HUANG Jianpeng, LIU Jianhua, JIANG Li

（Guangdong Provincial Hospital，Guangzhou510120，Guangzhou）

Abstract:  Objective:  By observing the change of motor evoked potentials from Hegu acupoint and ora-facial area in the state of pathology, the object is to probe the mechanism of plasticity in across-representation of the cerebral motor cortex, which provides a basic evidence for the Meridian theory.  Method:  Transcranial magnetic  stimulation  was  applied  to  the  hand-representation  and  face-representation  in  motor  cortex before and after the forearm ischemic nerve block. Meanwhile,  the electromyography records the motor evoked potentials from the First dorsal interosseus and Orbicularis oculi muscle. Results: 1. The MEPs from First  dorsal  interosseus:  the  latentperiod  is  20.76±0.45  ms,the  amplitude  is  535.26±1.25  uV,  the  Motor threshold is 52.83±9.17%; the MEPs from Orbicularis oculi muscle: the latentperiod is 8.28±0.23 ms,the amplitude is 130.65±0.25 uV, the Motor threshold is 60.0±10.4 %; 2. In pathological conditions, the block of time is 40.61±3.60 minutes.With times’ extending, the area of hand-representation is narrowing.3. The latentperiod and the amplitude are significantly relative to the time of blocking. To dislodge ischemic nerve block, the hand area are recovered.  Conclusion：After INB, the MEPs from the target muscles show the changes  of  the  amplitude  and  the  amounts  of  the  stimulated  points.  It  may  be  one  of  the  biological mechanism of “the specific relation of ora-facial area and Hegu acupoint” in physiological condition.

Key  words  Acupuncture  and  moxibustion,  the  specific  relation  of  ora-facial  area  and  Hegu  acupoint, transcranial magnetic stimulation, ischemic nerve block, functional reorganization