Study On The Effect Of Electrical Acupuncture At TE5 Acupoint On Different Representations Of Motor Cortex In Healthy Subjects

ObjectiveLocal and remote acupoint selection is the basic principle of acupuncture and moxibustion.In present study,we observe the effect of electrical acupuncture(EA)at“Waiguan”point(TE5)on the motor cortical excitability of the forearm,hand,face,upper arm and leg representations in healthy volunteers,and explore the local and remote effects of acupoints with brain plasticity as the starting point,so as to provide the scientific evidence of acupoint selection and compatibility.MethodFall off into the standard of healthy volunteers 15 cases,including 3 male,age:23 to 34 years old.Each participant received real and sham electrical acupuncture in separate sessions,with a washout period of at least 2 weeks.The order of the exposures(real-sham or sham-real)was chosen randomly for each participant.In electrical acupuncture group,transcranial magnetic stimulation(TMS)mapping is performed on the forearm,hand,face,upper arm and legrepresentations of the motor cortex.In sham group,TMS is performed on the forearm and hand representations.The different TMS variables were then extracted:(1)sum of the average MEPs amplitude at each active site(SMEP),(2)representation area,(3)center of gravity(CoG).Result1.Effect of EA on forearm representationIn EA group,the SMEP of forearm representation increased significantly compared with that before EA(before vs after:6.5±4.7mv vs 8.3±6.1mv,P=0.023),the representation area and COG of forearm representation had no significant change(before vs after:19.7±4.3cm2 vs 21.1±6.4 cm2,P>0.05 for area;(6.0±0.7,7.9±2.0)vs 6.0±0.8,7.8±2.0,P>0.05 for COG).In sham group,there was no significant difference was found in any of three indexes in forearm representation.2.Effect of EA on hand representationIn EA group,the SMEP of hand representation increased significantly compared with that before EA(before vs after:12.5±6.9mv vs 15.8±9.4mv,P=0.009),the representation area and COG of hand representation had no significant change(before vs after:20.1±5.0 cm2 vs 21.3±5.6 cm2,P＞0.05 for area;(6.0±0.7,7.9±2.0)vs 6.0±0.8,7.8±2.0,P>0.05 for COG).In sham group,there was no significant difference was found in any of three indexes in hand representation.3.Effect of EA on face representationIn EA group,the SMEP of hand representation reduced significantly compared with that before EA(before vs after:6.0±4.1mv vs 5.2±3.6mv),the representation area and COG of hand representation had no significant change(before vs after:22.4±9.1 cm2 vs 20.5±7.7 cm2,P>0.05 for area;(7.3±1.4,6.5±1.3)vs(7.2± 1.5,6.5± 1.4),P>0.05 for COG).In sham group,there was no significant difference was found in any of three indexes in face representation.4.Effect of EA on upper arm and leg representationsThere were no significant changes in the SMEP(before vs after:9.1±4.4mv vs 10.0±6.0mv,P>0.05 for upper arm;4.2±2.0mv vs 4.3±2.1mv,P＞0.05 for leg),area(before vs after:20.5±5.8 cm2 19.7±5.3 cm2,P>0.05 for upper arm;15.0±4.6 cm2 vs 15.6±4.6 cm2,P>0.05 for leg)and COG(before vs after:(4.6±0.9,8.9± 1.3)vs(4.7±1.2,8.8± 1.4),P>0.05 for upper arm;1.2±0.5,8.9±1.4)vs(1.0±0.6,9.0±1.4),P＞0.05 for leg of upper arm and leg representations of motor cortex before and after the intervention.ConclusionThis study shows that electroacupuncture at Waiguan point has a co-activation effect on different parts of the upper limb,and a competitive inhibition effect on the face,but no significant effect on the leg.It is suggested that the near and far therapeutic effects of acupoints may be related to the extensive horizontal internal connection between different representations of motor cortex,which is of great guiding significance for local acupoint selection,remote acupoint selection and acupoint compatibility in clinical acupuncture.