TMS as a Tool for the Evaluation of Neuromodulatory Effects of Transcutaneous Vagus Nerve Stimulation

Transcutaneous vagus nerve stimulation (tVNS) has been investigated as a potential treatment for epilepsy with inconsistent results. The combination of transcranial magnetic stimulation with electromyography (TMS-EMG) and electroencephalography (TMS-EEG) allows to investigate the neuromodulatory effect of interventions such as tVNS by evaluating changes in motor evoked potentials (MEPs) and TMS-evoked potentials (TEPs). The goal of this study is to objectively evaluate the effect of tVNS on cortical excitability with TMS-EMG and TMS-EEG. These findings are expected to provide insight in the mechanism of action and help identify more optimal stimulation paradigms. In this prospective single-blind cross-over study, 15 healthy subjects will undergo active and sham tVNS during 60 minutes, using a maximum tolerated stimulation current. Single and paired pulse TMS will be delivered over the right-sided motor hotspot to evaluate MEPs and TEPs before and after the intervention.