Niimi Maki, Ohira Takayuki, Akiyama Takenori, Hiraga Kenji, Kaneko Yousei, Ochiai Masato, Fukunaga Atsushi, Kobayashi Masahito, Kawase Takeshi
Department of Neurosurgery, School of Medicine, Keio University, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582, Japan.
Neurol Res. 2008 Apr;30(3):239-43. doi: 10.1179/016164107X230801. Epub 2007 Sep 10.
The aim of this study is to investigate a source of cortical magnetic fields evoked by index finger movements.
We analysed both movement-related cortical fields (MRCFs) and somatosensory-evoked fields (SEFs) by single equivalent current dipole (ECD) method in six healthy subjects. Dipole locations were superimposed on MR images of each individual subject.
The first component after finger movement (movement-evoked field I, MEFI) was observed in all subjects. The dipole of MEFI was oriented posteriorly, and was located on the posterior wall of the central sulcus of the hemisphere contralateral to the movement. The SEFs showed three major components: N20m, P30m and P60m. The dipoles of P30m and P60m were orientated posteriorly, similarly to the MEFI dipole, while that of N20m was orientated anteriorly. The dipole location of MEFI was closely located to P60m, not to N20m and P30m. The mean location of the MEFI dipole was significantly (p<0.05) superior to N20m.
These findings suggest that MEFI would be generated in the sensory area (area 3b) affected by multiple afferents and activities, and that the source of the MEFI is not identical to that of the N20m component.
本研究旨在探究食指运动诱发的皮质磁场源。
我们采用单等效电流偶极子（ECD）方法，对6名健康受试者的运动相关皮质场（MRCFs）和体感诱发电场（SEFs）进行了分析。将偶极子位置叠加在每个受试者的磁共振图像上。
所有受试者均观察到手指运动后的第一个成分（运动诱发场I，MEFI）。MEFI的偶极子向后定向，位于与运动对侧半球中央沟的后壁上。SEFs显示出三个主要成分：N20m、P30m和P60m。P30m和P60m的偶极子与MEFI偶极子一样向后定向，而N20m的偶极子向前定向。MEFI的偶极子位置与P60m紧密相邻，与N20m和P30m不相邻。MEFI偶极子的平均位置显著高于N20m（p<0.05）。
这些发现表明，MEFI可能在受多种传入神经和活动影响的感觉区域（3b区）产生，且MEFI的源与N20m成分的源不同。
