Brain electrical source analysis of primary cortical components of the tibial nerve somatosensory evoked potential using regional sources
Brain electrical source analysis of primary cortical components of the tibial nerve somatosensory evoked potential using regional sources
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DOI：
10.1016/s0168-5597(98)00040-9
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发表时间：
1998-11-01
期刊：
影响因子：
--
通讯作者：
Treede, RD
中科院分区：
文献类型：
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作者：
Baumgärtner, U;Vogel, H;Treede, RD
胫神经体感诱发电位（SEP）显示较高的幅度同侧的刺激，而硬膜下记录显示在对侧半球的足部区域的源。我们现在通过在P40时间窗（34-46 ms）内进行脑电源分析来研究这种矛盾的偏侧化。刺激踝后胫神经（8例受试者）。在每一侧，2048个刺激施加两次。使用32个磁共振成像（MRI）验证的电极位置（带通0.5-500 Hz）记录SEP。在每种情况下，同侧（0.45 +/- 0.14 μ V）的P40振幅高于对侧（-0.49 +/- 0.16 μ V）。然而，最佳拟合区域源始终位于对侧半球，距中线的平均距离为8.2 ± 4.3 mm。阳性指向同侧由额向（P37）转移到顶向（P40）。P40的偶极矩比P37的偶极矩强2.5倍，这使得P40在EEG记录中最突出。然而，与切向P37偶极子相比，它的斜偶极子取向在MEG中被系统地低估了。偶极子方向解释了头皮电位分布的个体差异。SEP振幅较小时，产生在优势（左）半球。这可以通过位于左半球更深位置的源（5.4 +/- 1.6 mm）和更切向的方向（Delta theta = 17.5 +/- 2.3度）来解释。(C)1998爱思唯尔科学爱尔兰有限公司保留所有权利。
Tibial nerve somatosensory evoked potentials (SEPs) show higher amplitudes ipsilateral to the side of stimulation, whereas subdural recordings revealed a source in the foot area of the contralateral hemisphere. We now investigated this paradoxical lateralization by performing a brain electrical source analysis in the P40 time window (34-46 ms). The tibial nerve was stimulated behind the ankle (8 subjects). On each side, 2048 stimuli were applied twice. SEPs were recorded using 32 magnetic resonance imaging (MRI)-verified electrode positions (bandpass 0.5-500 Hz). In each case, the P40 amplitude was higher ipsilaterally (0.45 +/- 0.14 mu V) than contralaterally (-0.49 +/- 0.16 mu V). The best fitting regional source, however, was always located in the contralateral hemisphere with a mean distance of 8.2 +/- 4.3 mm from the midline. The positivity pointed ipsilaterally shifting from a frontal orientation (P37) to a parietal direction (P40). The P40 dipole moment was 2.5 times stronger than the dipole moment of P37, which makes P40 most prominent in EEG recordings. However, with its oblique dipole orientation compared to the tangential P37 dipole, it is systematically underestimated in MEG. Dipole orientations explained interindividual variability of scalp potential distribution. SEP amplitudes were smaller when generated in the dominant (left) hemisphere. This is explained by deeper located sources (5.4 +/- 1.6 mm) with a more tangential orientation (Delta theta = 17.5 +/- 2.3 degrees) in the left hemisphere. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.