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A Gentle Introduction To The Wisdom Of The Nervous System

by Dr. Megan Kirk Chang

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This webinar offers an accessible introduction to the autonomic nervous system and its role in stress, trauma, and emotional well-being. Together, we’ll explore the three-part brain, the anatomy of the nervous system, and how our bodies respond to perceived safety and threat. We will discuss the concept of the Window of Tolerance, helping you better understand patterns of overwhelm, shutdown, anxiety, and emotional regulation. The session also explores the difference between stress and trauma, and how unresolved experiences can shape the body’s responses over time. Designed to be practical, compassionate, and easy to understand, this webinar provides foundational knowledge to support greater self-awareness, resilience, and healing. Please note: This session discusses trauma and is for educational purposes. It is not a replacement for professional medical or psychological care.

Transcript

Today's education piece,

Which is starting to really examine the most primitive part of our physiology,

Which is our autonomic nervous system.

Okay,

So.

Again,

Some of this might be.

.

.

Some of this might be repetitive,

But I wanna ground everybody in the same language.

So I'm just gonna get my screen shared here.

On the screen.

You should see the image of a brain.

Okay,

And we're going to look at the three-part brain.

Which was coined by McLean way,

Way back over 50 years or so.

According to McLean,

The human brain has evolved into three distinct regions.

We have At the outermost part of our brain,

The neocortex,

The midbrain,

Our limbic system,

And deep within.

Our reptilian brain,

Our most primitive version of the brain.

Okay,

So the neocortex.

Is the newest,

Most evolved region of the brain.

This is the part of the brain that's unique to human beings.

This is what makes our species the most evolved species in the world.

So the neocortex is our rational or thinking brain.

This is where our analytical mind lives.

This is where our decision-making,

Problem-solving capacity lives.

This is the largest,

Most evolved region of the brain.

Within the midbrain is our limbic system.

You've likely heard of this before if you've done any kind of trauma healing work.

Our limbic system consists of different regions.

We'll go through them next day.

Mainly,

We hear about our amygdala.

And our amygdala is an almond-shaped There's a small region in the brain that really is our threat detection center.

And this is our emotional and feeling brain,

This is the part of the brain that determines whether something feels threatening or dangerous and then sends a signal to our reptilian brain to respond.

Activate our autonomic nervous system.

So our reptilian brain is our most primitive part of our brain region.

It is where our instincts,

Our involuntary activation happens.

The reptilian brain is strictly about keeping us surviving.

Protection and survival is the purpose of our reptilian brain.

Okay,

So we have these three parts.

I'm gonna start with the reptilian brain.

We're gonna work our way out.

Okay,

So we this is again the whole scope of this course we come start our deepest core which is that oldest part of our brain that is similar to all vertebrates that have a spinal cord.

Is our reptilian brain.

We're going to move outwards to limbic neocortex and then into our periphery,

Which is our organs,

Muscles,

And tissues.

So let's move to the next slide here.

We've all heard these terms,

We've heard of stress,

We've heard of burnout,

We've heard of trauma,

And sometimes they get intermixed,

But I want to talk a little bit about how these are distinct.

Okay,

So when it comes to stress,

We have to remember that we are designed.

To navigate stress.

As human beings,

We navigate up and down,

In and out of stress multiple times per day.

It's a very normal human reaction.

To some extent,

We need certain levels of stress in order to function.

So even getting out of bed in the morning is actually a stress on the system.

Even walking down a set of stairs is putting a demand on the system.

So stress we oscillate in and out of to varying degrees throughout our day.

Reaching for a glass in the cupboard is technically a stress.

It's placing a demand on the body and we mobilize to meet that demand.

Okay,

When we think about stress,

We always think about some of those more extreme examples,

A loud door banging,

Slamming on the brakes to avoid a car crash.

Those are absolutely examples,

But we forget that as human beings,

We're designed to move in and out of stress multiple times a day.

You probably,

Some of you have said you're sweating already in this session.

That's a stress response.

So we're designed to fluctuate in and out of stress.

We have what lives in our nervous system.

