Neurosequential Model Series - Part 3: Understanding Long-Term Impacts of Trauma
Okay, we’ve covered four basic brain regions, what they do, and how our brain responds to nervous system activation and danger in the short term. In the long term, when learning about how trauma affects the brain over time, we have to first look at some important core concepts, one of which is called biological relativity. Biological relativity is the idea that the brain region that is developing is the most vulnerable to being affected by trauma. For instance, experiencing a traumatic event as a six month old could affect the development of the midbrain, whereas experiencing a traumatic event as a teen could impact the development of the cortex. The regions of the brain that are impacted are referred to as disorganized or dysregulated.
Another important idea is that development of the brain happens sequentially and interdependently, so when one area of the brain is changed by trauma, areas of the brain that develop after it are likely to be impacted too, because each region’s development is dependent on the regions before it. This is one of the reasons early childhood trauma is so damaging, it is likely to disrupt brain functioning in other regions even after the trauma is over. A third important concept I briefly touched on is use dependence, which is the idea that neural connections, and the subsequent brain regions that house them, become stronger with repeated use. Because of this use dependence, when we talk about brain dysregulation, certain regions of the brain can be overdeveloped if they were used very frequently, or underdeveloped if they weren’t used enough.
One caveat to all of this before we jump in: having these symptoms doesn’t necessarily mean someone experienced trauma during that time frame; there can be medical, genetic, and other causes for all of these symptoms of dysregulation and over/under development in each region. Likewise, folks may have experienced trauma at various times throughout their life, but not have these symptoms.
Brainstem disorganization/dysregulation means there was trauma in utero, most often meaning that the mother of the child experienced trauma while pregnant, but there can also be medical conditions specific to the fetus that create trauma and affect brainstem development. Additionally, medical interventions after birth that require things like a long NICU stay can have an impact on the brainstem. With brainstem dysregulation, we often see that someone’s autonomic nervous functions are out of whack; they might have an abnormally high or low resting heart rate, blood pressure issues, breathing problems, and skin sensitivities. We also see folks with abnormal metabolisms, for instance, those who either cannot gain weight despite a high caloric intake.
Since the midbrain controls our motor functions, midbrain dysregulation is pretty intuitive. Folks with midbrain dysregulation may have poor fine motor skills (bad handwriting), clumsiness, and sensory systems that are over or under active, which can result in sensory seeking behavior or sensory avoidant behavior. We also see difficulty with the natural rhythms of eating and sleeping. When babies experience trauma during the first few years of life, such as not being picked up and held or not soothed when upset, we can sometimes see these motor delays. In my past career as a foster care case manager, there were times where we would get babies into our care between 9-12 months who were frequently left in a crib or car seat, and they had major motor delays because they never got to practice moving their bodies and exploring, which left the midbrain underutilized and therefore underdeveloped.
Limbic dysregulation impacts relationships, emotional reactivity, and short term memory. Limbic overdevelopment is caused by having to exist in a fear state regularly for survival, often by experiencing relationships that lacked a sense of safety in childhood. When folks have an underdeveloped limbic system, they might have difficulty reading social cues and might not get pleasure in healthy relational interactions. With an overdeveloped limbic system, people are more likely to become easily anxious, upset, or aggressive, and may take a long time to calm down. An overdeveloped limbic system also presents as hypervigilance and being quick to enter fight or flight, sometimes unnecessarily. Limbic system dysfunction in general looks like emotional immaturity, including few age-appropriate friendships, difficulty with interpersonal relationships and using unhealthy forms of reward, like substance abuse or self-harm.
Because the cortex does executive functioning tasks, concrete and abstract thought, and insight and self-awareness, folks with cortex dysregulation struggle in those areas. When I think about trauma that can impact cortical development, I think about trauma in adolescence such as separation from caregivers, concussions, prolonged substance abuse, and even social disruptions like bullying or moving. Additionally, since the cortex is the last region to develop, dysfunction in lower regions can create dysfunction in the cortex. Cortex dysregulation often looks like executive dysfunction, where people struggle with things like time management, impulse control, and planning. Cortex dysregulation may also result in educational problems, like difficulty with math, reading, and writing. In the therapy world, I often see cortex dysregulation show up to create problems with communication and insight or self-reflection, as well as overly selfish behaviors.
One final, general, concept is the hopeful reality of neuroplasticity. Most of us know that our brain is an organ that is making and changing neural connections throughout each day and throughout our lives. Because our brains have this amazing ability, none of this brain region dysregulation is set in stone, it can always change. In the next post, we’ll discuss ways to use that neuroplasticity to your advantage, and how to use interventions specific to each brain region that may be dysregulated.
