Elucidating the mechanisms and loci of neuronal excitation by transcranial magnetic stimulation using a finite element model of a cortical sulcus
Elucidating the mechanisms and loci of neuronal excitation by transcranial magnetic stimulation using a finite element model of a cortical sulcus
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DOI：
10.1016/j.clinph.2008.07.248
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发表时间：
2008-10-01
影响因子：
4.7
通讯作者：
Miranda, P. C.
中科院分区：
文献类型：
--
作者：
Silva, S.;Basser, P. J.;Miranda, P. C.
目的：这项工作的目的是阐明什么物理机制和刺激发生在大脑中，在经颅磁刺激（TMS），考虑到皮质的几何形状和组织heterogeneity.Methods：TMS的理想化的计算机模型的开发，包括一个刺激线圈，皮质沟，和周围组织。的感应电场的分布进行计算，并产生相关参数的估计预测的轨迹和类型的神经元刺激TMS期间，假设三种不同的刺激mechanism.Results：组织异质性强烈影响的空间分布的感应电场，因此刺激机制是占主导地位的，它的作用。神经元的刺激可能发生在脑回、脑回唇和脑沟壁中。受刺激的细胞可以是具有中到大口径轴突的锥体细胞，也可以是中等口径的皮质内纤维。结论：结果突出了皮质折叠对磁场和电场对皮质组织的作用的影响。意义：组织的几何形状和电导率的异质性都必须考虑到准确预测TMS中的刺激位点和机制。(C)2008年国际临床神经生理学联合会。由Elsevier爱尔兰有限公司出版。保留所有权利。
Objective: This work aims to elucidate by what physical mechanisms and where stimulation occurs in the brain during transcranial magnetic stimulation (TMS), taking into account cortical geometry and tissue heterogeneity.Methods: An idealized Computer model of TMS was developed, comprising a stimulation coil, a cortical sulcus, and surrounding tissues. The distribution of the induced electric field was computed, and estimates of the relevant parameters were generated to predict the locus and type of neurons stimulated during TMS, assuming three different stimulation mechanisms.Results: Tissue heterogeneity strongly affects the spatial distribution of the induced electric field and hence which stimulation mechanism is dominant and where it acts. Stimulation of neurons may occur in the gyrus, in the lip of the gyrus, and in the walls of the sulcus. The stimulated cells can be either pyramidal cells having medium to large caliber axons, or intracortical fibers of medium caliber.Conclusions: The results highlight the influence of cortical folding on the action of magnetic and electric fields on cortical tissue.Significance: Tissue geometry and heterogeneity in electrical conductivity both must be taken into account to predict accurately stimulation loci and mechanism in TMS. (C) 2008 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.