Neurohacking Everyday Fear

Week 7

Anatomy & Physiology of Fear

Anatomy of Fear

Physiology of fear

Anatomy of Fear

Fear is a complex response system that includes multiple pathways, dozens of hormones, including epinephrine and norepinephrine, and multiple parts of the brain including the amygdala, thalamus, hypothalamus, hippocampus, and the sensory cortex.


In this video, we are going to examine some the anatomical features involved in the fear response as well as some of the body chemistry going on. The most efficient way to do this is a plain old laundry list of descriptions.


This video is for those info nerds out there, so if anatomy and physiology really isn’t your thing, not to worry – skipping this video will not prevent you from successfully applying the fear forward method to your daily fears.


But, if you’re still with me – let’s get deeper into the science.


Let’s start with the anatomy, or physical structures, involved in the fear response.


Since fear is an emotion, we need to talk about the limbic system.


There is some debate around what is and what is not included in the limbic system, so for us here we’re going to just simply say that the limbic system is a set of structures deep within the brain that work together.


Exactly how these structures birth the wide spectrum of human emotion is still not really understood, but – we do know a bit about some of the functions of the structures – so let’s start there.


The almond-shaped amygdala, sometimes called our fear center, gets fired up when we’re afraid or when we are around other people that are scared, nervous or anxious.


The thalamus is a two-lobed structure that sorts out all the sensory signals coming into the brain and sends them to the proper region of the cerebral cortex. Think of it like the person in the backroom of the post office that is sorting all the incoming mail so it can go to the right part of the country... although this probably all done by a robot now – but... whatever, I’m still using it as an example.


Next up, the hypothalamus, which literally means under the thalamus, is all about maintaining homeostasis. Homeostasis is the ability for the body to keep things in the happy middle. You probably heard the goldilocks and the three bears story as a kid, well the human body is a lot like that... it doesn't want to be too hot or too cold. Doesn't want to be too hungry or too full. The body wants to be just right and helping to maintain all the systems in that just right place is the hypothalamus. Since the hypothalamus is the musical conductor of the physiological symphony that accompanies emotions, it is the signal from the hypothalamus that makes our heart

pound and our palms sweat when we’re scared or stressed out.


And finally, the hippocampus - the hippocampi are structures adjacent to the amygdala and they play a crucial role in our ability to form memories.


When the amygdala and the hippocampus interact with one another that’s when we get learned fears.


What is super cool about the hippocampus is that its one of the very few brain regions where you get to make new neurons, those specialized brain cells, as an adult. Like many aspects of neuroscience, our research has not shown a clear explanation of how these new neurons assist in memory formation, but as time and technology advance, we will hopefully know one day soon.


But what we do know more about is the physiology of fear, up next!

Physiology of Fear

Next up are the major neurotransmitters and hormones involved in the fear response.


Neurotransmitters and hormones are the chemical messengers of the body. When they’re released, they tell the body to do something or stop do something.


Neurotransmitters are chemical messengers of the nervous system and are therefore released by neurons in order to talk to other neurons.


Hormones, while similar in function, travel around in the bloodstream, AKA the circulatory system, instead of the nervous system.


When we talk about the stress response or fear response, we’re usually focused on glutamate, epinephrine and norepinephrine.


Glutamate, a neurotransmitter, is released by the amygdala when we get scared that sets off a few reactions in the body.


First, our quickest response to fear is to freeze or flinch. This happens when the amygdala releases glutamate and activates a very evolutionarily ancient part of our brain called the periaqueductal gray. Glutamate also fires up the hypothalamus to get the fight or flight response going. When the hypothalamus receives the glutamate signal that its go time, it sends a message to the adrenal glands to produce epinephrine, that most people refer to as adrenaline. This is when we see the body really kick into high gear in preparation for some serious movement – to either fight the big scary danger or to run far far away. Epinephrine is both a neurotransmitter and a hormone, depending on where its being released in the body.


When the fear response is activated, Epinephrine along with a few other hormones, causes a bunch of reactions in the body that most of us are familiar with. All these changes occur in order to ramp up and prepare so there is as much energy and blood flow as possible for our skeletal muscles. Some of these don’t necessarily have a huge impact for us in this course, like faster heartbeat, shorter, quicker breathes, an increase in blood sugar, pupil dilation, and blood being re-routed from the skin to the muscles. But a select few of the stress response reactions do.


When we’re in the throes of a stress or fear reaction, our muscles naturally tense up. For many people this is visually noticeable and can make others uncomfortable, especially if they don't know you very well. If you don’t have your fear under control, others around you begin to share in your nervousness and anxiety – making it difficult for potential clients and investors to want to spend time discussing your project. I bet, you have at least a few memories of a speaker being so nervous on stage that it was painful to watch.


Another stress response that entrepreneurs need to pay close attention to is the deregulation of nonessential systems during a fearstorm. A fearstorm is going to be those times in our life where our fears are in control of our thoughts and our bodies are physiologically reacting to that fear. Nonessential systems for the body are things like digestion, keeping our immune system strong, and making new cells. Which means if you don't have a good handle on your fear of failure, speaking, or selling – you’re going to quickly wear your body out. And if you’re being controlled by fear and stressed all the time, there’s a good chance that this down-regulation could end up making you gain unwanted weight too – sorry.


Lastly, and perhaps most importantly for entrepreneurs, is when a fearstorm hits, our brains don’t really care about our success or our goals. A brain in the throes of a fear response is all about survival and has no time for your pitch deck or client meeting. The “automatic” part of your brain overrides your ability to focus on small tasks so that it can divert all the energy to focus on the threat. Mastering your relationship with fear and having your parasympathetic nervous system at the wheel of your bus means you can dramatically increase the quality of your decision making, your performance, and your leadership.


Mmmmmm .... that sounds good. Let’s do that, together, in the next unit.

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