How Does Trauma Affect Memory?

How Does Trauma Affect Memory?

childhood trauma and traumatic memories

Traumatic Memories

Remembering traumatic events is in some ways beneficial. For example, it allows us to review the experience and learn from it. Also, by replaying the event/s, its/their emotional charge is diminished.

However, sometimes the process breaks down and the memories remain powerful and frightening. Sometimes they seem to appear at random, and at other times they can be TRIGGERED by a particular event such as a film with a scene that shows a person suffering from a similar trauma to that suffered by the person watching it.

Traumatic memories can manifest themselves in any of the 3 ways listed below:

FLASHBACKS
INTRUSIVE MEMORIES
NIGHTMARES

1) FLASHBACKS

These are often intense, vivid and frightening. They can be difficult to control, especially at night.

Sometimes a flashback may be very detailed, but at other times it may be a more nebulous ‘sense’ of the trauma.

Sometimes the person experiencing the flashback feels that they are going mad or are about to completely lose control, but THIS IS NOT THE CASE.

Traumatic_memories

2) INTRUSIVE MEMORIES

These are more likely to occur when the mind is not occupied. They are more a recollection of the event rather than a reliving of it. When they do intrude, they can be painful. Often, the more we try to banish them from memory the more tenaciously they maintain their grip.

3) NIGHTMARES

These can replay the traumatic events in a similar way to how they originally happened or occur as distorted REPRESENTATIONS of the event.

HOW RELIABLE ARE MEMORIES OF TRAUMATIC EVENTS?

There used to be concern that some memories of trauma may be false memories. However, the latest research suggests that memories of trauma tend to be quite accurate but may be distorted or embellished.

However, false memories CAN occasionally occur. This is most likely to happen when someone we trust, such as a therapist, keeps suggesting some trauma (eg sexual abuse) must have happened.

It is important to remember, though, that parents or carers will sometimes DENY or DOWNPLAY and MINIMIZE our traumatic experiences due to a sense of their own guilt. In other words, they may claim our traumatic memories are false when in fact they are not.

REPRESSION :

Very traumatic memories may sometimes be REPRESSED (buried in the unconscious with no conscious access to them). In other words, we may forget that a trauma has happened. As I suggested in PART 1, this is a defense mechanism. Sometimes the buried memories can be brought back into consciousness (eg through psychotherapy) so that the brain may be allowed to process and work through the memories allowing a recovery process to get underway.

 

Trauma, Memory And The Brain :

New memories are stored in the region of the brain known as the hippocampus. However, not all memories that enter the hippocampus are stored by the brain permanently.

Only some are transferred to the cerebral cortex for long-term storage; the rest fade away. The more important the memory, and, in particular, the more intense the emotions connected to the memory are, the more likely it is to be permanently stored. This process in called memory consolidation.

When an event occurs that is very threatening or damaging to us, the stress of this causes stress hormones ADRENALIN and CORTISOL to be released into the brain.

The effect of these stress hormones is to strengthen the memory of this threatening or damaging event.

The stress hormones released into the brain (in particular, the amygdala) also ensure the memory of the negative event becomes strongly associated with the emotions (such as fear and terror) that it originally evoked.

intrusive_memories

So, for example, if we are viciously attacked and maimed by a savage and demented Rottweiler, cortisol and adrenaline will be released into our brain to ensure that the memory is indelibly stored. These same stress hormones will also ensure that the emotions we felt at the time of the attack, such as fear and terror, also become strongly associated with the memory of our unfortunate encounter with the less than friendly canine miscreant.

This way of storing such memories evolved for the survival value it confers on our genes.

Also, when extremely traumatic events occur, the hippocampus can become so excessively flooded by stress hormones such as cortisol and adrenaline that it incurs damage.

