基于样本熵的磁刺激穴位加权脑功能网络研究

脑功能网络的构建与分析可帮助探究大脑工作机制。本研究旨在构建并分析磁刺激内关穴脑功能网络，为探索针灸学作用机理提供理论依据。目前，为简化网络计算的复杂性，很多相关研究集中于二值脑功能网络，忽略了节点间连接强度。本研究采集磁刺激内关穴前、中、后3种状态的脑电信号并基于样本熵和互信息方法构建3种状态下反映节点间真实连接程度的加权脑功能网络；利用复杂网络理论对3种状态下加权脑功能网络拓扑性质进行对比性分析。实验结果表明，刺激状态与刺激前状态相比，网络的平均度、平均聚类系数、全局效率均有提高；刺激状态与刺激后状态相比，网络的平均度、平均聚类系数、全局效率整体也呈增强趋势；刺激后状态与刺激前状态相比，除少数被试的网络拓扑特征基本保持不变或小幅度减少外，其余均呈增长趋势，且增长程度不同，考虑与刺激的累积效应和个体差异有关。研究结果表明，磁刺激内关穴使网络各通道间连接强度提高，集群化程度加强，信息传递效率提高。

Study of the Weighted Brain Functional Network Based on the Sample Entropy under Magnetic Stimulation at Neiguan Acupoint

The construction and analysis of brain functional network can help to explore the working mechanism of brain.The therapeutic effectiveness of acupuncture was explored through the construction and analysis of brain functional network under magnetic stimulation at Neiguan(PC6)acupoint in this study.At present,a lot of related studies are devoted to the research of un-weighted network regardless the strength of connections among nodes to simplify the complexity of network computing.In this study,three kinds of Electroencephalograph(EEG)signal were recorded under pre-stimulated state,stimulated state and post-stimulated state at PC6 acupoint;weighted brain functional network was constructed by using sample entropy and mutual information theory;the topological features of weighted brain functional network for the three states were comparatively analyzed by using complex network theory.The experimental results show that the average degree,average clustering coefficient and global efficiency of the weighted brain functional network at stimulated states are increased compared to the pre-stimulated states;these topological features of network at stimulated states also show an increased trend compared to the pro-stimulated states;except that the topological feathers of the network for few subjects remain unchanged or decreased slightly,these topological features of the network for most subjects at pro-stimulated states show an increased trend compared to the pre-stimulated states and the increase rates of different subjects are different considering the cumulative effect of stimulation and individual differences.These results indicate that the connection strength of the network is enhanced,clustering of the network is increased,efficiency of information transmission is improved through stimulating PC6 acupoint