Timing of Acupuncture during LTP-Like Plasticity Induced by Paired-Associative Stimulation.

Xiao-Kuo He,Xin-Yi Guo,Qian-Qian Sun,Cheng Chen,Li-Dian Chen,Hui-Hua Liu

doi:10.1155/2019/9278270

Abstract

The aim of this study was to investigate the time-dependent effects of acupuncture on the excitability and long-term potentiation- (LTP-) like plasticity induced by paired-associative stimulation (PAS) over the primary motor cortex (M1). The present examination is the first to report the influence of acupuncture on the motor-evoked potential (MEP) throughout the treatment process, including baseline (before acupuncture), the needle in situ, and the needle removal. Subsequently, the LTP-like plasticity induced by paired-associative stimulation (PAS) was explored, which consisted of 200 pairs of electrical stimulation of the ulnar nerve at the first dorsal interosseous (FDI), followed by transcranial magnetic stimulation (TMS) over the bilateral M1. TMS-MEP amplitudes over the bilateral M1 in resting conditions were measured throughout the whole treatment process. Finally, we confirmed the behavioral measurements. Significant changes were found in both the contralateral and ipsilateral acupuncture sizes as compared to the baseline values. Our results indicated that acupuncture modulated the excitability of M1, and the synaptic plasticity was time-dependent. We concluded that acupuncture should be combined with rehabilitation techniques to improve the motor function in stroke patients. Therefore, we put forward the combined application of the acupuncture timing and rehabilitation for higher therapeutic effectiveness. This trial was registered in the Chinese Clinical Trial Registry (registration no. ChiCTR-IPR-1900020515).

Highlights

Acupuncture is an ancient Chinese therapeutic method which has rapidly gained popularity all over the world
Paired-associative stimulation (PAS) was found to induce long-lasting bidirectional after-effects on M1 excitability depending on the interval between a pair of associative stimulation protocols [10]; these after-effects are referred to as long-term potentiation- (LTP-) like and long-term depression- (LTD-) like plasticity as they are thought to be dependent on mechanisms similar to those of synaptic plasticity studied at the cellular level [11]
motor practice (MP) caused an increase in first dorsal interosseous (FDI) muscle motor-evoked potential (MEP) amplitude as compared with the baseline values (1 16 ± 0 041; P < 0 001), whereas a decrease in MEP amplitude (0 61 ± 0 041; P < 0 001) occurred when pretreatment with acupuncture was implemented

Summary

Introduction

Acupuncture is an ancient Chinese therapeutic method which has rapidly gained popularity all over the world. Its mechanism of action remains uncertain, some studies provided further evidence in favor of the capacity of acupuncture to affect motor cortex excitability and plasticity [4,5,6,7]. The effects of acupuncture on TMS measures of the motor cortex excitability have been previously examined [4,5,6,7]. Paired-associative stimulation (PAS) was found to induce long-lasting bidirectional after-effects on M1 excitability depending on the interval between a pair of associative stimulation protocols [10]; these after-effects are referred to as long-term potentiation- (LTP-) like and long-term depression- (LTD-) like plasticity as they are thought to be dependent on mechanisms similar to those of synaptic plasticity studied at the cellular level [11]

Objectives

Methods

Results

Conclusion