神经调控技术对脑功能研究及脑神经精神疾病诊疗具有重要意义，然而现有的无创神经调控方法难以实现针对特定脑区的深部高空间分辨率电刺激。基于磁声耦合效应的经颅电刺激（Transcranial magneto–acoustical stimulation, TMAS）作为一种新型无创神经调控技术，因可以实现对深部脑区的无创高空间分辨电刺激而成为目前研究的热点。

TMAS的基本原理是超声波可以在位于磁场环境的神经组织中，通过磁声耦合效应形成局部电流，进而影响神经的电活动。由此可知，TMAS 在实施过程中还存在超声的刺激过程，且已有研究表明，磁声耦合电刺激与超声刺激（Transcranial ultrasound stimulation, TUS）都对神经活动具有影响，因此不同物理场在影响神经活动过程中如何发挥作用对探究TMAS作用机制具有重要意义。

本文首先对TMAS与TUS作用于小鼠运动皮层的神经调控效果进行了实验研究与对比分析，结果显示，相比于TUS，TMAS可以更快地引起小鼠运动皮层对刺激的响应，且诱发强度更大的肌电信号。在运动皮层活动的调控过程中，磁声耦合电场和超声场均发挥了作用。

基于上述研究和相关文献结果，本文提出应用耳聋模型鼠消除TMAS中超声声场通过骨传导和局部生物组织对小鼠运动皮层活动的影响，研究磁声耦合过程中耦合电刺激和超声刺激对小鼠运动皮层活动各自的调控作用。结果显示，在本文研究的实验条件下，相对于磁声耦合电刺激，聚焦超声刺激对小鼠运动皮层神经活动的影响作用更强。

为进一步研究TMAS中耦合电场对神经活动的影响，本文使用离体细胞作为实验对象，对TMAS对细胞活动的作用和影响进行了初步探索。结果显示耦合电场可引起细胞群的趋向性运动和细胞形态的变化，对深入研究TMAS的神经生物学机制具有参考意义。

为进一步分析TMAS中磁声耦合电场对生物组织的作用，本文对TMAS在低电导率类生物组织中产生的磁声耦合电场进行了检测与分析。结果显示，相对于高电导率材料的实测磁声耦合电场与仿真结果基本符合，低电导率类生物组织材料的实测磁声耦合电场小于仿真结果，说明在低电导率生物组织更为复杂电磁和力学条件下，TMAS多物理场耦合过程的建模和仿真还有更深入的工作需要开展。

最后，对本文的研究工作进行了总结。TMAS是一种结合了耦合电场与声场的复合刺激，本文通过实验研究，分析了TMAS中耦合电刺激与聚焦声刺激对神经组织的作用，探讨了TMAS神经调控的作用机制，为TMAS应用于脑神经无创精准刺激奠定了实验基础，有助于推动精准脑科学研究与精准脑病诊疗方法和技术的深入开展。

Neuromodulation have a great significance to the study of brain function and neuropsychiatric treatment. However, it is difficult to achieve the electrical stimulation of high spatial resolution for specific regions of deep brain about the existing noninvasive neuromodulation methods. Transcranial magneto-acoustical stimulation (TMAS) is the focus of current research as a new type of noninvasive neuromodulation technology due to its high spatial resolution and precise electrical stimulation for deep brain regions.

The theoretical basis of TMAS is that the local current can be formed when ultrasound propagation in tissues in the presence of a magnetic field, and the current will affect the electrical activity of nerves. It can be seen that there is ultrasound stimulation in the process of TMAS, and studies have shown that both TMAS and transcranial ultrasound stimulation (TUS) have an effect on nerve activity. Therefore, how different physical fields play a role in neuromodulation is very important for exploring the mechanism of TMAS.

Firstly, this paper study and compare the neuromodulation effects of TMAS and TUS on the motor cortex of mice. The results show that TMAS can induced the faster response and induce stronger EMG signals of the motor cortex of mice which compared with TUS. Both the coupled electric field and the ultrasonic field play an important role in the process of modulating the motor cortex.

Based on the above study and related research results, this paper study the effect of electrical stimulation and ultrasonic stimulation to mice in the process of TMAS using deaf model mice, which eliminate the effects of ultrasonic field on bone conduction and local biological tissues for mouse cortical activity. The results show that ultrasound stimulation has a stronger effect on the motor cortical nerve activity in mice compared with coupled electrical stimulation under the experimental conditions.

Furthermore, this article uses isolated cells to exploration the effect of TMAS on cell activity preliminarily as to study the effect of the coupled electric field on neural activity. The results show that the coupled electric field can cause the trending movement of cells and changes in cell morphology, which provides a reference for further research on the neurobiological mechanism of TMAS.

In order to analyze the effect of magnetic-acoustic coupling electric field on biological tissues, this paper detects and analyzes the coupling electric field generated by TMAS in low-conductivity biological tissues. The results show that the measured coupling electric field of the high-conductivity material is basically consistent with the simulation results. The measured coupling electric field of the low-conductivity biological tissue material is smaller than the simulation result, which indicated that there is still more work need to be done to model and simulate the multi-physics coupling process of TMAS for the low-conductivity biological tissue under the more complex electromagnetic and mechanical conditions.

Finally, the work of this paper is summarized. TMAS is a complex stimulus method that combines magnetic and ultrasound. In this paper, the effect of coupled electrical stimulation and focused acoustic stimulation on neural tissue in TMAS is analyzed by experimental studies, and the mechanism of TMAS neuromodulation is discussed. These work laid an experimental foundation for the application of TMAS to noninvasive and precise stimulation of brain nerves, and helped to promote the in-depth development of precision brain science research and precision encephalopathy treatment.