There's a part of our brain, called the amygdala, that takes in what we see and experience, and based on those sights and experiences, it determines if there is a threat, or danger. When the amygdala says "yup, that's a threat - we're in danger", it sends messages to ramp up the body to prepare for an attack.
We have all heard of these "preparations for an attack" responses -
Flight (running away from the problem)
Fight (attacking or fighting the problem)
Freeze (feeling "paralyzed" or "frozen" when confronted with the problem)
Fawn - this is a new one (accepting any and all consequences of doing nothing, like a new baby fawn)
(Source: Wikipedia)
Or as I call it "the alarm center" sends messages to the the brain stem, and our memory system in the brain, and our emotional system. They all work together, and connect things we experience based on the memory we have, feelings we experience, and the physical reactions we have.
(Source: Wikipedia)
Controls all of our automatic body functions - breathing, blinking, digestion, sweating - all those things we don't tell our bodies to do. It's the oldest part of our brain - meaning that it was around long before the other areas of the brain evolved. It's sometimes called the "reptilian" brain, due to us sharing the same structure with ancient - ANCIENT- man.
These automatic responses are really useful when we are in danger - adrenaline helps our muscles to react, increased blood pumping through the heart, and we "zoom" in on the threat.
Source: http://www.brainfacts.org/3d-brain#intro=false&focus=Brain-limbic_system-amygdala
The memory system, which involves the amygdala, the hippocampus, the cerebellum, and the prefrontal cortex, take our experiences, and codes it in a way that the brain can pull from it as needed -- or as triggered.
Source: Brain Post https://www.brainpost.co/weekly-brainpost/2021/1/4/how-should-we-think-about-the-brains-response-to-threat-86kda
The emotional system, which includes the amygdala, the insula or insular cortex, and a structure in the midbrain called the periaqueductal gray, processes what we experience as happiness, disgust, pain, or other emotions we may have.
So if the brain is doing all this extra work to sense everything as a threat, and the brain stem is constantly preparing the body to fight, flight, freeze, or fawn -- where is the extra energy coming from to do this?
Well, unfortunately, and also fortunately, it takes its energy from other parts of the brain not needed.
One of those places, is the prefrontal cortex - I like to call it the "thinking brain".
The prefrontal cortex is our seat of reasoning, what separates us from the animal kingdom. It is where we use logic, rationality and rational thinking, "executive functioning" (organizing, being flexible, self-control, doing/completing/identifying tasks, keeping our emotions in check) .......... basically it's the part of your brain that gets you your job, lol.
"Are you saying that when I get anxious,
my body prepares for a threat/danger,
and the part of my brain that can stop this,
is shut off??!!"
Yup ...........that's exactly what I'm saying.
But look at it from this perspective -- imagine waking up one morning and getting ready for your job or the day. And you walk outside of your home, and see a sabre toothed tiger right in front of you.
Do you need to stop and think about why the sabre toothed tiger is there?
Are you recalling in that moment that sabre toothed tigers are extinct, and should not be outside your door?
Are you thinking about who you can call, animal control/police/national guard/zoo, to come and get this tiger?
UMMM NO .......YOU'RE NOT......
Our typical instinct would be to turn back around, go in your home, and find an escape!!!!
That's the amygdala working as it should - and not allowing you to be in danger. You don't need to "think" or rationalize in those situations, you need to react, and get to safety -- so you survive!!!
So there is a reason for the brain to "shut off" the thinking part when we are in danger, or perceiving a threat. But with anxiety, you are "in danger" and perceiving threats all ...the .... time.
Which doesn't give your thinking brain much time or opportunity to tell yourself that speaking in front of a room of people is not a dangerous situation.
The brain's way of calculating danger and threats is so fast, so instantaneous, so "built in", it happens before we can even stop it with our "super thinking powers" in the prefrontal cortex.
It's kind of on a circuit.
You see/perceive something, memory and emotion send a message about how you feel/remember this something, amygdala sounds the alarm, brain stem jumps into action ............and now you're sweating bullets, feeling paralyzed and wanting to run from the presentation you need to give.
Anxiety in action .........smh