Our autonomic nervous system,

Two different branches,

The parasympathetic and the sympathetic.

We know of the sympathetic as our fight or flight system.

And that's the system that gets activated when we detect stress to mobilize us into action.

So that means we can either fight off or flee.

A potential threat or danger.

Now,

Back hundreds and hundreds of years ago as human beings,

We really were fighting or fleeing.

Physical danger.

Our biggest stressors were being attacked by wild animals or by neighboring communities that were in conflict.

Now.

In our day-to-day,

Stress is more psychological in nature.

And the interesting thing is that the brain doesn't know the difference between a real or an imagined danger.

We can think ourselves into a stress response.

Now,

The one thing I want to mention here is that stress isn't always bad.

We often give stress a really bad reputation,

But there's eustress and distress.

Eustress refers to stressful events that actually are joyful.

The marriage of a child bringing a child into the world.

Graduation,

You know,

Lots of really good examples where excitement and joy mobilize our body.

Laughter.

Laughter is even a eustress.

It's putting a demand on the body.

Distress is what we typically know,

And distress are events that are upsetting,

Triggering,

Overwhelming,

For example,

But it's important that we know that both kinds of stress can exist.

Eustress is happy,

Joyful related stress and distress more broadly.

Upsetting.

Burnout,

I mention here because especially in the last year,

I don't know if any of you are frontline workers or know of frontline workers or if you're care providers,

Carers,

Caregivers for either young children or elderly,

Burnout is very real.

So I wanna mention it here as well.

So burnout is chronic stress exposure that has not been addressed or managed.

And it's not necessarily because the person doesn't want to address it or manage it,

But it's because it's so compounded and repetitive almost zero possibility to be able to manage the stress.

This is extreme exhaustion and depletion,

Cynicism and disconnection.

As a result of work-related obligations.

So,

Burnout is directly linked to work or obligatory tasks.

So whether it's your workplace environment or your obligations as a care provider.

Okay,

And then there's trauma.

So with trauma.

The intensity of the stimulus,

The stress stimulus.

Is so extreme and potentially life-threatening or repetitive over time that it's linked to a more extreme physiological response.

And we're gonna dive into that today.

Okay,

So I'm gonna dive in a little bit more detail.

So a lot of people ask me,

Are burnout and trauma the same?

So burnout and trauma share similar physiology in the body,

But the root cause is different.

Burnout is prolonged psychological and physical burnout related to work.

Or the nature of work-related duties.

Where trauma is something that's completely outside of our control.

We might be blindsided or it's repetitive over time,

Not as a result of work related necessarily.

We can understand burnout when we understand trauma biology.

And you're gonna start to see the linkages of stress,

Burnout,

And trauma here in the next few slides.

Okay,

So as I mentioned,

The stress versus trauma response,

Let's look at the difference.

So on the top part of your screen,

Don't worry if you can't read the small font.

I couldn't get this any bigger because it is a JPEG image.

But basically that top bar is this oscillation up and down.

Throughout our day.

We rise to meet a demand and then we have the capacity to discharge the stress energy out of our body and return to homeostasis.

This is the natural stress response cycle.

We can meet the demand and then when the demand is over,

We can settle into homeostasis and balance again.

When it comes to trauma,

That stimulus is so extreme that the ability for us to discharge the stressful energy is either not possible or becomes extremely challenging,

Especially if we have repetitive exposures to trauma stimuli.

So one of two things can happen.

We can either feel stuck on on,

So this hypervigilant,

Panicky,

Shaky,

Flighty,

Inability to calm,

Restless kind of state of being.

And oscillate between stuck on off,

Where we collapse,

We're exhausted,

We can't even feel that motivation to,

You know,

Get back again.

We're withdrawn,

We're shut down,

We might even dissociate.

Okay,

So this can be such a confusing.

Experience for folks to oscillate between the two to kind of feel like What am I going to be this day?

Am I going to be stuck on on or am I going to be collapsed and withdrawn?

And when we know about our three-part brain,

Which we'll dive into more next day,

We start to make meaning about this experience as human beings,

But we're not really great at making accurate meaning sometimes because we have a negativity bias in which we filter.

