Maioli Claudio, Falciati Luca, Marangon Mattia, Perini Sergio, Losio Antonio
Department of Biomedical Sciences and Biotechnologies, University of Brescia, Viale Europa 11, 25123 Brescia, Italy.
Eur J Neurosci. 2006 Apr;23(7):1931-8. doi: 10.1111/j.1460-9568.2006.04698.x.
The aim of this study was to investigate in humans the effects of acupuncture upon upper-limb motor-evoked potentials (MEPs), elicited by transcranial magnetic stimulation of the primary motor cortex. It is known that peripheral sensory stimulation can be used to induce short- and long-term changes in motor cortex excitability. Data show that the simple insertion of the needle is an adequate somatosensory stimulus to induce a significant modulation of MEP amplitude, the sign of which (facilitation or inhibition) is specific to the investigated muscle and to the point of needle insertion. Moreover, MEP changes in upper-limb muscles are also observed following needling of lower-limb sites, revealing the presence of long-distance effects of acupuncture. Finally, the modulation in muscle excitability considerably outlasts the time period of needle application, demonstrating the induction of long-term plastic changes in the central nervous system. In addition, results have shown that the effects on muscle excitability are not restricted to the stimulation of well-coded acupoints, as described in traditional Chinese medicine, but they can also be induced by needling of nonacupoints, normally not used for therapeutic purposes. The possible neuronal mechanisms underlying the observed effects of acupuncture are discussed in relation to the available neurophysiological data regarding the interlimb reflexes and the changes in the representational cortical maps induced in humans by a prolonged somatosensory stimulation.
本研究旨在探讨针刺对经颅磁刺激初级运动皮层所诱发的人类上肢运动诱发电位（MEP）的影响。已知外周感觉刺激可用于诱导运动皮层兴奋性的短期和长期变化。数据表明，单纯进针就是一种足够的体感刺激，可诱导MEP波幅发生显著调制，其调制的正负（易化或抑制）因所研究的肌肉及进针点而异。此外，针刺下肢穴位后也可观察到上肢肌肉MEP的变化，这表明针刺存在远距离效应。最后，肌肉兴奋性的调制在进针后相当长的时间内持续存在，表明中枢神经系统发生了长期的可塑性变化。此外，结果表明，对肌肉兴奋性的影响并不局限于传统中医所描述的对编码明确的穴位的刺激，针刺非穴位（通常不用于治疗目的）也可诱导这种影响。结合关于肢体间反射以及长时间体感刺激在人类中所诱发的皮层代表区图谱变化的现有神经生理学数据，讨论了针刺所观察到的效应背后可能的神经元机制。
