There is evidence that electroacupuncture (EA) acts through the modulation of brain activity, but little is known about its influence on corticospinal excitability of the primary motor cortex (M1).
Objective:
To investigate the influence of EA parameters on the excitability of M1 in healthy individuals.
Methods:
A parallel, double blind, randomized controlled trial in healthy subjects, evaluating the influence of an EA intervention on M1 excitability. Participants had a needle inserted at LI4 in the dominant hand and received electrical stimulation of different frequencies (10 or 100 Hz) and amplitude (sensory or motor threshold) for 20 min. In the control group, only a brief (30 s) electrical stimulation was applied. Single and paired pulse transcranial magnetic stimulation coupled with electromyography was applied before and immediately after the EA intervention. Resting motor threshold, motor evoked potential, short intracortical inhibition and intracortical facilitation were measured.
Results:
EA increased corticospinal excitability of M1 compared to the control group only when administered with a frequency of 100 Hz at the sensory threshold (p < 0.05). There were no significant changes in the other measures.
Conclusion:
The results suggest that EA with an intensity level at the sensorial threshold and 100 Hz frequency increases the corticospinal excitability of M1. This effect may be associated with a decrease in the activity of inhibitory intracortical mechanisms.
RossiniPMBarkerATBerardelliA, et al. Non-invasive electrical and magnetic stimulation of the brain, spinal cord and roots: basic principles and procedures for routine clinical application. Report of an IFCN committee. Electroencephalogr Clin Neurophysiol1994; 91(2): 79–92.
2.
VeldmanMPMauritsNMZijdewindI, et al. Progress in motor control: somatosensory electrical stimulation improves skill acquisition, consolidation, and transfer by increasing sensorimotor activity and connectivity. J Neurophysiol2018; 120: 281–290.
3.
StaggCJAntalANitscheMA. Physiology of transcranial direct current stimulation. J ECT2018; 34: 144–152.
RiddingMCMcKayDRThompsonPD, et al. Changes in corticomotor representations induced by prolonged peripheral nerve stimulation in humans. Clin Neurophysiol2001; 112(8): 1461–1469.
6.
TrudgenACirilloJByblowWD. Somatosensory and transcranial direct current stimulation effects on manual dexterity and motor cortex function: a metaplasticity study. Brain Stimul2019; 12(4): 938–947.
7.
SchabrunSMChipchaseLSZipfN, et al. Interaction between simultaneously applied neuromodulatory interventions in humans. Brain Stimul2013; 6: 624–630.
8.
SchabrunSMJonesECancinoELE, et al. Targeting chronic recurrent low back pain from the top-down and the bottom-up: a combined transcranial direct current stimulation and peripheral electrical stimulation intervention. Brain Stimul2014; 7: 451–459.
9.
LoYLCuiSL. Acupuncture and the modulation of cortical excitability. Neuroreport2003; 14: 1229–1231.
10.
BoschPde RoverPStaudteH, et al. Schizophrenia, depression, and sleep disorders: their traditional oriental medicine equivalents. J Acupunct Meridian Stud2015; 8(1): 17–22.
11.
KimYSHongJWNaBJ, et al. The effect of low versus high frequency electrical acupoint stimulation on motor recovery after ischemic stroke by motor evoked potentials study. Am J Chin Med2008; 36(1): 45–54.
12.
AndrewsRKSchabrunSMRiddingMC, et al. The effect of electrical stimulation on corticospinal excitability is dependent on application duration: a same subject pre-post test design. J Neuroeng Rehabil2013; 10: 51.
13.
VeldmanMPMaffiulettiNAHallettM, et al. Direct and crossed effects of somatosensory stimulation on neuronal excitability and motor performance in humans. Neurosci Biobehav Rev2014; 47: 22–35.
14.
ChipchaseLSSchabrunSMHodgesPW. Corticospinal excitability is dependent on the parameters of peripheral electric stimulation: a preliminary study. Arch Phys Med Rehabil2011; 92(9): 1423–1430.
15.
ChipchaseLSSchabrunSMHodgesPW. Peripheral electrical stimulation to induce cortical plasticity: a systematic review of stimulus parameters. Clin Neurophysiol2011; 122(3): 456–463.
16.
WhiteheadALJuliousSACooperCL, et al. Estimating the sample size for a pilot randomised trial to minimise the overall trial sample size for the external pilot and main trial for a continuous outcome variable. Stat Methods Med Res2015; 25: 1057–1073.
17.
ChenZXLiYZhangXG, et al. Sham electroacupuncture methods in randomized controlled trials. Sci Rep2017; 7: 40837.
18.
