The vagus nerve is the longest and most complex nerve in the body. It acts as the link between our bodies and the faces and voices of people around us. So, we can see it as the biology of safety versus danger as members of a tribe. Because believe it or not, our biological science still operates as it did in primitive times, when safety in numbers was key to survival.
The vagus nerve stimulates the Autonomic Nervous System (ANS) while sending alerts to the brain and vital organs. It’s both the cause and effect of how we respond to threats. Will we call for help? Will we keep our focus? Or will we become frantic (fight/flight)? Or collapse and give up (Freeze or dissociate)? The vagus nerve is also the cause and effect of the balance (or imbalance) of our cortisol and serotonin levels.
If you’ve ever heard of the Polyvagal Theory, poly-vagal is referring to the many branches of the vagus nerve. But the good news is, its many branches is determined by two major systems, not unlike the ANS, which has the parasympathetic (calm) and sympathetic (fight/flight) nerve. The vagus nerve has the VVC (ventral vagal complex) and the DVC (dorsal vagal complex). Since both the VVC and DVC stand for something-vagal complex, let’s call the VVC Ventral and the DVC Dorsal in this article. And this way, it will be easier to follow and with less confusion over which three-letter acronym is which.
But first: If you need a primer on any of the science terms mentioned so far, Trauma Glossary 3 (Brain and Body on Trauma) has you covered. Section 2 of that glossary covers the nervous system (including the ANS). Section 3 covers the body chemicals, which includes cortisol and serotonin.
The Two Halves of the Vagus Nerve
Think head, throat, and torso and you’ll understand where the vagus nerve is and what it impacts. Now think top versus bottom and you’ll understand where its two systems, the Ventral and the Dorsal operate. Both systems alert the brain, but one alerts the top (Prefrontal Cortex, the “Social and Executive Functioning Brain”) while the other alerts the bottom (Primitive Brain, or “Lizard Brain”).
Below is a visual aid originally featured in my article, Healing Trauma: The Most Important Parts of the Brain. But it’s useful here so that you get the overall picture. Each section of the brain has a specific theme.
The Ventral is the one that alerts the top of the brain and it’s also concerned with the throat and the top portion of the torso. So, the Dorsal alerts the bottom of the brain and the bottom half of the torso. Now that we have the basics, let’s break down what each of them do.
Ventral (Top) as the Social-Engagement System
Associate the Ventral with social engagement and you will always remember which vitals it influences. The throat, chest (heart and lungs), and diaphragm. When we speak, our lungs fill with air and then it pushes through our vocal cords (throat). And if we need to speak loudly, ask any stage actor or public speaker. They will tell you that if you want to be heard all the way to the back of the room, you must know how to push from the diaphragm. And the diaphragm is just beneath the lungs. Pretty convenient, huh?
The Ventral alerts the top section of the brain, the Prefrontal Cortex, also known as “the seat of empathy and reason.” Remember what I said earlier, how our biological science still operates as it did in primitive times? Well, this is where we function as members of a tribe. It’s the social support of being seen and heard and reciprocating.
Think mirroring, because when the Ventral is in charge, we smile when someone smiles at us, nod our heads when we agree, or frown sympathetically when someone shares a painful story. That’s because the Ventral is signaling the nerves that activate our face muscles, middle ear, and voice box (larynx).
When the Ventral experiences these positive engagements, it sends signals to the chest. The heart slows and we breathe deeper. We feel safe and we are able to be present. Conversely, in painful or stressful experiences, our voices change, the heart speeds up, and we breathe rapid, shallow breaths. So, how does the Ventral respond to threats? Either by crying for help (and push from the diaphragm!) or by staying focused and leading others to safety.
Dorsal (Bottom) as the Body’s House Manager
What does house management look like in the body? It’s ensuring that we have all the basic necessities for survival. Eating and digestion is our daily maintenance. And of course, someone must take out the trash so that the home is free of toxins. In other words, urination and bowel movements.
The Dorsal is in charge of the stomach, kidneys, and intestines. It alerts the bottom part of the brain, specifically the Brain Stem, which happens to be that part of the brain concerned with basic housekeeping: eating, sleeping, and peeing and pooping. And this is where the vagus nerve becomes both the cause and effect of our cortisol and serotonin balance (or imbalance).
