Start your free trial today and get unlimited access to America's largest dictionary, with: 1  More than 250,000 words that aren't in our free dictionary. 2  Expanded definitions, etymologies, and usage notes. 3  Advanced search features. 4  Ad free!
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.
1 Experts donât know the exact causes of anxiety disorders. Your genetics, environment, and personal history likely play a part.  Certain parts of the brain, including the amygdala and hippocampus, are being studied for their role in causing anxiety.