摘要目的:探讨男性长期吸烟者默认网络有效连接的异常改变，及其与吸烟临床特征的相关性。方法:回顾性分析2014年1月至2018年12月通过微信等网络平台招募的131名受试者的静息态功能磁共振成像数据，其中长期吸烟者76名［长期吸烟组，男性，年龄20~55（32.1±6.3）岁］，对照者55名［对照组，男性，年龄22~55（32.3±7.4）岁］。长期吸烟者定义为每天吸烟不少于10支，烟龄2年以上且符合美国精神障碍诊断统计手册第4版（DSM-Ⅳ）关于物质依赖诊断标准的人群。选取默认网络中4个主要节点为感兴趣区，分别为左侧顶下小叶（LIPL），右侧顶下小叶（RIPL），后扣带回皮质（PCC），内侧前额叶皮质（mPFC）。基于动态因果模型分析吸烟组及对照组默认网络有效连接（EC）的改变。并分析有差异的EC与尼古丁依赖量表评分（FTND）、吸烟指数及烟龄的相关性。结果:与对照组相比，吸烟组LIPL至PCC、PCC至mPFC的EC减弱（EC分别为-0.091、-0.174，均贝叶斯后验概率>0.95），RIPL至PCC的EC增强（EC为0.136，贝叶斯后验概率>0.95）。此外，从LIPL到PCC的EC与吸烟指数呈负相关（ r=-0.282， P=0.017）。差异有统计学意义的EC与FTND评分及烟龄在组间比较时未发现存在相关性（ r=-0.103、-0.089，均 P>0.05）。 结论:长期吸烟者在IPL-PCC-mPFC神经回路中表现出异常的信息传递，并与吸烟指数相关。

abstractsObjective:To investigate the alterations in effective connection of default mode network (DMN) in long-term male smokers and its correlation with clinical characteristics of smoking.Methods:A total of 131 subjects through WeChat platform and underwent resting-state functional magnetic resonance (rs-fMRI) examinations were recruited, including 76 long-term smokers [long-term smoking group, male, aged 20 to 55 (32.1±6.3) years] and 55 non-smokers [healthy controls, male, aged 20 to 55(32.3±7.4) years] from January 2014 to December 2018. Long-term smokers were defined as those who smoked at least 10 cigarettes per day for more than 2 years, and met the Diagnostic and Statistical Manual of Mental Disorders-Four Edition (DSM-Ⅳ) criteria for substance dependence. Four major nodes of DMN, including left inferior parietal lobule (LIPL), right inferior parietal lobule (RIPL), posterior cingulate cortex (PCC), medial prefrontal cortex (mPFC) were chosen as for the region of interest. The effective connectivity (EC) alterations of DMN between smoking group and healthy controls were compared using dynamic causal modeling (DCM). The correlation between EC with significant difference among the two groups and Nicotine Dependence Scale (FTND) score, pack-year score and smoking duration were evaluated.Results:Compared to the healthy controls, the EC of LIPL to PCC and PCC to mPFC were decreased in the smoking group (EC = -0.091, -0.174, respectively, Bayesian-PP>0.95), and the EC of RIPL to PCC was increased (EC = 0.136, Bayesian-PP>0.95). Besides, EC of LIPL to PCC showed negative correlation with pack-year scores( r=-0.282, P=0.017). No significant linear correlations were observed between EC with significant group difference and FTND score or smoking duration ( r=-0.103、-0.089,all P>0.05). Conclusion:Long-term smokers showed multiple abnormalities in IPL-PCC-mPFC circuits, and associated with the pack-year scores.