中文摘要：

目的 探索单胺氧化酶A基因多态性对健康男性青少年静息状态下脑基础活动的影响.方法 对31例MAOA低活性的健康男性青少年及25例MAOA高活性的健康男性青少年进行静息态磁共振成像扫描,采用低频振幅（ALFF）的方法,比较两组受试者全脑各区域ALFF值的大小差异.然后将有显著性差异的脑区作为ROI,提取ROI中的ALFF值,并对个体的ROI ALFF值与Barratt＆#39;s冲动量表分数做相关.结果 与MAOA高活性的健康男性青少年相比,MAOA低活性的受试者在脑桥区域（MNI坐标：-6,-19,-23;6,-16,-17;-6,-25,-32）ALFF值（P＜0.001）显著降低.此外,在MAOA低活性的群体中,个体脑桥的ALFF值与BIS值呈显著正相关（r=0.398,P=0.02）.结论 MAOA基因多态性与脑桥的自发神经活动存在一定关联性,MAOA低活性的健康男性青少年所存在的脑桥部位自发性脑部活动的降低可能是冲动及攻击的一个重要风险因素.

英文摘要：

Objective To examine the effects of a functional polymorphism of the monoamine oxidase A （MAOA） gene on spontaneous brain activity in healthy male adolescents.Methods Resting-state fMRI was performed on 31 healthy male adolescents with the low-activity MAOA genotype （MAOA-L） and 25 healthy male adolescents with the high-activity MAOA genotype （MAOA-H）.The amplitude of low-frequency fluctuation （ALFF） of the blood oxygen level-dependent （BOLD） signal was calculated using REST software,and was compared between two genotype groups.The region ROIs showed significant difference.The ALFF data in ROIs were related to BIS scores.Results Compared with the MAOA-H group,the MAOA-L group showed a significant decrease of ALFF （P〈0.001） in the pons （MNI coordinates：-6,-19,-23;6,-16,-17;-6,-25,-32）.In addition,the BIS scores were positively correlated with ALFF in pons in the MAOA-L group （r=0.398,P=0.02）,but not in the MAOA-H group.Conclusions There exists relevance between the polymorphism of MAOA and the spontaneous brain activity in pons.And the lower activity of spontaneous brain activity in pons may be a key risk factor for impulsivity and aggression.