Capone Fioravante, Motolese Francesco, Cruciani Alessandro, Rossi Mariagrazia, Musumeci Gabriella, Norata Davide, Marano Massimo, Pilato Fabio, Di Lazzaro Vincenzo
Department of Medicine and Surgery, Unit of Neurology, Neurophysiology, Neurobiology and Psichiatry, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21 - 00128 Roma, Italy; Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo, 200 - 00128 Roma, Italy.
Department of Medicine and Surgery, Unit of Neurology, Neurophysiology, Neurobiology and Psichiatry, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21 - 00128 Roma, Italy; Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo, 200 - 00128 Roma, Italy.
Clin Neurophysiol. 2025 Jan;169:47-52. doi: 10.1016/j.clinph.2024.11.012. Epub 2024 Nov 26.
The mechanisms of actions of transcutaneous auricular vagus nerve stimulation (taVNS) are still unclear, however the activity of the cholinergic system seems to be critical for the induction of VNS-mediated plasticity. Transcranial Magnetic Stimulation (TMS) is a well-suited, non-invasive tool to investigate cortical microcircuits involving different neurotransmitters. Herein, we evaluated the effect of taVNS on short-latency afferent inhibition (SAI), a TMS paradigm specifically measuring cholinergic neurotransmission.
Fifteen healthy subjects participated in this randomized placebo-controlled double-blind study. Each subject underwent two different sessions of 1-hour exposure to taVNS (real and sham) separated by a minimum of 48 h. Real taVNS was administered at left external acoustic meatus, while sham stimulation was performed at left ear lobe. We evaluated SAI bilaterally over the motor cortex before and after exposure to taVNS.
No side effects were reported by any of the participants. Statistical analysis did not show any significant effect of taVNS on SAI.
Our study demonstrated that cholinergic circuits explored by SAI are different from circuits engaged by taVNS.
Since the influence of VNS on cholinergic neurotransmission has been exhaustively demonstrated in animal models, further studies are mandatory to understand the actual impact of VNS on cholinergic circuits in humans.
经皮耳迷走神经刺激（taVNS）的作用机制尚不清楚，然而胆碱能系统的活性似乎对迷走神经刺激介导的可塑性诱导至关重要。经颅磁刺激（TMS）是一种非常适合用于研究涉及不同神经递质的皮质微回路的非侵入性工具。在此，我们评估了taVNS对短潜伏期传入抑制（SAI）的影响，SAI是一种专门测量胆碱能神经传递的TMS范式。
15名健康受试者参与了这项随机安慰剂对照双盲研究。每位受试者接受两次不同的1小时taVNS暴露（真实和假刺激），间隔至少48小时。真实taVNS施加于左外耳道，而假刺激在左耳耳垂进行。我们在暴露于taVNS之前和之后双侧评估运动皮质的SAI。
所有参与者均未报告任何副作用。统计分析未显示taVNS对SAI有任何显著影响。
我们的研究表明，SAI所探索的胆碱能回路与taVNS所涉及的回路不同。
由于在动物模型中已充分证明迷走神经刺激对胆碱能神经传递的影响，因此必须进行进一步研究以了解迷走神经刺激对人类胆碱能回路的实际影响。
