基于多物理场复合的新型无创脑深部精准刺激方法探究

Exploration of a Novel Noninvasive Deep Brain Precision Stimulation Method Based on Multiphysics Field Complexes

现有的无创电磁刺激技术,以临床应用最广的经颅磁刺激(TMS)为代表,尚无法突破聚焦性和刺激深度的技术瓶颈,实现对深部功能核团的直接精准刺激。本研究基于磁声耦合理论,结合TMS技术中的交变磁场,提出一种新的基于多物理场复合的无创脑深部精准刺激方法(MI-TMAS),以期实现对脑深部的直接精准聚焦刺激。基于磁声耦合理论和磁感应理论对MI-TMAS中的刺激物理场进行仿真研究,并搭建了MI-TMAS系统及多物理场测试平台,对刺激物理场分布并进行实测。结合仿真和实测结果,对MI-TMAS复合刺激电场的聚焦性和电场强度进行探究。结果显示,该方法能够在脑深部靶区产生聚焦声场、磁声耦合电场、磁感应电场等3个复合刺激物理场,可以在刺激深度50 mm处形成聚焦尺寸约6.2 mm(-3 dB)的复合刺激电场,其在脑深部电场的聚焦性明显优于TMS,且刺激电场强度大于稳恒磁场下的TMAS。本研究为MI-TMAS方法应用于在体神经调控提供了理论以及技术基础。

Existing noninvasive electromagnetic stimulation technologies,represented by transcranial magnetic stimulation(TMS),the most widely used clinical technology,are still unable to break through the technical bottlenecks of focus and stimulation depth and achieve direct and precise stimulation of deep functional nuclei.Based on the theory of magneto-acoustic coupling,combined with the alternating magnetic field in TMS,we proposed a new non-invasive deep brain stimulation method(magnetic induction-transcranial magneto-acoustic stimulation,MI-TMAS)based on multi-physical field composite,aiming to achieve deep brain stimulation,direct and precise focus stimulation.This paper simulated the stimulation physical fields in MI-TMAS based on the magneto-acoustic coupling theory and magnetic induction theory;and built the MI-TMAS system and multi-physics test platform and conducted actual measurements.Combining simulation and actual measurement results,the focus and electric field strength of the MI-TMAS composite stimulation electric field were explored.The results showed that this method generated three composite stimulation physical fields including focused acoustic field,magneto-acoustic coupling electric field,and magnetic induction electric field in the deep brain target area.By this way,a composite stimulation electric field with width of 6.2 mm(-3dB)at a stimulation depth of 50 mm was formed,which is in the deep brain.The focusing of the electric field was significantly better than that of TMS,and the stimulation electrical field intensity was greater than that of TMAS under a steady magnetic field.In conclusion,this method provided a theoretical and technical basis for the MI-TMAS method to be applied to in vivo neuromodulation.