SahinNOzcanESezenK, et al. Efficacy of acupuncture in patients with chronic neck pain—a randomised, sham controlled trial. Acupunct Electrother Res2010; 35(1–2): 17–27.
19.
ChenCYKeMDKuoCD, et al. The influence of electro-acupuncture stimulation to female constipation patients. Am J Chin Med2013; 41(2): 301–313.
20.
GroppaSOlivieroAEisenA, et al. A practical guide to diagnostic transcranial magnetic stimulation: report of an IFCN committee. Clin Neurophysiol2012; 123(5): 858–882.
21.
YangYEisnerIChenS, et al. Neuroplasticity changes on human motor cortex induced by acupuncture therapy: a preliminary study. Neural Plast2017; 2017: 4716792.
22.
RossiniPMBurkeDChenR, et al. Non-invasive electrical and magnetic stimulation of the brain, spinal cord, roots and peripheral nerves: basic principles and procedures for routine clinical and research application. An updated report from an I.F.C.N. Committee. Clin Neurophysiol2015; 126(6): 1071–1107.
23.
MaioliCFalciatiLMarangonM, et al. Short- and long-term modulation of upper limb motor-evoked potentials induced by acupuncture. Eur J Neurosci2006; 23(7): 1931–1938.
24.
SilvaMLSilvaJRPradoWA. The antinociceptive effect of electroacupuncture at different depths of acupoints and under the needling surface. Chin Med2012; 7: 3.
25.
MuthalibMReRZucchelliL, et al. Effects of increasing neuromuscular electrical stimulation current intensity on cortical sensorimotor network activation: a time domain fNIRS study. PLoS ONE2015; 10(7): e0131951.
26.
IshimaruK. Analgesic effects induced by TENS and electroacupuncture with different types of stimulating electrodes on deep tissues in human subjects. Pain1995; 63(2): 181–187.
27.
McCambridgeABZaslawskiCBradnamLV. Investigating the mechanisms of acupuncture on neural excitability in healthy adults. Neuroreport2019; 30: 71–76.
28.
SunZGPiYLZhangJ, et al. Effect of acupuncture at ST36 on motor cortical excitation and inhibition. Brain Behav2019; 9(9): e01370.
29.
SchüttMClaussenJC. Desynchronizing effect of high-frequency stimulation in a generic cortical network model. Cogn Neurodyn2012; 6(4): 343–351.
30.
DoeltgenSHDalrymple-AlfordJRiddingMC, et al. Differential effects of neuromuscular electrical stimulation parameters on submental motor-evoked potentials. Neurorehabil Neural Repair2010; 24(6): 519–527.
31.
MangCSLagerquistOCollinsDF. Changes in corticospinal excitability evoked by common peroneal nerve stimulation depend on stimulation frequency. Exp Brain Res2010; 203(1): 11–20.
32.
CharltonCSRiddingMCThompsonPD, et al. Prolonged peripheral nerve stimulation induces persistent changes in excitability of human motor cortex. J Neurol Sci2003; 208: 79–85.
33.
SchabrunSMRiddingMCGaleaMP, et al. Primary sensory and motor cortex excitability are co-modulated in response to peripheral electrical nerve stimulation. PLoS ONE2012; 7(12): e51298.
34.
MacPhersonHAltmanDGHammerschlagR, et al. Revised STandards for Reporting Interventions in Clinical Trials of Acupuncture (STRICTA): extending the CONSORT statement. J Altern Complement Med2010; 16: ST1–ST14.
35.
ZunhammerMEichhammerPFranzJ, et al. Effects of acupuncture needle penetration on motor system excitability. Neurophysiol Clin2012; 42(4): 225–230.
36.
QiaoLNYangYSLiuJL, et al. Contribution of GABAergic modulation in DRGs to electroacupuncture analgesia in incisional neck pain rats. J Pain Res2019; 12: 405–416.
37.
MaSX. Neurobiology of acupuncture: toward CAM. Evid Based Complement Alternat Med2004; 1: 41–47.
38.
TremblaySBeauléVProulxS, et al. Relationship between transcranial magnetic stimulation measures of intracortical inhibition and spectroscopy measures of GABA and glutamate+glutamine. J Neurophysiol2013; 109: 1343–1349.
39.
LiMWangKSuWT, et al. Effects of electroacupuncture on metabolic changes in motor cortex and striatum of 6-hydroxydopamine-induced parkinsonian rats. Chin J Integr Med2020; 26(9): 701–708.
40.
HsiehCL. The physiological mechanisms of 2 Hz electroacupuncture: a study using blink and H reflex. Am J Chin Med2002; 30(2–3): 369–378.
