循经感传过程中大脑皮层体觉区诱发电位的观察

<正> 循经感传现象是最常见的经络现象之一,研究循经感传的形成机理问题对进一步探讨经络的实质有重要的意义。目前对形成循经感传的特殊路线和规律的机理存在着“外周”“和“中枢”两种不同观点。因此,有必要对这个问题作进一步的研究。一般认为皮层诱发电位在一定程度上可以反映感觉的传入活动过程。本文对循经感传显著者在感传过程中的皮层体觉诱发电位的特点进行了观察,为探讨形成循经感传的机理及其与中枢神经系统的关系提供一些资料。

INVESTIGATION ON THE CORTICAL SOMATOSENSORY EVOKED POTENTIALS DURING THE ADVANCE OF THE PROPAGATED SENSATION ALONG CHANNELS

For the purpose of studying the mechanism of the propagated sensation along channels (PSC) and clarifying the relationship between PSC and the central neuvous system, this paper was designed to observe the chara- cteristics of cortical somatosensory evoked potentials (SEP) in the subjects with marked PSC. The investigation was performed on 10 subjects, whose PSC was kept stable, distinct and could reach the head, and 16 subjects without PSC. Electrical stimulation was delivered to the Jiaxi or Hegu. SEP were recorded simultaneously from four scalp points: corresponding to the areas of foot, arm representation contralateral to the stimulated side and bilateral face representation of somatosory area I(SI). The results are shown as follows: 1. In addition to the PSC perceived by the subject, a complex poten- tial consisting of 5 elements (P_1, N_1, P_2, N_2, P_3) could be recorded from the point corresponding to the contralateral foot representation in stimu- lating Jiaxi in the subjects with marked PSC. Their mean peak latencies were 45.1±4.63, 57.1±5.71, 72.9±7.34, 84.8±11.1 and 106±10.4 msec, respectively. The mean amplitudes of components C_1, C_2, C_3, C_4, C_5, which were composed of N_0-P_1, P_1-N_1, N_1-P_2, P_2-N_2, N_2-P_2, were 0.47± 0.19, 0.87±0.47, 0.98±0.52, 1.68±1.24, 1.41±0.16μv, respectively. View- ing on the distribution characteristics of SEP, the amplitude was the lar- gest in contralateral foot representation area but decreased markedly in other areas. The similar distribution was observed in 16 subjects without PSC. 2. Comparing the SEP from the foot representation area of the sub- jects with marked PSC with that of the subjects without PSC, the ampli- tudes of the majority of the components in the former were smaller than those in the latter, but there was no significant difference (P>0.05) bet- ween the two groups except for components C_4-C_5. The amplitude of com- ponents C_4-C_5 in the subjects with marked PSC was 2.6±1.59μv, while in the subjects without PSC was 4.24±1.83, the difference was signifi- cant (P<0.05). In accordance with the reports that the components C_4- C-5 might have a close relation to the perceptive procese of the somatic stimulation, we also found that there was a positive correlation between componets C_4-C_5 and the intensity of the needling sensation. 3. The results similar to those mentioned above were also observed when hegu was stimulated. 4. Observation on imitation of PSC was carried out in 10 subjects without PSC. The method of imitation was as follows: a soft painting bru- sh was moved repeatedly along the Gall Blabder Channel from foot to fa- ce at a speed of 20 cm per sec. The mean amplitude of components C_4-C_5 was 2.84±0.57μv during imitation. The control values derived from the recording before and after imitation were 4.45±0.7 and 4.85±1.02μv, re- spectively. The amplitude of component C_4-C_5 was markedly decreased during imitation (P<0.01) but recovered completely after imitation. The results demonstrated that the amplitude of components C_4-C_5 in the subje- cts with marked PSC was nearly the same as that in the subjects without PSC during imitation (P>0.5). The decrement of the amplitude during imitation was just equal to the difference between the two groups. The results mentioned above revealed that SEP in the subjects with marked PSC differed from that in the subjects without PSC. Components C_4 -C_5 of the former were much smaller than those of the latter. It seem that during the advance of PSC the functional activities of SI of the cere- bral cortex were interfered by some factors, which led to the decrease of the amplitude of SEP. This is a sensory physiological evidence of the existence of the PSC in reality. However, the cause of the interference remains to be further carified. Based on the results of imitation of PSC and the fact that the irradiation of excitation is limited by the surround inhibition and other mechanisms in somatosensory system, of which this is an important characteristic feature, it could be expected that the inter- ference of the functional activities of SI may be a reflection of the ac- tivation of the peripheral nerve fibers and receptors insequence by a certain agent advancing along the channels.