FOCAL MAGNETIC STIMULATION OF AN AXON
FOCAL MAGNETIC STIMULATION OF AN AXON
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DOI：
10.1109/10.293248
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发表时间：
1994-06-01
影响因子：
4.6
通讯作者：
BASSER, PJ
中科院分区：
文献类型：
--
作者：
BASSER, PJ
由麦克斯韦方程组导出了轴突受磁刺激时圆形线圈产生的感应电场。焦点和虚拟阴极和阳极区域被预测为线圈半径和方向的函数。预测了两个虚拟的阳极和阴极对，一个位于线圈的周长之外，在远场占主导地位。当线圈和神经离得很近时，一个在线圈的周长内可能会刺激轴突。当线圈与神经相切时（临床磁刺激中常用的方向），优势阴极-阳极对的焦点对线圈位置的变化极为敏感。此外，激活功能的曲率半径，即虚拟阴极在阈值时的大小，预计会随着线圈直径的减小和与神经的距离的减小而减小。这些预测可能有助于解释磁刺激外周轴突时观察到的传导速度和潜伏期的测量变化。
The induced electric field produced by a circular coil during magnetic stimulation of an axon is derived from Maxwell's equations. The foci and virtual cathodal and anodal regions are predicted as a function of coil radius and orientation. Two virtual anode and cathode pairs are predicted, one lying outside the coil's perimeter and predominant in the far field? and one lying within the perimeter of the coil which may stimulate the axon when the coil and nerve are in close proximity. When the coil is positioned tangent to the nerve, an orientation commonly used in clinical magnetic stimulation, the foci of the predominant cathode acid anode pair are extremely sensitive to changes tn coil placement. In addition, the radius of curvature of the activating function, a measure of the size of the virtual cathode at threshold, is predicted to decrease with decreasing coil diameter and distance to the nerve. These predictions may help explain observed variability in measurements of conduction velocity and latency during magnetic stimulation of peripheral axons.