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How Does Trauma Hijack the Brain?

A look at how traumatic experiences affect brain development.

Key points

  • Trauma can confuse the communication between the three parts of your brain.
  • Learn about and reflect on how each part of your brain reacts in different situations.
  • Use that information to help identify interventions that can help lessen the influence of these traumas.

Have you ever wondered how trauma might be impacting your brain?

Today, I’m going to discuss the concept of the triune brain and how each part of your brain may process traumatic experiences.

The triune brain model

Triune literally means “three in one.” The triune brain model describes three areas within the brain that have a unique way of understanding and processing information; however, they are meant to function as a cohesive whole.

The reptilian brain

In the triune brain model, the oldest part is the reptilian brain, which includes the brain stem and cerebellum. It operates on instinct and is responsible for the survival-related functions of the body.

The reptilian brain is most closely associated with body processing. Instinctive trauma responses, such as fight, flight, freeze, or startle responses, and crying for help are all examples of reptilian brain functions. The reptilian brain also controls the autonomic responses that we experience as body sensations and basic life-sustaining processes, like digestion, heart rate, body temperature, and respiration.

The reptilian brain is active 24/7 to make sure that these vital functions are working properly. Because the reptilian brain governs basic instinctive actions, it acts very quickly. If a frisbee is flying at your head, you don’t typically have to think about your response: Your reptilian brain will make you duck instinctively.

The mammalian brain

The mammalian brain, a.k.a. the emotional or limbic brain, is responsible for our emotional and relational experiences. The mammalian brain includes the thalamus, amygdala, and hippocampus.

Emotions lend another dimension to our experience by letting us know of our likes and dislikes, which helps identify what is emotionally important or meaningful to us and adds emotional richness to our lives and relationships.

In regards to our relationships, the mammalian brain allows us to be aware of our impact on others and of their impact on us, and it allows us to socially engage with and attach to others. It’s also responsible for us feeling drawn towards or away from things and for holding emotional memories of our experiences.

How do these parts of the mammalian brain work? The thalamus receives information from our five senses. When that information includes threats or danger cues, the amygdala signals us to protect and defend ourselves. The amygdala also alerts us to cues associated with good feelings. The hippocampus remembers this information and consolidates important stimuli and responses into long-term memory. These experiences of shared pleasure or pain are also encoded as nonverbal memories of attachment experiences, laying down templates for expectations of future relationships.

Source: Eldar Nurkovic/Shutterstock
Source: Eldar Nurkovic/Shutterstock

The neocortex

The neocortex, a.k.a. the cerebral cortex, the frontal cortex, or the neomammalian brain, is the front structure of our brain and is split across the left and right hemispheres.

The right hemisphere is associated with creativity and intuition. It processes information in a more symbolic, implicit, and nonlinear fashion.

The more rational left hemisphere matures and develops beginning in childhood through early adulthood. It contains most of our language abilities. This hemisphere of the brain processes information in an explicit, logical, analytical, and linear fashion. The corpus callosum is a bridge between the left and right hemispheres of the brain. It aids in the communication and consolidation of information between the hemispheres. It’s important for our functioning that everything is integrated and linked.

How trauma impacts brain development

The development and functioning of the three brains rely on our childhood experiences. This includes early attachment figures like caregivers, conditions in our environment, and traumas.

These experiences affect how our brain understands stimuli, as its goal is to help us to adapt as best we can to both positive and negative life experiences. You may be able to start imagining what the landscape of our brains could look like if we have many traumatic experiences throughout our lives, especially early childhood as our brain is growing.

If we have ongoing or repeated threats in life, our brains become hypersensitive to cues that remind us of those traumatic experiences. We can then have intense emotional reactions to cues, and our reptilian brain will activate our flight, fight, freeze, or fawn survival responses.

For example, if you grew up with a hypercritical parent who engaged in verbal abuse, you may have intense anxiety anytime someone questions your actions. You may have a fawning response, such as people-pleasing to your own detriment. Another example might be if you ran into a man who had a similar build and face as a person who aggressively stalked you in college. You might feel emotionally numb, disassociated, or frozen.

When we are triggered and in a threat mode, our neocortex is temporarily less active. When we are in danger, our mammalian and reptilian brains take over and prompt us to act quickly in order to stay alive.

While this is good in the case of ducking from a frisbee, it can make it incredibly difficult to think clearly, analyze, plan, or learn new information.

Because of how each of our three brains processes trauma, these experiences might not allow them to work in unison. For instance, our neocortex might tell us that we are safe, but our emotions and our body will tell us that we are not. If one part of our brain is more dominant, it can override the others. Most of us, at least to some degree, have had at least one experience where we were so overwhelmed that our thinking brain stopped functioning.

I sometimes think of it as the “blue screen of death” that older computers used to get when there was a malfunction. There was only one way out: You had to reboot the system.

Rebooting the system

Working through trauma is highly personal and specialized, but I can offer a few tips to get you started.

Think about how each of your three brains responds in various situations. Remember that your neocortex is cognitive processing, the mammalian brain is emotional processing, and the reptilian brain is body processing. Try to identify situations in which each is most active. These can be situations that are both positive and negative.

This information can be used later when you are identifying interventions that can help combat anxiety and trauma responses. A skill that works when we are at a 3 out of 10 might be different from a skill that works at an 8 out of 10. When you’re lower on the scale, you might notice that cognitive interventions like positive self-talk are more helpful; however, when you’re at an 8, you might need to do physical activities, like breathing exercises, to help calm you down.

The most important thing is to give yourself what you need without judgment. The great thing about our brains is that they are amenable. The more you acknowledge trauma responses, the more you can teach your brain to respond more effectively and significantly reduce or eliminate the impact of these traumas.