The Polyvagal Theory and the Vagus Nerve Complex

Keeping Us Alive and Safe


The nervous system has one primary purpose: protect us and keep us alive. Our conceptual and somatic minds (i.e., the "physical body") are constantly scanning the environment for cues indicating threat, danger, and/or safety. When we detect danger we are triggered into a protective, defensive, or survival response (fight/flight and/or shutdown/immobilization). Shifting into such a nervous state temporarily can be adaptive and protective. But remaining in such a state beyond its functional efficacy can be maladaptive and profoundly unhealthy, as our restorative, regulatory, and otherwise health-supporting systems and functions are depressed or entirely turned off during a defensive/survival response. Remaining stuck in a defensive/survival response, such that excess sympathetic energy (the adrenal-stress response) remains active yet contained within us, is trauma. Healing from trauma does not require "revisiting" or "returning to" the initially-triggering event in active memory. Rather, healing from trauma ("regulating" emotionally-energetically-neurophysiologically; i.e. "re-tuning" our systems from dissonance to harmony) entails releasing the stuck, excess energy that was activated during a defensive response. This process cannot be directly, totally controlled, dictated, or planned, as our somatic minds operate dynamically-non-linearly-spontaneously. When we are properly, safely supported and enabled in releasing unresolved traumatic energy, we return to a healthy condition characterized by the playful, spontaneous emergence of our various living energies.


From Dualism to Dynamics

The Polyvagal Theory of the vagus nerve was proposed by Stephen Porges, Ph.D. in 1995. The vagus (Latin meaning "wandering") nerve is the 10th cranial nerve and connects the central nervous system to the brain and various other muscle groups, tissues, organs and their respective systems and functions (e.g. respiration, heartrate, facial expression, digestion/metabolism, immune system, etc.). Along with the other cranial nerves and the rest of the nervous system, the vagus nerve serves the essential role of keeping us safe and alive.

"The human nervous system has one primary function: to ensure the survival of our physical body. The nervous system is composed of the brain, the brainstem, the cranial nerves, the spinal cord, the spinal nerves, and the enteric nerves."  -- Stephen Porges (2018, p. 35)

The Polyvagal Theory has profound implications for understanding and redressing neurophysiological dysregulation (i.e. "trauma" -- see below for why I emphasize dysregulation rather than speaking of trauma). Supplanting the modern, dualistic view of nervous system function, it presents an emergent, holistic, and dynamic framework of neurophysiological activity. It also enables direct and practical engagement with our nervous system so that we can learn and develop skills for autonomously and creatively responding to distressing situations and experiences.

Anatomy of the Nervous System

Autonomic Nervous System

  • Sympathetic: fight or flight
  • Parasympathetic: rest and digest; feed and breed
  • Dorsal branch: immobilization/shut-down response
  • Ventral branch: the "vagal brake" - regulates other branches' activity

Central Nervous System

  • Brain, spinal cord, retinal/optic nerve, olfactory nerves
  • Functions to integrate and communicate sensory information, connecting various brain regions to the rest of the nervous system and other tissues (e.g. fascia) throughout the body


The adaptive functions of the autonomic nervous system and how it can become maladaptive

The video below, created and published by the Polyvagal Institute, provides a basic overview of the nature and function of the autonomic nervous system. Following the video, I explain these functions in more detail and nuance.

Assessing Situations: Scanning for Cues of Safety and/or Danger

We employ two general levels/types of awareness to scan our environments for cues of safety and/or danger. While these are separated in concept, they ideally work as an integrated function.

1. Neuroception: somatic-embodied cognition (i.e. "body")

2. Perception: reflective-conceptual cognition (i.e. "mind")

Our cognitive systems continually monitor our surroundings in an effort to detect environmental cues that signal either potential or imminent danger and/or safety. The large majority of this monitoring is done "subconsciously," i.e. it is a primary task of our nervous systems manifest in, as and through our total cognitive embodiment. "Conscious" thought -- what I call variously conceptual or reflective thought, cognition, or mind -- plays a role in this, but it is secondary to the primacy of non-conceptual, qualitative somatic cognition.

One of the main reasons this monitoring task is performed by the somatic mind rather than the reflective mind is that our conceptual cognition is far too slow and cumbersome to adaptively scan, detect, and react to threats in our environments. As John Dewey says, the somatic mind has "an efficiency of operation which it is impossible for [conceptual] thought to match." Though he wrote this in 1925 (in his book Experience and Nature), recent research has thoroughly confirmed this idea.

