How is the brain affected by fear and danger?

Why Do We Feel Fear?

To understand the effect of fear on the brain, it is important to know why we feel fear in the first place.

Fear is one of the basic and important emotions that has helped humans survive, by making them fear a certain danger and then run away or hide from it.

In other words, the primary role of fear — survival — helps explain why it sometimes appears with great intensity.

What Happens in the Brain When We Are Afraid?

To simplify this answer, Dr. Daniel Siegel depicted the brain in the shape of a hand.

Place your thumb in front of you, then close the remaining fingers over the thumb. You will notice a shape that resembles the brain, where the brain regions are as follows:

• The wrist represents the spinal cord.
• The thumb represents the amygdala, the part of the brain that alerts the nervous system and starts making some changes in the body, known as the “fight or flight response.”
• When you close your fingers over your thumb, you form the cortex area.

To explain the effect of fear on the brain in this way, here are the details:

1- The Limbic System and Fear

The limbic system is a region in the brain that consists of several important parts, such as the amygdala and the hippocampus.

This system is an important center for emotions, memory, and reactions. The amygdala, in particular, is responsible for detecting danger and sending a signal to our autonomic nervous system to respond accordingly.

To make it simple, let’s assume you were stung by a bee. The hippocampus stores a memory of this event and links it with the feeling of fear. So, the next time you see a bee, the amygdala recognizes this danger, and you will feel fear.

In this case, a hormone responsible for fear — cortisol — is released. As a result, you will notice changes related to the fight or flight stage, such as:

1. Increased heartbeat.
2. Increased breathing rate.
3. Increased energy supply to the muscles to facilitate escape.

2- The Cortex and Fear

Now it is time for the cortex to intervene — the area responsible for thinking. In the cortex, you can also find ways and solutions to the situations you face during your day.

The prefrontal cortex specifically analyzes the situations sent by the amygdala to determine the appropriate reaction.

To illustrate the effect of fear at this stage, open your fist while keeping your thumb tucked in. This is what happens in the brain during fear — but what does it mean?

We lose communication between the cortex and the amygdala. As a result, we can no longer effectively communicate with others, control our emotions, or respond with logical thinking!

Important note: We do not have to be in real danger to enter a state of fear, as any stressful situation can cause an increase in cortisol levels and disrupt communication between parts of the brain.

Remember… children find it even more difficult to respond to stressful situations and regulate their emotions because the prefrontal cortex does not fully develop until the age of 25.