So we start to say things about ourselves like,

What's wrong with me?

Or this isn't gonna get better.

I'm broken,

Or I'm not enough,

We start to create this narrative about these oscillating feelings,

This fragmented feeling.

Within our system to start to make meaning about it,

But we don't always accurately make the right meaning.

I wanted to share.

Oh,

I see a question.

So I'm just going to pause for a minute and.

Stop the share for a second and.

Who had a question?

Was it?

Oh,

Less.

Okay.

Are there key differences between healing burnout or trauma,

And how would we recognize the difference of either within us,

Please?

So.

Like I mentioned with burnout,

Burnout is really work obligatory related,

Where trauma is not always related to work.

It can be,

But it can be emotional abuse,

Sexual abuse,

Physical abuse,

Racialized trauma.

These don't have to be work related.

However,

Through the experience of repetitive trauma exposure,

We can move into a similar state as burnout,

Which is that withdrawn,

Shut down state.

What I invite you to think about is instead of trying to identify if it's a burnout or trauma,

Is assume that it could be either and that's okay.

And we're gonna talk about what that shutdown response looks like.

We're gonna get into how do we heal from that,

But we gotta understand what it means first from the neurophys,

Okay?

Yeah,

Great question though.

OK.

So.

I'm showing you from my own research the difference between the physiology of somebody who does not have any trauma exposure or any clinical mental health disorder and a person who has clinical post-traumatic stress disorder,

Which can happen,

Not always,

But can happen after the experience of trauma.

And this is me like nerding out a little bit,

But I love this.

So on the top part of that picture is the person with no history of trauma exposure or mental health condition.

And the red line refers to the heartbeats over time.

The blue line is the respiration or breath pattern.

So we can see,

And this is the exact same time chunk,

This is during a meditation practice,

Very different patterns of heartbeat depending on a person's exposure to trauma.

So in the top bar,

When the person inhales,

The heartbeats start to quicken a little bit.

When the person deeply exhales,

The heartbeats spread out.

And this is what flexible autonomic nervous system looks like.

And this is an indicator of health.

We want that flexibility.

We want to inhale and see the heartbeat quicken because inhale is linked to sympathetic nervous system and exhale is linked to parasympathetic rest and digest.

On the bottom part of your screen.

Is a participant that has clinical PTSD.

And what we see is a more rapid breath cycle.

So more breaths in that same window,

But we also see this invariant heartbeat where the heart rate is just not really flexible with the breath at all.

And this could be for a couple of reasons.

One,

The breath could be really shallow,

So we're not actually stimulating the various parts of the nervous system.

Or the chronic stress exposure over time is so intense that the body has become rigid in its response.

And so I just like to show this to you because This is what physiology,

This is what's going on on the inside.

And we want to,

As we heal,

We want to increase our flexibility in our autonomic nervous system.

So that's one thing I want you to take away throughout this week is how do I increase the flexibility of my autonomic nervous system?

How do I get out of rigidity and constriction and into expansion and flexibility?

And that's just something to ponder.

So this is probably going to be refresher for folks.

With our autonomic nervous system,

We typically hear about two branches,

Our sympathetic system,

Which is classically known as fight or flight,

And our parasympathetic system,

Which is classically known as rest and digest.

Okay,

When we go into sympathetic activation.

Lots of things happen involuntarily.

Could you imagine if we had to tell our heartbeat to increase or we had to tell our lungs to breathe quicker?

So this is all happening subconsciously,

Involuntarily.

The body detects danger or threat and our heart rate is going to increase,

More blood flow goes to our muscles and tissues so that we can fight or flee.

Our digestion ceases because it's not the priority,

Fighting or fleeing is,

So our digestion starts to turn off a little bit.

The main neurotransmitters,

And don't worry,

There's no test on this,

But the main neurotransmitters of our sympathetic nervous system is the secretion of adrenaline,

So epinephrine and norepinephrine.

And these neurotransmitters do a whole host of chemical hormonal reactions in our body to help mobilize us to meet the demand.

