The main objective of the study will be to investigate whether treatment with non-invasive vagus nerve stimulation (nVNS) on top of best medical practice in acute ischemic stroke patients results in less infarct growth in the penumbra and smaller infarct volumes compared with those of patients not treated with nVNS. The study will be a prospective randomized clinical trial with blinded outcome assessment (PROBE design). 150 patients will be randomized to nVNS with the gammaCore Sapphire™ device on top of best medical practice versus best medical practice alone (including intravenous thrombolysis and/or thrombectomy if indicated). If patients are randomized to nVNS, two stimulations of two minutes each will be applied in the neck every 15 minutes in the first 3 hours. Thereafter two stimulations will be applied every 8 hours over the next 5 days or until discharge, whichever occurs first. The stimulation side in the neck will be the radiological side of the stroke. The primary endpoint will be the final infarct volume on MRI scan on day 5 of patients treated with nVNS compared with those of patients not treated with VNS.