10/26/2021
It seems fitting to start this week by looking into the science of fear by starting where the fear begins - the brain.β
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π° Fear starts in the amygdala. It's the amygdala's job to notice things in our environment. When it detects something it perceives as a threat, it prepares other parts of the brain to react. It triggers a cascade of physical responses too. You see and hear more clearly. Your heart rate and breathing quicken to prepare your body for flight-or-fight.β
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The hippocampus wakes up and teams up with the pre-frontal cortex to decide if the threat needs to be taken seriously. Together they evaluate the danger in the context of the situation to see if a fear response is warranted. If you saw a gorilla coming at you on the street, you would probably be terrified. However, put that same gorilla in a habitat in a zoo, and she isn't so scary. π¦β
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If a threat is determined as genuine, the amygdala is allowed to keep going unfettered. However, if the danger isn't determined to be real, the amygdala is told to shut down operations, and we begin to calm down. β
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There is an in-between real and unreal perceived threats. When a threat is perceived as real but not quite accurate enough, the amygdala is told to just dial it back a notch or two. This lessens the fear response in the rest of the brain, but it is still there. We are still just a little scared. Scary movies, anyone? πβ
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The amygdala also tells the hypothalamus to tell the pituitary gland to release hormones, but more on this in the hormone edition later in the week. π
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People always talk about fight-or-flight, but you never hear them talk about the other "f" - freeze. Some people, and other animals, freeze when they perceive a threat. This happens because an area of the brain known as the periaqueductal gray (PAG) receives sensory information about the danger. At the same time, the cerebellum is receiving this same information to coordinate body movements. When there is "cross-talk" between these two areas of the brain, a person will end up freezing when up against a scary situation. π³β
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Tomorrow we look at neurotransmitters involved in the fear response!