急性烟草戒断诱发注意下降的脑网络机制研究

Early withdrawal is the critical period for quitters to quit smoking successfully. Difficulty concentrating in this period is the main reason for some smokers' failure to quitting. Therefore, the underlying neural mechanism of the withdrawal symptoms is one of the key scientific problems to be solved. Previous studies and our experiments have demonstrated that withdrawal symptoms are mainly based on the effects of long-term smoking on acetylcholine receptors in the brain and their distribution in brain regions (reward circuits), while attention performance is mainly based on the resource allocation between default mode network, salience network and executive control network (DMN-SN-ECN). Thus, we hypothesized that acute withdrawal affects higher cognitive functions such as attention by regulating the dynamic relationship between DMN-SN-ECN networks through reward circuit. This project intends to use the mediating effect analysis and the pharmacological magnetic resonance imaging to study the effect of the change pattern of reward circuit and three-network resource allocation on attention performance in smokers after acute withdrawal. Connectomics was used to explore other brain networks involved in attentional performance, to provide new inspirations for smoking cessation interventions.

戒断早期是关系到戒烟者能否戒烟成功的关键时期，在此阶段产生的注意难以集中是造成部分吸烟者戒烟失败的重要原因。因此，研究这一戒断症状背后的神经机制是破解戒烟难题亟待解决的关键科学问题之一。既往研究及我们前期实验表明，戒断症状的出现主要基于长期吸烟对脑内乙酰胆碱受体及其所分布脑区（奖赏环路）的作用，而注意表现主要基于默认网络-突显网络-执行控制网络（DMN-SN-ECN）间资源分配。为此，我们提出假说：急性戒断通过奖赏环路调节DMN-SN-ECN三网络间的动态关系达到对注意等高级认知功能的影响。本项目拟采用中介效应分析、药物磁共振成像方法，对吸烟者急性戒断后奖赏环路及三网络资源分配的改变模式对注意表现的作用开展研究；并采用连接组学探索其他参与注意表现的脑网络；以期为戒烟干预提供新的启示。

烟草戒断是全世界烟民面临的难题。大量神经生理学及神经影像学研究表明长期吸烟可影响大脑结构和功能的改变，但上述改变在戒烟过程中是否可逆，能否预测后续的戒烟结果尚不清楚。此外，吸烟行为与认知表现密切相关，但两者在脑内的交互作用尚未明确。本研究利用多模态磁共振成像技术采集吸烟者脑功能及脑结构数据，结合戒烟情况及认知状态，分析吸烟者脑影像数据与戒烟结果、认知状态的关系。已有的数据分析发现：①凸显网络的重要节点（岛叶）在烟草成瘾和戒断中的纤维束微结构改变；②奖赏环路的重要节点（纹状体、丘脑）在烟草戒断中的结构和功能改变，并可用以预测戒烟结果；③认知状态与吸烟对脑内环路（基底前脑、皮层-纹状体环路）的交互作用。这对进一步理解烟草戒断的脑内机制提供了影像学证据，为临床戒烟治疗提供依据和指导。