Professor Bruce McEwen discusses how the amygdala is involved in processing fear and stress.
Starting with the amygdala, it is the brain area that’s involved in fear, fear learning, also to some extent in aggression. It’s also a brain structure that is involved in turning on the stress response, turning on the adrenaline, turning on the ACTH [adrenocorticotropic hormone] that causes cortisol secretion. It’s also an area that’s involved when you’re stressed and see something dangerous, like a snake walking in the woods. You freeze and then you later move back. It’s involved in all of these primary actions that are related to stress and self-defense.