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.
The anatomy of anxiety. Anxiety is a reaction to stress that has both psychological and physical features. The feeling is thought to arise in the amygdala, a brain region that governs many intense emotional responses. As neurotransmitters carry the impulse to the sympathetic nervous system, heart and breathing rates increase, muscles tense, and blood flow is diverted from the abdominal organs to the brain. In the short term, anxiety prepares us to confront a crisis by putting the body on alert.