The full story of how our cognitive systems manifest this complementary phenomenon of neuroception+percepetion (neuroception is a term created by Stephen Porges to describe "subconscious"-embodied cognition; i.e. "perception without awareness") could fill a whole book, but the key idea is the following:

Most of our cognitive determination of the relative condition of safety~~~danger of our environment is non-conceptual, directly sensory, qualitative and embodied/somatic, and occurs prior to and often without explicit, reflective interpretation or analysis. Our somatic minds are attuned to the qualitative aspects of our environments, as these provide the most direct and accurate information as to whether a situation is safe or dangerous. Thus, engaging and working with the sensory capacities of our embodied minds is crucial for effective, extensive, and sustainable neurophysiological/emotional regulation.

Neurophysiological Shifts during a Defensive/Survival Response

When our embodied minds detect danger or threat, we are triggered into a defensive or survival response: the vagus nerve complex adjusts energy flow in the body to support defensive or survival activities such as fighting or fleeing (sympathetic activation) or immobilization/shut-down ("playing dead:" dorsal branch parasympathetic dominance). In the face of actual and immediate danger, this is an adaptive function that helps keep us safe and alive. However, these energetic shifts can become maladaptive when they persist longer than is immediately useful for the organism or culture.

The defensive-survival response follows a "phylogenetic order," meaning that we will seek safety/comfort through a sequence of nervous system functions, which sequence follows the evolutionary history of mammalian nervous system development. That is, we first utilize what Porges calls the

(1) social engagement system, the most recent evolutionary adaptation. This involves the ability to engage pro-social behaviors such as play, eye-contact, physical touch, partner dance, etc. Communicative qualities such as the tone, pitch, speed, and prosody of voice, facial expression, body language, etc. are paramount in social engagement. If our social environment fails to support us in feeling safe, we will then shift into a nervous state of 

(2) sympathetic arousal: This is the "fight or flight response;" high energy, hyperactivation. If this fails, we then resort to the most ancient aspect of our nervous system, the 
(3) dorsal branch of the parasympathetic nervous system: This is the "immobilization," or freeze/shut-down response, characteristic of animals or reptiles that "play dead" in a last-ditch effort to influence a predator to lose interest in its prey and move on to something else.

Energetic Shifts in Defensive-Survival Responses: Temporarily Adaptive but Chronically Maladaptive

  • Sympathetic arousal - i.e., the "fight or flight" response
  • When we are triggered into a fight or flight response -- where sympathetic nervous activity is dominant -- the somatic mind (i.e. "body") redirects energy flow to support literal fighting or fleeing behavior. In such an activated nervous state, there are over 2,100 chemical reactions throughout the body that prepare our muscles, cardiovascular, and respiratory system for fighting or fleeing. This includes an acute release of cortisol and adrenaline, among many other activating-energizing compounds and reactions. Heart rate and respiration jumps up, blood pressure increases, and blood flow is directed toward the large muscle groups and away from functions and systems like digestion, metabolism, detoxification, and repair. In short, the body forgets all typical restorative and immune functions and prepares for battle.
  • Dorsal-branch, parasympathetic dominance
  • If the sympathetic, fight or flight response fails to establish safety for the organism, the vagus nerve shifts into an "immobilization" response, where activity in the dorsal branch of the parasympathetic nervous system becomes dominant. This is essentially "playing dead" -- the organism basically shuts down. In this state, health-supporting functions and processes are suppressed or depleted. Digestion, metabolism, immune function, heart rate, respiration/oxygen exchange, complex "higher order" cognition, etc. -- all these functions and systems require a lot of energy, which means they effectively go offline during the shut-down/immobilization response, characterized by dorsal-branch dominance.

Shifting temporarily into one of these nervous states -- i.e., either sympathetic dominance or dorsal-parasympathetic dominance -- can be adaptive and will typically not harm the organism. However, if the organism -- for various reasons, see below -- remains in one of these defensive/survival states for too long, harm will occur and they can be said to be maladaptive. In short, getting stuck in a hyper-aroused (excessive sympathetic activity; i.e. sympathetic dominance) and/or hypo-aroused (too little sympathetic activity; i.e. dorsal dominance) undermines our innate ability to heal and maintain health because the systems and functions necessary for health are suppressed, depleted, and/or shut down.

For one of the seminal medical treatises on this health-undermining phenomenon of trauma, please see Dr. Gabor Maté's When the Body Says No: Exploring the Stress-Disease Connection

Maladaptive Outcomes: Becoming Chronically Stuck in a Defensive-Survival Response

How and why do we get stuck in a defensive-survival response? There are multiple reasons for this and the neurophysiology is massively and extensively complex, but I will outline the key factors here.

