【作者】 杨硕；

【导师】 杨庆新； 徐桂芝；

【作者基本信息】 河北工业大学 ， 电工理论与新技术， 2007， 博士

【摘要】 磁刺激技术是一种无创、无痛地刺激人体中枢及周围神经组织的新技术。它利用低频的时变磁场将体外的能量间接传输到人体内的神经-肌肉系统。在过去几十年的发展过程中,磁刺激已经广泛应用到众多医学和临床研究中,正在逐步形成新的领域。根据河北省自然科学基金资助项目“经颅磁刺激系统设计及其对肢体神经影响的研究”(编号:E2006000037)的要求,本文由磁共振成像(MRI)技术获得的图像抽取解剖结构信息建立几何头模型,对不同类型线圈在头部进行磁刺激时的电磁场分布进行了分析研究,对磁刺激穴位引起的脑电活动进行了实验研究,同时对磁刺激硬件系统的原理和设计进行了系统研究。主要内容如下:1.实现了磁刺激头部磁场和感应电场分布仿真计算对磁刺激求解场域的数学模型的建立及求解方法做了较详细的分析,由核磁共振成像获得的头的断层图片构造了三维真实头有限元电磁场数值计算模型,对磁刺激激励脉冲电流进行了求解,在此基础上首次对磁刺激时头部磁场和感应电场的分布情况进行了研究。该结果可以对磁刺激进行精确地空间定位,确定深部靶组织的刺激强度。这可以大大提高磁刺激的效率,并可以使得磁刺激量化更加精确和具体。对四种类型线圈在磁刺激头部时的磁场和感应电场分布和影响进行了求解和分析,并对三种不同绕法圆形线圈产生的磁场和感应电场分布和影响进行了求解和分析。2.研究了磁刺激神门穴对人体脑电活动的影响首次结合磁刺激和脑电,对健康人的神门穴进行了不同频率下的磁刺激,记录并分析了磁刺激时的脑电信号。结果表明,磁刺激神门穴会引起人脑电信号中慢波成份分布率的增加,快波成份分布率的减少。单脉冲磁刺激神门穴诱发的慢波成份的分布率要大于重复磁刺激诱发的,而单脉冲磁刺激神门穴诱发的快波成份的分布率要小于重复磁刺激诱发的。重复磁刺激神门穴时,随着刺激频率的增高脑电信号中慢波成份的分布率减少,快波成份的分布率增多。3.研制了单脉冲磁刺激系统研制了磁刺激硬件系统,整个系统分为主电路和控制电路两部分。每部分的电路选用高精度、高速度的器件,保证了系统的高性能。该系统可以成功进行单脉冲磁刺激,可以满足单脉冲磁刺激技术研究的基本需要。更多还原

【Abstract】 Magnetic stimulation is a relatively new technique of non-invasive and painless technology of the central and peripheral neural tissues. It takes advantage of low-frequency time-variant magnetic field to couple external energy into human neural-muscular system. In the past decades, magnetic stimulation has grown dramatically in popularity and been used in several applications in medical and clinical research.According to the Natural Science Foundation of Hebei Province under Grant E2006000037, a realistic head model used in Finite Element Method has been developed from MRI. The electromagnetic field induced in the head by magnetic stimulation has been analyzed. The electromagnetic field distributions produced by four kinds of coils have been analyzed respectively. The effect of point magnetic stimulation on brain activities has been studied. The magnetic stimulation hardware system has been designed. The main research work is as follows:1. Electromagnetic field simulation based on transcranial magnetic stimulation using 3D realistic head modelThe mathematic model used in the simulation of magnetic stimulation has been described in detail. The 3D realistic head model has been build from MRI. The input current in the coil of magnetic stimulation system has been calculated. The distribution of electromagnetic field during the magnetic stimulation on the head has been analyzed. Using the simulation, the stimulation sites could be located precisely and the efficiency of magnetic stimulation experiments could be improved.The electromagnetic fields produced by four different kinds of coils have been analyzed. The effect of three kinds of windings of circle coil on the electromagnetic distribution has also been analyzed.2. Researches on the effect of magnetic stimulation at point on brain activities The EEG is recorded and analyzed when the subjects is stimulated at SHENMEN point by magnetic stimulation in different frequency.The results show magnetic stimulation at SHENMEN point make the healthy people produce more slow-wave components and less fast-wave components than that the healthy people produced in quiet. The single pulse magnetic stimulation is more efficient than the repetitive magnetic stimulation. With the frequency increased, the action effect became weakened.This result is useful for deeper research on the effect of magnetic stimulation on neural function.3. Design of single pulse magnetic stimulation systemThe magnetic stimulation system consists of main circuit part and control circuit part. The components used in each part are high speed and high precision elements, and these ensure the high performance of the whole system. This system can meet the primary need of single pulse magnetic stimulation.更多还原