Most human behaviour involves a part of the body few people know about - the vagus nerve. In his brilliant book, “My Grandmother’s Hands”, Resmaa Menakem beautifully calls the vagus nerve, the soul nerve, as it is this unifying organ of the entire nervous system that in many ways defines what it means to be human.
It is now widely acknowledged in the field of psychological trauma treatment that the distressing symptoms of traumatic stress are largely experienced in the body. Clients will often locate body based processes like tightness in the chest, a churning in the gut, a knot in the throat, or shaking in the legs. So, in order to heal trauma we must turn toward the body as part of the recovery process. As a result, there has been a surge in the use of ancient practices such as yoga, mindfulness, Tai chi, Qigong, Feldenkreis, Rolfing, Cranialsacral Therapy both as therapeutic modalities, or as an adjunct to psychological therapy.
The word vagus means “wandering” in Latin and it is an apt description of the soul nerve as it wanders from the brainstem down to the abdomen. Many nerves have either sensory or motor function, while the soul nerve does both, which is why it is not a nerve in the way most scientists typically think of one. It is a highly complex and extraordinarily sensitive organ that communicates through sensations and subtle movements. This communication occurs not only between different parts of an individual’s body, but also between different bodies. Your soul nerves reaches into most of your body, including your throat, lungs, heart, stomach, liver, spleen, pancreas, kidney, and gut (both the large and small intestines). It is the largest organ in the body’s autonomic nervous system, which regulates all of your body’s basic functions. It is also heavily involved in the critical body functions of digestion, respiration, and heart rate. It operates as a two-way communication highway as information flows back and forth from the organs to the brain. Through the vagus, the brain is able to know if all is well in the body, and if it’s safe to relax.
The largest part of the soul nerve goes through your gut, which has about 100 million neurons, more than your spinal cord. This is why we sense so many things in our belly (commonly referred to as a “gut instinct”) - and why some biologists call our gut our “second brain”. The second brain is where our body senses coherence, flow or the rightness or wrongness of things.
To better understand the critical role this nerve plays, it can be helpful to zoom out and look at more of what the nervous system does and how it stays in balance. Your nervous system is divided into your Central Nervous System (CNS) - made up of your brain and spinal cord - and Peripheral Nervous System (PNS) - which connects the CNS to the rest of your body. Your PNS is further divided into your voluntary (i.e., stretching your arms overhead) and involuntary actions (i.e., breathing). According to the Polyvagal Theory, the Autonomic Nervous System (largely the involuntary actions) comprises a three-part hierarchical structure: the Dorsal Vagal system, the Sympathetic Nervous system, and the Ventral Vagal system. The Dorsal Vagal system, which is oldest of the systems, is part of the Parasympathetic Nervous system. The Dorsal Vagal nerve immobilises the body in response to life threatening situations by facilitating a shut-down response. The Sympathetic nervous system, which is comparatively newer to evolve, mobilises the body in response to threat by activating the fight-or-flight response. It’s estimated that 75% of all Parasympathetic nerve fibers come from the vagus nerve and when these are activated, the involuntary processes mentioned earlier (digestion, respiration, and heart rate function) can happen. However, for our Parasympathetic system to activate, our stress levels need to be relatively low.
Most importantly, mind-body therapies help to activate the Ventral Vagal system, which is the newest and most evolved of the structures. This “social engagement” system is the branch of the parasympathetic nervous system that helps you relax and connect to others when you feel safe. The challenge with trauma survivors is that the body’s stress response is triggered constantly, from both external and internal stimuli (triggers). And since the nervous system doesn’t know the difference between what’s life-threatening and what’s not, it responds the same way to all of these stresses, leading to feelings of chronic unsafety.
A key piece of trauma treatment then is how we can actively work to strengthen our parasympathetic and thus the soul nerve function to feel safe when you are actually in conditions of safety. With an increasing number of people living in a state of constant stress (but seldom under current conditions of actual life threat), the knowledge that there are practices that are imbedded into various therapeutic modalities (Internal Family Systems Therapy, EMDR, Sensorimotor Psychotherapy, Somatic Experiencing, The Comprehensive Resource Model) to support bringing balance and safety back into our bodies is profound. Additionally, strengthening the soul nerve function helps decrease inflammation, lower heart rate, and blood pressure, while most importantly boosting emotional resilience. Your soul nerve is therefore vital to your health and well-being. Without it, you literally would not be human.