Trauma & Neuroscience: Part II

This is the continuation of the first blog post by guest writer Lenore Hall. Read the first post here.


We are well-informed of how stress affects our brain. Working in stressful environments, raises the risk of Alzheimer’s by 20% (Rousseau, 2016). Our ability to learn is hugely affected by traumatic and stressful experiences that impact the way neurons connect and shape our brain architecture. The following is an attempt to briefly summarize the incredible complexity of the neuroscience involved in brain development, learning and stress (Siegel, 2013 & Perry, 2007).

The brain can be divided into three working areas, with development organized from bottom to top. The lower brainstem and midbrain regions are simplest and develop first, starting in utero and continuing into adulthood. Moving upward and outward, it develops increasing complexity within the limbic system and cortex. These areas ‘awaken’ sequentially during development, each area more complex and relying upon successful organization of the lower area. Trauma occurring early in development affects the sequential development of the higher brain regions.

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BRAINSTEM (SURVIVAL brain): this includes the body’s life-support systems that work automatically to keep us alive. These are connected to the alarm system that drives the fight/flight response triggering release of adrenaline via the sympathetic nervous system. This is the alert system activated under stress.

MIDBRAIN (SOCIAL/ EMOTIONAL/ IMPLUSIVE brain): continues developing until approximately aged 25, and includes the reward centers and vital communication with the alarm center, enabling us to feel basic emotions such as fear and anger as well as happiness and satisfaction. This area allows us to make vital social connections and to control our levels of stress.

CORTEX (SMART brain): growth continues throughout life and controls conscious thought, planning and language. This area is always dependent on the ‘relaxed’ state of the survival brain, meaning that our ability to think rationally, plan and function socially is entirely dependent on how we learn to control the brainstem’s threat response or, how safe we feel in our world. When our brain is alarmed, our ability to think clearly and our sense of being in control is greatly reduced. 

Our “SURVIVAL” brain, when under threat or alarmed, communicates directly with all other areas via release of adrenaline, activating the body’s fight/flight/freeze response. However, when poorly regulated it causes dysfunction in all other brain areas. For example, repeated trauma while the brain is still developing causes it to be on constant high alert, which affects memory, attention, impulse control and the ability to learn. Consistent high levels of adrenaline correlate with increased anxiety, arousal and irritability which long-term results in heightened startle response, enhancing the child’s impression of the world as dangerous and unsettling. 


The “SOCIAL/EMOTIONAL/IMPLUSIVE” brain links the complex interconnecting circuits of the limbic system, amygdala and hippocampus with the brainstem and cortex. These systems are vital in weaving together attachment, emotions, memory, motivation, and evaluations; directly influencing how we learn and whether we learn to survive or thrive.