A Brief Guide to Trauma's Impact on the Brain

Information to Promote Healing and Transformation

By Dario Martinez

Trauma leaves a powerful “imprint” on the human brain that makes it hyper-sensitive to potential threat. The slightest hint of danger can automatically trigger a chain-reaction of brain activity that mobilizes the entire body into a “survival response.” This is the brain’s natural way of defending against re-traumatization, and it’s highly effective when threat is real.

Unfortunately, many trauma survivors find themselves going into automatic “survival responses” even when they’re in situations that they “know” to be “safe.” Normal brain functioning that I will describe in a few moments, makes it difficult for traumatized individuals to control their brain’s response to perceived threat. Trauma literally hijacks the brain and creates an extremely confusing conflict between what trauma survivors KNOW and what they FEEL.

For example, adult victims of childhood sexual abuse may KNOW that their current sexual partner(s) are completely safe, but a part of them might inexplicably FEEL nervous, jumpy or even scared if somebody tries to initiate sex with them. They KNOW on a rational level that they’re safe, but on an emotional level they FEEL terror, because the emotional parts of their brain continue to equate sex with violation.

I want to emphasize the importance of this internal conflict because it’s a major source of confusion and suffering for people who have been traumatized. Whenever we're faced with stressful or potentially dangerous situations, and there's a conflict between what we FEEL and what we KNOW; the emotions that we FEEL will almost always prevail over what we KNOW to be true -- which is why adult victims of childhood sexual abuse sometimes continue to feel nervous or scared when people they KNOW to be "safe" try to initiate sex. 

For reasons that I will explain in a moment, the human brain is structured so that emotional needs take precedence over rational thinking whenever we're faced with a perceived threat. This dynamic works well when our survival is at stake, but it can be extremely disorienting for traumatized people who continue to feel unsafe in situations that they know to be safe.   

To address this issue, I usually start by providing my clients with basic information about the impact that trauma has on brain functioning. Many people find this useful because it “normalizes” some of the most confusing aspects of their experience while simultaneously providing important clues about how to promote healing and transformation. My intention in sharing this information here is to offer a sense of hope to people who are suffering.

By definition, trauma is any experience that causes people to become so flooded with overwhelming emotion, that important parts of the brain either temporarily shut down or go completely “offline.”  For the purposes of this discussion, I’m going to focus on four parts of the brain that are impacted:

1. Brain Stem, also known as the Reptilian Brain: manages “automatic” bodily functions such as breathing, digestion and other processes that don’t require conscious thought. For a discussion about trauma, the Brain Stem is important because it also manages the five automatic “survival responses;” more commonly known as Fight, Flight, Freeze, Submit and Cry for Help.

2. The Limbic System: creates and manages our emotional response to experience by constantly evaluating how things make us feel. The Limbic System works closely with the Brain Stem to mobilize our bodies into action when we feel our survival is at risk.
3. Amygdala: Part of the Limbic System, the Amygdala is like a car alarm. It receives input from all of our sensory systems, and sounds an alarm if it perceives danger or threat. When the Amygdala’s alarm is strong enough, the Brain Stem mobilizes the entire body into one of the five basic survival responses.

4. The Frontal Lobes: Also known as the Thinking Brain: Responsible for “executive functioning” such as problem solving, decision making and rational thought.

Each part plays an important role in the brain’s management of perceived danger. Here’s a simple example of how they work together:

If I touch a hot stove, I’ll probably automatically jump back to avoid getting burned. To put this in brain terms:

  • The sensory system in my hand notices intense heat and sends a message to the Limbic Regions of my brain.
  • Before I’m able to consciously register any awareness of heat, my Amygdala (car alarm) springs into action and sounds an alarm.
  • The Limbic System bypasses the “executive functioning” of my Frontal Lobes because there’s no time to think about what’s happening.
  • The Limbic System mobilizes the Brain Stem into action.
  • I go into an automatic “flight” response to avoid getting burned.

This entire process happens in less than a second. Because we’re talking about trauma, it’s important to highlight two important aspects of this process:

  1. Survival responses are automatic, and often occur without any conscious participation on our part.
  2. “Rational thinking” in Frontal Lobes is either bypassed or goes completely offline. From a survival perspective, this makes complete sense. If I took time to get in touch with the sensation of heat and then took even more time to make a conscious decision about what to do, my hand would already be burned.

