The Vagus Nerve And How It Facilitates Central Nervous System (CNS) Functions
Polyvagal Theory suggests the Vagus Nerve is the body’s physical manifestation of human emotional evolution from “fight or flight” to more conscious responses and loving behavior.
Understanding The Central Nervous System (CNS)
The Central Nervous System (CNS) is the executive center of the entire nervous system and consists of the brain and spinal cord.
The CNS receives its information and delivers its directives to and from the body through the Peripheral Nervous System, consisting of cranial and spinal nerves.
The Role Of The Autonomic Nervous System (ANS)
These two systems interact with the Autonomic and Somatic Nervous Systems. For now, we will focus on the Autonomic Nervous System (ANS), which has two subdivisions: the Sympathetic and Parasympathetic systems.
The Parasympathetic System conserves body energy and promotes “housekeeping” functions during rest. It is associated with inner calm and homeostasis. It puts “brakes” on the sympathetic nervous when it is too aroused. Thus, the Parasympathetic System is a “demobilizing” system.
The Sympathetic System activates body systems during stimulating activities such as “fight or flight.” It is associated with high arousal and emergency responses. Thus, the Sympathetic System is a “mobilizing” system.
Now For The All-Important Vagus Nerve
The Vagus Nerve is the 10th of the twelve cranial nerves. It is the longest and reaches from the brain to the lower viscera and back to the brain.
Like previous systems, it has two separate systems or “pathways.”
One pathway is the Ventral Vagal (front side of the vagus nerve), and the other is the Dorsal Vagal (back side of the vagus nerve).
These two vagal pathways deliver messages from the body (afferent influences) to the Central Nervous System and from the brain to the body (efferent influences).
Each vagal pathway has its own adaptive, self-protective function. Both inhibit (put brakes on) the arousal/mobilization activities of the sympathetic division of the Autonomic Nervous System (ANS) when the sympathetic division is overactive (in a state of alarm, mild, moderate, or extreme).
The Vagus Nerve And ANS Work Together For Survival
According to Polyvagal Theory, the Vagus Nerve transforms stress responses into calm.
Once again, we have mobilizing and immobilizing strategies built into our self-protecting nervous system as follows:
The PARASYMPATHETIC division (of the ANS), historically known as the “rest or digest ” response system, is associated with inner calm and homeostasis.
The SYMPATHETIC division (of the ANS), historically known as the “fight or flight” response system, is associated with mobilization, such as high arousal and emergency responses.
The VENTRAL BRANCH (of the vagus nerve ) is the most recent evolutionary development and is associated with lower arousal levels as displayed during relaxation and positive social engagement activities.
DORSAL BRANCH (of the vagus nerve) ) is the oldest evolutionary development associated with immobilization when confronted with real or imagined danger. It is associated with shutdown withdrawal from threats and depressive behaviors.
The Ventral Vagal Pathway: The Key To Relaxation And Calm
When we activate the ventral vagal alone, using Relaxation Therapy (RT) and other calming procedures, we experience calmness, safety, and security. Under non-threatening circumstances, we are emotionally open, social, and connected. We experience positive sensations, feel good, and are more explorative and friendly.
When a real or perceived threat enters the scene, and the danger challenges us, the ventral vagal “breaks” the mobilization process, and we experience DORSAL vagal activity, such as mild to moderate to severe withdrawal, which is demobilizing states.
When a real or perceived threat is experienced as insurmountable, we shut down even more and emotionally remove ourselves from the scene, as observed in the “freezing response,” simulation of death, and complete immobilization.
Deep Rhythmic Breathing Stimulates The Ventral Vagal Pathway
Stimulation of the ventral vagal releases an array of anti-stress enzymes and hormones such as acetylcholine, prolactin, vasopressin, and oxytocin. Acetylcholine assists digestion and has an inhibitory effect on cardiac tissue, lowering heart rate and blood pressure.
Deep rhythmic breathing, with a long and slow exhalation, is key to activating your ventral vagal branch, slowing heart rate, and lowering blood pressure, especially when stressed and during challenging performance anxiety.
Mobilizing The Ventral Vagus Nerve For Safety And Trust
The ventral vagal is the most recent evolutionary development, while the dorsal vagal is the oldest and most primitive. Both pathways work to regulate emotional states by applying “brakes” to sympathetic mobilization during heightened emotional arousal, creating balance and adaptability.
Interactions between the ventral vagal, dorsal vagal, and other systems give rise to significant emotional states that influence how we move and connect with the world.
- Mobilization Without Fear:
When the ventral vagal interacts with the sympathetic subdivision, it creates a state of relaxed movement. This is seen in playful activities like dancing, sports, and yoga. These moments allow us to feel “in flow,” socially engaged, and balanced, whether alone or in a group setting. Activities such as Tai Chi or playing a musical instrument exemplify how this relaxed mobilization enhances our connection to ourselves and others. - Immobilization Without Fear:
When the ventral vagal interacts with the dorsal vagal, it fosters calm, safety, and trust. This state encourages physical stillness, emotional security, and social connection, as seen in moments of intimacy or bonding. A genuine hug is a simple yet powerful example of this connection, reflecting the ability to immobilize without fear while building trust and closeness.
The Impact Of Overwhelming Threats
When a real or perceived threat becomes overwhelming, the nervous system shifts to protective extremes. The dorsal vagal pathway may dominate, leading to withdrawal, isolation, and the “freezing” response. As the threat intensifies, we may become immobilized entirely, exhibiting behaviors like feigned death or complete shutdown.
Understanding these responses through Dr. Stephen Porges’ Polyvagal Theory helps us recognize that these reactions are not signs of weakness but rather survival strategies deeply rooted in our biology. This insight allows us to approach such states with compassion and informed strategies for recovery.
Staying Calm Through Relaxation Therapy
Relaxation Therapy offers practical techniques to help regulate your nervous system by activating the ventral vagal pathway. By doing so, you can achieve a sense of calm, resilience, and emotional balance, even in stressful or challenging situations.
Understanding your vagus nerve empowers you to navigate life with greater security and trust. Whether through deep rhythmic breathing, mindful movement, or social engagement, you can create a foundation for well-being and inner peace, enabling you to thrive in both personal and social environments.