Everyone remembers the celebrations, such as weddings and parties, where your friends and family gather to have the time of their lives. We remember the events that bring joy to our life. Unfortunately, we also tend to remember those ‘not so fun’ events that may cause stress and/or anxiety in our everyday lives. Many of us can remember where we were when we heard about the events on 9/11. However, you probably don’t know where you were on 9/10.
Many times we wish we could erase some of these past stressful events from our memory and instead remember more of the events that have escaped from our recollection. However, our brain’s wiring and decisions on what to remember has its benefits.
It is an evolutionary phenomenon for our brains to recollect past events. We learn from our mistakes. However, many times the emotional load of past events may cause stress and/or anxiety that affects our everyday lives. In some situations, our memories that carry along strong emotions with them can become pathological, such as in posttraumatic stress disorder (PTSD) or Generalized Anxiety Disorder (GAD).
How stressful memories can lead to disorders in the brain:
Pathways involving glucocorticoid hormones (aka steroid hormones) and altercations with gene transcription impact the formation of memories.
The function of memory consolidation is heightened by glucocorticoids. During a stressful event, these stress hormones are released. Pharmacological testing has been used to determine which specific receptor leads to an adaptive response to a stressor. This was achieved by inhibiting glucocorticoid receptors found in the dentate gyrus region of the hippocampus. It was found that these receptors did not produce the adaptive response of quickly immobilizing when inhibited. Thus, glucocorticoid receptors in this region of the brain are involved in response to stressful events.
Also found in the dentate gyrus region of the hippocampus was a high quantity amount of altered proteins known as the H3S10p-K14ac histone. This histone wraps up DNA and increases the expression of “immediate early genes” such as c-Fos and Egr-1.
c-Fos: involved in long term changes for adaptive behaviors
Egr-1: important for memory formation and learning
These proteins are directly involved with forming strong memories and consolidation processes as well. This underlying mechanism can thus cause an increase of “noisy” thoughts that are characterized with the intense memories of the stressors.
What does this all mean?
The dentate gyrus plays a pivotal role in the encoding of information and the H3S10p-K14 histone plays a central role in kick-starting gene transcription required for long-term changes in neuronal function. As of right now, treatments of PTSD involve medications commonly prescribed for anxiety. However, there is a difference between these disorders. More research on the stress response and the formation of strong memories could potentially advance the treatment methods for PTSD.
We only sometimes remember the good and the bad, but we almost always remember the ugly. How can we control the effects these ‘ugly’ memories have on us, yet still remember the ‘good’ memories? It’s a question where much more research is needed, but the research presented is a good start!
For more information on the research presented follow this link:
https://www.frontiersin.org/articles/10.3389/fpsyt.2014.00005/full
For more information on PTSD follow this link:
