Vagal Nerve and Limbic System Regulation
The vagus nerve runs from the base of your brain, down your neck and then branches out in the chest, to your heart and stretches all the way down to the rest of your body and major organs.
This nerve has long been thought of as a "remarkable internal sensory system" as it works to regulate things like:
This nerve is a major pathway of communication to the brain and carries an extensive range of signals from our digestive system and organs to the brain and vice versa.
The most important function of the vagus nerve is afferent, bringing information from the inner organs (gut, liver, heart, and lungs) to the brain.
This suggests that the inner organs are major sources of sensory information to the brain and the vagal nerve is how they communicate.
The vagal nerves represent the main component of the parasympathetic nervous system, a whopping 75% of our parasympathetic nerves in our PSNS are vagal nerves and they connect to major organs and assist in regulation of our mood, immune responses, digestion, and heart rate.
The parasympathetic nervous system is a subdivision of the autonomic nervous system (ANS) which regulates the bodily functions which are outside of our voluntary control, therefore being automatic.
You may know it as “rest and digest” because it’s the system that provides us with relaxation once an emergency or high stress situation has passed. When stressed, the PSNS triggers the necessary responses in order to return the body to homeostasis.
One of these responses is the release of acetylcholine (Ach).
ACh is a neurotransmitter that plays a role in muscle movement, thinking, working memory, and other aspects of the brain. ACh binds to nicotinic and muscarinic receptors and stimulates muscle contractions in the parasympathetic nervous system. Low levels have been associated with memory impairment and brain disorders.
If your parasympathetic nervous system is never being activated due to chronic stress either being sent from
1) chronically inflamed organs constantly sending stress signals to the brain
2) life/emotions/stress constantly sending stress signals to the brain
then your vagus nerve is also never being activated and your body isn’t releasing ACh.
Without an active PSNS, the body will be in a consistent state of elevated stress responses and the regulation of our everyday bodily processes will be dysfunctional, such as being unable to digest food or control our bladder.
The PSNS, therefore, plays a vital role in both physical and mental health through helping the body to calm down from stress reactions that can cause adverse effects such as elevating blood pressure.
Low vagal tone is associated with:
Poor emotional regulation
Used as a measurement for a person's sensitivity to stress
Meanwhile, a healthy vagal tone is associated with the opposite: positive emotions and psychological balance and studies show that high vagal nerve activity predicts better cancer prognosis
Vagal Nerve Stimulation
Singing, literally just singing your favorite songs, humming, chanting, etc.
Cold Exposure (2 min cold shower)
Walking in nature
Anything that relaxes you
Gut microorganisms can also activate the vagus nerve
If the nerves in this system are damaged, this can interfere with messages being sent between the brain and organs such as the heart, blood vessels and sweat glands. If the PSNS is under active it may result in symptoms such as having constantly high blood pressure and heart rate. This is because the parasympathetic is unable to function properly to calm down the body after times of stress and if left unchecked it can cause an array of different issues including:
Ø Digestive issues
Ø Bladder dysfunction
Ø Abnormal sweating
Ø Lack of pupillary response
Ø Lack of salivation
Ø Bowel issues
Ø Being unable to control internal body temperature.
Ø Visual problems, e.g. blurriness
If we want our vagus nerve to send positive signals back to the brain we need to elicit positive reactions in our vital organs, meaning taking the time to heal vital bodily systems so they no longer continue to send out distress signals to the brain.