The group’s findings suggest that procedures used by clinicians to indirectly reactivate traumatic memories render a window whereby those memories can be altered, or even erased completely, says Stephen Maren, professor of psychological and brain sciences at Texas A&M University.
In therapy, imaginal reminders are often used to safely retrieve traumatic memories of experiences. For example, Maren says a military veteran wounded by an improvised explosive device may be asked to re-experience trauma cues—like the lights and sounds of the explosion—without the negative consequences. The idea is that the fear responses can be dampened through this exposure therapy.
“The one major challenge is when you do the extinction procedures, it doesn’t erase the original trauma memory,” Maren says.
“It’s always there and can bubble back up, which is what causes relapse for people who re-experience fear.”
With this in mind, the researchers hoped to answer whether they could isolate a memory and drive fear responses by reactivating it artificially—and potentially disrupt the original memory itself.
Maren says their findings suggest that procedures currently used by clinicians to indirectly reactivate traumatic memories create an opportunity to change or eliminate them.
To do this, the researchers used a conditioning procedure in which a cue becomes indirectly associated with a fearful event. When the cue is presented later, it indirectly reactivates a memory of the event and increases activity in the hippocampus, a brain area important for memory.
The study shows that indirectly reactivating a contextual fear memory through re-exposure to the cue can make the memory vulnerable to disruption.
Maren says further research is needed to answer if scientists can produce a permanent loss of the traumatic information.
The research appears in the journal Nature Neuroscience.
The National Institutes of Health funded the research.
Source: Texas A&M University
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