Kakigi R
Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
Neurosci Res. 1994 Aug;20(2):165-74. doi: 10.1016/0168-0102(94)90034-5.
Topography of somatosensory evoked magnetic fields (SEFs) following stimulation of the median nerve were investigated in normal subjects. N20m-P30m-N40m-P60m and their counterpart, P20m-N30m-P40m-N60m, were identified in the hemisphere contralateral to the stimulated median nerve. Their equivalent current dipoles (ECDs) were considered to be located in the hand area of area 3b in the primary sensory cortex (SI). Restricted deflections, P25m and N25m, were considered to be generated in area 1 in SI. Therefore, short-latency deflections less than 40 ms were considered to be hybrids of ECDs generated in areas 3b and 1. Middle-latency deflections, N90m-P90m, were considered to be generated in the second sensory cortex (SII), but they were greatly affected by the much stronger fields generated in SI. The N30m deflection, which was a magnetic reflection of the N30 potential of somatosensory evoked potentials (SEPs), were widely recorded in the frontal area. The generator site of N30 of SEPs is considered to be the supplementary motor area (SMA). However, ECDs of N30m were located in SI, and no significant ECD generated in the frontal area including SMA was detected. No significant deflections other than small N90m-P90m in SII were identified in the hemisphere ipsilateral to the stimulated nerve. No significant deflections whose ECDs were generated in the mid-parietal area were identified. In conclusion, short- and middle-latency SEFs are mainly generated in area 3b in SI contralateral to the stimulated median nerve, and responses generated in area 1 of SI and SII affect the SEFs to some degree.
在正常受试者中研究了正中神经刺激后体感诱发电磁场（SEF）的地形图。在受刺激正中神经对侧的半球中识别出了N20m - P30m - N40m - P60m及其对应成分P20m - N30m - P40m - N60m。它们的等效电流偶极子（ECD）被认为位于初级感觉皮层（SI）3b区的手部区域。受限偏转P25m和N25m被认为是在SI的1区产生的。因此，小于40毫秒的短潜伏期偏转被认为是3b区和1区产生的ECD的混合。中潜伏期偏转N90m - P90m被认为是在第二感觉皮层（SII）产生的，但它们受到SI中产生的强得多的场的极大影响。N30m偏转是体感诱发电位（SEP）N30电位的磁反射，在额叶区域广泛记录。SEP的N30的发生器部位被认为是辅助运动区（SMA）。然而，N30m的ECD位于SI，在包括SMA在内的额叶区域未检测到明显的ECD产生。在受刺激神经同侧的半球中，除了SII中的小N90m - P90m外，未识别出其他明显的偏转。未识别出ECD在顶叶中部区域产生的明显偏转。总之，短潜伏期和中潜伏期SEF主要在受刺激正中神经对侧的SI的3b区产生，SI的1区和SII产生的反应在一定程度上影响SEF。