"Trauma" is a wounding

The term "trauma" derives from the Greek traûma, meaning "a wound, hurt, or defeat." In contemporary culture, "trauma" is typically used to refer to the harmful event ostensibly causing the trauma one experiences. However, a more accurate understanding of trauma (and how to prevent and heal from it) requires understanding the neurophysiology of defensive-survival responses.


In short, while *what* happens to us is definitely an important factor (i.e., the event/experience that triggers us into a defensive response), *how we respond* to that event is the crucial factor -- and the factor that allows us agency in influencing whether we are truly traumatized or not (and/or, to what degree we are traumatized).


Trauma is not what happens to you. Trauma is what happens inside you, as a result of what happens to you." - Gabor Maté

Consider an all-too-common experience in American life: automobile crashes (since 1900, American drivers have killed more people than the entire history of U.S. military conflict has killed American soldiers). Most folk would reasonably agree that being in (or even just witnessing) a violent car crash would be traumatizing. But, such an experience is not necessarily "traumatizing" in the sense of a neurophysiological wounding. That is, two people can be in the same car during a crash, but only one person may develop PTSD while the other may not. What makes the difference? If the event itself is inherently traumatizing, why would one person emerge with PTSD and the other be okay? (Assuming, in this case, that both passengers were somehow not physically harmed, or only sustained minimal injuries such as bruises and minor cuts.)

The difference is how we respond or don't respond to a triggering event. Peter Levine, Ph.D., the clinical psychologist who has worked with Stephen Porges throughout his career and has established the Somatic Experiencing approach to healing trauma, recounts in his book Waking the Tiger: Healing Trauma - The Innate Capacity to Transform Overwhelming Experiences that while he was once struck by a car while walking across the street, he was not traumatized by this experience. How could this be? Is being hit by a negligent driver in a 4,000 lb vehicle not inherently traumatic?

Not necessarily! Before I detail how and why Peter Levine was able to experience such a violent event without developing PTSD or any form of lasting trauma, we must understand what "trauma" is, from a neurophysiological standpoint.

As I mentioned above, shifting into a defensive-survival response is at least potentially adaptive. What is harmful/maladaptive is remaining in a defensive-survival response beyond its adaptive, functional efficacy. When we get stuck in such a response, as I noted above, our abilities to emergently/spontaneously self-regulate and self-heal are curtailed. We cannot manifest health when our systems' energies are prioritizing fighting, fleeing, or feigning death. Remaining chronically stuck in this state is quite literally a (neurophysiological-psychic-spiritual) wounding.

What is colloquially called "trauma," thus, is more accurately the phenomenon of being prevented from spontaneously self-regulating after the immediate experience of a triggering/threatening event, and thus getting stuck in a fearful, defensive physio-cognitive-relational state of being, which significantly undermines our abilities to maintain health physically, emotionally, spiritually and relationally.


***Lest I be misunderstood or misinterpreted, I am emphatically not saying that extreme, violent, or distressing events are not inherently harmful or dangerous. I am not claiming that events and experiences classically categorized as "traumatizing" -- such as assault, military combat, racism, or oppression -- are benign. There are, obviously, direct and inherent harms attendant such experiences. I am focusing on the use of the term "trauma" and how to understand it from a neurophysiological perspective.***

***Far more than a mere semantic concern, this nuance is crucial for understanding how trauma manifests, how to prevent it and heal from it, and most importantly: how and why we can manifest creative agency and autonomy in healing/regulating from trauma when it does occur. If the traumatizing element in an experience is exclusively a matter of what happens to us (the event/experience/situation itself), then the sad conclusion is that we are helpless to self-heal and collectively heal in the face of an often overwhelmingly dangerous, violent, and threatening social reality. If trauma is only a matter of the inevitable life experiences that trigger us into a defensive-survival response, then we are resigned to being hapless victims of life, which will -- eventually, in some form or another -- inescapably undermine our sense and reality of safety.***

***It is within or through the interface between what happens to us and how we respond that we can exercise agency, autonomy, and self-healing. Our experience in the world is always a precarious mixture of the two: what happens (the event/situation happening around or to us, which to some degree is not within our total control) and how we perceive, interpret, and respond following that experience (the holistic, longitudinal cognitive-neuro-emotional-physiological-social-relational response to what happens).***

Preventing Trauma by Allowing Spontaneous Self-Regulating Functions-Behaviors

As noted above, shifting into a defensive-survival response is not necessarily or inherently harmful. This can be highly adaptive and functional. But when we remain in such a response beyond its practical, immediate efficacy in protecting ourselves and/or bringing about a sense of safety (whether mitigating the dangerous conditions and/or escaping from them), these nervous system conditions become literally -- and often severely -- "traumatizing" -- i.e. wounding.

