New research suggests a period of rest following a traumatic event can help reduce the subsequent development of involuntary “memory intrusions,” a frequent symptom of post-traumatic stress disorder. Memory intrusions can be both visual or non-visual and are often referred to as flashbacks.
The study, published in Scientific Reports, discovered memory disturbances in PTSD may be mitigated by a process that occurs in the brain that can be facilitated by rest and sleep. Specifically, investigators discovered increased consolidation — storage and contextualization of memories in the brain — helps to alleviate memory intrusions. Experts believe this finding could shed new light on treatment and prevention.
Lead author Dr. Lone Hørlyck, from the Institute of Cognitive Neuroscience at University College London, said, “Over a lifetime, many people experience traumatic events, but most people do not develop persistent trauma symptoms.
“Identifying which mechanisms might contribute to memory intrusions in PTSD is important, as these disturbances comprise an important maintaining factor in the disorder.”
For the study, researchers presented 85 participants with emotionally negative videos, followed by either a period of wakeful rest or a simple control task, where participants were required to pay attention to numbers on a screen.
The videos comprised highly emotional content, such as badly injured people or serious accidents.
Researchers found that participants who had a period of rest following the viewing of negative videos reported fewer memory intrusions related to the videos over the following week.
In contrast, there was no difference between rest and the simple control task on a follow-up memory test assessing how much participants remembered when they wanted to.
Rest and certain phases of sleep are known to increase processing in the hippocampus, a key region of the brain that helps put memory in context.
According to the investigators, the results suggest that a strengthening of this contextual memory system is beneficial in preventing memory intrusions following trauma.
Senior author Professor Neil Burgess, of the Institute of Cognitive Neuroscience, said, “The coherence of memories is often compromised when people are exposed to psychological trauma, resulting in emotional memories popping up involuntarily and out of context.
“However, the binding of an event memory with its context may be partly restored with rest, facilitating deliberate control of the memory.
“The results show that specific brain systems could be targeted to reduce development of PTSD and may explain why treatments that focus on re-exposure and integrating the trauma with other information are beneficial.”
Hørlyck added, “Our findings contribute to a better understanding of the mechanisms that are at play when some people develop memory disturbances following trauma while others do not.”