Where and what TMS activates: Experiments and modeling
Where and what TMS activates: Experiments and modeling
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DOI：
10.1016/j.brs.2017.09.011
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发表时间：
2018-01-01
影响因子：
7.7
通讯作者：
Ugawa, Yoshikazu
中科院分区：
文献类型：
--
作者：
Laakso, Ilkka;Murakami, Takenobu;Ugawa, Yoshikazu
背景：尽管最近在导航和建模技术方面取得了进展，但经颅磁刺激（TMS）激活的结构的类型和位置仍然未知。目的：研究电生理测量与脑内电场的关系，定位经颅磁刺激的激活位点。方法：19例（女性7例，男性12例，年龄22 +/- 4岁）采用前内侧定向单相经颅磁刺激（TMS）在左侧初级运动皮质（M1）上方多个位置记录第一背骨间肌的活动和静息运动阈值。结构磁共振图像用于构建每个受试者头部和大脑的电场模型。通过寻找计算的电场最能解释所测量的MTs的线圈位置依赖性的位置来估计皮层激活位点。结果：实验和建模显示了测量的运动阈值（MTs）和计算的电场的个体差异。当TMS线圈在头皮上移动时，手旋钮区域的计算电场与测量的mt值变化一致。组水平分析表明，电场与测量的mt值显著相关，相关性最强（R-2 = 0.69），这表明最有可能激活的部位是手旋钮的腹侧和外侧。该部位与目标肌肉的随意收缩无关。结论：本研究表明，经颅磁刺激结合个性化电场建模可用于运动皮层的高分辨率制图。(c) 2017 Elsevier Inc.版权所有。
Background: Despite recent developments in navigation and modeling techniques, the type and location of the structures that are activated by transcranial magnetic stimulation (TMS) remain unknown.Objective: We studied the relationships between electrophysiological measurements and electric fields induced in the brain to locate the TMS activation site.Methods: The active and resting motor thresholds of the first dorsal interosseous muscle were recorded in 19 subjects (7 female, 12 male, age 22 +/- 4 years) using anteromedially oriented monophasic TMS at multiple locations over the left primary motor cortex (M1). Structural MR images were used to construct electric field models of each subject's head and brain. The cortical activation site was estimated by finding where the calculated electric fields best explained the coil-location dependency of the measured MTs.Results: The experiments and modeling showed individual variations both in the measured motor thresholds (MTs) and in the computed electric fields. When the TMS coil was moved on the scalp, the calculated electric fields in the hand knob region were shown to vary consistently with the measured MTs. Group-level analysis indicated that the electric fields were significantly correlated with the measured MTs. The strongest correlations (R-2 = 0.69), which indicated the most likely activation site, were found in the ventral and lateral part of the hand knob. The site was independent of voluntary contractions of the target muscle.Conclusion: The study showed that TMS combined with personalized electric field modeling can be used for high-resolution mapping of the motor cortex. (c) 2017 Elsevier Inc. All rights reserved.