Trauma changes our brains on a fundamental level, the psychologically traumatised brain causes inscrutable eccentricities which can (and do) cause it to overreact – or misreact – to stimulus and the realities of life. These neurological “misreactions” become established in part due to the effect that trauma has on the release of certain stress-responsive hormones, such as norepinephrine, along with the effect upon various areas of the brain involved in memory – particularly the amygdale and the hippocampus.
The amygdale is the part of the brain responsible for communicating the emotional importance and evaluation, via the thalamus, of sensory information to the hippocampus. In accordance with the amygdales evaluation the hippocampus will activate to a greater or lesser degree, and functions to organise this information and integrate it with previous similar sensory events. Under a normal range of situations and conditions this system works well and effectively to consolidate memories according to their emotional priority and content. However, at the extreme upper end of this hormonal activation, as with traumatic situations, a breakdown occurs. Overwhelming emotional significance registered by the amygdale actually leads to a decrease in hippocampal activation, this results in some of the traumatic input not being organised properly, not being stored as a unified whole, and not being integrated with other memories. This results in isolated sensory images and bodily sensations that are not localised in time or even in situation, nor integrated with other events. In effect these fragments of memory float about in the mind, ready to reappear at any moment.
To make matters even more complex, trauma may temporarily such down Brocas area, the region of the brain which translates experience into language, the means that we more often use to relate our experience and feelings to others and even to ourselves.
Regular memories are formed and are subject to meaningful modification, they can be retrieved when needed and can be conveyed to others through language and expression. In contrast, traumatic memories include chaotic fragments, which are sealed off from modification or modulation. Such memory fragments are wordless, placeless, and eternal. Long after the trauma has receded into the past the brains record of them may remain a fractured mass of isolated and confused emotion, images and sensations which can ring through the person like an alarm at any moment.
These sensations and feelings may not be labelled as part as belonging to memories from long ago, in fact they may not be labelled at all, as they may have been formed without language. They merely are, they come forward to take over the body giving no explanation, no narrative, no place or time, they are free-form and ineffable.
The traumatised brain has, effectively, a broken warning device in its limbic system. A bit like an old fuse box where the fuses tend to melt for no reason, reacting to an emergency when there is none.