Now,

If long-term stress is an occurrence,

The adrenaline system might get fatigued,

So we move into another longer-term stress activation,

Which is known as our HPA axis,

Our hypothalamic pituitary adrenal axis.

Don't worry about memorizing that,

But that system in our body is what releases cortisol to help us keep that energy to meet the stressor or demand.

Our parasympathetic nervous system,

On the other hand,

Kicks in when we feel like the threat or danger has passed.

And so the main neurotransmitter of the parasympathetic system is acetylcholine.

And this gets released through a whole host of reactions to bring our heart rate back to resting state,

To help our blood pressure regulate,

Our digestion now starts to kick in.

And stimulates saliva,

Our pupils contract,

They don't dilate anymore,

They contract back to regulatory vision.

Okay,

So these are just the basics of the autonomic nervous system.

We know parasympathetic and sympathetic nervous system.

Many people don't know that there's another part of our autonomic nervous system,

Which is our enteric nervous system.

Start with that next day,

But that is the bi-directional communication from our brain to our gut.

So our enteric nervous system is like a web-like structure of neurons within our gut lining.

And it's really important that we spend some time on the enteric nervous system because so many folks who experience trauma also have gut dysbiosis it's called.

So imbalance in the gut and we're going to dive into that next day.

But today I want to ground us in sympathetic versus parasympathetic.

We know sympathetic is fight or flight and parasympathetic is rest and digest.

Many of you may have heard of the polyvagal theory.

This is by Dr.

Steven Porges.

And this is where I want to spend a little bit of time.

So if you have a blank piece of paper,

I highly recommend bringing it out.

And I want on your piece of paper to divide the page equally into three different sections.

If you want to draw a ladder like you see on the right,

Feel free to do that as well.

I want you to create your own autonomic ladder.

And we're going to dive into the polyvagal theory.

So Dr.

Porges actually proposes that instead of our classic sympathetic and parasympathetic nervous system,

We actually have a third subsystem that is mediated by the vagus nerve.

So our vagus nerve is one of the largest nerves in our body.

And it makes up about 80% of the parasympathetic nervous system.

It has a very big role.

But what Dr.

Porges says is that our vagus nerve is not unitarian.

It's not a single nerve that only acts one way.

It's actually subdivided into two different subsystems.

So we can think about the polyvagal theory much like we do with a ladder.

So we have our ventral vagal nervous system at the top of the ladder.

Okay,

So I'd love for you on your piece of paper to draw out the three different steps on the ladder.

So at the top of your ladder is ventral vagal.

And in the middle of your ladder is sympathetic nervous system.

And the bottom of your ladder is dorsal vagal or dorsal vagal complex.

So I'll give you just a moment there to get those three sections.

Because I'm going to stop sharing the screen share and come chat with you about this.

Because I want you to create your own understanding of the polyvagal theory and reflect on this throughout the week.

Okay,

So take a couple more moments,

Divide your paper into three.

We've got ventral vagal at the top.

Sympathetic nervous system in the middle,

Dorsal vagal at the bottom.

So we're going to work our way bottom up because Dr.

Porges suggests that the dorsal vagal complex is the trauma response.

That is where the trauma response happens.

Okay,

So feel free to write as much as you need in this section to explain this.

So the dorsal vagal complex.

Is the Um.

The most primitive part of our vagal nerve evolution.

This is similar to reptiles and vertebrates as well.

And this is a third defense strategy.

So instead of fight or flight,

We now have freeze.

And we've heard of the freeze response or immobilization response.

So the freeze response is what lives in the dorsal vagal system.

Our dorsal vagal complex are the nerves that innervate organs and viscera below the diaphragm.

Our ventral vagal is above the diaphragm,

We'll move into that shortly,

But our dorsal vagal nerve Innervate.

Viscera,

Our visceral organs below the diaphragm.

So namely our reproductive organs,

Parts of our digestion.

It also has a link to our heart as well.

A very small link comparatively,

But it does have a link.

The dorsal vagal complex,

If it's one thing you take away today is the understanding of dorsal vagal shutdown freeze response,

Because this is where the trauma response lives.

