Trauma and Memory

 Memory is the way past events affect future function (Daniel Siegel, The Developing Mind)

What is Memory?

Memory refers to a set of processes that assist us to acquire, store, retain and retrieve, and recognise information that comes from both within our brain/body and from the external environment.

• Immediate memory lasts for just a few seconds.
• Short-term memory stores information that has been minimally processed and is available only for a few minutes.
• Short-term memory is transferred into long-term memory only when repeated use of the information facilitates neurochemical changes that allow it to be retained. This can last for many years.
• Implicit Memory is non-verbal and active before birth. It can be experiential and sensory information and is fundamental to how the brain stores traumatic representations within the sub-cortical areas – brain-stem, diencephalon, cerebellum and limbic system.  This memory lacks conscious awareness and is recorded and retrieved without awareness.
• Explicit Memory develops after the brain systems are in place following the 1st birthday.  This memory is conscious and stored in the cortical area of the brain.  It has three components: semantic/factual memory, episodic memory and narrative/autobiographical memory. 
• Semantic memory develops from about 18 months old and is about the ‘way things work’.
• Episodic memory also develops at this time and is more about discrete events that occur at different points in time. 
• Narrative memory happens a little later between 2-3 years and has to do with the sense of self and time.

How memory is used

As children grow, their ability to store language and concepts does also.  Memory structures in the limbic system increasingly develop the capacity to store the sensory parts of an experience separate to the details (the who, what, when and where) which are recorded in the cortex.  Other areas of the brain then work to bring together these different facets of the memory, as well as further entwining associations with similar experiences. 

Children and young people become prepared for the complexities of social interactions through this free flow of information.  They learn to reflect on memories in calm states.  Painful memories can also be held off in order to not be overwhelmed with the intensity of sensory experiences from their pain when it is counterproductive to them.

The impact of trauma on memory

When a child is exposed to complex trauma it can affect how well key brain structures work, particularly how they integrate the different dimensions of memory.  In many cases the emotional and physiological echoes of a traumatic experience become stored as pieces of a memory in the limbic system, cerebellum and brain stem without any reference points.  The dots are not connected i.e. the facts of the event are not connected with the physical and emotional reaction to it.

It has also been acknowledged that, in fact, the intensity that the sensory memory fragments are stored is the same intensity as they were experienced at the time.  Therefore, when a child or young person is exposed or confronted with things associated with a traumatic experience from their past, they can be flooded with the full force of the sensory memory fragments that have been triggered in the present moment.  Much of a traumatised child’s memory is stored in their limbic system and is therefore implicit or subconscious. Therefore these powerful feelings often occur without any awareness that what they are experiencing is from their past or of what has triggered them. 

These triggers can be subtle and diverse.  They may be a look, a song, sound smell, certain foods or certain places.  When experienced they place a child in the midst of either hyperarousal or hypoarousal.  As an observer, the child’s behavior may seemingly ‘come out of the blue’.

An example of this may be the sound of a raised voice in the classroom and that it triggers a fear response from child that relates to the raised voice of an abusive parent.  In this moment, the child is unable to understand that the feelings they are experiencing are related to the threat from harm from the raised voice of an abusive parent, and not the non-threatening raised voice in the classroom in that moment.

These experiences leave children and young people who have experienced trauma to find it difficult to make sense of what has happened to them and what continues to drive their thoughts, feelings and behaviour.

This impact of trauma on memory can be demonstrated in different ways:

• Traumatised children may lose the ability to make sense of their experience or build narrative about their life that draws meaning and understanding – Narrative memory
• Traumatised children may not remember events that may have occurred during the week or who they were with and what they have learned - Episodic memory
• Traumatised children may have an impaired working memory – short-term memory.  This impacts a system that is required to carry out complex cognitive tasks such as learning, reasoning, remembering instructions and comprehension.

More specifically, children and young people who experience:

• Neglect where their needs are ignored or inconsistently met, develop memory templates that are by definition unpredictable.  These children do not have a basis or guidelines to know what is coming or how to respond to it. Therefore they are often reactive and struggle to find relationships safe.
• Abuse or violation are hurt and then blamed.  These children experience their internal stress reactions being amplified for those who are supposed to care for them, establishing distorted memory templates.  They will view relationships often as unable to be trusted to meet their needs of being reassured or soothed when they are aroused.