Vagus nerve stimulation (VNS)

Vagus nerve stimulation delivers electrical pulses to the cervical vagus nerve through a surgically implanted cuff electrode, and is an FDA-approved therapy for drug-resistant epilepsy and for treatment-resistant depression. A noninvasive variant, transcutaneous auricular VNS, stimulates the vagal cutaneous branch at the ear. Mechanistically, VNS recruits vagal afferents that project to the nucleus tractus solitarius and, from there, engage broad neuromodulatory systems including the locus coeruleus noradrenergic and raphe serotonergic pathways.

VNS illustrates peripheral neuromodulation and closed-loop dosing: a cardiac-based responsive mode triggers extra stimulation on ictal tachycardia, the heart-rate surge that often precedes or accompanies a seizure. It is also the platform for paired-stimulation plasticity therapies, in which brief VNS is time-locked to a rehabilitation movement or a sensory event to enhance task-specific plasticity, a strategy cleared as an adjunct for upper-limb motor rehabilitation after stroke.