Kakigi R, Koyama S, Hoshiyama M, Shimojo M, Kitamura Y, Watanabe S
Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
Electroencephalogr Clin Neurophysiol. 1995 Aug;95(2):127-34. doi: 10.1016/0013-4694(95)00053-2.
The topography of somatosensory evoked magnetic fields (SEFs) following stimulation of the right and left posterior tibial nerves was investigated in 5 normal subjects (10 nerves). The main deflections N37m-P45m-N60m-P75m and their counterparts P37m-N45m-P60m-N75m were identified in the hemisphere contralateral to the stimulated nerve. Their equivalent current dipoles (ECDs) were located in the foot area of the primary sensory cortex (SI), probably in area 3b. Restricted minor deflections, P40m-N40m and N50m-P50m, were considered to be generated in area 1 in SI. As the generator sources of P37m-N37m, P40m-N40m and N45m-P45m were temporarily changed and interfered with each other, the direction of ECDs appeared to be rotated with the passage of time. Small middle-latency deflections, N100m-P100m, were clearly identified in 2 subjects. ECDs of these deflections were found in the second sensory cortex (SII), in both hemispheres, although they were clearer in the hemisphere contralateral to the stimulated nerve. In conclusion, short- and middle-latency SEFs are mainly generated in area 3b in SI contralateral to the stimulated nerve, and responses generated in area 1 of SI and SII affect the SEFs to some degree, but interindividual differences are large compared with SEFs evoked by upper limb stimulation.
在5名正常受试者（10条神经）中，研究了刺激右侧和左侧胫后神经后体感诱发磁场（SEF）的地形图。在受刺激神经对侧的半球中识别出主要偏转N37m - P45m - N60m - P75m及其对应成分P37m - N45m - P60m - N75m。它们的等效电流偶极（ECD）位于初级感觉皮层（SI）的足部区域，可能在3b区。受限的微小偏转P40m - N40m和N50m - P50m被认为是在SI的1区产生的。由于P37m - N37m、P40m - N40m和N45m - P45m的发生器源随时间临时变化且相互干扰，ECD的方向似乎随时间旋转。在2名受试者中清楚地识别出小的中潜伏期偏转N100m - P100m。这些偏转的ECD在双侧第二感觉皮层（SII）中被发现，尽管在受刺激神经对侧的半球中更明显。总之，短潜伏期和中潜伏期SEF主要在受刺激神经对侧的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，但与上肢刺激诱发的SEF相比，个体差异较大。
