基于微波前向散射法对大脑神经活动的检测研究

The existing nerve signal detection technique (EEG) is difficult to detect the deep brain signal in the noninvasive state and there exist some drawbacks such as complex operational procedure. The aim of this research is to develop a neural signal detection technology to overcome the drawbacks of the EEG. The technology is based on the microwave forward scatter method, and it has the advantages of non-contact noninvasive deep brain signal detection and so on. In this research, we will establish the electromagnetic equivalent model for multi-layer time-varying medium in neural excited region, and we will study the mechanism of the interaction between microwave and brain nerve signal in time-varying media by the microwave forward scatter method. The simulation model of the functional regions and the head will be established to research the time-varying characteristics of the functional region. In complex electromagnetic environment of the brain, the characteristics of the microwave forward scattering, microwave energy distribution, microwave spectral response and so on will be researched. Then, the experiment of brain activity will be carried out by microwave approach. By these series of researches, critical theoretical and technical support can be obtained for microwave based brain nerve signal detection approach. This approach provides a new way to the diagnosis and follow-up of neurological diseases such as Alzheimer's disease, Parkinson's syndrome. At the same time, it would be benefit to promote the development of artificial intelligence technology, artificial neural network, brain and computer interface and other disciplines. In addition, it will also have great impacts on information technology, automation technology and other related industries.

大脑通过大脑神经信号表征和控制着人体的生理行为，大脑神经信号的非接触活体无创深脑检测的研究极具重要的科学意义和应用价值。本课题拟开展基于微波前向散射法对大脑神经活动进行微波探测研究。通过建立神经兴奋区多层时变媒质的电磁等效模型，分析微波前向散射法检测时变媒质下大脑神经活动的机理。建立头部仿真模型，分析大脑复杂电磁环境中微波前向散射特性、微波能量分布、微波频率选择性等特性。并研究微波检测大脑神经活动的实验测试方法。这一系列研究为大脑神经兴奋区活动的微波探测方法提供关键理论和技术支持，有助于临床医学提高对大脑神经系统损伤病变诊断和检测的可靠性和准确性，为自闭症、上瘾、阿尔茨海默病、帕金森综合症和药物依赖等神经系统疾病诊断、跟踪治疗提供依据。除此，也有助于推动人工智能技术、人工神经网络、脑机接口等学科的发展，将对信息技术和自动化技术等相关产业带来革命性的影响。

非侵入式的大脑功能区活动状态检测是当今脑科学领域的主要议题之一，利用微波技术对大脑功能区活动状态检测研究，对人类脑科学的发展有着重要的意义。本课题主要工作如下：首先，结合大脑功能区的生理特性，分析了脑功能区神经元细胞在神经兴奋时细胞膜内外钠、钾离子浓度会发生周期性变化及脑组织电参数随之变化的原因。其次，建立传输模型，分析推导了散射信号与时变介质的介电常数、电导率之间的函数关系，通过推导结果可以得出介质的动态特性会引起散射信号传输相位的同频变化。然后利用电磁仿真软件对大脑触觉功能区与视觉功能区的微波探测进行了模拟仿真，在电磁仿真软件中引入三维高精度大脑模型，且依据人脑在微波状态下真实的电参数特性为大脑模型配置相应的参数。为了理论验证，设计了用于脑功能区探测的共形天线阵列测试平台，其中包含小型化宽带定向天线、宽带射频开关电路、共形天线阵列支架。并且进行了基于微波散射法的脑功能区模拟实验研究，配制了不同浓度的脑功能区模拟液，用于模拟脑功能区活动时不同状态。