Effects of coil orientation on the electric field induced by TMS over the hand motor area
Effects of coil orientation on the electric field induced by TMS over the hand motor area
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DOI：
10.1088/0031-9155/59/1/203
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发表时间：
2014-01-06
影响因子：
3.5
通讯作者：
Ugawa, Yoshikazu
中科院分区：
文献类型：
--
作者：
Laakso, Ilkka;Hirata, Akimasa;Ugawa, Yoshikazu
手部运动区域经颅磁刺激 (TMS) 引起的反应取决于刺激线圈的位置和方向。在这项工作中，我们通过计算研究了多个线圈方向和位置的感应电场，以确定大脑的哪些部分受到影响，以及运动皮层激活的敏感性如何取决于电场的方向。有限元方法用于计算 TMS 在头部和大脑的两个独立解剖模型中感应的电场。线圈的方向影响电场的强度和穿透深度，并且电场很大程度上取决于目标神经元所在的沟的方向。在目标皮质区域中提供最强电场的线圈位置可能会偏离最近的头皮位置约 1 厘米的距离。与之前的实验数据一起，结果支持了这样的假设：皮层对垂直于皮层层的场最敏感，而对平行于皮层层的场相对不敏感。这对于 TMS 的靶向具有重要意义。为了确定最有效的线圈位置和方向，必须考虑生物因素（目标轴突的方向）和物理因素（电场的强度和方向）。
Responses elicited by transcranial magnetic stimulation (TMS) over the hand motor area depend on the position and orientation of the stimulating coil. In this work, we computationally investigate the induced electric field for multiple coil orientations and locations in order to determine which parts of the brain are affected and how the sensitivity of motor cortical activation depends on the direction of the electric field. The finite element method is used for calculating the electric field induced by TMS in two individual anatomical models of the head and brain. The orientation of the coil affects both the strength and depth of penetration of the electric field, and the field strongly depends on the direction of the sulcus, where the target neurons are located. The coil position that gives the strongest electric field in the target cortical region may deviate from the closest scalp location by a distance on the order of 1 cm. Together with previous experimental data, the results support the hypothesis that the cortex is most sensitive to fields oriented perpendicular to the cortical layers, while it is relatively insensitive to fields parallel to them. This has important implications for targeting of TMS. To determine the most effective coil position and orientation, it is essential to consider both biological (the direction of the targeted axons) and physical factors (the strength and direction of the electric field).