Consider a simple physical wound such as getting a minor cut on one's skin. What, exactly, is "wounding" about this? It is the separation of a previously integrated-unified system, in this case the otherwise continuous surface of the skin. The wound is the violent rending of the skin along the cut. And healing this wound, of course, entails the skin growing back together to suture the gap.

In similar manner (though of course this is much more complex), a "psychic" wounding manifests the same basic phenomenon: a previously unified, functionally-integrated system is forced into a duality or multiple fragments; an energetic and functional separation occurs, causing literal "dis-ease" in our systems' homeodynamics.

In an ideally healthy-regulated-safe nervous state, all aspects of our nervous systems are active in a dynamic, polyvalent ratio of mutually-supportive function. When we are triggered into a defensive-survival response and our energies shift to support fight/flight or we shut down, our nervous system manifests a dualized -- or imbalanced, divided, fragmented, separated -- condition. This is a wounding as much as -- if not more than, in some cases at least -- a physical wounding such as a cut on the skin or even a broken bone. Remaining stuck in such a bifurcated, separated/fragmented, dualistic nervous condition is what is typically called "trauma."

However, this can be prevented. (At least theoretically; trust me, I know that practically, the situation is always vastly more complex than our conceptual rendering of a phenomenon can convey.)

In Peter Levine's book, he describes how he responded to being hit by a car, which was the crucial factor in preventing him from being, technically, traumatized by the crash, even though he was, obviously, physically harmed by the experience. 

Here is the crucial matter: Following a triggering event, if we are allowed and supported in spontaneously self-regulating from a defensive-survival response back into a regulated/balanced/homeodynamic state, we will self-heal (at least on the level of nervous system energy/function; physical damage is another matter, of course, but not totally separate from this, either).

The only reason we don't self-regulate after such an experience is that we are restricted from doing so by our surroundings (people, resources, conditions) and/or ourselves (this is a complex matter I'll address later).

This restriction of our innate, natural, powerful self-healing/self-regulating abilities is the traumatizing factor following a shift into a defensive-survival response.

Peter Levine was not traumatized after being stuck by a moving vehicle because he was allowed and supported in releasing/purging the excess energies manifested during his initial shift into a hyperactivated, sympathetically-aroused defensive response. Although, initially, his sympathetic defensive energies were exacerbated by a bystander who came to help but who spoke aggressively, quickly, and roughly grabbed Levine's arm to check his pulse. While the intention here was good, the effect was harmful because the qualities of engagement of this man sent Levine's somatic mind cues of danger, rather than safety or calm.

After successfully asking this man to step back, Levine's next human connection after the crash was making reassuring eye contact with a woman who witnessed the event and came to sit by him while they waited for the ambulance. The woman remained calm, spoke in a comforting voice, and reassured him that he would be okay and that help was on the way. This comforting, supportive human interaction kept Levine's social engagement system online, which prevented him from shifting entirely into a state of excessive sympathetic hyperactivity.

Later, while riding in the ambulance, Levine noticed his hands spontaneously moving toward his face and head. The paramedic initially wanted to restrict his movements, concerned that he might cause further structural damage (to bones, ligaments, etc.) by moving on the stretcher. But, Levine explained that he is a trauma expert and convinced the paramedic to allow him to move as his body wanted. These spontaneous movements were delayed defensive behaviors -- his body was carrying out its innate defensive response, which was initially compromised by being struck by the car without any warning.

Allowing these movements, retroactively, enabled Levine to complete the natural defensive-survival response that was triggered during the event. Thus, he was not stuck in such a response, which enabled his body to shift back into a regulated neurophysiological condition wherein his body's restorative and healing capacities were brought back online. Presumably, had he not experienced these safety-engendering factors (the comforting human support from the calm woman witness, being allowed to spontaneously move in the ambulance, breathing freely, etc.), he likely would have been "traumatized" by this event, and may have qualified for a diagnosis of PTSD (which is, in essence, being chronically stuck in a severely dysregulated nervous state -- i.e., the ongoing maintenance of a sympathetic-adrenal response long after the event that triggered such a response).

