Investigation into the influence of stimulation area and coil orientation on the results of navigated transcranial magnetic stimulation (nTMS) mapping of lower limb intracortical excitability

IF 2.3 4区医学 Q2 BIOCHEMICAL RESEARCH METHODS

Journal of Neuroscience Methods Pub Date : 2025-08-20 DOI:10.1016/j.jneumeth.2025.110559

Ralf Becker , Sabrina Lorenz , Jan Coburger , Christian Rainer Wirtz , Andrej Pala , Thomas Kammer , Gregor Durner

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引用次数: 0

Abstract

Background

Transcranial magnetic stimulation (TMS) is widely used to assess corticomotor excitability. Coil orientation and stimulation location are crucial for eliciting motor-evoked potentials (MEPs) and determining resting motor thresholds (RMT). Since the cortical foot area is challenging to examine, identifying the optimal coil angle and location is essential.

Method

Eleven healthy volunteers underwent navigated TMS mapping using a predefined protocol. Stimulation was applied at six locations around the tibialis anterior (TA) motor hotspot, with coil direction varied in 45° increments. Mapping was performed using the Nexstim NBS 5.0 system, and statistical analysis was conducted in RStudio 2024.

Results

TA cortical representation mapping was successful in all participants. The mean hotspot was located in the precentral gyrus, 6–13 mm lateral to the midline. The highest MEP amplitude was observed at a stimulation angle of 90°, perpendicular to the falx cerebri.

Comparison with Existing Methods

Unlike previous studies with limited coil orientations or without MRI-guided neuronavigation, our approach systematically evaluated multiple directions and locations. The findings align with prior research regarding optimal stimulation sites and angles.

Conclusion

We refined the anatomical stimulation area and preferred angle for lower-extremity TMS. These findings may improve clinical applications, especially when considering individual and pathological differences.

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刺激区域和线圈方向对导航经颅磁刺激（nTMS）绘制下肢皮质内兴奋性结果影响的研究

经颅磁刺激（TMS）被广泛用于评估皮质运动性兴奋性。线圈的方向和刺激位置对于激发运动诱发电位（MEPs）和确定静息运动阈值（RMT）至关重要。由于皮质足区是具有挑战性的检查，确定最佳线圈的角度和位置是必不可少的。方法：即使是健康的志愿者也使用预先确定的协议进行导航TMS映射。在胫骨前肌（TA）运动热点周围的6个位置施加刺激，线圈方向以45°增量变化。使用Nexstim NBS 5.0系统进行制图，并在RStudio 2024中进行统计分析。结果所有受试者的皮层表征映射均成功。平均热点位于中央前回，中线外侧6-13 mm。在与大脑镰垂直的90°刺激角处，MEP振幅最大。与以往的研究不同，我们的方法系统地评估了多个方向和位置，不像以前的研究那样限制了线圈的方向或没有mri引导的神经导航。这些发现与之前关于最佳刺激位置和角度的研究一致。结论完善了下肢经颅磁刺激的解剖刺激区域和优选角度。这些发现可能会改善临床应用，特别是考虑到个体和病理差异。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Neuroscience Methods 医学-神经科学

CiteScore

7.10

自引率

3.30%

发文量

226

审稿时长

52 days

期刊介绍： The Journal of Neuroscience Methods publishes papers that describe new methods that are specifically for neuroscience research conducted in invertebrates, vertebrates or in man. Major methodological improvements or important refinements of established neuroscience methods are also considered for publication. The Journal''s Scope includes all aspects of contemporary neuroscience research, including anatomical, behavioural, biochemical, cellular, computational, molecular, invasive and non-invasive imaging, optogenetic, and physiological research investigations.