Both aspects of this process are vital to our survival, but frequently become a major source of suffering for people who have been traumatized. To explain why, I’m going to tell a short story about a 9-year-old boy named David.

One day David was walking home from school. He was feeling excited about playing with neighborhood friends later that afternoon. When he turned the corner near his house, he saw a burly man with a beard coming toward him. David didn’t think twice about the man because he had no reason to feel threatened in his neighborhood. When the man got close enough, he assaulted David.

David was traumatized by the experience. Shortly afterward, he stopped going out to play with friends because his neighborhood no longer felt safe. He also started feeling panic whenever he noticed burly men or men with beards getting close to him. This became problematic at home because both his father and uncle were burly men with beards. His father was devastated when he noticed that David appeared to get nervous and “jumpy” around him.

Unfortunately David’s response to being traumatized is completely normal. Because the survival response is automatic, and the brain's Frontal Lobes are bypassed, David is unable to take the time to differentiate between burly men with beards who are strangers and burly men with beards who love him.

On a purely rational level, David KNOWS that his father isn’t trying to hurt him, but as I pointed out before, the Frontal Lobes are completely bypassed when the brain perceives a strong enough threat. Without Frontal Lobes, David’s brain is literally unable to register “dad.”

Instead, his sensory system perceives “burly man” and “beard” which causes the Limbic Regions of his brain to be flooded with strong emotions like fear and terror. Before his Frontal Lobes can come back online to identify the burly man as “dad”, the Amydala has already sounded an alarm and David’s Brain Stem mobilizes his entire body into a survival response.

To make this situation even more confusing for trauma survivors, the brain has a natural “negativity bias” which causes negative, unpleasant thoughts and emotions to have a much greater impact on brain functioning than neutral or positive stimuli.

From a survival perspective, the negativity bias makes complete sense. If we want to live longer, we need to remain hyper-aware of  “negative” things in our environment that represent potential danger. When David’s traumatized brain sees his father coming toward him, it becomes challenging to notice all the positive things that his father represents, because his brain’s “negativity bias” automatically causes him to zero in on negative characteristics like “beard” and “burly.”

This is the way trauma works: our brain becomes hyper-focused on scanning the environment for anything that reminds us of past traumas. Because the brain is so focused on negative stimuli, everything starts to feel dangerous. People and places that once felt safe can instantly morph into menacing threats.

As the perception of threat increases, the Amygdala goes into overdrive. It becomes like a hypersensitive car alarm that goes off constantly. Each time the Amygdala sounds its alarm; we’re subjected to the following automatic process:

  • The brainstem mobilizes the entire body for survival
  • Heart rate quickens
  • Body secretes massive amounts of “stress hormones” like Cortisol
  • Breath rate increases
  • Depending on the survival response that gets activated, we either experience a big adrenaline-fueled burst of energy (Fight or Flight) or we “shut down” (submit or freeze).

If trauma’s fear-based thought distortions are pervasive enough, this process starts happening more and more frequently. People who’ve experienced severe trauma often move through life in a chronic survival response.

Needless to say, this can be exhausting!

As a therapist, I collaborate with my clients to interrupt the brain’s distorted functioning by working toward three primary goals:

  • Calm the Nervous system
  • Make the survival response less “automatic”
  • Exert greater control over the Limbic, emotional regions of the brain by bringing Frontal Lobes and rational thinking back online

To accomplish these goals, I use a combination of

  • Education
  • Mindfulness practices to promote “Distress tolerance”—which helps people learn how to “tolerate” and manage stressful situations.
  • Emotion Management Techniques.

Mindfulness practices and emotional management techniques are especially useful in trauma work because building mindful awareness of what’s ACTUALLY happening around us in the present moment can help us learn how to differentiate between “perceived” threats and “actual” threats. By definition, mindfulness techniques also invite rational thinking back online—which makes the brain’s natural survival responses much less “automatic.”

Please click here for links to more information about Mindfulness Practices and Emotion Management techniques.

Copyright © 2020, Dario Martinez. All rights reserved.



Licensed Marriage and Family Therapist

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