“面口合谷收”的脑机制

"面口合谷收"是上千年来祖国医学在医疗实践中的经验总结,指位于手阳明大肠经的"合谷穴"能有效治疗大肠经远端循行所过部位"面口部"的疾患(如牙痛、面神经麻痹等).本研究采用单电极和阵列电极电生理技术探讨来自口面部和手部的传入在恒河猴感觉皮层神经元的位域关系,探讨"面口合谷收"的脑机制.在3b区可以记录到外周感受野分布在合谷穴区和口面部相互毗邻的神经元,也记录到合谷-下唇双感受野的会聚神经元.电生理学绘制3b皮层位域图的结果表明,这些神经元确实是在3b皮层并不重合但相互接壤.结扎正中神经和桡神经3个月后3b皮层拇指-口面交接部神经元能够发生可塑性变化.口面部刺激引起反应皮层位域明显扩大深入到拇指的皮层1~2 mm处,表明拇指皮层位域发生了明显的功能重组.本研究表明,"面口合谷收"的脑机制是相互间的接壤关系,并在神经损伤情况下会发生相互"入侵"的脑功能重组的可塑性变化.

Brain Mechanism Responsible for "the Treatment of Orofacial Diseases by Acupuncture at Hegu Acupoint"

"The treatment of orofacial diseases by acupuncture at Hegu (LI4)", as a conclusion of ancient physicians before more than 1000 years, exhibits the effect of acupuncture at Hegu point on orofacial diseases, such as toothache and facial paralysis. However, how to correlate Hegu and face and its biological mechanism still remain elusive. Here we investigated the relationship of the somatosensory cortex areas representing face and hands using single electrode and electrode array recording in macaco monkeys. We found that in 3b area, the neurons receiving signals from Hegu are neighboring to those areas receiving signals from the orofacial receptive field separately; the convergent neurons of Hegu and lower lip were also found. The somatopographic map based on the electrophysiological recordings showed that those units are neighboring to each other but not overlapping in 3b area. Three months after the ligations of the median nerve and musculospiral nerve, the plasticity could be found in the neurons adjacent in thumb-orofacial regions in 3b area of cortex; the region which was response to the orofacial stimulation was significantly enlarged to the depth of 1-2 mm in cerebral cortex of thumb, suggesting the functional reorganization in the cortex of thumb. Therefore, "the treatment of orofacial diseases by acupuncture at Hegu" exhibits the adjacent representing areas receiving signals from Hegu and face in the 3b somatosensory cortex separately, and functional reorganization as the representing area invasion may occur under pathological conditions.