Sometimes, staying motionless is the best plan for instance, if you are a small mammal or if you are well-camouflaged, staying still could save your life.Ī 2014 study identified the neurological root of the freezing response. When they are frightened, most animals freeze for a few moments before they decide what to do next. The idea of our bodies preparing to fight or fly makes good sense from a survival standpoint - but how would freezing be of any use? An animal that simply stands rooted to the spot would make an easy snack for a predator, you might think. So, we get to experience the rush of fear before our more reasonable brain centers dampen it down. This partly explains why people enjoy watching scary movies their sensible “thinking brain” can overpower the primal parts of the brain’s automated fear response. If the hippocampus and prefrontal cortex decide that the fear response is exaggerated, they can dial it back and dampen the amygdala’s activity. They help us understand whether our fear response is real and justified, or whether we might have overreacted somewhat. Along with the prefrontal cortex, which is part of the brain involved in high-level decision-making, these centers assess the threat. The hippocampus, which is a brain region that is dedicated to memory storage, helps control the fear response. These hormones can also: boost activity in the heart and lungs reduce activity in the stomach and intestines, which explains the feeling of “butterflies” in the stomach inhibit the production of tears and salivation, explaining the dry mouth that comes with a fright dilate the pupils and produce tunnel vision and reduce hearing. Circulating cortisol turns fatty acids into energy, ready for the muscles to use, should the need arise.Ĭatecholamine hormones, including epinephrine and norepinephrine, prepare muscles for violent action. The body also releases cortisol in response to ACTH, which brings about the rise in blood pressure, blood sugar, and white blood cells. The pituitary gland secretes adrenocorticotropic (ACTH) hormone into the blood.Īt this time, the sympathetic nervous system - a division of the nervous system responsible for the fight-or-flight response - gives the adrenal gland a nudge, encouraging it to squirt a dose of epinephrine into the bloodstream. The amygdala is able to trigger activity in the hypothalamus, which activates the pituitary gland, which is where the nervous system meets the endocrine (hormone) system. Share on Pinterest When we are afraid, it sets off a sophisticated, coordinated response in our brains and bodies.