Why it is important to work the vagus nerve when working with trigeminal problems.
The bridge of union is the anatomical connection
Within the medulla oblongata of the brainstem, there are 4 vagal nuclei, onto which axons of the vagus nerve emerge from or converge onto. These include:
- The dorsal motor nucleus
- The nucleus ambigus
- The solitary nucleus
- The spinal trigeminal nucleus
The dorsal motor nucleus supplies parasympathetic efferents primarily to the gastrointestinal tract and lungs. The efferent fibers that arise from the nucleus ambiguus supply the muscles of the soft palate, pharynx and larynx. It also gives rise to branchial efferent fibers and preganglionic parasympathetic neurons for the heart.
The solitary nucleus receives primary afferents from visceral organs, as well as taste information. Finally, the afferents that converge on the spinal trigeminal nucleus relay sensory information regarding pain, temperature and deep touch of the outer ear, the dura of the posterior cranial fossa and the mucosa of the larynx.
The vagus nerve exits the brain from the medulla oblongata of the brainstem. Specifically, the nerves emerge by a series of rootlets between the olive, or the olivary body, and the inferior cerebellar peduncle.
It then travels laterally exiting the skull through the jugular foramen. The sensory ganglia of the the vagus nerve consists of a superior and inferior ganglionic swelling. The vagus nerve is joined by the cranial root of the accessory nerve , just after this inferior ganglion.
The vagus nerve trunk subsequently passes down the neck between the carotid artery and the internal jugular vein, within the carotid sheath. At the base of the neck, the nerve enters the thorax, however, the right and left vagus nerve take different paths after this point. The left vagus nerve travels anterior to the aortic arch, behind the primary left bronchus and into the esophagus. The right vagus nerve travels behind the esophagus and primary right bronchus.
Both left and right vagus nerves subsequently enter the abdomen through the esophageal hiatus of the diaphragm and follow their own individual path to their terminal branches.
The direct connection between V ( trigeminus) and X ( vagus) is the spinal trigeminal nucleus (SP5) caudal nucleus and responsible for the proprioception of the trigeminal nerve and is also sensitive.
But, also It is known that c-fos is a marker of SP 5 activity, if you want to act on a nucleus of the nervous system it is effective to work on the markers and that vagotomy decreased the activity of c-fos, therefore, in addition to an anatomical connection, a functional connection is also established.
That is to say, I need the vagus nerve to be intact. When the vagus nerve is electrically stimulated, it increases the connectivity of the neurons of the superior tract and that goes to the insula and the anterior cingulate cortex, reinforcing the synaptic connections between all these structures.
It is important because in clients with migraine because there is a relationship between the connectivity of these structures and migraine attacks, the more connectivity the space between crises and crises are lengthened, so they are reduced in time, so that in addition, the catastrophizing of your client to new migraine situations are reduced, therefore the chronicity also lowers, and the client puts less focus on this and the new cognition reinforces the improvement, breaking the loop.
In addition, this stimulation of the vagus inhibits trigeminal pain, and also inhibits the activity of microglia and SP5 astrocytes.