People who’ve been through callous things, like abuse or combat, often have a hard time afterward. It’s called PTSD, and it can make them remember the bad stuff in a scary way, like having flashbacks or feeling very anxious.Â
A study from Yale University shows that when people with PTSD think about these harrowing memories, their brains act differently compared to when they remember sad or neutral things. It’s not the same as thinking about, for example, losing a pet or enjoying a nice walk on the beach.
In a study with 28 people who have PTSD, researchers discovered that when these individuals remembered everyday experiences, their brain patterns were similar. However, when they thought about traumatic events from their past, each person’s brain reacted differently.
Yale’s Ilan Harpaz-Rotem, professor of psychiatry and psychology at Yale and co-senior author of the paper, said, “When people recall sad or neutral events from their experience, the brain exhibits highly synchronous activity among all PTSD patients. However, when presented with stories of their own traumatic experiences, brain activity was highly individualized, fragmented, and disorganized. They are not like memories at all.”Â
The research, done with researchers from Icahn School of Medicine at Mount Sinai in New York, was published on November 30 in the journal Nature Neuroscience.
In the study, the 28 participants were asked various questions about their harrowing experiences, sad events (like losing a family member), and peaceful moments. Each person’s story was written down and read to them while they had fMRI scans, which show brain activity using blood flow.
The researchers discovered that when people remembered sad or peaceful experiences, the part of the brain responsible for making memories (called the hippocampus) showed similar activity in all subjects. This suggests normal memory formation.
However, when the participants heard stories about their traumatic experiences, the similarity in hippocampal activity disappeared. Instead, each person’s hippocampus showed unique and scattered activity, unlike the usual synchronized patterns in regular memory formation.
The findings might explain why people with PTSD struggle to remember traumatic events clearly. According to the researchers, it also suggests why these memories can cause severe symptoms.
Harpaz-Rotem said, “These insights may help psychotherapists guide PTSD patients to develop narratives about their experiences, which may help them eliminate the sense of immediate threat caused by their trauma.”
This research contributes to our understanding of the neural mechanisms underlying traumatic memories and their impact on individuals with PTSD. The distinctive brain activity observed during the recall of traumatic events provides valuable information for future studies aiming to develop targeted therapeutic interventions for those affected by post-traumatic stress disorder.
Journal reference:
- Perl, O., Duek, O., Kulkarni, K.R. et al. Neural patterns differentiate traumatic from sad autobiographical memories in PTSD. Nature Neuroscience. DOI:10.1038/s41593-023-01483-5.