There is a definite link between stress and gut health. You see, serotonin is the mood stabilizer to cortisol’s stress response. Cortisol is also in charge of the stomach acids we need for digestion, and meanwhile, there is more serotonin in the stomach than there is to the brain. When we feel calm and safe, our digestion has a better chance at regulating. But how often do we feel a twist in our core or a heavy weight in the stomach when experiencing heartbreak or stress? Nervous energy tends to make us pee more often. When we worry or when we are seriously dreading something, we get an upset stomach with a strong urge to poop or vomit.
So, how do we know when the Dorsal has taken over in a threatening situation? One sign is losing control of our urine or bowels and literally wet or defecate ourselves. The body is falling to collapse mode, or the Freeze response. The brain blanking out (dissociating) in the moment is another sign. The Dorsal sees a threat as hopeless and inescapable, and so it gives up.
“I’m Not Going Down without a Fight!” How the ANS Works with the Vagus Nerve
According to the Polyvagal Theory, the Ventral (Top) is the one responsible for synchronizing the Autonomic Nervous System (ANS) . And in this way, new options are opened so that we don’t have to give up just because no one is around to help.
If you recall earlier (in the introduction) that the ANS also has two systems. They are the Sympathetic Nerve (fight or flight response) and the Parasympathetic Nerve (calm, relaxing). So, in a threatening situation there’s an interesting top-down order that happens in the brain and it’s synchronized with our vagus nerve and ANS.
- (Top) Social-Engagement System: The Ventral and the Prefrontal Cortex call for help.
- (Middle) Fight or Flight: This is where the ANS steps in. The Sympathetic Nerve activates in the mid-section of the brain: the Limbic System or “Emotion Brain.” This is how we remember that we are more than just a head and a torso. We also have arms and legs. We can use them to run, or stand our ground and fight.
- (Bottom) Freeze: The Dorsal and the Primitive or “Lizard Brain” feel powerless against the threat, and so they start shutting down. The ANS is still involved. The difference is, the Parasympathetic Nerve has been activated. In so doing, it has put the brakes on the Sympathetic Nerve because fight or flight is not an option.
So, when we put it all together, it looks something like this.
Trauma Programs the Brain and the Body
We are all shaped by our experiences. We make choices based on what we have learned from them and we call it our programming. But our bodies are programmed just as much as we are on a cognitive level. Nowhere is this more obvious than in child developmental trauma: Complex-PTSD and DID. That’s because the brain and body developed in an adverse home. Let’s take a look at how repeated exposure to trauma impacts our programming from the bottom to the top:
*And just a heads up, certain terms underlined below can be found in Trauma Glossary 2 (Ongoing Problems You May Have), just in case you need to know what they mean.
3. Parasympathetic, Dorsal, and Primitive Brain:
Digestion problems, autoimmune disorders like fibromyalgia, numbed emotions, dissociation, and depersonalization. The body is programmed for learned helplessness, all because the child experienced repeated abuse by their caretaker. So, the body learns to respond to new threats by shutting down, not unlike animals in the wild do when caught in the jaws of a carnivore. “There is no escape and no one can save me.” The body is literally preparing itself to die.
2. Sympathetic and Limbic System:
Paradoxical breathing, armoring, hyper-vigilance, also trouble regulating emotions, especially anger and anxiety. “I must keep my guard up, the next threat is right around the corner.” The child has grown up walking on eggshells, anticipating and trying to avoid triggering the abusive parent. Muscle tension becomes the new normal, so does breathing backwards, which over-stimulates the fight-or-flight response. The Limbic System is also home to the amygdala. So, when the body is stuck on anticipation, it tends to cause a threatening situation to appear more frightening than reality. And that’s when we experience amygdala hijacking.
