When a frightening or threatening event occurs, input from our sensory organs—the sights, sounds, and smells of danger—are transmitted directly to a pair of tiny, almond-shaped nerve clusters deep in the brain called amygdalae. The amygdalae immediately send alert messages to other parts of the brain that trigger the release of glucocorticoids, the fight-or-flight stress hormones such as cortisol and norepinephrine.