Healing from Trauma

Slow, Subtle, Spontaneous

***In this section, I will describe some of the basic principles of healing from trauma. This should not be taken as a plan, guide, strategy, or formula for resolving trauma. While there are general dynamics of nervous system function common to every human on Earth, the complex, contingent ways that trauma manifests are unique to each individual. Moreover, the process of releasing the stuck energy that constitutes trauma is by necessity non-linear/spontaneous/dynamic and thus in principle unpredictable to some degree. Given all this, I offer the insights below as purely informational-educational descriptive content -- this is not a prescription for action! If you want to safely, sustainably, and effectively process trauma, please connect with a clinical professional trained in some type of trauma-informed somatic therapeutic modality. It is only by working primarily through the "body" -- the somatic mind -- that trauma can be substantively and reliably healed. Talk therapy is insufficient for thorough, sustainable trauma resolution.***

Safety is Key

  • As Stephen Porges and Bonnie Badenoch summarize: "Safety is the treatment."
  • The single most important element in healing from trauma -- via the expression/release of stuck survival energies initially manifested during a prior triggering event -- is actually feeling safe. It is not enough to simply be told "you are safe." One's somatic mind -- i.e. body-nervous system -- must actually feel safe in order to shift out of a defensive-protective state.
  • There is a parallel dynamic between shifting into and shifting out of a defensive-survival response: we are triggered into such a state not because we analytically deduce or reflectively determine that a situation is unsafe or threatening; this shift occurs spontaneously and emergently, the "decision" being made by our somatic minds, not our reflective-conceptual-analytic minds. In like fashion, we cannot reason our way out of a fearful, defensive-protective state. We must literally experience conditions of safety that communicate to our somatic minds through qualitative cues and experiences that we are truly safe, at least to a relative degree -- enough to enable us to let down our guard at least somewhat, to begin reconnecting with the sensations of our embodied minds.

The Control Trap: Safety is Spontaneity, but Spontaneity Can Feel Unsafe

Trauma is "Tonic Immobility"

Shifting out of a defensive/protective response can be very tricky because of the dynamic complexity of our cognitive systems. Namely, we can experience our own internal, somatic sensations as threatening or unsafe, especially when we're stuck in states of chronic dysregulation/defensiveness. In such states, our nervous systems come to be highly attuned to detecting cues of threat or danger, even in situations that are relatively safe or at least benign.

  • The clinical term for this is tonic immobility. This is a nervous state in which the fearful emotion of a sympathetic fight-flight response becomes coupled with somatic sensation and immobility. Crucially, "immobility" is not inherently bad or harmful: when truly safe, we can enter this nervous state without feeling triggered (it is basically a state of deeply relaxed vulnerability). But when we shift immediately from a sympathetic-dominant state to an immobilized state in a defensive-survival response, the hyperactive fear state is absorbed and contained within our soma -- the sentient body -- and when we remain in this state over time, fear and thus danger comes to characterize our somatic experiencing all along the spectrum of excitation-relaxation.
  • In such a state of trauma, which is tonic immobility, we progressively lose our ability to experience sensory stimulation while feeling safe. We are increasingly likely to experience perturbations in the environment as threatening (regardless of whether, or how, dangerous they really are), and this triggers us further into a heightened state of fear. This trend results in a progressive narrowing of our "window of tolerance" or "zone of comfort," which is our ability to experience sensory stimulation and emotional-somatic sensation and remain regulated (i.e., not be triggered into a defensive-survival response).
  • This progressive narrowing, coupled with a deepening and increasingly complex experience of tonic immobility, makes it very challenging to come out of this condition, which is to heal from trauma. This is why, if you have complex and chronic unresolved trauma, it is absolutely essential to work with a therapist trained expressly in polyvagal-based trauma-informed somatic therapy. Without a deep, nuanced, and dynamic understanding of this complex neurophysiology of trauma, a therapist will be limited (and, sadly, can even further complicate a client's experience of tonic immobility) in supporting a person in re-developing and expanding the self-healing capacities that are essential for and definitional of healing from trauma.

The Control Trap: "Control" Exists for and as Machines; Not Living Systems!

  • When we feel significantly unsafe, we naturally seek to control situations and our own movements and feelings, as this can provide us with a sort of "surrogate safety" by making at least some aspects of our experiencing consistent and thereby predictable. Consistency and predictability can be comforting to our nervous systems, whereas unpredictability, chaos, uncertainty, and surprise can be unsettling. The paradox, however, is that in a very general sense, the more we try to control, the less adaptively we can respond to inevitable changes in the environment and within ourselves.
  • Moreover, even though there might seem to be an intuitive sense that controlling ourselves and our environments will make us feel safe, controlling actually *prevents* a holistic, robust feeling of safety precisely because in a regulated, safe, calm, vulnerable state, our cognitive energies flow/emerge spontaneously.

The characteristic form of energy-activity of living systems (defined, technically, as: thermodynamically-open, informationally-closed, structurally-determined spontaneously organized autopoietic systems diachronically and tensionally stabilized in a condition of far-from-thermodynamic equilibrium via metabolic-structural coupling with a supportive ecological niche) is dynamic, non-linear spontaneity.

