What is the Polyvagal Theory?
We used to believe that our nervous systems had two states: rest & digest (parasympathetic), or fight & flight (sympathetic). The polyvagal theory identifies a third type of nervous system state: the social engagement system. The social engagement system helps us navigate relationships.
The polyvagal theory explains that as human beings we have three distinct nervous system states that support different types of behaviour.
When a person feels safe enough, ventral vagal neural circuitry supports social engagement, and is part of our parasympathetic nervous system.
When a person feels threatened, our sympathetic nervous system mobilizes us to flee or fight. This is our first line of defense.
When a person feels overwhelmed by threat, dorsal vagal neural circuitry moves us into freeze/shut down. This is our second line of defense, and is part of our parasympathetic nervous system.
What is the Nervous System?
Our nervous system is essentially the body's electrical wiring, and coordinates actions and sensory information by transmitting signals to and from different parts of the body.
Structurally, the nervous system has two components: the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord. The PNS consists mainly of nerves that connect the CNS to every other part of the body. The peripheral nervous system is divided into two major parts: the somatic nervous system (voluntary control of body movements) and the autonomic nervous system (involuntary, automatic).
The Autonomic Nervous System
The autonomic nervous system (ANS) is the part of the peripheral nervous system that is responsible for regulating involuntary body functions, such as blood flow, heartbeat, digestion, and breathing. In other words, it is the autonomic system that controls aspects of the body that are usually not under voluntary control. The ANS is divided into two main branches, the parasympathetic and sympathetic nervous systems.
The sympathetic nervous system (SNS) mobilizes us to take action. This could be the get up and go energy required to initiate in life, or could be an unconscious response to perceived danger in the environment- where your body initiates the fight-or-flight stress response.
The parasympathetic nervous system (PNS) is the slowing down part of the nervous system and has two branches:
Ventral Vagal: safety, connection, social interaction
Dorsal Vagal:
low tone- rest and relax
high tone- shock, freeze, shut down
The Vagus Nerve
The vagus nerve is the tenth cranial nerve, and the longest and most complex nerve in your body. The word vagus comes from the Latin vagare, meaning to wander. So the vagus nerve is known as the wandering nerve. And wander it does! From the brain to the face, ears, larynx, heart, lungs, and guts.
The vagus nerve plays a crucial role in determining our psychological, emotional and physical wellbeing. A lack of proper functioning in the vagus nerve can lead to myriad symptoms including anxiety, depression, migraines, and irritable bowel syndrome.
As your therapist, I will help you learn to regulate your vagus nerve and retune your nervous system in order to heal from trauma, initiate deep relaxation, and improve sleep and digestion.
Ventral Vagal
As a human being, the ventral vagal system is where we want to spend the vast majority of our time. This is our social engagement system, and we are wired to be social creatures. Here we feel safe to rest in connection, enjoy novelty, and to be present, open and curious.
In the ventral vagal state we have access to our higher cortical functioning, the evolutionary newer parts of our brain. Another way to say this is that all of our intelligence is online. In this state we can accurately read cues in our environment. This is also a highly restorative state for the body: stress hormones and inflammation are reduced.
Mobilization: Fight/Flight
Our survival system works hard to keep us safe, and has helped our species to survive for hundreds of thousands years. When our nervous system moves into sympathetic arousal adrenaline and cortisol are released, our heart rate and breathing increases, and blood moves to our legs and arms. We are ready to run or fight.
But what if it’s not a tiger that elicits this intense response, but rather your bosses facial expression, or your friend’s tone of voice? Then you have all these stress chemicals running through your body, your digestion has shut down, and the evolutionary newer part of your brain has shut off!
This is why it is so important for us to do our trauma healing, and to learn to modulate our stress responses.
Dorsal Vagal
If there is no chance of running or fighting the tiger, we move into our dorsal vagal system. Basically we collapse and play dead, give up, go into shock. There are some survival advantages to this. We move into an energy preservation state, and blood moves from our periphery to our core. This decreases our chance of bleeding to death. Our pain and fear tolerance increases as we become detached from an unbearable situation.
But what happens when what was unbearable for you as a child triggers this nervous state response in you as an adult? This is why it is so crucial for us to heal our trauma. We can become free from the prison of the past.
‘Safety is the Cure’
Dr. Stephen Porges coined the term neuroception to describe how our neural circuits distinguish whether situations and people are safe or dangerous.
These responses are not voluntary. On a neurobiological level our nervous system is picking up information in the environment and evaluating that information on a subconscious level.
Depending on our nervous system state, trauma history and attachment style, we interpret this environmental stimuli through our own lens.
In ‘safe’ feeling states we can access higher cortical function, and greater diversity of expression. In ‘dangerous’ states those systems turn off and we are defensive.
Here is a fantastic 9 minute video on Trauma and the Nervous System: a Polyvagal Perspective.
“Trauma compromises our ability to engage with others by replacing patterns of connection with patterns of protection.”
— Stephen Porges