Resting-state Brain Network Study Of Adolescent Smoking Addicts Based On Small-world Attribute Analysis

Smoking is becoming more common among adolescents,whose brains are still at a critical stage of consciousness management and emotional management.Smoking damages the physical and mental health of the addict,so it is necessary to prevent and stop adolescents from smoking.Thanks to the gradual improvement of medical imaging technology,now there is a new understanding of tobacco-dependent individuals.As investigations had revealed that the brain function changes in tobacco-dependent adults,but few studies have been conducted on the whole brain network of adolescent smokers.In this thesis,the topological properties of the brain functional networks of adolescent smokers and nonsmokers were analyzed by using Graph Theory Analysis(GTA).The result showed that both adolescent smokers and nonsmokers had small-world properties in their brain function network.However,compared with those of nonsmokers,the topological properties of the brain function network of adolescent smokers changed significantly,as evidenced by the decrease in shortest path length(Lp)and the increase in global efficiency(Eglobal)as well as local efficiency(Elocal).Moreover,their shortest path length(Lp)showed a significant negative correlation with the cumulative number of cigarettes smoked(Pack-years),and their the global efficiency(Eglobal)showed a significant positive correlation with the degree of nicotine dependence Fagerstr?m Test for Nicotine Dependence(FTND).In addition,a significant increase in nodal efficiency was observed in the brain regions of smoking adolescents,and their brains showed significantly higher nodal efficiency in the left olfactory cortex(OLF.L),bilateral caudate nucleus(CAU.L/R),and bilateral hippocampus(HIP.L/R),of the temporal pole,right superior temporal gyrus(TPOSUP.R)and the left subtemporal gyrus(ITG.L).Most of these parts are located in brain regions related to cognitive control,emotional control,and memory.Finally,this thesis used Network-based statistical methods(NBS)to examine the brain areas with significant nodal efficiency differences between the two groups of subjects.The results showed that showed that compared with nonsmoking adolescents,the right hippocampus(HIP.R)of adolescent smokers have enhanced connections with the left subtemporal gyrus(ITG.L),and their left caudate nucleus(CAU.L)had significantly enhanced connections with bilateral lateral hippocampus(HIP.L/R)and the left inferior temporal gyrus(ITG.L)respectively.By analyzing the topological properties of brain function network in adolescent smokers,this thesis found that the topological properties of brain function network in adolescent smokers has changed,more specially in the brain node and brain function network connection,and all these changes are closely related to their cognitive deficits.