Thursday, December 20, 2012

The Amygdala: An “Exciting” Part of the Brain

"If I Only Had A Brain!"


Amygdala is the Latin word for almond. Anatomically, it is part of our limbic system including the hippocampus and basal ganglia. This group of structures deals with 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 6.5.7). 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 (16.3.1). 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 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 (14.2.2). 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 (274). 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 5.2.2). 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)


  1. Inspiring read (although, ironically, my amygdala now recognizes itself as a possible threat: I'm afraid it's too small).
    To me, the hardest thing is to actually deal with emotional memories. It's really easy to run, hide or sedate - I think wisdom is a choice, to a certain degree.

  2. Reframe in an honest way! Forgive yourself too!!!!!!!

  3. I try. It's an ongoing process. We're never done learning and reframing, are we? I guess that's part of what makes life a meaningful journey.

  4. The brain is capable of so many things, that alone is scary! My father is getting radiation treatment for a brain AVM right now and he has seizures. I wake up in the middle of the night almost once a week in the middle of a full blown panic attack, crying, trying to catch my breath, for no specific reason. It has been happening to me alot lately...Your reunion with the guys and paul has really cheered me up! Ive been waiting so long for something like that to happen, and to see you looking happy onstage with pat and dave again was so wonderful. There is something magical about the 3 of you. I know it had to be difficult at first to stand up there with another lefty at SNL... Im sure many surreal thoughts were flying through your head, but your fans had those same emotions... weve missed ya! and It made me cry... like a little baby lol SNOT AND EVERYTHING. so thanks for cheering me up during a very difficult time in my life.... <3 Heather

  5. Krist -

    You may want to experience the long-term aftereffects of hyperbaric oxygen therapy. Many months after a severe rearend collision on I-5 in 2010, the effects of a concussion finally started to set in dramatically. I was like an old man forgetting even the simplest of tasks and thoughts. It was only after 40 sessions of HBOT last year that my short-term memory finally starting functioning properly once again. And along with it came a surge of past memories, many that had been tucked away over the decades and forgotten. At first, it was like a slow trickle and recently, it's been more like a floodgate burst open. The details are vivid as if they happened just yesterday and the context with much of what is happening in my life today is suddenly so clear. I still think about where my mind might be today had I not been able to get treated after such a severe concussion to my brain!

    We have so much more to learn about our brains as you've so clearly pointed out. I tell many of my friends that I believe we're sitting on the cusp of some major advances in brain studies that 10 years from now, we'll be looking back and shaking our heads realizing just how primitive we've been in what we knew in the past. There has been so much focus on physical fitness that most people seem to forget that old saying, "A sound mind in a sound body."

    Keep exploring - it keeps you young!

    All the best
    An old acquaintance
    (remember Christmas dinner many years back at the Harbor Club in Seattle?)
    Robert L.

  6. Our brain is really wonderful ! Great text. Always sharing knowledge.

  7. The reciprocal interaction between the amygdala and the prefrontal cortex is, I think, pretty cool. Beyond just inciting negative physical reactions, the amygdala often has a direct influence on behavior. If not moderated by the pfc, a lot of reactive behavior, spurred by negative emotion, would result!

  8. I wrote a song heavily referencing this part of the brain once. You can check it here if anyone is interested...