经颅直流电刺激的定向优化及机制研究

发布时间：2018-12-12 07:33

【摘要】：经颅直流电刺激是一种非侵入式脑刺激技术,其利用微小的颅外恒定电流改变大脑神经元活性。近年来,经颅直流电刺激以无创、安全和经济的突出优点,在脑损伤修复、神经疾病治疗、认知与情绪调控等领域得到了广泛发展应用。但如何实现大脑皮层定向刺激是经颅直流电刺激研究必需解决的现实问题。本课题围绕电流刺激的定向问题,分别从电刺激关键参数、神经元兴奋机制及定向优化方法三方面开展研究,研究结论可为辅助制定合理的刺激方案及保障过程的安全性和有效提供支持。论文的主要工作如下:1)建立经颅直流电刺激数值研究模型。实现头颅数值计算模型的构建,并通过脑电实验验证计算模型的正确性,为解决定向刺激的逆向优化问题提供正向数值研究基础。2)系统评价关键参数影响颅内电场分布问题。基于电磁场正问题的有限元计算方法,明确不同电极参数对脑区的聚焦性能、电流利用效率等指标的影响,为设计定向刺激方法提供关键参数的参考。3)为验证经颅直流电刺激生物效应及关键参数的分析评价结果,分别从宏观行为学任务表现能力和脑电节律频率特性方面开展实验研究,为明确经颅直流电刺激的生物效应和作用机制研究提供实验基础。4)研究经颅直流电刺激与神经元放电特性及敏感性的关系。利用神经元数值计算模型,分析电流刺激调控神经元发放特性的机制,可为经颅电流刺激理论的深入研究提供基础。5)为解决刺激电流的定向问题,结合临床安全性和有效性的基本要求,建立逆问题研究的理论模型,并设计优化约束条件,实现脑区定向高效刺激的目标。论文的主要结论包括:1)建立三维经颅直流刺激关键参数评价模型,补充和完善经颅直流电刺激系统,为进一步开展应用研究提供技术保障;2)基于关键参数的评价,开展多项实验验证研究,首次证实左背外侧前额叶皮层的经颅直流电刺激可提高复杂计算任务能力,并从计算神经学角度初步揭示了电流刺激的作用机制;3)首次提出并实现九电极布局策略和电流刺激逆向优化方法,有效解决经颅直流电定向聚焦刺激问题,为临床高效合理的制定刺激方案提供参考。
[Abstract]:Transcranial direct current stimulation (TDC) is a non-invasive brain stimulation technique, which changes the activity of brain neurons using small constant extracranial currents. In recent years, transcranial direct current (TDC) stimulation has been widely used in the fields of brain injury repair, nerve disease treatment, cognitive and emotional regulation and so on, with the outstanding advantages of non-invasive, safe and economical. But how to realize the directional stimulation of cerebral cortex is a practical problem that must be solved in the study of transcranial direct current electrical stimulation. In this paper, we focus on the orientation of electric stimulation from three aspects: the key parameters of electrical stimulation, the excitation mechanism of neurons and the orientation optimization method. The research results can provide support for establishing reasonable stimulus programs and ensuring the safety and effectiveness of the process. The main work of this paper is as follows: 1) the numerical model of transcranial direct current stimulation (TDC) is established. The construction of head numerical calculation model is realized, and the correctness of the model is verified by EEG experiment. In order to solve the inverse optimization problem of directional stimulation, it provides the basis of forward numerical research. 2) the key parameters are systematically evaluated to influence the distribution of intracranial electric field. Based on the finite element method for the forward problem of electromagnetic field, the effects of different electrode parameters on the focusing performance and current utilization efficiency of the brain region are determined. In order to verify the biological effects of transcranial direct current (TDC) stimulation and the results of analysis and evaluation of the key parameters, Experimental studies were carried out in terms of the performance of macro behavioral tasks and the frequency characteristics of EEG rhythms. In order to clarify the biological effect and mechanism of transcranial direct current stimulation (TDC), the relationship between transcranial direct current stimulation (TDC) and neuronal discharge characteristics and sensitivity was studied. Using the neuron numerical calculation model, the mechanism of current stimulation regulating neuronal release characteristics is analyzed, which can provide a basis for the further study of transcranial current stimulation theory. 5) to solve the problem of the orientation of stimulation current. According to the basic requirements of clinical safety and effectiveness, the theoretical model of inverse problem research is established, and the optimal constraint conditions are designed to achieve the goal of directional and efficient stimulation in brain region. The main conclusions are as follows: 1) to establish a three-dimensional evaluation model of the key parameters of transcranial direct current stimulation, complement and perfect the transcranial direct current stimulation system, and provide technical guarantee for further application research; 2) based on the evaluation of key parameters, a number of experimental validation studies were carried out to prove for the first time that transcranial direct current (TDC) stimulation in the left dorsolateral prefrontal cortex can improve the ability of complex computing tasks. From the point of view of computational neurology, the mechanism of current stimulation was preliminarily revealed. 3) for the first time, a nine-electrode layout strategy and an inverse optimization method for current stimulation were proposed and implemented to effectively solve the problem of transcranial direct current directed focusing stimulation, and to provide a reference for the effective and rational formulation of stimulation scheme in clinical practice.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R741

【相似文献】