When the body detects that fighting or fleeing from a danger or threat is not possible,

Involuntarily,

So outside of our conscious awareness,

The dorsal vagal complex will kick in so it spikes.

To a massive degree to put us in a freeze response.

So what that means can be a number of things.

The classic example.

That I like to use as an example is when a cat captures a mouse in its mouth and we see the mouse look limp.

We assume that it's deaf or it's dead.

Okay,

So the dorsal vagal system in our body kicks in to collapse us.

To make us go limb.

To faint.

To death fane,

It's called,

So put the appearance of death.

So we're limp and we might have a flat affect in our face.

Um,

Might cause us to urinate or defecate ourselves.

Again,

This is not by choice.

We don't consciously choose this.

Our body has detected that fighting or fleeing from a threat or danger is not possible,

So we move into this third defense strategy called freeze or immobilization.

We completely freeze.

So many of the clients I work with talk about Why didn't I do something?

Why didn't I fight back?

Why didn't I escape?

I just went limp.

I collapsed.

I blacked out.

And.

This course could just sum up in one breath right now.

It is.

That your body actually went into a third defense strategy outside of your conscious awareness and did everything that it needed to do to help you survive.

So let's go back to that cat and mouse example.

Okay,

So the mouse is caught in the cat's mouth and it looks like it's limping.

And it's dead.

Okay,

This is adaptive.

For two reasons.

One,

If the cat thinks,

Hmm.

Nice.

I got the mouse.

It's dead.

It might loosen its grip.

So that actually is a survival strategy for the mouse to appear dead so that the mouse or the cat actually loosens its grip so the mouse can get away,

One more chance to get away.

As human beings,

This translates similarly.

We might move into freeze response to look less viable to a perpetrator.

So that might be a survival mechanism.

Again,

You're not consciously choosing it.

It's happening outside of your conscious choice.

The second reason this happened.

Is if the cat is going to eat the mouse,

The freeze response eliminates the psychological and somatic harm from actually being eaten.

As human beings,

We have that same capacity.

If fighting or fleeing the danger is not possible,

We have the ability outside of our conscious awareness to move into that freeze response to eliminate the somatic and psychological reality of that harmful,

Painful experience.

Now,

It's very difficult to measure this.

Have this in experimental evidence,

But this is what's thought to happen in automobile accidents,

Fatal car accidents.

It's thought that the body dissociates and goes into a freeze response before the person somatically even is aware of the experience.

Okay,

So I share this with you and some of this might be really stirring up light.

If you're thinking about your past exposures to trauma,

You might think,

Oh yeah,

I totally froze or went limp or completely blacked out.

And.

.

.

Give yourself permission.

Those permission slips coming back.

To acknowledge that that was your body doing what it needed to do to survive that experience.

The trauma response lives in that dorsal vagal shutdown immobilization state.

So that's why it's so important to hone in on that,

Is it's an involuntary system.

That is happening outside of your conscious choice.

Through your nervous system function,

It detected that fighting or fleeing was not going to be the best defense strategy.

So it went into dorsal vagal shutdown.

And so many people I work with.

Jess.

Like almost 100% of the people I work with say.

I can't believe I did that.

What's wrong with me?

I didn't handle that the way that I should have.

And I'm like,

When you understand your autonomic nervous system,

Everything that happened was absolutely your body's way of working for you.

We attach the meaning and we get into brain regions next day to that experience.

And again,

We look at ourselves and say,

We didn't do it right.

We didn't do enough.

We weren't correct in how we handled that.

And then we put ourselves in this perpetual.

Stress response.

Okay,

So dorsal vagal shutdown.

My hope today is that you really understand that if you have components of your exposure in your life that you don't recall or remember,

Or you feel like you blacked out,

Fainted,

Went limp.

Collapsed.

That that Makes sense.

Given what you were exposed to.

I don't even need to know what you were exposed to.

If your body went into that,

That was your body's way of saying,

This is the defense strategy that I need to use.

So I'm gonna just pause there for a minute and see if there's any questions about dorsal vagal.

Shut down.

