive disorder,in the striatum, heroin addicton showed reduced functional connectivity between ventral, dorsal caudate and orbitofrontal cortex,,but increased functional connectivity between ventral, dorsal putamen and orbitofrontal cortex in present study,which proved the theory about transition of key point form ventral striatum to dorsal striatum in the mechanism of chronic addition.The results of ALFF in present stuy showed there was abnormal acivity in caudate,anterior cingulate gyrus,hippocampus,thalamus,insula,which intensively associated with drug addiction,and it also proved the ability ofALFF to locate the brain region with abnormal function.At last,the abnormal change of functional connectivity in the heroin addicts undergoing drug-relaed cue stimulation were inconsistent with the resting-state data,which might reflect the limitation of resting-state fMRI in functional connectivity study.