Trauma and the brain

Updated: Jul 29, 2019

Trauma can be a result of one event or the result of several less severe events spread over a period of time (Richards, n.d.). The following is a description of infant brain development when exposed to long-term stress within its environment. The brain responds similarly to trauma as a result of one event in terms of flooding the brain with chemicals (stress hormones) and impact on memory as well as impact on linkages within the brain (ASCA, n.d.). The cortex has two hemispheres, right and left, and each is responsible for processing experience in different ways. In the infant the right hemisphere develops first (Gibson, n.d.), experiencing everything non-verbally and mainly through body sensation, images and emotions. It is responsible for relational and emotional processing and is very sensitive to negative interactions in its environment. The left hemisphere catches up to the right at about 18 months of age. It experiences in a linear way through language, symbols and words. It is responsible for thought processing and is inclined towards positive interactions in its environment (Graham, 2008). Ideally at about 12 months of age an integration of information processing between the left and right hemispheres begins to take place with most adults becoming left-brain dominant (Graham, 2008). Though if the right brain experiences extended periods of anxiety the stress hormone cortisol is released (Narvaez, 2011). High levels of cortisol affect the integration of the left and right hemispheres which results in insufficient engagement. What this means is that the individual becomes right-brained dominant, prone to negative emotions and excessively responsive to minor triggers as an adult (ASCA, n.d.). As stated the hippocampus integrates perceptions and emotions into memory, it controls feelings, processes information and gives context to memories and events. As it carries out its processing the amygdale influence the relay of information to the cortex which is attempting to make sense of the incoming information (ASCA, n.d.).​ It has been found that those who’ve been brought up in an environment in which they experienced chronic stress have a smaller hippocampus. The reason being is that while the hippocampus is coated with receptors for the stress hormone cortisol it is at the same time compromised by high levels which suppress its ability to function. This is especially true of the hormones released by the ‘fight or flight’ response in the amygdale (Congleton, 2015). When the hippocampus is inhibited the transfer of information to the cortex – the reasoning, thinking centre of the brain – is not adequately carried out and this results in the cortex being unable to differentiate between a real threat and one that is imagined. The hippocampus shows evidence of developing differently in children who experience environments where they feel unsafe or threatened. These children are more susceptible to stress hormones, such as adrenaline and cortisol and they have a greater chance of developing as adults who have problems controlling their anger and emotions. There will be a greater likelihood that they will be highly stressed, they’ll exhibit behaviours of self-harm, suffer from anxiety and be prone to suicidal tendencies (ASCA, n.d.). Lastly, overactive amygdale result in an overactive fear response. This combined with a hippocampus which has been damaged or inhibited will also cause an individual to have trouble both storing and retrieving memories, making these adults more likely to develop symptoms related to PTSD and depression (ASCA, n.d.).

​Next post: Other responses to trauma within the body/brain


Adults Surviving Child Abuse. (n.d.). Impact on the physiology of the brain. Retrieved from

Congleton, C. (2015). Mindfulness can literally change your brain. Retrieved from

Gibson, L. (n.d.) Escaping the right brain trap. Retrieved from

Graham, L. (2008). The neuroscience of attachment. Retrieved from

Narvaez, D. (2011). Dangers of “crying it out”. Retrieved from

Richards, N. (n.d.). Trauma’s impact on the body. Retrieved from

#memory #feelings #unsafe #stress #adrenaline #cortisol #anger #emotions #selfharm #anxiety #suicide #depression #chronicstress #receptor #reasoning #thinking #PTSD

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