It's a lot,

So if you're feeling hot right now,

Like whew.

Not a bad thing.

We're learning about the nervous system.

Okay,

So a private question is,

Am I right that shutdown can repeat in lesser scenarios long after the trauma?

Yes,

So really fantastic question.

So this is where it gets interesting,

Is it takes that one time to go into dorsal vagal shutdown and our nervous system becomes rewired around that.

Shutdown and moving from shutdown to activation and back to shutdown.

Our nervous system becomes altered in a very predictable but very confusing manner when we go into dorsal vagal shutdown because now we start to oscillate in and out.

And shutdown dissociation can be on the far end of the spectrum of complete blackout,

Fainting limp.

And then on the lighter end of the spectrum,

You know,

Driving from point A to point B and not really recollecting how you got home.

From where you were driving from that lighter stage of dissociation.

Okay,

So there's a big spectrum of how it occurs.

We don't always faint collapse and go into shutdown.

If we did in a trauma exposure,

We might have experiences of,

You know,

More moderate to mild experiences of dissociation.

Okay,

So really great question.

Um So Les says,

I guess appetite can be significantly affected.

Absolutely.

That's why the enteric nervous system,

The gut brain connection needs to be talked about.

And that's going to be next day because it requires kind of that standalone information as well.

Absolutely.

When we're in sympathetic fight or flight,

Our digestion is not the priority.

Our priority is fighting or fleeing.

So we lose that nerve connection really because we're prioritizing something else.

So that's good.

Katie,

Is this why there are significant periods of amnesia from prolonged traumatic events?

Absolutely.

This is absolutely why,

Because the survival mechanism of dorsal vagal shutdown alters certain parts of our body to survive in the way that it needs to.

And we're gonna dive into the brain regions that get impacted by trauma next day.

Namely the hippocampus,

Which is our memory formation center.

So absolutely.

And it's not uncommon when we start to do the healing work,

I call it popcorn effects.

When we start to do,

You know,

Meditation or start to access some of this healing work,

Some fragments of memories start to come back or new linkages between things that we've gone through in our life start to come back.

Not always,

But it's not uncommon.

So perfect.

So we have dorsal vagal shutdown in the middle of your ladder.

We now have sympathetic dominance or sympathetic activation.

So we classically know this as fight or flight.

Okay,

So rapid heartbeat,

Flighty,

Panicky.

High anxiety,

Hypervigilance,

So just constantly looking out for danger,

Feeling like you've got to watch your back.

Everything feels like a threat or danger even if it's seemingly mild,

An interaction with somebody.

Maybe an exaggerated startle response.

Maybe a certain tone of voice,

For example.

So sympathetic,

Mobilization is in the middle and that's just our body's way of fighting or fleeing off the dangers.

We've got our boxing gloves on,

We're ready for the fight,

We're like on the lookout.

I don't want to overspend time there because I think that gets overemphasized a lot.

But that's the sympathetic middle part of the rung.

And then the top rung that I do want to spend time on is ventral bagel.

Okay,

So ventral vagal,

As I said,

Is part of the vagus nerve that innervates above the diaphragm.

Okay,

So the ventral vagal nervous system innervates our heart,

Our lungs,

It innervates our larynx,

So our vocal cords.

This is really important,

So write this down.

The vagal nerve,

Ventral part of our nerve.

That innervates above the diaphragm.

So heart.

Lungs,

Our larynx and vocal cords.

Are they're called striated muscles of the face,

So the muscles of the face that emote,

So our ability to smile,

To look surprised,

Eyebrow raising.

Um,

Innervate into our ears.

So our listening.

Innervate our eyes,

Our sight.

So the ventral vagal nerve fibers innervate regions above the diaphragm.

And our ventral vagal system.

Is.

Our newest.

Evolution.

Of our vagus nerve.

And we share the ventral vagal system with mammals that rear their young.

So any kind of mammal that rears their young ones,

There's a ventral vagal system.

Human beings have the most evolved because of our evolution.

But our ventral vagal system.

Is directly linked to our social engagement safety system.

Okay,

As human beings.

