The brain is one of the most complex systems to understand. It’s even harder to understand how it works when PTSD is a factor. The easiest way to understand the brain is to think of yourself as having two brains. You have the Thinking Brain, which is the cortex, the top layer of the brain. This part of the brain is where critical thinking takes place. The Thinking Brain is where the ability to stay organized, stay on task, analyze, and think things through is happening. This part of the brain has the ability to inhibit or control our impulses, which involves the capacity to stop and think and not act on our first instinct, but, instead do what is needed or most appropriate. When we are upset, it’s the part of the brain that says, “Stop! That’s your boss! If you cuss him out, you will get fired and then you won’t have a job!”

Underneath the Thinking Brain is the limbic system or the Emotional Brain. The limbic system controls many of the complex emotional behaviors we think of as instinct. Limbic system structures are involved in many of our emotions and motivations, particularly those that are related to survival. Different areas of the limbic system have a strong control over emotions such as pleasure, pain, anger, fear, sadness, sexual feelings, and affection.




Two structures of the Emotional Brain that play an important role in PTSD are the amygdala and the hippocampus. The hippocampus is involved in memory forming, organizing, connecting emotions and senses–such as smell and sound–to memories, and storing this information away in long term memory for later use.

The amygdala activates the body’s alarm system (the fight or flight response). The amygdala has the unique ability to scan all signals–sights, sounds, smells, etc. It performs threat assessment and say’s either “there’s danger” or “it’s safe.” The amygdala answers one critical question for survival as stated by Daniel Goleman, “Do I eat it or does it eat me? This is not a question you want to go google.” The amygdala is a hair trigger that makes rapid judgments about a situation.  It knows nothing about reasoning or cognitive functions and is powerful enough to skip the reasoning and planning part of the brain in order to take immediate action. When this happens it is called an amygdala hijack.

Under normal circumstances, the amygdala and hippocampus communicate with one another and with the rest of the brain in a smooth fashion. However, traumatic stress disrupts the communication between these different areas. The Thinking Brain cannot get the message through to the amygdala that the danger is over and it’s okay to relax. The hippocampus cannot take the emotional information processed by the amygdala and store it away as a long term memory. So your memories of trauma stay with you all the time, and you continue to feel as if you are in constant danger.

This explains why a veteran who experienced traumatic events in combat may suffer a surge of anxiety years later when a helicopter flies over head. That helicopter was associated with a traumatic experience. So when your brain hears it, it sends warning signals that danger may be near. The amygdala has no clue if you’re in Iraq or home in the United States. It can’t tell the difference in location and act accordingly. The biggest problem is this part of the brain cannot tell the difference between a real threat and an imagined threat. So now you have the brain in a “hijacked” state where everything is an emergency, and it runs in crises mode all the time. Remember flight or fight happens subconsciously, so it’s not something that we can control easily, especially after months of combat or traumatic experiences. And programming like this is not something that can be rewritten overnight. So go easy on your veteran.