Transcranial electric stimulation of motor pathways: a theoretical analysis
Transcranial electric stimulation of motor pathways: a theoretical analysis
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DOI：
10.1016/j.compbiomed.2003.12.005
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发表时间：
2005-02-01
影响因子：
7.7
通讯作者：
Stecker, MM
中科院分区：
文献类型：
--
作者：
Stecker, MM
对大脑的经颅电刺激的反应是评估麻醉患者中的运动通路的重要手段。本研究的目的是阐明经颅刺激产生的轴突兴奋的模式，并证明这种模式是如何受到头骨-CSF-脑复合体的电导率或几何形状变化的影响。为此，在恒定电流条件下，得到了电极放置在三壳球模型上的问题的解析解。计算产生的电位、电流和场，并计算径向组织轴突的理想化集合的“激活函数”，以估计刺激产生的膜去极化的程度。电磁/辐射效应改变这些解决方案的程度也estimated.The模式的刺激只是轻微地依赖于导电性和CSF层的厚度。在脑表面以最低阈值刺激非常接近阳极的轴突。更远的轴突受到更高阈值的刺激，最大刺激点移近球体中心。在阴极附近，离电极边缘5- 7度处刺激最大，但激活函数的峰值幅度一般比阳极上低20倍。(C)2004爱思唯尔有限公司保留所有权利。
The response to transcranial electrical stimulation of the brain is an important means of assessing motor pathways in the anesthetized patient. The purposes of this study were to elucidate the pattern of axonal excitation produced by transcranial stimulation and to demonstrate how this pattern is affected by changes in the conductivity or geometry of the skull-CSF-brain complex. To this end, analytic solutions to the problem of electrodes placed on a three shell spherical model were obtained under constant current conditions. The potentials, currents and fields generated were computed and the "activating function" was computed for an idealized set of radially organized axons in order to estimate the degree of membrane depolarization produced by stimulation. The degree to which electromagnetic/radiation effects change these solutions was also estimated.The pattern of stimulation was only slightly dependent on the conductivity and the thickness of the CSF layer. Axons very close to the anode were stimulated with lowest threshold at the brain surface. Axons further away were stimulated with higher thresholds and the point of maximum stimulation moved nearer the center of the sphere. Near the cathode, stimulation was maximal about 5-7degrees away from the edge of the electrode but the peak magnitude of the activating function was generally 20 times lower than over the anode. (C) 2004 Elsevier Ltd. All rights reserved.