The Vagus Nerve

In Helpful Stuff, Latest Research by christine

The Vagus Nerve

(and its importance to you overall wellbeing!)

Many people are not familiar with the vagus nerve, and yet it is paramount to our overall health.  Deriving an understanding of the vagus nerve offers a concreteness to why many health practitioners promote the concept of “holistic” wellbeing (in other words: everything is interconnected – we cannot effectively treat a symptom such as the ones that present with an autoimmune disease without looking at the psychological and emotional wellbeing of an individual).  

So, what is the vagus nerve?

The vagus nerve is the longest of the cranial nerves and passes through the neck and thorax to the abdomen connecting the brain to major systems in the body including the stomach, gut, heart, lungs, throat, and facial muscles.  The vagus nerve controls your inner nerve centre – the parasympathetic nervous system.  While some cranial nerves in our bodies have either sensory or motor functions, others have both.  The vagus nerve is one such a nerve and oversees a vast range of crucial functions, communicating motor and sensory impulses to every organ in your body. 

The sensory functions of the vagus nerve are divided into two components: Somatic components (such as sensations felt on the skin) and Visceral components (sensations felt in the organs of the body).

Polyvagal Theory

A pioneer in the field of behavioural neuroscience, Stephen Porges is responsible for the development of something known as “Polyvagal Theory”.  Polyvagal Theory explores the connections between early attachment (parent-child attunement – for more on this see: https://blacksheepcounselling.com/2017/12/attachment/), traumatic exposure, and your health as related to the functioning of the vagus nerve.

Porges’ Polyvagal Theory Polyvagal (PVT) posits that there are three functions of the autonomic nervous system: social communication, defensive mobilization, and defense immobilization.  Getting stuck in defense-responses is a key symptom of vagus nerve disorders such as post-traumatic stress disorder, “PTSD” (for more on post-traumatic stress, see: https://blacksheepcounselling.com/2017/08/post-traumatic-stress-a-systemic-disorder/).

The social communication system (also know as the “ventral vagal complex”) is the branch of the vagus nerve responsible for having a calming, soothing effect and also your facial expressivity.  The social nervous system oversees both the expressive and receptive domains of verbal communication such as guiding the rhythm and tone of your speech and contributing to the meaning of your communications.  Your social nervous system augments your ability to listen to others by picking up on others’ micro-expressions (emotional nuances within communications), as well as increasing empathic attunement.  The social communication system is greatly affected by those who have experienced long-term, chronic trauma exposure as they often lose the ability to accurately assess whether people or their environments are safe (their distress response can become highly activated when no actual threat is present, creating the individual to feel anxiety, panic, overwhelm or despair).  PVT has been a major scientific breakthrough in that it has moved previous research in the study of things like dissociative disorders from the so-called “soft-science” type of research to what can be considered “hard-science” (using tools like PET and fMRI). 

Bioelectronics

In reaction to the success of vagal nerve stimulation to treat inflammation and epilepsy, there is a rapidly growing branch of medical sciences known as bioelectronics.  Bioelectronics uses implants to deliver electric impulses to various areas of the body as a means of treating illness with fewer medications and fewer side effects.   Research has determined that the vagus nerve prevents inflammation.  While a certain amount of inflammation related to injury or illness is considered normal, an overabundance is linked to diseases and conditions such as sepsis, rheumatoid arthritis, fibromyalgia and other autoimmune diseases.  The vagus nerve operates a wide network of fibers working in conjunction with your organs.  When the nerve receives a signal for emerging inflammation (the presence of cytokines or a substance called tumor necrosis factor), it alerts the brain and draws out anti-inflammatory neurotransmitters that regulated the body’s immune response.   

There is promising research that stimulating the vagus nerve may contribute to the treatment of Alzheimer’s disease as lab studies have evidenced that stimulating the vagus nerve strengthens memory by releasing the neurotransmitter norepinephrine into the amygdala, which consolidates memories. 

Additional facts related to the vagus nerve

  • It is linked to your intuition, your “gut-feeling”. The vagus nerve tells your brain how you are feeling via electric impulses called “action potential”. 
  • It works closely with your heart. The vagus nerve is responsible for controlling your heart rate via electrical impulses to specialize muscle tissue (the heart’s natural pacemaker) in the right atrium, where acetylcholine release slows the pulse.  Doctors determine you heart rate variable (HRV) by measuring the time between your individual heart beats, and then plotting this on a longitudinal chart. 
  • It awakens your body’s relaxation response. When your distress response is activated and flooding your system with the stress hormone cortisol and adrenaline, the vagus nerve tells your body to chill out by releasing acetylcholine.  The vagus nerve’s tendrils extend to many organs sending instructions to release enzymes and proteins like prolactin, oxytocin, and vasopressin which aid in providing a sense of calm.  The stronger one’s vagus is, the more likely they will be able to recover after injury, stress, and illness.
  • It helps you breathe. The vagus nerve elicits the neurotransmitter acetylcholine signaling your lungs to take in oxygen.
  • Recent research conducted at the Icahn School of Medicine at Mount Sinai established the vagus nerve as an essential component of the brain system that regulates reward and motivation. The discovery of right gastrointestinal vagal neurons as conveyers of reward signals can be used to inform future treatment approaches for those suffering from substance abuse, eating, and emotional disorders.
  • Fun facts:
    -the name “vagus” is derived from the Latin meaning “wandering” because it wanders sending out sensory fibers from the brain stem through organs in the neck, throat, and abdomen-the vagus nerve was historically cited as the “pneumogastic” nerve

“A healthy vagus nerve supports your digestive system, helps to regulates your sleep patterns, and calms down your nerves. Learning to regulate vagal tone is associated with a reduction in inflammation and better prognosis in people suffering from chronic illness, migraines, auto-immune disorders, anxiety, and depression. Healthy vagal tone involves engaging your social nervous system. You can learn to manage the symptoms of vagus nerve disorders by skillfully working with your mind and body to tone your vagus nerve. Mind-body therapies* effectively increase your resilience by helping you develop your capacity to feel safe, calm, and connected—even during times of stress.”  -Dr. Arielle Schwartz

*Mind-body therapies include behavioural, psychological, social, expressive, and spiritual approaches to wellbeing.  Examples include somatic psychotherapy, talk therapy, Eye Movement Desensitization Reprocessing (EMDR), meditation, mindfulness, and self-compassion practices, prayer, guided imagery, Yoga, neurofeedback, Observed and Experiential Integration (OEI), Urge Surfing, hypnosis, brainspotting, dance, art, and music therapy, massage therapy, Feldenkrais Method, Pilates, progressive muscle relaxation, Qigong, Tai Chi, and others.  Mind-body therapies are also clinically referred to as Complementary and Alternative Medicine (CAM). 

~Christine 

References:

Banich, M. T., & Compton, R. J. (2011).  Cognitive neuroscience (3rd ed.).  Belmont, CA:  Wadsworth. 

Gut branches of vagus nerve essential components of brain’s reward and motivation system (2018, September 21).  Neuroscience News.  Retrieved from https://neurosciencenews.com/gut-reward-motivation-9899/

Rosenfeld, J. (2015, July 2).  9 fascinating facts about the vagus nerve.  Mental Floss.  Retrieved from http://mentalfloss.com/article/65710/9-nervy-facts-about-vagus-nerve