Naka D, Kakigi R, Koyama S, Xiang J, Suzuki H
Department of Integrative Physiology, National Institute for Physiological Sciences, Myodaiji, Okazaki, Japan.
Electroencephalogr Clin Neurophysiol. 1998 Apr;109(2):168-77. doi: 10.1016/s0924-980x(97)00080-5.
We studied the effects of interfering tactile stimulation applied to the foot ipsilateral and contralateral to the stimulation on somatosensory evoked magnetic fields (SEFs) following tibial nerve stimulation at the ankle. Equivalent current dipoles (ECDs) of all 4 components, 1M-4M, in all sessions were estimated to be very close each other, around the foot area of the primary sensory cortex (SI). The 1M, 2M and 4M components were significantly reduced in amplitude by the ipsilateral-foot interference, and we consider that this phenomenon is due mainly to 'saturation' of the neurons in area 3b of the SI. In contrast, the 3M component was significantly enhanced in amplitude by the contralateral-foot interference. We suspect that this result was due to the effects of neuronal activities in areas 2, 5 and/or 7, which receive inputs from both sides of the body, i.e. to 'bilateral function'. Considering the various types of interference effects on SEFs and somatosensory evoked potentials (SEPs) observed in not only the present, but also in the previous studies, we conclude that both SEFs and SEPs following tibial nerve stimulation are generated mainly by ascending signals mediated by cutaneous fibers of the peripheral nerves rather than the muscle afferents.
我们研究了在踝部刺激胫神经后，对刺激同侧和对侧足部施加干扰性触觉刺激对体感诱发电磁场（SEFs）的影响。在所有实验环节中，1M - 4M这4个成分的等效电流偶极子（ECDs）估计彼此非常接近，都在初级感觉皮层（SI）的足部区域附近。同侧足部干扰使1M、2M和4M成分的幅度显著降低，我们认为这种现象主要是由于SI区3b神经元的“饱和”。相反，对侧足部干扰使3M成分的幅度显著增强。我们推测这一结果是由于2区、5区和/或7区的神经元活动的影响，这些区域接收来自身体两侧的输入，即“双侧功能”。考虑到不仅在本研究中，而且在先前的研究中观察到的对SEFs和体感诱发电位（SEPs）的各种干扰效应，我们得出结论，胫神经刺激后的SEFs和SEPs主要由外周神经的皮肤纤维介导的上行信号产生，而不是肌肉传入神经。
