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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.
Some people who suffer from anxiety disorders cannot recall any traumatic event that might explain their condition. This lack of recall might be due to a of the hippocampus. The massive activation of receptors for the secreted by the adrenal glands may cause a reduction in the volume of the hippocampus. This may be one explanation for the learning deficits observed in rats that are subjected to stress, or the weak explicit memories of humans who are very anxious.