As Richard Campbell explains, "[Thermodynamic] openness and non-linearity make a complex system in principle unpredictable and uncontrollable: because of positive feedback, the tiniest internal or external perturbations can be amplified into global changes. ...'Spontaneous' here means that no internal or external agent is in control of the process." (The Metaphysics of Emergence, 2015: 21213)

  • This fact is very difficult for people in our culture to understand, accept, and embrace. Our culture is obsessed with and addicted to control. (As just one of countless scholarly analyses of the pervasiveness of control imperatives in industrial-commercial-bureaucratic-administrative culture, see James Beniger's The Control Revolution.) Industrial culture's fear-based addiction to control has profoundly skewed our perception, experience, and study of living systems, including ourselves. Here is just one example: you may very well be thinking, "But letting go of control is dangerous, too, because that means I'll be out of control!" This is a false dichotomy of the most pernicious order. When it comes to working with our cognitive-nervous-emotional-relational energies, the options are not limited to either being "in control" or "out of control." I expand on this in a blog post (coming soon).
  • To more effectively and accurately understand trauma, cognition, and the human experience generally, we must forget "control" and invite any number of other metaphors, methods, approaches, qualities, and ideas. One of the most common alternative terms in clinical trauma circles is regulation. This is an apt term for multiple reasons. The primary reason is that a more accurate understanding of processing the stuck emotional energies in trauma encourages us to think in terms of letting emotional energies flow rather than "letting go of" supposedly discrete emotions like fear, anxiety, etc.
  • When we understand that emotional energies precisely are continually flowing, changing, dynamic energies, we can experience and work with them in very different ways. Namely, we can learn that our options are emphatically not limited to either uncontrollable expressions of emotion or artificially stoic repressions of emotion. Emotion is a basic, fundamental, necessary, unavoidable element of human existence. To suppress, repress or deny emotions is to be at their mercy (because we cannot actually deny them; they just grow in strength the more they are repressed, like the opposite phenomenon of a Chinese finger trap); to intelligently, adaptively, and reflexively move with them is to optimize our holistic cognitive functioning. And, at the core of learning to do the latter is the regulation of the flow of emotional energies.

Emotional Regulation, the "Vagal Brake," and Safe Spontaneity (i.e., "play"!)

What is emotional/neurophysiological "regulation?"

Throughout this website, I have frequently written about neurophysiological regulation and dysregulation. Like many phenomena within human cognitive experience, these are simple-in-concept but sometimes-very-complex-and-dynamic-in-practice. So, as always, know that this brief overview does not comprehensively detail all complexities and dynamics of these phenomena.

The key to understanding emotional regulation is in the neurophysiology of the vagus nerve complex. Stephen Porges, Ph.D. brilliant research and Polyvagal theory has revolutionized our understanding of this. Extensive empirical, evolutionary, and clinical evidence now reveals how our nervous systems shift variously from states of calm, safe relaxation to hyper-aroused, excited activation. I won't explain all of this fully, as such a detailed explanation requires book-length treatments. For good resources on this, see the "Sources" list at the bottom of this page.

The primary component of regulation is what's called the "vagal brake." The vagal brake is the ventral branch of the parasympathetic nervous system. Traditionally, our emotional-nervous states were conceptualized dualistically: either we are relaxed, calm, and safe (the "feed and breed" state - parasympathetic dominance), or we are triggered into an excited adrenal-cortisol state of hyperactivity ("fight or flight" state - sympathetic dominance). While on the right track, this model is simplistic to the point of misleading and inaccurate.
Porges' research has revealed that the parasympathetic nervous system has two branches, each with very different functions. Simply being in a parasympathetically-dominant (hereafter PS) state does not mean we are in a state of calm, safe relaxation. We may be in a PS-dominant state and still be frightened and feeling unsafe. So, what's really going on?

The key is the discovery that the ventral branch of the PS nervous system acts as a regulatory mechanism to manage and modulate activity in both the sympathetic nervous system (excitability; fight/flight; arousal; etc.) and the dorsal branch of the parasympathetic. Throughout our entire lives, all aspects of our nervous system are fully active. It is the ventral branch of the PS, the "vagal brake," that "dampens" the effects of the other branches of the nervous system such that we can safely engage socially -- in communication, physical touch/intimacy, play, friendly competition, debate/dialogue, etc. (That is, we can engage these and other activities with a degree of vulnerability and remain regulated and feeling safe, rather than being triggered into a defensive/survival response and literally attacking another person.)

Here is a very basic overview of vagus nerve function in a situation that begins safe and becomes threatening.

