The Biological Basis of Trauma: Part 1: Defining Trauma
This blog is the first in a three-part series delving into the biological basis of trauma. The purpose of this series is to help us develop insight into how trauma affects us, so that we can understand how to work with the havoc it has wreaked in our lives. Remember as you read this series, this is not an unchangeable tale of doom. If you are alive, you have the potential to change your narrative. Yes, trauma does change us. Our minds and bodies developed to survive dreadful, violent realities. So, yes, we are different. But different does not mean defective. So use this information to help you understand the demons you tango with, so that you can move forward in creating the story you want to live!
Trauma has seemingly become a mental health buzzword. It and its effects are brought up regularly, even in mainstream society. Just because we hear (and use) the word, though, doesn’t mean we actually know what it means. What does it really mean if something is traumatizing? How is the experience of the memory any different then just a bad experience? Let’s dig into the meaning of trauma at the biological level, so we can really understand what the word means.
Typical Sensory Processing
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To understand how trauma is different than a typical memory or experience, we first need to understand how the brain processes information. Now I am not a neuroscientist, and I am betting that most of you reading this aren’t either. So, I have taken the most typically accepted research out there and super simplified it to make it a bit more understandable.
Let’s start with sensory information. This is the data your sense organs (eyes, nose, skin, etc.) gather. Now, remember this is the raw data that hasn’t made it to our brains yet. Once our brain processes this data, we will have perceived it. But for right now it is merely a sensory awareness. It is a bit of color reflected in the eye, or an echo of sound tickling our ear hairs.
Well, the first stop for this sensory data is our thalamus in the limbic system. Think of the brain as a business, with multiple stories. The limbic system is on the ground floor. The biggest concern of the limbic system is survival. They want to keep the business standing and make sure whatever information comes in gets routed to the correct place so everything functions correctly.
When sensory information comes in, its like knocking on the door. Well, the person that answers that door (98% of the time) is the thalamus. He opens the door wide, looks at the guy standing there and makes a decision about how big a threat this guy is and what should be done with him. The thalamus’s decision is based on intrinsic genetic data and our past memories.
Now if the thalamus looks the guy over and says, “he’s not a threat”, the guy gets told to register with the hippocampus (our memory center) and then the guy gets routed upstairs. Once the information is sent upstairs, we become aware of it. We have an actual knowledge or perception of the data. Once this happens the logical big-wigs on the top floors of our brain figure out what to do with him. Reading this blog is the kind of information that is getting sent to the top floor. The thalamus takes the information from they eyes, identifies it is as non-threatening, and allows the logical part of your brain to deal with it.
The Stress Response
Now, if the thalamus looks the guy over and says “this dude is a threat!”, then the thalamus keeps the guy on this floor and reports they guy to the amygdala. The amygdala is the part of the brain that is responsible for starting our adrenal response. Also known as our flight and fight response. Essentially, he’s like a head-honcho, quick-response, tactical operative. The amygdala makes an instantaneous assessment of just what kind of threat this guy is and activates an alarm to alert everyone on the ground floor and in the basement that a threat needs to be dealt with. This alarm is our adrenal response.
A real-life example of this is if you were out walking and you saw a snake. The thalamus would relay this information to the amygdala, the amygdala would active our adrenal response, our body would respond by flinching back. All of this would happen before the information ever made it to our conscious awareness. Only after we had jumped back to avoid danger, would the limbic system file a report with the people upstairs so they could know what had happened. This whole process is known as the fear response.
Stress Vs. Trauma
Of course, there are different levels of threats. For most people, a snake in the path is equivalent to a guy trying to get through security with a kitchen knife. If this guy shows up again, the amygdala isn’t going to over react. He’s just gonna do his job, pat the guy down, get the knife, and route the guy appropriately. But what happens if an event is so huge it truly threatens our life. Well, this is where trauma comes in. Trauma can be seen as an extreme fear response. When a traumatic event happens, it is like someone trying to get through security strapped with a bomb while holding someone you love hostage at gun point. If that guy shows up again, or anyone who even looks like him, the amygdala’s response is going to be a hell of a lot bigger.
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Now the thing about the amygdala is that he has perfect memory. Once he processes a threat, he will remember this guy if he ever sees anything like him in the future and he will react the same way again. He will not seek out input from the slower logical big-wigs upstairs. He will simply do what needs to be done instantaneously. This is important to our survival. The amygdala taking control of the whole business and reporting after the event ensures we don’t get bit by a snake, or blown up by the hostage taker.
And this is why traumatic memory is different than other memories. Most memories are stored in the hippocampus. Basically, the secretary in charge of the sign-in sheet. The nice thing about the hippocampus is that he will usually also make notes about how a guy is connected to this or that other guy, and networks with the logical big-wigs upstairs to make sure files are up to date and accurate. This is why when we think about a regular memory it is not a supercharged experience, we can do so logically, and its often tempered by other similar memories.
Traumatic memories, though, are held onto by the amygdala. Because a traumatic event is perceived as life threatening, the amygdala needs that memory close for future use. His job, after all, is to protect our life, so he needs to hold on to the data that will keep us alive. The amygdala, though, can’t afford to store memory the way the hippocampus does. In a life and death situation, there just isn’t time for it. He needs to react physical, not cerebrally. So, he bypasses all logic, focuses only on the stimuli in front of him, and acts. The memory is almost like a protocol. A series of movements and adjustments the body needs to make to survive the situation again. When we recall a traumatic event, we are recalling it through the amygdala. Which is why these memories are much more physical.
In fact, some believe that when you recall a traumatic memory, the systems in your body will change to reflect exactly what you experienced in that moment. The levels of neurochemicals in your head, the tightness in your gut, the fluttering of your heart. Whatever you physically felt in that moment of terror, you will physically feel again. And because the amygdala doesn’t have time to network, there are no other memories to temper the experience. There is only that single moment of terror, lived again. Because that is how the amygdala remembers. It is the amygdala’s attempt to survive the threat.
The reality is, in the moment of terror, the response of the body is probably what allowed us to continue living. It ensured our survival. The problem, though, is that the amygdala will raise that alarm when anything similar occurs. This is called triggering. So even though that protocol is not needed now, the amygdala pulls the alarm anyways because it thinks the protocol is needed. And sadly, when you’ve gone through trauma, you often feel threatened or unsafe. And when you feel threatened or unsafe, your amygdala is on high alert and ready for shit to go down. So, he is even more likely to pull the alarm when it’s not needed.
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Again, this is a super simplification of the process. If you’re interested in the science and theory behind traumatic memory, I highly encourage you to look into Bessel Van Der Kolk. Pretty much anything by him. He is a pioneer of trauma research and has helped inform many of the theories of traumatic memory currently used in treatment and research. And if you are looking for a definition of trauma, I suggest looking at the Diagnostics and Statistics Manual of Mental Disorders 5 (DSM-V). This is THE manual used throughout the U.S. for diagnosing mental disorders. I’ve provided Here’s a link to the PTSD diagnostic criteria. Section A defines what the mental health world currently considers trauma to be.
