| Objectiveto compare the effects of paired associative electroacupuncture and transcranial magnetic stimulation(PAET)and traditional paired associative stimulation(PAS)on the excitability of human motor cortex in healthy volunteers,and to explore whether PAET can induce long-term potentiation(LTP)and long-term depression(LTD)effects,so as to provide a scientific basis for whether PAET can be used as a new treatment mode.Methods22 healthy volunteers were included in this study,4 of them fell off,and 18 were included in the analysis,including 10 males and 8 females,aged from 18 to 27 years old,with an average of 21.3 years old.Using the crossover design(Self-control of the same body),all subjects took part in experiment 1 first,they randomly received four interventions,including PAET25 group,PAS25 group,PAET 10 group and PAS 10 group,15 subjects among them were randomly assigned to simple electroacupuncture group and simple rTMS group according to random sequence in trial 2.The elution period between groups was one week.The frequency of associative stimulation in each group was 0.25Hz,and the electrical and magnetic stimuli were sent out almost at the same time.The total duration of stimulation was 15 minutes.Both PAET25 and PAET 10 groups received paired associative electroacupuncture(at "Neiguan" point,P6)and transcranial magnetic stimulation.The intensity of TMS was able to elicit MEPs of 1 mv(MEPs-lmv),and the intensity of electroacupuncture was to observe the muscle twitch of the right hand according to the subjects’s tolerance,but it was not more than 3 times the sensory threshold.Electrical stimulation preceded magnetic stimulation 25ms in PAET25 group,while the magnetic stimulation preceded electrical stimulation 10ms in PAET10 group.Both PAS25 and PAS 10 groups received paired percutaneous median nerve electrical stimulation and TMS stimulation.The intensity of TMS was MEPs-lmv,and the intensity of electrical stimulation was 3 times of the sensory threshold.Electrical stimulation preceded magnetic stimulation 25ms in PAET25 group,while the magnetic stimulation preceded electrical stimulation 10ms in PAET10 group.The simple electroacupuncture group received electroacupuncture stimulation,and the intensity of electroacupuncture was to observe the muscle twitch of the right hand according to the subjects’s tolerance,but it was not more than 3 times the sensory threshold.The rTMS group received rTMS stimulation,and the intensity of TMS was MEPs-1mv.Transcranial magnetic stimulation technique was used to record the amplitude,latency,resting motor threshold(RMT)and cortical resting period(CSP)of motor-evoked potentials(MEPs)at the best stimulation point of motor cortex corresponding to abductor pollicis brevis(APB)in right hand before and within 1 hour after intervention.Results1.Changes of excitability of motor cortex before and after intervention in each group(intra-group comparison)①Effect of PAET25 on excitability of motor cortex Compared with that before intervention,the MEPs amplitude(%)of the best stimulation point in PAET25 group increased with time(P<0.001),and the effect lasted for at least 60 minutes.There was no significant change in the CSP(%)(P=0.844).There was no significant change in the latency(%)(P=0.525).RMT decreased with time(P=0.024),and the effect lasted for at least 60 minutes.②Effect of PAS25 on excitability of motor cortex Compared with that before intervention,the MEPs amplitude(%)of the best stimulation point in PAS25 group increased with time(P<0.001),and the effect lasted for at least 60 minutes.The CSP(%)increased with time(P<0.001),and the effect lasted for at least 60 minutes.The latency(%)had no significant change(P=0.573).There was no significant change in RMT(P=0.087).③Effect of PAET10 on excitability of motor cortex Compared with that before intervention,the MEPs amplitude(%)of the best stimulation point in PAET10 group decreased with time(P<0.001),and the effect lasted for at least 60 minutes.There was no significant change in the CSP(%)(P=0.565).The latency(%)prolonged with time(P=0.009),and the effect lasted for at least 60 minutes.RMT increased with time(P=0.004),and the effect lasted for at least 60 minutes.④Effect of PAS10 on excitability of motor cortexCompared with that before intervention,the MEPs amplitude(%)of the best stimulation point in PAS10 group decreased with time(P<0.001),and the effect lasted for at least 60 minutes.There was no significant change in the CSP(%)(P=0.123).The latency(%)prolonged with time(P<0.001),and the effect lasted for at least 60 minutes.RMT increased with time(P=0.016),and the effect lasted for at least 60 minutes.⑤Effect of simple electroacupuncture on excitability of motor cortexCompared with that before intervention,there was no significant change in the MEPs amplitude(%)of the best stimulation point in the corresponding cortex after intervention in the electroacupuncture group(P=0.120).There is no significant change in CSP(%)(P=0.141),latency(%)(P=0.527)and RMT(P=0.790).Effect of simple electroacupuncture on the motor cortex:⑥Effect of simple rTMS on excitability of motor cortexCompared with that before intervention,there was no significant change in the MEPs amplitude(%)of the best stimulation point in the corresponding cortex after intervention in the rTMS group(P=0.110).There is no significant change in CSP(%)(P=0.083),latency(%)(P=0.482)and RMT(P=0.790).Comparison of intervention effects among groups①There was no significant difference in the change trend of MEPs amplitude(%)between PAET25 group and PAS25 group,and there was no significant difference in pairwise comparison at each time point(P=0.122).There was a significant difference in the changing trend of CSP(%)between the two groups(P=0.001).In the pairwise comparison at each time point,the CSP(%)in the PAS25 group was higher than that in the PAET25 group(P<0.05).There was no significant difference in the change trend of latency(%)between the two groups(P=0.695),and there was no significant difference in pairwise comparison at each time point(P>0.05).There was no significant difference in the change trend of RMT between the two groups(P=0.424),and there was no significant difference in pairwise comparison between the two groups at each time point(P>0.05).②There was no significant difference in the change trend of MEPs amplitude(%)between PAET10 group and PAS10 group,and there was no significant difference in the change trend of MEPs amplitude(%)between the two groups(P=0.331),and there was no significant difference in pairwise comparison between the two groups at each time point(P>0.05).There was no significant difference in the change trend of CSP(%)between the two groups(P=0.465),and there was no significant difference in pairwise comparison between the two groups at each time point(P>0.05).There was no significant difference in the change trend of latency(%)between the two groups(P=0.656),and there was no significant difference in pairwise comparison at each time point(P>0.05).There was no significant difference in the change trend of RMT between the two groups(P=0.253),and there was no significant difference in pairwise comparison between the two groups at each time point(P>0.05).ConclusionUnder physiological conditions,both PAET25 and PAS25 could increase the excitability of motor cortex,while both PAET10 and PAS 10 could reduce the excitability of motor cortex,and the effect lasted for at least 60 minutes.There was no significant difference between them,indicating that paired associative electroacupuncture and transcranial magnetic stimulation(PAET)can induce a sustained,stable and effective LTP or LTD effect similar to the traditional paired associative stimulation(PAS).It provides a preliminary scientific basis for PAET as a new treatment model and its application in the rehabilitation treatment of nervous system diseases. |
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