The Amygdala: An “Exciting” Part of the Brain

By Krist Novoselić (December 20, 2012)

Krist with Scare Crow
("If I only had a brain.")

The brain is usually referred to as if it were a single organ. However, the brain is a system with multiple and distinct components performing certain tasks for the body and mind. One such component, the Amygdala (amygdaloid nucleus), plays an important part in our emotional processes. It can jolt our bodies in fear, form emotional memories, helps us feel our dreams and can shape the effects of certain stress disorders and phobias. Indeed, the amygdala is where the excitement is at in our bodies.

Amygdala is the Latin word for almond. Anatomically, it is part of our limbic system including the hippocampus and basal ganglia; addressing motivation, learning and memory. The amygdala is a mass of gray matter reaching into each hemisphere of the brain. The two amygdale sit on the horn-like tips of the hippocampus. They work with our sympathetic nervous system to put the body in a state of “fight-or-flight”. This means the body puts all its resources towards surviving a threat. The amygdala assesses stimuli extremely fast and that is how we get excited – information on a potential threat is sent directly from the thalamus and our body reacts with increased heart rate and better vision among other effects, such as processes of the bowels being stopped. While this is occuring, the thalamus sends information about the stimulus to the cortex which, to put it loosely, takes a while to think about it. This dual appraisal system gets us on our feet to aid in survival. However, the cortex could determine the stimulus was only a harmless spooking thus signaling the amygdala an all-clear so our body can relax.

The amygdala has an important role in memory. It reminds us, for better or worse, of past situations. Since it is so emotional, the amygdala is responsible for those persistent thoughts we wish we would forget (Schacter, Gilbert, Wegner). It nags us with recollections of painful or shocking events. Flash bulb memories are vivid in our minds where we can remember where we were and what we were doing at the moment bad news came. Now when I hear someone say, “I still get worked up over that old situation”, I know it is the amygdala causing physiological reactions. We need not fret too much however, as we can deal with persistence in memory and reframe things to help cope with lingering emotional pain. It’s about looking at the past in a new way that can facilitate emotional healing.

The amygdala is central in fear conditioning. Rats who were conditioned to associate a tone with pain reacted with freezing, which is a natural response to a threat where they crouch down motionless. The animal’s appraisal of the tone caused its amygdala to activate the sympathetic nervous system’s physiological effects.

Rats were conditioned in a lab experiment to get physically stressed out by a tone. But some people get stressed at the mere thought of rats! A quick trip to the The Indexed Phobia List site tells us this is referred to as zemmiphobia. While this is a pseudo-medical term, the real fear could be based in preparedness theory, which means there is a natural reason to be afraid of rats who can bite and spread disease. As a result of adaptation, humans could be predisposed to fear rats. I have seen a person shriek at the sight of a rat – an example of the amygdala in action! Phobias are also linked to high levels of activity in the amygdala. A phobic disorder is persistent and excessive fear of specific objects. For example, this means some people can be really afraid of rats in a way that is irrational.

The size of the amygdala can also affect our behavior. Japanese researchers have evidence produced by brain scans that a smaller amygdala is associated with anxiety in patients with panic disorder (Hayano, et al., 2009). The researchers first diagnosed the patients using the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). Anxiety disorders are number 7 on the DSM-IV list. The research states, “The basic conception of PD [panic disorder] is fear of panic attack and anticipatory anxiety, ‘Panic attack may happen to me’. Fear and anxiety are inseparably connected the function of the amygdala, and the sense of fear is stored in the hippocampus area (267).” It is that nagging, persistent memory that creates the vicious circle of the fear of a panic attack causing an attack itself. The research suggests a smaller amygdala could indicate a dysfunctional aspect of that region of the brain. In other words, the little amygdala is causing big worries that lead to negative physical reactions.

Being an excitable part of the brain, the amygdala works day and night to even affect our sleep. This is how we intensely feel emotion in our dreams, whether it is bliss, terror, love or awe (Schacter, Gilbert, Wegner). The amygdala is acting with the visual association area of the brain, conjuring emotionally stirring images that can result in a nightmare and waking up from a scary dream.

Why am I compelled by the amygdala? I suppose it is my frequent interaction with it. Certain emotional memories persist in my mind. Some are good but I can’t seem to shake many that are bad. Recollections of painful events and personal losses come back to me every now and then. I still feel these events and that is my amygdala at work. Personally, hard life experiences have almost always resulted in hard lessons. It is not like Dr. B.F. Skinner experimenting on a rat, but it can be fear conditioning of sorts. The term, “once bitten, twice shy” could be about reacting to memories of real pain stored in the amygdala. Sometimes, with those persistent memories, I wonder if I only knew then what I know now? It is not about so much about knowledge but rather it is wisdom and that is something time and experience can produce – or I would at least hope so! The amygdala is there to remind us of what experiences felt like so we can avoid them if possible. Those little “almonds” strung together in the middle of our brain could be the roots of our own wisdom – which means knowing how to go about current situations because we are frequently reminded by feeling similar past experiences.


Hayano, F., Nakamura, M., Asami, T., Uehara, K., Yoshida, T., Roppongi, T., Otsuka, T., Hirayasu, Y., Inoue, T., (2009) Smaller amygdala is associated with anxiety in patients with panic disorder. Psychiatry and Clinical Neurosciences 63 266–276

Schacter, Gilbert, Wegner Psychology (Second Edition)

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