Brain and Behavior

The Major Structures of the Brain

What do the amygdala and the hypothalamus do?

The amygdala seems to be an early responder to emotionally significant signals from the environment. It is particularly reactive to fearful stimuli. The amygdala activates the hypothalamus, which in turn activates the autonomic nervous system, in part through control of important hormones. The autonomic nervous system regulates the physiological components of emotion. For example, imagine that a vicious dog has broken free of its leash and is now lunging toward you. Immediately, your amygdala responds to the perception of danger. It sends signals to the hypothalamus, which then activates the autonomic nervous system, resulting in the rapid heartbeat, sweaty palms, and heavy breathing associated with fear.


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