Emotions are complicated. They’re so complicated that scientists still don’t even fully understand them! One thing that scientists do know, though, is that some of our biggest feelings are caused by a tiny part of the brain called the amygdala.

The amygdala is a bundle of important nerve cells deep inside the brain. Everyone has two amygdales—there’s one in each half of the brain. The amygdala works with the parts of the brain that control memory, behavior and emotion, and this tiny group of cells packs a big punch when it comes to emotions, especially stress and fear.

Most people don’t like to feel scared, but humans are fascinated by it! Think of all the spookiness in the month of October. The rush of energy and emotion people get by being scared can be enjoyable in controlled situations, like a scary movie or an amusement park ride.

No matter the source of the scare, the amygdala’s role is the same. The amygdala is like a bridge connecting two very different parts of the brain: the part that controls the body functions you aren’t aware of (like breathing) and the part that “thinks” for you.

This means that when your amygdala gets information that tells you something scary is happening, it can send signals that make your heart race and your breathing get faster, making you feel scared!