脑机接口中的一种事件相关电位分离模型  

An isolation model of event-related potentials in brain-computer interfaces

作　　者：马征[1] 邱天爽[1] 

机构地区：[1]大连理工大学电子信息与电气工程学部生物医学工程系,大连116024

出　　处：《中国科学：信息科学》2015年第9期1218-1228,共11页Scientia Sinica(Informationis)

基　　金：国家自然科学基金(批准号:81241059;61172108;61139001);国家科技支撑计划(批准号:2012BAJ18B06)资助项目

摘　　要：事件相关电位(ERPs)分析揭示了脑机接口的认知神经机制,并为脑机接口技术的突破提供新的思路.然而与传统ERP研究不同的是,脑机接口中刺激呈现的时间间隔要远小于前者,并在平均信号中可以观察到较强的周期性干扰,致使其中包含的ERP成分的幅度和潜伏期等重要参数较难准确得到,为进一步的ERP分析造成障碍.目前关于这一干扰的形成原因和消除方法尚缺乏相关研究.本文首先建立了ERP信号的分离模型.模型认为ERP成分的混叠效应解释了平均信号中的周期性干扰.而后提出Toeplitz方法和差异波方法对模型进行求解,以消除干扰并恢复ERP成分.使用实测实验数据和公开数据库的数据对所提出模型与求解方法进行分析,结果表明,Toeplitz方法可以从非靶刺激平均信号中恢复出ERP成分,而差异波方法则可以有效地抑制混叠效应,并分离出基线平稳且各成分突出的ERP信号,从而验证了所提出模型与方法的合理性.本文的研究为脑机接口的ERP分析中周期性干扰的解释与消除提供了依据,并进一步为脑机接口的认知研究提供保障.The underlying neural cognitive basis of brain-computer interfaces （BCIs） can be revealed by eventrelated potentials （ERPs） analysis, which provides another way of perceiving the extraordinary advancements in the BCI field. However, the stimulus onset asynchronies in BCIs are far shorter than those in traditional ERP studies. Moreover, strong periodic disturbances can be observed in averaged BCI signals; these cause difficulties in evaluating ERP component parameters such as amplitudes and latencies, which are required for ERP analysis. The mechanisms of such disturbances, as well as the methods to suppress them, are still unknown in the literature. In this study, an ERP signal isolation model of a BCI was built, which demonstrated that the overlapping effect of ERP components contributed to the periodic disturbances. To isolate ERP components from the contaminated signals, a Toeplitz method and difference-wave method were further proposed for the solution of the model. Experimental results showed that, by using the Toeplitz method, ERP components could be recovered from the averaged signal corresponding to the non-targets of the BCI; meanwhile, the difference wave exhibited a strong ability to suppress the overlapping effect, and ERP signals with relatively flat baselines could be obtained. These results validated the rationality of the proposed model. The study provides grounds for the explanation and suppression of the periodic disturbances in ERP analyses, while providing reasonable support for cognitive research of BCI.

关 键 词：脑机接口 事件相关电位 信号模型 认知 P300 

分 类 号：TN911.7[电子电信—通信与信息系统]