Stress reshapes memory, influencing PTSD symptoms and offers pathways to potential therapies.

It has been found from the findings of SickKids that; stress interferes with all kinds of neural functions including the manner in which brain retrieves memories. Their recent study defines how stress reduces memory specificity and adds to PTSD, and also discusses possible ways to reverse this process (1^✔ ✔Trusted Source
Stress disrupts engram ensembles in lateral amygdala to generalize threat memory in mice

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Relations between Stress and Memory

Can you imagine tripping during a speech? The stress from this event might make you anxious the next time you are asked to deliver a presentation, because,at one time your mind has linked that particular situation to a bad experience. This is a type of stress that follows a memory stressor.
However, pressure from what is considered severe stress, including a traumatic incident or constant anxiety, tends to expand beyond that. Such effects are explained by the concept of Stress-induced aversive memory generalization. For instance, a fear appears while listening to fireworks or car backfiring. Unfortunately, this generalized fear means a lot to individuals with PTSD since it alters the conduct of normal activities in their everyday lives.

Writing in Cell, Drs. Sheena Josselyn and Paul Frankland and Dr. Matthew Hill have worked to determine the neural basis of stress-induced memory generalization. They established that high stress changes how the brain puts information into its network and recalls it, thus causing generalized fear.

Their findings also revealed a potential breakthrough: It is for this reason that by interrupting the specific cerebral processes, it is quite likely that normal memory selectivity could be regained to lower the impact of PTSD.

How Stress Affects Memory

In a preclinical study, the authors trained stress-induced memory generalization by making the subjects encounter stress before witnessing an adverse event. They found out that, such stress brought modifications to the memory engrams, the patterns in the brains that contained the memories.

Usually, they are defined as a set of working neurons that become the retrieval cues for the specific experience, but stress increases the number of neurons that become involved, resulting in a generalized fearful memory. Whenever these large engrams were activated, fear responses were seen even in safe situations, mirroring PTSD symptoms in humans.

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The work also examined the endocannabinoid system, a complex in the brain that deals with memory and emotional regulation. The endocannabinoids act as natural signals that improve memory consolidation, as well as associate particular stimuli to specific behaviors.

The normal levels of endocannabinoids are balanced and failure to create them interrupts the levels of interneurons which in turn makes the memory less specific. This disruption not only leads to an increase in the size of memory engrams but also increases the generalization of fearful memories.

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Considering that endocannabinoid receptors were blocked on those particular interneurons, the given researchers managed the engram size, as well as prevent the development of generalized fearful memories.

Clinical psychologist Dr. Josselyn says, “Endocannabinoid receptors are the ‘Velvet Rope’ for memory, deciding who can enter the process.” If stress releases too much of the endocannabinoids; then the rope drops and clears general aversive memories. This way, blocking these receptors may help to avoid one of the most severe PTSD symptoms.”

Notably, the study also links stress-altered memory and how it affects the developing brain. Early studies in Science have established that the young brain has a tendency to create larger memory engrams that are more general. It means that it is possible to examine the connection between stress, memory specificity, and age as all of them are similar.

Besides exploring the effects of stress on memory, this study provides hope to the victims of PTSD. By focusing on particular brain aspects, the therapies helpful for memory accuracy can be achieved and people can control their live.

Reference:

1. Stress disrupts engram ensembles in lateral amygdala to generalize threat memory in mice – (https://www.cell.com/cell/abstract/S0092-8674(24)01216-9)

Source-Medindia