  • In a calm, relaxed, safe state, a person's "vagal tone" (i.e., the relative degree of strength and agility of the ventral branch acting on the sympathetic and dorsal PS) is "high" or "strong." The presence of strong yet variable/agile ventral activity enables us to variously engage socially, be emotionally expressive without being overwhelmed by emotion, become excited without feeling anxious, and relax/unwind without feeling depressed.
  • If we neurocept (i.e., perceive without explicit, reflective awareness) cues of danger/threat in our environment, however, it is a shift in the activity of the ventral branch that precipitates a shift into a defensive/survival response. As noted above, the sympathetic nervous system is already 100% online before this shift. In a true survival situation, it would take far too long to bring online and fully activate a complex, body-wide system such as the sympathetic nervous system. So, our nervous systems have evolved a clever adaptation: to shift instantly into sympathetic dominance (fight/flight) when threatened, the ventral branch of the PS -- the vagal brake -- simply lets off. The deactivation of the vagal brake and the taking over of the sympathetic nervous system are one in the same, simultaneous process.
  • I won't provide the full details here, but it should be noted that a further and more complicating protective response occurs when the fight/flight response fails to create a sense of safety. If we are first triggered into a sympathetic fight/flight response, and that strategy fails to mitigate the perceived threat, then our nervous systems automatically shift into a state of dorsal PS dominance, which manifests energetically-behaviorally as immobilization, shut-down, or freezing (i.e. "playing dead"). In this state, activity in the dorsal branch (the 600-million year old, reptilian nervous system) overrides activity in the sympathetic nervous system. Our bodies essentially shut down. We feign death.
  • When this occurs, the massively intense, hyperactive energy triggered during the previous sympathetic fight/flight response (potentially huge amounts of adrenaline, cortisol [the stress hormone], and countless other neurochemical agents and functions) is suddenly "stuck" within us. This energy remains active within our systems, even while we consciously no longer feel or act according to it, given the now-dominant activity of the dorsal PS, which effectively shuts down our systems to protect us from feeling the pain of a truly life-endangering assault or attack.
  • After such a sequence of events, returning to a state of calm, safe relaxation can be very tricky, for multiple reasons. I won't detail all these here. But basically, the challenge is that when we then begin to come out of dorsal dominance/immobilization, the previously-activated and stuck sympathetic-adrenal energy will suddenly be released, and the acute re-experiencing of this energy can be re-triggering to our systems if we aren't adequately supported in allowing for this, and/or don't know what's happening. We can't simply shift from a state of immobilization to regulation. We must first re-engage the sympathetic response that was instantly curtailed in the prior shift into immobilization, release that excess activated energy, and then we can (potentially, at least, assuming a variety of other necessary safety-supportive factors and conditions) return to a regulated state.

***A reminder: In these brief discussions I am not providing a plan of action or therapeutic steps that you should follow to heal from trauma. I am merely describing the function of our nervous system and how/why traumatic states occur. If you want to heal from trauma, please connect with a clinical professional trained specifically in the Polyvagal Theory and some form of somatic therapy modalities. The information provided here is not to be taken as a recipe, formula, or strategy for actually trying to release unresolved trauma. Without adequate support of a thoroughly regulated guide, it is possible to be re-triggered by one's attempt to release unresolved trauma. However, with such adequate support, this process can be remarkably effective, safe, sustainable, and liberating!***


Emotional Regulation as Somatic "Tuning" -- Dynamic Tension Creates Harmony

One of the most misleading aspects of much pop-psychological and expert psychological writing on emotional regulation is the falsehood that the solution to being "stressed" (sympathetic arousal, hyperactivity, anxiety) is to simply "rid" ourselves of stress. This is not physiologically or ontologically possible. "Stress" is an inherent and necessary phenomenon of living systems. There is always some tension in our bodies.

Too much or too little tension (especially over time) is the problematic potential. In this sense, we can think of ourselves like musical instruments. Consider a stringed instrument like a guitar, or a drum. If a guitar string is tensioned too much or too little, it will not vibrate properly and thus not produce a harmonious sound. Likewise with a drum head: what enables an instrument to resonate harmoniously is a proper, balanced degree of tension. If there is too much or too little tension in a drum head, it will not sound good and is more liable to damage when played.

Obviously, human neurophysiology is vastly more complex than a guitar string or drum head, but these same basic principles apply at least in heuristic form. Health is not simply a total lack of stress: complete lack of stress/tension in a living system = death. The crucial matter is developing the qualitative-emotional agility of our somatic minds such that we exhibit "high" or strong "vagal tone," which is the variable ability of the ventral branch of the parasympathetic (the "vagal brake") to dynamically, adaptively, and smoothly regulate and modulate activity in the other branches of the nervous system. This equips us to travel fluidly along the wide, multidimensional, dynamic spectra of excitation-relaxation which constitutes living activity.

