Stress Hardware Review: The Amygdala


There are things I cannot do. I cannot watch my people suffer. I cannot sit when something must be done. I cannot judge those who are different. There are things I cannot do. Run. Hide. Ignore. There are things I cannot do. But there are certainly things I will do!

Padmé Amidala in Star Wars: Clone Wars

One of the most important structures of the brain’s limbic system is the amygdala, which in Queen Amidala’s imaginary brain produced behavior that was characteristically cool and aloof at times, forceful and passionate at others, but always kept in balance by poise and careful deliberation. An exemplar of good stress management.

amygdala The human amygdala is an almond-shaped double  complex (one on each side of the brain) of multiple small nuclei located immediately beneath the cerebral cortex of the medial anterior pole of each temporal lobe. It has abundant bidirectional connections with the hypothalamus as well as with other areas of the limbic system. The amygdala is understood to be a behavioral awareness area that operates at a semiconscious level. It also appears to project into the limbic system one’s current status in relation to both surroundings and thoughts. The most important function of the amygdala is to make the person’s behavioral response appropriate for each occasion… or not, as the case may be.

What specific stress behaviors are directly regulated by the amygdala? We can only infer, as the Maker did not provide a user manual, through observing what happens when the amygdala is accidentally or intentionally removed. Take the jump to find out.

eat-dirtWhen significant portions of the amygdalae are removed in a monkey, the constellation of changes in behavior that results is called the Klüver-Bucy syndrome, which is evidenced by an animal that is not afraid of anything, has extreme curiosity about everything, forgets rapidly, has a tendency to place everything in its mouth and sometimes even tries to eat solid objects, and often has a sex drive so strong that it attempts to copulate with immature animals, animals of the wrong sex, or even animals of a different species.

Although similar lesions in human beings are rare, afflicted people respond in a manner not too different from that of the monkey. Without the amygdala’s regulatory interventions, human behavior takes a strange turn indeed.

 It is not coincidental that in times of extreme or prolonged stress there is often no conscious realization of fear (at least not until after the threat has somewhat abated); there is an heightened awareness of one’s surroundings and a strong “need to know” (aka curiosity); a loss of memory for certain events (if events are traumatic, forgetting serves to lessen their impact); a desire to consume disparate foods (most often of the comfort kind but often simply new or unusual); and a need to experience sexual gratification (frequently through sexual intimacy with others, but not necessarily so).

trauma9-11The amygdala in humans is now being shown, using functional MRI imaging, to be the area of the brain that is best correlated with emotional reactions. The emotional aspect of the response of the individual is passed on to the frontal cortex, where “decisions” are made regarding possible responses. In this way, the response of the individual is given an opportunity to incorporate the emotional aspect of the situation. It is thought that the emotional overreactions in Alzheimer’s patients are related to the destruction of neurons in the amygdala.

Positron emission tomography (PET) scans of patients diagnosed with social phobia indicate that blood flow is increased in areas of the amygdala associated with fear responses when the patients are asked to speak in public.

It is also believed that the amygdala plays a central role when stress attacks. Panic attacks are intense anxiety experiences that occur suddenly and are characterized by intense fear in situations where there is no actual imminent danger. Physical symptoms of a panic attack may include palpitations, difficulty breathing, chest pain or discomfort, choking or smothering sensations, excessive perspiration, or dizziness. Panic attacks often include the fear of going crazy, losing control, or dying. A real case of amygdala hijack, which bypasses the right destination (a balanced reaction) and goes directly to a whole ‘nother place where reality is suspended and anything goes (including walking onto incoming traffic and making love to a chocolate bar).