Kim B S, Uchikawa Y, Kobayashi K, Kawakatsu M, Kotani M
School of Science and Engineering, Tokyo Denki University, Saitama, Japan.
Neurol Clin Neurophysiol. 2004 Nov 30;2004:95.
3-D magnetic measurements of the bilateral somatosensory evoked fields (SEFs) by electric stimulus to the right thumb for four normal subjects were carried out, using a three-dimensional (3-D) second-order gradiometer connected to 39-channel SQUIDs, which can detect magnetic field components perpendicular to the scalp (Br) and tangential to the scalp (Btheta, Bphi) simultaneously. To discuss the relationship between the phase lag and stimulus repetition frequency (SRF), the delay times of a component synchronous with the SRFs (1.99 to 27.02 Hz) were calculated by the convolution of the reference signal and the SEF wave (BPF: 15-40 Hz). The phase lag characteristic to the SRF in the contralateral hemisphere to the stimulus was linear in the ranges below 8 Hz and above 8 Hz in all magnetic components. The phase lag characteristic of the ipsilateral hemisphere to the stimulus was linear in only below-8 Hz in all components. It was tested for significance of the linear regression slope (beta not = 0, P<0.05).
对四名正常受试者通过电刺激右手拇指进行双侧体感诱发电场（SEF）的三维磁性测量，使用连接到39通道超导量子干涉仪的三维（3-D）二阶梯度仪，该梯度仪可同时检测垂直于头皮的磁场分量（Br）和切向于头皮的磁场分量（Btheta、Bphi）。为了探讨相位滞后与刺激重复频率（SRF）之间的关系，通过参考信号与SEF波的卷积（带通滤波器：15 - 40Hz）计算与SRF（1.99至27.02Hz）同步的分量的延迟时间。在所有磁分量中，刺激对侧半球中SRF的相位滞后特性在8Hz以下和8Hz以上范围内呈线性。刺激同侧半球的所有分量的相位滞后特性仅在8Hz以下呈线性。对线性回归斜率进行了显著性检验（β≠0，P<0.05）。
