Hari R, Nagamine T, Nishitani N, Mikuni N, Sato T, Tarkiainen A, Shibasaki H
Department of Brain Pathophysiology, Kyoto University School of Medicine, Japan.
Neuroimage. 1996 Oct;4(2):111-8. doi: 10.1006/nimg.1996.0035.
We followed cortical activation in eight healthy adults after electric stimulation of the left tibial nerve at the ankle. The recordings were made noninvasively with a whole-scalp neuromagnetometer. The first cortical activation peaked in different subjects at 37-45 ms in the foot area of the right (contralateral) primary somato-sensory (SI) cortex, with mean source current orientation perpendicular to the longitudinal fissure. The current orientation changed within the next 5 ms counterclockwise in all subjects, with a mean rotation of 64 degrees. A two-dipole time-varying model, with two dipoles differing by 28-119 degrees in orientation but less than 1 cm in location in the right SI cortex, explained the signal pattern satisfactorily during the first 100 ms. We suggest that the observed field patterns reflect sequential activation of different cytoarchitectonic areas in the foot SI cortex and imply considerable differences in the structural organization between the foot and the hand SI cortices. The initial activation is considered to take place in area 3b facing the interhemispheric fissure, and the later source, due to the systematic rotations of the field patterns, is assumed to reflect activation of area 5 in the anterior wall of the marginal ramus of the cingulate sulcus.
我们对8名健康成年人在脚踝处电刺激左侧胫神经后进行了皮质激活情况的跟踪研究。记录是使用全头型神经磁强计进行的非侵入性测量。首次皮质激活在不同受试者中于37 - 45毫秒时在右侧（对侧）初级体感（SI）皮质的足部区域达到峰值，平均源电流方向垂直于大脑纵裂。在接下来的5毫秒内，所有受试者的电流方向均逆时针改变，平均旋转64度。一个双偶极时变模型，其中两个偶极在右侧SI皮质中的方向相差28 - 119度，但位置相差小于1厘米，能够令人满意地解释最初100毫秒内的信号模式。我们认为观察到的场模式反映了足部SI皮质中不同细胞构筑区域的顺序激活，这意味着足部和手部SI皮质在结构组织上存在显著差异。最初的激活被认为发生在面对大脑半球间裂的3b区，而后期的源由于场模式的系统性旋转，被假定反映了扣带沟边缘支前壁5区的激活。