1. Ventral and Prefrontal Cortex:
Trouble focusing and prioritizing, avoidance, negative noticing, isolating, deficient dopamine levels, poor confidence, trust issues, and lacking a sense of purpose. Also parts of the midline of the brain (known as the Mohawk of Self Awareness) have deactivated all because the abusive parent has taught the child that their emotional needs don’t matter. So, the brain learns this and responds accordingly. It deactivates parts of the brain that signal emotional awareness and our sense of identity. The Ventral is to the midline of the brain as the Dorsal is to the brain stem. So, in other words, the brain’s midline calls dibs on the Ventral. Unfortunately, it doesn’t stop there. See also section 1 in Trauma Glossary 3, the parts of the brain listed under the Prefrontal Cortex. And those are just the parts of the brain most relevant to psychological trauma.
We learn to connect and bond with others through our first relationship. The one we develop with our parents. When we cannot form a safe and trusting bond with our parents, it causes a breakdown in our social engagement system. How can we feel like members of a tribe if we never experienced being seen and heard by our caretakers? And once the body and brain complete the programming: “I am not seen, I am not heard, and no one cares,” how can we remember to ask for help? And since a breakdown in our social engagement system also impacts our ability to stay calm and focused (executive functioning), how are we likely to respond in a threatening situation? When calling for help isn’t an option, will we fall to our Limbic System and fight or flight? Or will we fall to Primitive Brain and surrender?
How Do We Change the Programming?
Our experiences shape our programming. So, new experiences open new neuropathways and we can start breaking barriers. What sort of new experiences? Well, hold that thought, because the first thing we want to do is start with our breathing. To handle our experiences mindfully and emotionally regulated, we must start with calming both the ANS and vagus nerve. Remember where I said that repeated exposure to trauma causes us to breathe backwards? That’s paradoxical breathing and it over-stimulates the fight/flight response. Fortunately, it’s an easy fix and I’m saving you the trouble of looking it up in Master Toolbox 1.
Step 1: Breathing!
Paradoxical Breathing:
Master Toolbox 1
- Easy fix: Lie on the floor with one or two books on your stomach. The pressure on your stomach combined with your back against the floor forces the stomach to breathe correctly. Slowly inhale and exhale ten times. Each time, notice how your stomach expands on each inhale and goes in each time you exhale. Repeat this daily until your stomach starts doing this on its own.
Just in case you need to understand why this is so important, I wrote an article on the ANS and it focused on the importance of proper breathing. That article is here.
Step 2: Master Toolbox 2 Section 2 (Click here)
Once we have corrected our breathing and we are no longer over-stimulating the fight/flight response, we can start branching out with somatic work and other breathing exercises, specifically those for the vagus nerve. Section 2 of Master Toolbox 2 is a list of so many tools for the vagus nerve, to quote those here would blow out this already long article. There is also a miscellaneous list of somatic work under tools for the ANS.
I would like to add one more to the list for vagus nerve exercises, as a means of branching out one step further. As we’ve learned today, the vegus nerve is head, throat, and torso. So, what parts of the body are outside its reach? Our limbs! A lot has been written about paying attention to our hands and where our feet are planted (a grounding technique) while we are focused on our breathing. Also moving our arms up and down while using mindfulness breathing to calm our system. This is particularly useful while processing our trauma and we feel the emotional overwhelm. Think of the arm movement with mindfulness breathing as reminding the vagus nerve that it doesn’t have to carry the full burden. Our arms and legs are also here to pick up the slack.
Step 3: Branch Out Even More
Look up the underlined terms I mentioned that can be found in Trauma Glossary 2. Most have links that include tools for these problems in Master Toolbox 1. Pick something and go with it. Which problem needs your immediate attention and you can start doing something about it today?
You may also appreciate my article from last week if you’re curious about our cortisol and serotonin levels. A one-stop article using 7 charts in all on our body chemicals from low, ideal, to high and most importantly, how to use them to check in with ourselves to understand our own hormone levels. It includes links to articles that further expand on their meaning. That visual aid article is here.
Finally, if you would like to learn more about the midline of the brain (the Mohawk of Self Awareness), I wrote an article that can further educate you. It also includes step by step instructions on how to practice the all important tool, interoception on yourself. That article is here.
There are always things we can do about our problems, no matter how impossible they seem. We just need to be patient with ourselves and be willing to do the work and pick and choose what we can handle working on for now. After all, our problems did not develop overnight. So, they need time to work through.