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This small nucleus contains almost half of all the brain neurons that use norepinephrine as a neurotransmitter. The locus coeruleus also projects its axons to those parts of the brain that may be associated with panic disorders (the amygdala, hippocampus, septum, cortex, brainstem, reticular formation, etc). Stimulating an animal's locus coeruleus, like stimulating its amygdala, produces anxiety behaviours.
The physical symptoms of anxiety are caused by the brain sending messages to parts of the body to prepare for the âfight or flightâ response. The heart, lungs and other parts of the body work faster. The brain also releases stress hormones, including adrenaline.