Part One, Amy who?
I’m taking a nighttime stroll down my dark, quiet country lane. I see in front of me an even darker shape. At least ... I think I do. I stop and wait. It starts moving. Even in the dark, my brain knows that it is not Eileen’s trash can. It’s a bear.
In a millisecond my brain considers everything I’ve ever heard about bears. Not the “mind my own business” nice, local black bear stuff but the 9-foot-tall “I eat people” grizzly images. Forget about the stand-still advice. I run.
Not once during this encounter did I want to analyze further or Google up some additional information. My amazing brain, with astonishing speed, assessed the situation and organized a full body response.
Here’s how. (Keep in mind that this is a brain-insulting oversimplification.) Deep in my mid-brain is an almond shaped structure called an amygdala (ə-’mig-də-lə). Amy lives there with a circuit of other brain nuclei that deal with emotion and functions such as regulation of body temperature, body fluids, body weight and drives to eat and drink.
They are collectively called the Limbic System. In the brain, as in an archaeological dig, deeper equals older and the older the structure the more involved it is in staying alive –the prime directive. Fear is a default setting; no thought required.
So. Bear.
The outer layers of the brain (cortex) receive sense impressions- sight, sound, smell, taste, touch. The cortex and mid-brain exchange information. The information is deciphered and interpreted. Interpretation is important because you want to know the difference between a live bear and a stuffed bear, real gun and toy gun.
The brain knows the difference between running and running away.
Once I feel that the bear is a threat a cascade of physiological changes called a stress response (“fight or flight”) takes place. Epinephrine (adrenalin) and norepinephrine (noradrenalin) are released. They cause an increase in blood pressure, heart rate, blood glucose, use of glucose in muscle, sweating, blood coagulation (in case I get clawed) and increased cortisol, my natural steroid, so that I have inflammation regulation after the clawing.
Additionally, my pupils dilate, hairs stand erect and my head raises to scan the area. If I’m scared enough the brain will create a memory of the event. The body will also curtail some everyday functions like digestion and certain immune functions to devote more energy to the crisis.
This entire response was meant to be an on-off response with an immediate return to allostasis, the body’s way of maintaining balance by internally adapting to perceived or anticipated demands. The body removes the stress products from the blood often assisted by vigorous activity. Watch the deer: Noise, heads up, freeze, assess, run a few feet – go back to eating.
According to Jonathan Karp from the Department of Biology at Rider University: “A stress response is an evolutionary, adaptive function not designed to be chronically activated over months or years.” When fear is constantly stimulated either acutely or as a low-grade consistent stressor, we see disturbances in normal body function that can lead to disease.
Look back at the list of stress responses. Do you really want to do this all the time?
When fear is chronically activated we see disturbances in physiology and reactive behaviors such as agitation, hypervigilance, social isolation, insomnia, feelings of impotence, anxiety and fatigue. In short, many of the symptoms of Post Traumatic Stress Disorder or ... the behavior of some rescue animals.
The brain cannot distinguish real fear from anticipated fear. It must take all threats seriously. Therein lies the success of terrorism. Terrorists don’t actually have to do anything – just say they will. My personal favorites are the weather terrorists who have made an art form out of scaring people.
We can become habituated to a steady state stressor so we need new, exciting stimuli to activate the senses. Think network news with its dramatic music, tone of voice, pictures, vague inferences. Notice that no matter how horrific an event is we move quickly on to the next “disaster.” Except for the events of 9-11 which have served as our most potent precedent for fear.
Also, the brain itself can provide us with new fear stimulation. In a too-complex-to explain-now twist, fear can become chemically addicting and even pleasurable or entertaining.
Fear, working for the cause of self preservation, leads us to hypervigilance, the compulsive monitoring of our environment all too easily done in the electronic world. We are chemically rewarded by the control that constant safety checks give us.
But poor Amy is working overtime. I call it Amygdalitis.
How do we decide what to be afraid of in a world full of fear selections? Part Two of this topic will try to answer that question.
Dr. Victoria Burke is a Chiropractor and former faculty member of the Pennsylvania College of Chiropractic. She has been practicing in the Doylestown area since 1989.
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