Vagal Nerve Stimulator

"Vagus nerve stimulation (VNS) is a medical treatment that involves delivering electrical impulses to the vagus nerve. It is used as an add-on treatment for certain types of intractable epilepsy and treatment-resistant depression." wikipedia

https://www.webmd.com/depression/vagus-nerve-stimulation

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4017164/

https://www.hopkinsmedicine.org/psychiatry/specialty_areas/brain_stimulation/tms/faq_tms.html