What happens in the brain and body when you have post trauma stress?

Included is a simple drawing of the parts of the brain for an explanation of trauma and stress, and PTSD.  Of course the brain is not nearly as simple as I’m making it but it will help you understand why you have some of the symptoms you have, and that they are normal for what you have experienced.

BRAIN:Click for Options

Limbic system = amygdala + hippocampus: A group of interconnected structures that mediate emotions, learning, and memory.

Amygdala: Center of emotions. Controls fear response and determines level of threat. It processes reflexive and instinctual emotions (the survival instincts) like fear and anxiety. Learning, and memory are activated here as well. In brain imaging research scientists have found that severe stress lowers the threshold of the amygdala’s response to fear stimuli.

Hippocampus: It plays a significant role in the formation of long term memory. Neuroscientists are finding that the hippocampus in people with PTSD is smaller than other people, due to continued severe stress responses in the brain.

Prefrontal-cortex: This is the area of the brain that developed last in evolution.  It is the thinking part of the brain that controls impulses, attention span, focusing, organizing and follow

through. It plans, sets goals, and judges priorities. It allows us to suppress troubling memories and thoughts.

Basal ganglia: They control the body’s idling speed. When the basal ganglia are overactive,  anxiety, panic, fearfulness, and conflict avoidance are often the result.

Remember, the brain is another physical organ just like your heart, your lungs or your kidneys, but it regulates the emotions, thoughts, memories, and nervous system in your body. Post trauma stress begins as a body response to a threat. As soon as a real or imagined threat is perceived either consciously or unconsciously, your brain chemistry changes and the levels of adrenaline, norepinephrine, and cortisol  increase. The brain’s chief emotional center, the amygdala, which carries the survival instincts and reflexive emotions such as fear and anxiety, is activated.  It tells you how to react to a situation before you have conscious thought. The amygdala also keeps track of all your past good and bad feelings about memories, but not the facts such as names, time frame, and location.

That is the job of the hippocampus. It keeps track of the facts, but not the feelings, and plays a significant role in the formation of long term memory. Then if need be it sends these facts on to the prefrontal cortex or thinking part of the brain to plan, set goals, and judge priorities. If the hippocampus is overwhelmed by stress hormones it loses the ability to separate time, and during a flashback you actually believe “then” is “now.”

The inborn survival instinct is often called the “freeze, fight or flight response” and needs no thought. As soon as it is activated, the body directs most of the oxygen and blood to the brain stem and to the amygdala or emotional brain, not to the hippocampus and the prefrontal cortex that usually modulate the amygdala. The alarm sounds for only a thousandths of a second before the amygdala takes command and shuts down the hippocampus and the prefrontal cortex. The shut-down happens so quickly that there is no time to assess the threat logically. The body freezes for a moment, then fights, or runs. Watch a frightened deer. It freezes, then darts away. This temporary immobility allows the body to marshal enormous amounts of energy before it acts.

The amygdala sends panic messages into the rest of the brain, especially the hippocampus. It becomes hyperactive and sears fragments of memory onto the mind with a force that’s hard to extinguish. When a trigger in the present such as a noise or smell are associated with the past trauma, these past events reignite in the present taking the shape of nightmares and flashbacks. Remember the early behavioral studies by Pavlov done on dogs? The researchers rang a bell and then gave the dog a treat. Soon all they had to do is ring the bell and the dog began to salivate even without the treat. That’s how a gunshot may cause a PTS reaction such as a flashback, a memory, and a body reaction. Your mind has paired the gunshot with danger from the past.  Because of this intricate set of connections in the brain, the activation of one memory automatically triggers comparable memories. The reason memories are activated and connected in the present is because they evoke similar feelings, both emotional and physical.

The amygdala (emotional center) has no way of tracking names, time, or place. However it remembers bad feelings as though they are now. So in flashbacks, when something triggers a bad memory, the person goes right back to the past as though it is the present.

Why has the brain evolved in this way? Think of the “good old days” when all those lions and tigers and bears out there in a hostile environment were waiting to eat us for dinner. Over time the body developed a system to protect us from these threats.  As the body changed to help it survive, people developed a nervous system that alerted them of danger. Adrenaline andcortisol, called stress hormones, were pumped into the organs of the body, including the brain stem and the emotional centers in the brain, to increase the heart rate, make the breath come faster, tense the muscles, make us alert, and miraculously strong and ready to fight or run.

Normally, the person escaped from the predator and as the real or perceived threat ended, the adrenaline and cortisol levels receded to a balanced amount in the body.  The sudden surges saved the person’s life and actually helped the body tune up just like when we take a car on a highway and run it at high speed.

Animals have a similar freeze, fight or flight system in their body and react similarly to humans. If you watch animal planet, or Caesar Milan, or have read Temple Grandin’s books, you will discover stories of severely abused dogs or dogs in wartime with PTS and even PTSD. One story that I will always remember is of a German Shepherd that helped soldiers find Improvised Explosive Devices (IEDs) in Iraq.  The dog was a great warrior, carefully selected and trained, and very successful in saving people’s lives, but after encountering continued explosions for years, lapsed into PTSD and was sent home. A year later he still shook, cowered, hid, terrified of touch when triggered by certain noises.  Does this sound familiar?

Contrary to how we often see ourselves, the physical body, the emotions, and the mind are not independent entities. They are all irrevocably connected to the brain, a physical organ of the body with continuous close communication and feedback loops. Without the brain, the body, the emotions, and thoughts as we know them would not exist. Our thoughts and emotions are actually seated in distinct areas within the brain and are controlled by physical components such as hormones, enzymes, and proteins that are generated within the body.

According to Daniel G. Amen, M.D. in his book Change Your Brain, Change Your Life, he  found, using a brain SPECT (3-D imaging technique), that compared to other people, a veteran with severe PTSD had marked increased left side activity in the basal ganglia, a collection of nuclei outside and above the limbic system. This generally indicates chronic irritability or anger. He speculated that the veteran’s 13 month war experience set the basal ganglia to be on constant alert. The veteran had never learned to reset his brain back to normal.

Usually when the threat is gone, the adrenaline and cortisol surges end and the brain resets itself. But when a person has to live in constant threat and crisis like many of you did for months or years, the body becomes addicted to the surges of adrenaline as it would to a drug, and craves to get back to that level of excitement (fear and excitement are very similar). Life becomes meaningless without it. Many veterans feel useless when they come home, and sign up for another tour of duty or become policemen or emergency technicians. One of the veterans I saw became an FBI agent and worked undercover.

During the time of crisis people become detached and live with denial of what might happen to them. What I found with many of the people I treated for PTSD was that when their bodies believed they were no longer in danger they began to release the emotions they had hidden in order to function during the war. Many soldiers built firewalls around themselves while in combat and the walls served them well. However, when they came home, for many the walls collapsed. This is not unusual.

A young veteran who had been a nurse in Iraq told me, “Sure I saw a lot of gruesome things but I had no problems during the year I was in Iraq. I just did my job and went on my way. It wasn’t until after I came back that I started having nightmares. The nightmares were not of what I expected, but always of me killing someone by giving the wrong medication or a lethal dose of a drug I injected intravenously. In my dreams I would try so hard to get to my patients but couldn’t get to them in time to save them. My husband would wake me and hold me for a while until I stopped shaking. At the time it seemed to me that my mind felt safe enough to release the fears and memories I had held in my body, and only then was able to deal with the trauma of working with continual life and death situations.”

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