When we are born to our care providers,

We are born for connection for belonging.

For safety.

Through our care providers.

If we didn't get that as young children,

Our ventral vagal nervous system gets impacted.

So ventral vagal is all linked to safety,

Social connection,

And engagement.

Through our ventral vagal nervous system,

We detect in our environment,

Who is safe to be around.

Very primitively in our younger years,

If we have a strong ventral vagal system,

We can distinguish our mother's voice,

We can eliminate background noise and hear our mother's voice more clearly.

We can think of the mother singing a lullaby to their child.

Through the larynx and vocal cords,

We communicate.

Safety and connection with another.

Alternatively,

We also communicate unsafety.

When you raise your voice,

When you're angry,

Aggressive,

Harsh.

Is not.

Stimulating ventral vagal strength that's putting us into fight or flight or dorsal vagal shutdown.

So our ventral vagal nerve innervates our vocal cords and helps us communicate safety and connection to others,

But also we interpret communication and safety through the tone of voice of other people.

Okay,

So I've talked about listening,

Hearing,

Talked about vocal tone.

Also called ProCity,

P-R-O-S-O-D-Y.

So that,

Yeah.

Lullaby kind of tone that signifies I'm approachable,

I'm safe for you to be around.

Alternatively,

We can also communicate that.

And then our ventral bagel nerves innervate the striated muscles of our face.

This is why in the last year it's been really difficult for some folks to assess safety because we're wearing PPE.

Potentially a visor over our face and a mask.

So we're eliminating some of the communication that we're safe from.

Through our facial expression.

So think about for yourself,

How do you communicate to somebody either that you love or a complete stranger or your grocery clerk or your bank teller?

How do you communicate that you're a safe person to be around?

We generally have better eye contact.

We generally have like a lighter smile on our face.

We have engagement in our eyebrows.

We communicate through our face that we're approachable and comfortable.

When it comes to trauma.

And if we are oscillating in and out of dorsal,

Vagal and sympathetic,

We're not accessing ventral vagal.

So two things happen.

One,

We're not detecting safety and connection through other people.

The ventral bagel system can't work if we're in one of the other two defense systems.

They don't work that way.

So if we're in collapse shutdown or we're in.

Sympathetic overdrive.

We're not assessing safety really with people in our environment because we're on the lookout for threat and danger.

Also,

We're not communicating safety as well.

So one of the classic.

Symptoms of folks with trauma,

Not everyone,

And it varies on degrees.

Is lack of emotion in the face.

So looking really serious to flat affect.

So somebody who's been through tremendous shock trauma can have a flat affect.

I don't know if I can show an example for you.

I'm going to try,

But the eyes are generally lifeless.

And the face.

Is lifeless.

The person looks emotionless,

They look lifeless in their face.

Um,

It also can happen with dissociation if you're separating from your body.

You don't look present.

OK,

And that can vary on degrees as well.

So if it's one thing through the next seven days before we meet again,

Is to think about this nervous system ladder.

Where are you on the ladder?

OK,

And.

Ventral vagal can't occur when we're in sympathetic or dorsal vagal shutdown.

We can't assess safety from other people very clearly.

We miss cues.

We might misinterpret somebody's tone of voice.

We might misinterpret somebody's facial expression.

We might make assumptions really quickly,

But that makes sense given where we're currently at in our defense strategy in our body.

Okay,

We might also not be communicating safety.

How can we,

When we're in sympathetic or dorsal vagal shutdown,

How can we look approachable and comfortable when we're feeling threatened and afraid?

So think about.

Not only how are you assessing and interpreting other people,

But how what are the safety cues you're giving off or not giving off based on where you're at in your current defense strategy in your body.

So I'm going to just look at a couple of questions.

Okay,

So a private question says,

So if you were raised in an environment where your caregivers taught you to be afraid or scared of everything,

That part can be impacted in the feeling of unsafe comes up.

Yes,

Exactly.

So it doesn't have to necessarily be this shock trauma that happens.

It really refers to our environment and how we were reared.

How were we raised?

If we were raised to be afraid and fearful of everything,

What defense strategy is that totally activating?