This damage can then alter the way that the traumatic event is stored. Because of this the memory may become:

fragmented

‘foggy’ / ‘blurry’

distorted

inaccessible to conscious awareness

Furthermore, the memory of the extremely traumatic event may become highly invasive – especially when the person in possession of the memory is reminded of the traumatic event (even tangentially) – and constantly break through into consciousness wholly unbidden, re-triggering the release of excessive amounts of stress hormones into the brain ; this can lead to:

flashbacks

nightmares

obsessive rumination about the traumatic event

 

TRAUMA AND NON-DECLARATIVE MEMORY :

Our long-term memory can be divided into :

1. Declarative Memory (sometimes called explicit memory or narrative memory) – it is the part of our memory that we use for the conscious recall of facts or events.

Declarative memory depends upon language in order to organize, store and retrieve the information that it holds.

2. Non- Declarative Memory (sometimes called implicit memory, procedural memory or sensorimotor memory) – it is this part of our memory that allows us to automatically retrieve information connected to something we have learned without conscious deliberation.

Non-declarative memory

For example, we can get on a bike and ride it without having to concentrate on exactly how we’re doing it or go over in our minds the steps involved in how we learned to do it; indeed, we need not even remember when or how when learned to do it (I certainly don’t) – nevertheless, the necessary ‘know-how’ has been unconsciously, permanently retained.

Non-declarative memory, unlike declarative memory, does not depend upon language for the organization, storage and retrieval of information. Because of this, non-declarative memories are frequently very hard indeed to describe in words (try explaining all the tiny body and muscle adjustments necessary to maintain balance whilst riding a bicycle – yet the memory of exactly how to do this has been faithfully, unconsciously stored, courtesy of your non-declarative memory!).

TRAUMATIC EXPERIENCES ARE FREQUENTLY STORED AS NON-DECLARATIVE MEMORIES :

Due to their their utterly overwhelming nature, we often can’t completely and linguistically, mentally process our traumatic experiences which prevents them from being stored in declarative memory ; when this happens, the traumatic experiences are instead stored in our non-declarative memory.

THE FRAGMENTARY NATURE OF INCOMPLETELY PROCESSED TRAUMATIC MEMORIES :

The incompletely processed traumatic memories stored in non-declarative memory tend to be very fragmentary in nature. As we have seen, too, they are not stored in linguistic form but, instead, often in the form of :

bodily sensations (e.g. muscular tension, increased heart rate, hyperventilation)

images (e.g. these might come to us in nightmares or intrusively and unheralded during our waking hours as a result, often, of unconscious triggers – see below)

emotions (e.g. extreme anger or fear)

Also, our unconscious, non-declarative memories may express themselves through chronic, seemingly inexplicable symptoms and behaviours.

WHY WE FIND IT HARD TO ARTICULATE OUR TRAUMATIC EXPERIENCES :

Because the memory of our trauma has not been properly processed at the linguistic level we are likely to find ourselves unable to articulate our traumatic experiences in any coherent manner. (Click here to read my article on how we find it difficult to talk about our trauma).

TRIGGERS :

Bodily sensations, images, emotions, symptoms and behaviours linked to our non-declarative memories of our original, childhood trauma may be triggered whenever anything even remotely reminds us of this trauma.

In this way, we may find ourselves re-enacting aspects of our original trauma in our everyday lives months, years or, even (in the absence of effective therapy), decades after the actual experience of our childhood trauma is over.

 

RELATED POSTS :

TYPES OF DISSOCIATIVE AMNESIA IN COMPLEX PTSD

FIVE TYPES OF AMNESIA LINKED TO CHILDHOOD TRAUMA

CHILDHOOD TRAUMA AND MEMORY – WHY SOME REMEMBER AND OTHERS FORGET.

CAN ‘BURIED MEMORIES’ BE UNCOVERED BY HYPNOSIS?

 

David Hosier BSc Hons; MSc; PGDE(FAHE).

 

 

 

 

About David Hosier BSc Hons; MSc; PGDE(FAHE)

Psychologist, researcher and educationalist.

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