In other words, where machines and computers operate in linear, dualistic-binary, and consistently repetitive form, living systems manifest musical qualities of activity. Music -- and sound generally -- is a complex of dynamic and variable waveforms: literally wave-like patterns of energy flow. Emotional regulation is not a matter of finding a fixed, static, constant "middle point" and just staying there. Rather, truly healthy, adaptive, and agile neurophysiological regulation entails energetic variability that does not exist in machines.

As the neuroscientist and pharmacologist Dr. Candace Pert reminds us, a healthy heart is not one that beats in perfectly consistent, mechanical repetition; the healthiest heart exhibits spontaneous and dynamic variability in its rhythm and intensity. This basic principle applies to all aspects of our being. As the old saying goes, "everything in moderation, including moderation." This means that extremes (and, more specifically, remaining at extremes for too long) or absolute states are the conditions to be avoided.

As I explain in more detail on the Embodied Cognition page, computers and machines operate according to binary code, which consists simply of two absolute values: 1 or 0. In fundamental ontological contrast to machines, living systems manifest literally nothing absolute in this sense. There is always variability, dynamics, change, alteration, and a degree of unpredictability-spontaneity in the oscillation of our energies. These qualities are inherent in anything musical or generally aesthetically pleasing. So, when we hear harmonious sounds; see harmonious images; feel harmonious sensations; taste harmonious flavors; and smell harmonious aromas, we are literally sensing a qualitative-energetic phenomenon (i.e. "thing," "object," "entity," or experience) of health. In other words, such experiences are pleasurable because what we're engaging with sensuously literally embodies an energetic-structural-organizational coherence of rhythmic harmony, which is health.

To manifest such a condition within our own neurophysiology, we must be properly "tuned" -- we need some tension, but not too much. Moreover, to resonate harmoniously, i.e. be healthy, we need an agile, dynamic variability in such tension. The more rigidly consistent and repetitive our life activities, the more mechanistic we become. Conversely, the more nuanced and subtly dynamic our life activities and sensuous-emotional experiencing, the more musical we become. All great musicians can play with a highly-developed dynamic nuance and subtlety. Good music isn't just a matter of high volume, speed, intensity, or sheer technical skill. It is the subtle, qualitative and variable nuance of technique, musicality, dynamic, tempo, and tone that makes for truly awe-inspiring sound.

Thus, it is no coincidence and no mystery at all that singing, playing an instrument, and/or listening to high-quality music helps us feel good. Our own energy systems literally begin to resonate with the music we are playing/hearing, and such resonance literally is health, neurophysiologically speaking. So -- forget drugs, forget invasive surgical procedures, forget complex and contrived top-down "meditative" or "spiritual" exercises meant to generate some "output" of experience (such as "enlightenment") ....learn to dance, sing, and play in rhythmic harmony, and you'll begin to heal! I expand on this a bit more on the "Social Trauma and the Culture of Excitotoxicity" page.


The Polyvagal Theory of the vagus nerve and nervous system-emotional regulation shows that our nervous system and function is a dynamic, multi-component system that enables a poly-directional communication among the brain, nervous system, ECS, and other aspects of our neurophysiology. When we are safe, healthy and regulated, all branches of the nervous system are active yet balanced in a holistic coherence that enables us to move and feel freely, spontaneously, and adaptively (health = functional/integrated wholeness). When our somatic minds -- via a direct, non-conceptual, qualitative sensing of the environment -- detect signs of threat or danger (what Porges calls "neuroception" (perception without reflective awareness or analysis) in our surroundings, this holistic functional integration is disrupted as our bodies prepare to fight/flee, or shut-down in the face of imminent life-threat. This can be adaptive for very short periods of time, but if we are restricted from allowing such defensive/survival responses to run their full course, we will not return to a state of dynamic equilibrium: getting stuck in the imbalanced energetic states characteristic of defensive/survival responses is trauma, a neurophysiological wounding constituted in/as a condition of neurophysiological duality, imbalance, and energetic disproportion. We are fragmented within; the various "strings" of our somatic symphonies -- that is, the branches of the nervous system -- are tuned/tensioned disproportionately. We cannot "resonate harmoniously" and rhythmically when neurophysiologically dysregulated. To return to a state of health/harmony, we must release the excess sympathetic energy (too much tension) generated during a fight/flight response and return to a condition of holistic functional integration, which is akin to a guitar having all its strings tuned in relative proportion such that they can vibrate/resonate harmoniously.

Practically speaking, we need a "tuning fork" for such energetic tuning/regulation. And the acoustic-somatic-qualitative dynamics of natural wilderness ecologies can provide -- literally are -- just such a "somatic tuning fork!"

jQuery Tlačítko na začiatok by William from