Glossary
Vagus Nerve
What is the vagus nerve?
The vagus nerve, also called the vagal nerve or tenth cranial nerve (cranial nerve X), connects the brainstem with structures including organs in the chest and abdomen. It carries sensory information toward the brain and signals that help regulate organ function.
The name vagus means “wandering” in Latin, referring to the nerve’s extensive course through the body. It is a mixed nerve: its fibers carry both sensory information and motor signals.
Functions
Parasympathetic regulation
The vagus is a major part of the parasympathetic nervous system, often described as “rest and digest.” It contributes to regulation of functions such as heart rate and digestion. Vagal activity is not a single measure of relaxation.
Communication with internal organs
Vagal pathways connect the brain with the heart, lungs, and gastrointestinal tract. This is communication in both directions.
Neurotransmission and immune signaling
Acetylcholine is involved in vagal signaling. Vagal pathways also participate in studied neural-immune processes, including cholinergic anti-inflammatory pathways.
Associated conditions and treatments
Gastroparesis involves delayed stomach emptying and can result from vagal damage. It can involve nausea, vomiting, bloating, and reduced appetite; its cause and treatment require assessment.
Vagus nerve stimulation (VNS) uses electrical stimulation of the nerve. Implanted VNS has medical uses including selected epilepsy and depression cases. Evidence depends on the treatment, protocol, and patient group.
Why it matters
The vagus nerve helps connect brain and body regulation. Evidence about a biological pathway does not establish that every intervention described as vagal stimulation has a clinical benefit.