This is from Uri Bergmann, from Neurobiological Foundations for EMDR,“This excessive stimulation of the amygdala interferes with hippocampalfunctioning, inhibiting cognitive evaluation of experience and semantic representation. Memories are then stored in sensorimotor modalities, somatic sensations, and visual images.”
Interpretation: When there is excessive stress on the receiving, signalling and switching part of the mid-brain called the amygdala, then another part of the brain, the hippocampus, will be inhibited from ‘thinking’ about the experience to give it perspective. Memories of the event or experience are stored by the mind as feelings, body sensations and visual images and without the use of language (semantic representations) for understanding or interpretation, that is, hippocampal cognitive evaluation.
This means that for stressful experiences – this includes but is not limited to childhood – the ‘cognitive’ evaluation of the experience will be impaired and the information (memories) derived from it will be stored very differently than if there is no stress. This is important because the experiences shift from being memories you can consciously think about to memories that show up as feelings, body sensations or images only. This may result in having feelings such as anxiety or fear and not understanding them or knowing where they’re coming from.
This has implications for childhood experiences and how the memories were stored or, in many cases, how they weren’t stored. Some people do not remember their childhood. This is why: they were under constant stress and their hippocampus was not being accessed and memories based in language were not being made or recorded. Some people only remember the “bad” things. This is because the “bad” memories were stressful and therefore imprinted into memory more strongly as feelings, images and body sensations. Because of that, they are always running in the background, activate easily and are the hardest to let go.
This also has an impact on the emotional emotional development in the adult. Child brains that are developed in highly stressful circumstances can grow into adult brains that are angry much of the time, depressed and unable to make good decisions. Adults that grew up in childhoods of chronic stress, often have emotionally undeveloped brains, fear is easily triggered and they are living much of the time in their survival circuits. This results in immaturity, impulsivity, unregulated emotions or the inability to have well-thought-out behavior.
Because highly charged emotional memories are stored in the body as feelings, body sensations and visual images they are accessed or remembered as the same way. It is often the case that current experiences activate those feelings-memories, and there is no awareness that that is what is happening. Consequently, the person just feels bad, or anxious, or depressed and doesn’t know why.
It is also true that in real time, if you become anxious or stressed, your brain will not get the hippocampal cognitive evaluation of what is currently being experienced. This is because the amygdala doesn’t send it (thehippocampus) the signal it needs to ‘think’ about the experience, so it can then return its’ conclusion of safety or danger. Consequently, the person feels in danger, even though the situation may not be dangerous. (Examples are seeing a bear but not realizing it’s in a zoo, or a car backfiring loudly and not realizing you’re not in a war zone.)
People may live in the state of not accessing their ‘thinking’ brain constantly because whenever there is even the least bit of stress, their brain shuts off access to cognitive evaluation. Basically, they are not accessing the reasoning part of their brain in a meaningful way, beyond what is needed for survival.
(As an aside, I think this is what is happening when people commit atrocious acts such as murder/suicide or other such crimes. They’re living out of their survival circuits, where the hippocampus – thinking brain – is not accessed, and they’re living in fear, anxiety and paranoia. People may live like this for years and then, at some point, act out.)
In a more normal sense, when we, or others, do things that it seems like we weren’t thinking about it, then that’s probably right, we weren’t. The thinking part of the brain was shut off because of a wiring circuit that was shut off by a stress switch.
The lesson here is to calm the amygdala, whenever possible. One way to do that is to live “mindfully.” That is, keep partial attention on your inner state at all times, and when feelings, body sensations, or images appear, welcome them and allow them to resolve within, rather than projecting them without.