In the book “Lethal Warriors – When the New Band of Brothers Came Home” by David Philipps the following paragraphs David uses provides a great physiological analogy of what happens in the stressed brain of PTSD as stated by Sister Korverman. *(David Phillips is a feature writer for the Colorado Springs Gazette)
From Page 83 of David Phillips book “Lethal Warriors – When the New Band of Brothers Came Home”…
The hippocampus acts as an emotional adviser to the amygdala. Though the range of its function is not fully understood, it is known to be vital to recording, organizing, and storing memories, - especially memories with strong emotional weight. Humans have more neural connections between the emotional duo of the amygdala and hippocampus and the logical part of the brain that any other species. The connections are strongest at a spot just behind the forehead called the medial prefrontal cortex. This part of the cortex is believed to play a role in the awareness of manners and accepted social behavior, among other things. In studies where healthy subjects were asked to consider complex moral decisions, such as whether to throw one person out of a lifeboat to save five, the medial prefrontal cortex lit up on neuro-imaging scans that showed where brain activity was greatest. The medial prefrontal cortex is where we define who we think we are.
Those millions of connections between the center of the self and morality and the emotional brain act kind of like the reins of a horse rider as held when perched on a wild stallion. The stallion quick to startle ruled by emotions – represents the amygdala and hippocampus. The rider – logical, calm and calculating – is the cortex.
Just as a rider can pull the reins to calm a startled horse if there is no reason to gallop, the logical mind can send calming “false alarm” messages to a startled amygdala if it does not perceive a real threat. The amygdala often responds faster than the cortex, which is why if someone jumps out and yells “Boo” you will jump and your heart will start racing a split second before you realize it is a joke, not a threat, and your cortex sends a “whoa” message to your amygdala.
During longs bouts of extreme stress, the hierarchy of horse and rider can break down. At first, everything works as it is designed to. During a real threat the cortex will not rein in the amygdala. The amygdala will signal the R-complex that there is an emergency and the body will go into full “fight or flight” mode. The complex will prepare for an attack by spiking the body with performance enhancing adrenaline and endorphins that boost energy and act as natural painkiller. In small doses, these chemicals help the body respond to the threatening situation of the moment, but over time, they become toxic and start to damage parts of the brain. They can literally cause cells to burst and connections between part of the brain to wither and die.
Researchers studying PTSD using MRI scans have found that the prefrontal cortex and hippocampas in combat veterans seem to shrink. Blood flow in both parts of the brain during threatening situations is decreased. That means the amygdala does not have as much logic for memory to help it decide whether to throw the emergency switch. The amygdalae itself, in contrast, can become enlarged and hyperactive, making them more likely to sound the alarm. At the same time, the neurons connecting the cortex and the amygdalae – the calming reins, shrink in number and size. Severing the connection between the amygdalae and prefrontal lobes purposefully though surgery is called a lobotomy. This infamous brain surgery often rendered patients so disastrously vacant and disabled that it was all but abandoned in the twentieth century. Prolonged combat stress is not as severe or irreversible as a lobotomy, but to some degree, it has some of the same effect.
The understanding of the relationship between the cortex, the limbic system and combat is far from perfect. Researchers are not sure whether the poor connections between the frontal lobe and the amygdalae found in a PTSD sufferer is a preexisting condition that caused the stress reaction or a result of the stress. Additionally not every combat veteran seems to have a breakdown in balance between the neocortex and the amygdala; the factors controlling who does are far from clear. But this much seems to be true; in some troops, as stress takes its toll, the wild stallion gets stronger, the logical rider gets weaker and the reins begin to fray. In a real, measurable way, on a cellular level, humanity dissolves, soldiers lose themselves and the primitive bestial part of the brain starts to take over.
Traumatic Brain Injury (Page 88 – Lethal Warriors)
Everyone has a specific capacity for stress. Think of it like a bathtub. Some people may have bigger tubs, some smaller. All of the stresses of war – traumatic or merely grueling, grief and killing, fear and gore – pour into the tub. Stresses from home pour in along with stresses from the war zone. If the tub overflows, it results in a combat stress injury. The intensity of the flow of stress and the time exposed, as well as each person’s ways to cope (the drain) control whose tub overflows. No one has yet figured out how to gauge the size of each person’s tub, the speed of their drain, or how well or quickly each individual can recover from a spill.
To further complicate things, many soldiers in modern conflicts suffer from traumatic brain injuries, or TBIs. A major IED blast sends out a shock wave traveling at 1,600 feet per second – about 1,000 times atmospheric pressure shoots right through armor, helmets, skulls, and brains. The brain not only gets knocked around in the skull by the pulse, but the quick changes in pressure seem to cause tiny gas bubbles to rip small holes in the brain. Multiple blasts can compound the injuries. Over a 150,000 troops have been diagnosed with mild TBIs and studies suggest many thousands more suffer without a diagnosis. Some of the symptoms of the TBIs seem obvious: slurred speech decreased motor skills, and problems with memory. But TBIs can also cause soldiers to be irritable, aggressive and overly emotional. These symptoms overlap almost entirely with PTSD, and they can linger years after the injury.* Complicating the injuries, it is not uncommon for soldiers who have been in combat to have both, which can make it hard for the medical staffs to know what to treat.
*Hal Bernton “Troups Suffer Long-term Brain Impacts from Shock Waves, Seattle Study Finds,” Seattle Times, June 13, 2010
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