The Vagus Nerve

What is the Vagus Nerve?

The Vagus nerve is cranial nerve 10 of the 12 cranial nerves. In latin, vagus means “wandering”. It got this name because it splits off and connects to many organs in the gut including the heart, lungs, kidney, large intestine, small intestine, and liver. The image below illustrates these connections.

(Image from http://www.net1device.com/interiorgif.htm)

The vagus nerve is known as a mixed nerve meaning it both receives input from the body and sends signals to various muscles and organs of the body. It isn’t an even mix, though, about 80% of the axons inside the vagus nerve are sending signals from the body to the brain (George et al. 2000). Yale provides a good overview of the mixed pathways to be discussed later at this link. The image below gives a general picture the locations of the brain stem that send signals via the vagus nerve, the regions of the brain that receive input from the vagus nerve, and exactly what those signals are important for..

Image from Goldberg's Neuroanatomy Made Ridiculously Simple

As shown in the above diagram, the signals that travel through the vagus nerve can be lumped into four categories – somatic motor, visceral motor, somatic sensory, and visceral sensory. The sensory signals are the ones coming into the brain, while the motor signals are the ones leaving the brain.

Next subsection:

What is vagus nerve stimulation?

Other Subsections:

What are cranial nerves?

What is the vagus nerve? (top of this page)

How does vagus nerve stimulation work?