A Conceptual Review of Vagus Nerve Stimulation: From Neuroanatomy to Clinical Applications

The vagus nerve (cranial nerve X) is the longest and most widely distributed cranial nerve. It acts as the main parasympathetic link between the brainstem and the organs of the chest and abdomen. The vagus nerve arises from four nuclei in the brainstem, leaves the skull through the jugular foramen, travels within the carotid sheath, and gives off organ-specific branches in the neck, thorax, and abdomen. It carries parasympathetic, branchial motor, visceral sensory, and somatic sensory fibers, allowing two-way communication between the brain and the body. Vagus nerve stimulation (VNS) is a neuromodulation technique that delivers electrical impulses to the vagus nerve to modulate central and autonomic nervous system activity.¹ It is an established therapy for drug-resistant epilepsy and treatment-resistant depression, with growing evidence in post-stroke rehabilitation, obesity, migraine, cluster headache, and inflammatory disorders.² This article reviews the anatomical basis, mechanisms, clinical applications, adverse effects. The FDA has approved another vagus nerve stimulation device for use after a stroke. For people who have trouble using their hand or arm after a stroke, the device helps make new pathways in the brain during exercise. This can help people regain the use of the affected hand or arm.8