Decades of treatment of military veterans and sexual assault survivors have left little doubt that traumatic memories function differently from other memories. A group of researchers at Yale University and the Icahn School of Medicine at Mount Sinai set out to find empirical evidence of those differences.
The people listening to the sad memories, which often involved the death of a family member, showed consistently high engagement of the hippocampus, part of the brain that organizes and contextualizes memories.
When the same people listened to their traumatic memories — of sexual assaults, fires, school shootings and terrorist attacks — the hippocampus was not involved.
“What it tells us is that the brain is in a different state in the two memories,” said Daniela Schiller, a neuroscientist at the Icahn School of Medicine at Mount Sinai and one of the authors of the study.
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The traumatic memories appeared to engage a different area of the brain — the posterior cingulate cortex, or P.C.C., which is usually involved in internally directed thought, like introspection or daydreaming. The more severe the person’s PTSD symptoms were, the more activity appeared in the P.C.C.
