Understanding the Triune Brain and Trauma
Over the last 2-3 decades, there has been a significant increase in findings related to brain development and functioning. Due to these developments, understanding trauma and the impacts to the human brain have directly correlated to finding successful interventions for trauma resolution.
A Yale neuroscientist, Paul MacLean, described the brain as the “triune brain” or three brains in one that are developed in stages from bottom up.
Reptilian brain
Mammalian brain
Cerebral cortex.
Starting with the reptilian brain: located at the base of the skull and in charge of all the human functions we do not have “conscious control over.”
Brain stem: regulates breathing, digestion, reflex responses, blood pressure, bowl and bladder control
Cerebellum: coordinates balance, voluntary movements and posture
Basal ganglia: assists in coding procedural memory (routine behaviors or can viewed as muscle memory) and houses the reward center of the brain that helps encode habitual behaviors and learns from conditioning (positive/negative reinforcers)
Then the mammalian brain (limbic system): housed in the midbrain area, right above and between the brain stem. This part of the brain regulates human emotional responses and understanding of attachment. Overall, this part of the brain is involved in most of the “typical” trauma responses.
Thalamus: linked with the brainstem and receives sensory input from the external world, this part of the brain is unique due to its activity involving all levels of the brain (brain stem, limbic system, and pre-frontal cortex)
Hypothalamus: regulates autonomic nervous system responses (sympathetic-activation/increase in heart rate and parasympathetic-decrease in heart/rest), body temperature and food/drink intake
Amygdala: known as the “fear center” and has a direct link to the thalamus which sends the amygdala sensory information to assess in order to determine if stimuli is safe or unsafe. Depending on how amygdala assesses information, it sends signals to the hypothalamus to release specific hormones. For example, if an experience if pleasurable it may send dopamine (our reward neurotransmitter) or when around a loving care giver, it may release oxytocin (a neurotransmitter which promotes bonding and attachment). If stimuli is dangerous or unsafe, the amygdala will signal for hypothalamus to release cortisol or adrenaline which mobilize the fight, flight, freeze, and fawn responses
Hippocampus: sits directly on top of the amygdala and helps the brain organize emotional experiences into time and context. It sends the information to the pre-fontal cortex shifting implicit responses to explicit memory.
Lastly, the thinking brain or cerebral cortex: refers to the frontal lobes or outside layer of the brain, which separates humans from other mammals due to higher-thinking, language, and emotion regulation.
Separating the right from left hemispheres:
Right hemisphere: more directly linked to emotional brain, spatial reasoning, metaphorical thinking, nonverbal communication and processing negative emotions
Left hemisphere: has more connections to the pre-frontal cortex, analyzing logic, verbal communication, integrating positive emotions and organizing (sequencing) our life experiences in a coherent narrative.
Dorsolateral pre-frontal cortex: involved in working memory, decision making, planning, insight/awareness, and relationship to the external surroundings
Medial pre-frontal cortex: directly linked to emotion regulation and impulse control, receives input from the limbic system (specifically the amygdala and hippocampus) to form explicit memories and house conclusions/decisions based on our past experiences. However, when the emotional brain is highly activated, the medial pre-frontal cortex is unable to access executive functioning. For example, the term “he flipped out” is referring to emotional brain taking over responses and hindering the pre-frontal cortex to assist with regulation.
Putting it all together: So you have all this information regarding functions of different parts of the brain but what do this have to do with trauma? Let me break it down.
You are faced with a dangerous event
This sensory information is taken in through your senses and sent to the thalamus for the amygdala to determine if it is safe or unsafe. If it is unsafe, the hypothalamus releases hormones which activate the fight, flight, freeze, and fawn responses.
These responses are our brains efforts to do everything in our power to stay safe whether that is fighting, running away, or numbing ourselves to be able to endure significant pain.
In efforts to insure safety for the future, the amygdala encodes all the sensory information associated with the dangerous/threatening event to form implicit memory.
Implicit memory includes the felt experience portion of the memory:
The most significant part (worst image)
Cognitions: conclusions/meanings made about self, others, and world
Emotions experience in the event
Body sensations: what did you feel in your body when the event happened
The amygdala will encode the implicit memory and anything moving forward which seems the same or similar (anything that brings up the worst part, cognitions, emotions, and/or body sensations) to the original event will trigger the fight, flight, freeze, fawn response.
Keeping the cerebral cortex from being able to shift sensory stimuli to explicit memory which can be filed away in long term memory (the factual details of the event, knowing there is a beginning and end, and overall meaning of the event).
What can help?:
There are several therapies which are evidenced based and found to be helpful in stabilization and resolution of trauma.
Here at Alternative Therapeutics, EMDR (Eye Movement De-sensitization and Re-processing) therapy is the major therapy utilized.
EMDR utilizes our brains natural healing process by accessing memory networks with bilateral stimulation.
Bilateral stimulation (or dual attention stimulus in EMDR talk) is the process using specific sensory stimuli (visual, auditory or tactile) to create rhythmic left-right pattern.
For example:
Eye movements: following the therapist’s hand in a back and forth pattern with your eyes
Auditory/Tactile: using a machine called a theratapper or audio/tac machine which includes tappers: which vibrate to facilitate the back/forth rhythm and headphones: which use a tone to facilitate the back/forth rhythm
This left-right pattern assists with keeping the person present and focused on a certain stimulus, while simultaneously having them bring up a distressing memory, thought, emotion, and/or body sensation.
EMDRIA reports, “this process involves communication between the amygdala (the alarm signal for stressful events), the hippocampus (which assists with learning, including memories about safety and danger), and the prefrontal cortex (which analyzes and controls behavior and emotion).
Researcher and well-known therapist, Arielle Schwartz says: “EMDR Therapy changes maladaptive neural networks by connecting the traumatic memory with new information. The distressing thoughts and emotions are blended with new positive thoughts and emotions; embodied awareness allows frozen sensations in the body to resolve through healing movements.”
Overall, EMDR helps the person with shifting implicit responses to explicit memory by reducing the level of disturbance related to the distressing event, installing 2. a healthier conclusion/meaning related to the event, and releases any discomfort still held in the body.
For more questions regarding EMDR or how trauma impacts the brain, feel free to contact us!
This blog was adapted from the work of Paul MacLean, Courtney Armstrong, Daniel Siegel, Mary Vicario, EMDRIA and Bessel Van Der Kolk.
Please see these resources for more information:
https://www.findinghopeconsulting.com/
“Rethinking Trauma Treatment: Attachment, Memory Reconsolidation, and Resilience” by Courtney Armstrong
“Mindsight: The New Science of Personal Transformation” by Daniel Siegel
“The Body Keeps the Score” by Bessel Van Der Kolk
Written by: Chase Harshbarger, MA, LPCC