Traumatic Memories Really Do Feel Different

It has long been understood that people who have experienced trauma have a different relationship to those memories than they would to memories of typical, everyday events. Even memories with negative emotional connotations, like sadness, still seem to be in a different category than memories of trauma—where shock and helplessness force the body into an extreme threat response. The intrusion that comes with re-experiencing traumatic memories often involves the entire body and can send people into devastating cycles of flashbacks, nightmares, and even dissociative states.

Similarly, the way that these memories are encoded or retrieved has often seemed different than typical memories, which can lead to fragmented recall, more inconsistent recollections, or even entire swaths of blacking out or not remembering. The differences between the experience of traumatic memories versus regular memories have long been understood by clinicians to require special care, and they have formed the foundation of various theories of how the body stores trauma. These differences have also informed the development of various treatment protocols for post-traumatic stress disorder, and discussions around exactly when and how traumatic memories should be encouraged to be recalled and re-experienced, and how people can be supported during that process.

The Brain and Traumatic Memories
New research from the journal Nature Neuroscience is providing more concrete evidence that the brain definitively treats traumatic memories differently than it does everyday memories, even ones that have negative emotions like sadness attached to them. A recent study, led by researchers at Yale University, involved 28 people who had been diagnosed with PTSD and examined the neural responses associated with their recall of various stories of their lives.

When the study's participants recalled day-to-day life experiences, brain activity patterns looked very similar across all of the participants. Specifically, the hippocampus was heavily involved and was activated when the participants were recalling relaxing experiences or even sad experiences. This is what has long been expected with typical memory formation. But when they were asked to recall stories and memories associated with their trauma, their brain activity, as measured by fMRI, was no longer consistent—and in fact, all the usual rules of the ways that memory recall takes place in the brain did not seem to apply.

This time, the hippocampus was barely involved, if at all. Instead, the posterior cingulate cortex, an area of the brain typically associated with processing internally directed thought, was significantly activated. Ilan Harpaz-Roten, one of the senior authors of the paper and professor of psychiatry and psychology at Yale, described the latter patterns of brain activity as "highly individualized, fragmented, and disorganized; they are not like memories at all."

This could help explain exactly why traumatic memories may truly be qualitatively different than non-traumatic memories, and why they often take on a quality of being more intrusive, and their effects more unpredictable and debilitating. These memories are perhaps less akin to how we think typically of recalling an experience and instead are more like reliving that experience. Trauma therapists and trauma survivors have long conceptualized trauma this way, as the body truly revisiting the experience, but to have actual scans of brain activity conveying the difference in these concrete ways is an important step forward.

This also potentially brings hope within the realm of PTSD treatment. Might this inform researchers looking at new treatment techniques of a new direction to focus on? Perhaps being able to move traumatic memories into the realm of everyday memories is something that can be guided and quantified through brain scans. Perhaps that will newly be conceptualized as a concrete goal when reprocessing traumatic memories—and one that we can measure, and could in itself have the effect of making traumatic memories eventually feel more neutral, and less distressing.

Time will tell. But for now, anyone who viewed traumatic memories as simply extreme versions of everyday memories, rather than having characteristics that are truly qualitatively different, has new reason to revise that assumption. Perhaps more than ever, this latest data will help empower trauma survivors with the knowledge that their symptomology is due to clear neurological differences, and it can continue the quest for their experiences to be taken seriously for all of their physical and emotional effects.