Is it ventral vagal?

It's usually sympathetic,

Be on the lookout,

Get those boxing gloves on,

Or potentially moving into maybe a lighter version of dorsal vagal shutdown because it's exhausting to be on the lookout so often.

Okay,

So that can wire our nervous system to feel unsafe everywhere.

Okay,

So really great comment.

This is all nuanced as well.

So,

Okay,

So another,

Susan says,

If you're not in ventral,

Might the muscles around the eyes be affected?

Um.

It's possible,

But from the perspective of eye contact and safety with eye communication,

The nonverbal communication through the eyes.

What you might be thinking about is if you have symptoms with the eyes.

We're going to talk about inflammation in the body because if we're in constant stress or dorsal vagal shutdown.

We're inflaming the body to metabolize to meet demands.

So this might.

Over time chronically cause some eye conditions.

Okay,

And we're gonna make some linkages.

We're gonna start to dive into what is true for us.

In our physical symptoms.

If your eyes are affected,

The healing question is,

What might you not be seeing or looking at?

Okay,

If your voice is affected,

If you constantly have throat infections or strep throat or lose your voice.

Where are you not sharing your voice or sharing your story?

Where are you keeping things inside and not using your voice?

And we're going to get into more of that,

The link between the physical symptom and the possible link to trauma.

Not saying that everything is linked to trauma without knowing everyone's health history,

But we're going to start to look at,

Is there something here that's linked to unresolved trauma?

Okay,

So really great questions.

Um So that's the polyvagal theory.

And then the final.

Thing before we move into some somatic practicing.

Is the window of tolerance,

Which is another thing that we hear in healing recovery.

And some people think they're the same.

And there's some distinct differences that I just want to go through.

Because one of your homework tasks is to think about your window of tolerance and how do we stretch it a little bit.

So,

Polyvagal Theory looks at.

.

.

Three different behavioral defense or safety states.

We've got our dissociative dorsal bagel shutdown freeze response,

Sympathetic fight or flight response,

And then ventral bagel safety connection belonging.

With the window of tolerance.

This is a little bit different.

This looks at.

More of your day-to-day capacity to move in and out of stress.

So it's not linked to trauma per se,

But our window of tolerance is how do we navigate our day-to-day lives,

The day-to-day happenings in our lives,

Through our window of tolerance.

So we all have a window of tolerance,

Which is in the middle zone here.

Which is our optimal functioning zone.

We can carry on with the flow of life.

Our window of tolerance is that space where we don't get overly hooked by or affected by events in our day-to-day.

If our window of tolerance is quite small,

We might push into one of two different states.

We might move into hyperarousal,

Which we've heard before today,

That overwhelmed,

Panic,

Feeling unsafe,

Reactive,

Bracing thought.

Or we might push into hypoarousal.

So no,

Like lack of energy,

Collapsed,

Shut down,

Just can't,

We don't have the capacity to take on anything more.

And so I share these two with you because they often get interlinked,

But they're very different.

Polyvagal theory is really about understanding the trauma response,

The defense strategy of the freeze immobilization state.

And the window of tolerance is how do we navigate our day to day?

Function.

Okay,

So when it comes to healing,

The question is,

How do we stretch that window of tolerance just a little bit so we don't move into hyper arousal or hypo arousal?

How do we stretch just a little bit more,

Even just one more breath at a time?

Okay,

But I wanna give five minutes,

Five to seven minutes to go get a glass of water,

To set up your space for some somatic practicing,

To shake out what we just learned about.

I want you to compartmentalize this right now.

And okay,

We took in some information,

But now we're gonna get into the body.

Okay,

So you might have some questions burning right now.

And we're gonna practice being okay to not have those questions answered just now.

Let the questions just live there.

So I'm going to give five minutes.

I have to take a quick bio break.

We're going to come back and reconvene and get right into a somatic practice.

© 2026 Dr. Megan Kirk Chang. All rights reserved. All copyright in this work remains with the original creator. No part of this material may be reproduced, distributed, or transmitted in any form or by any means, without the prior written permission of the copyright owner.

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