Study reveals how fear memories transform over time, offering new insights into PTSD

An innovative study, published in Natural communicationsreveals the mechanism behind two seemingly contradictory effects of fear memories: the inability to forget but the difficulty of remembering.

Led by researchers from Sony Computer Science Laboratories, Inc., ATR Computational Neuroscience Laboratories and the University of Tokyo, the study shows how fear experiences are initially remembered as broad associative memories, but over time time, become integrated into episodic memories with a more specific memory. chronology.

Researchers conducted experiments using functional magnetic resonance imaging (fMRI) and machine learning algorithms to track brain activity as participants experienced simulated threatening events, such as a car crash.

They found that immediately after a fear-inducing event, the brain relies on associative memories, generalizing the fear regardless of the sequence of events. However, the next day, the dorsolateral prefrontal cortex takes over a role initially directed by the hippocampus to integrate the sequence of the event into the fear memory, thereby reducing the scope of the fear.

The study also highlights that highly anxious people, who are at greater risk of suffering from PTSD, may have difficulty with this memory integration. Their brains exhibit weaker integration of temporal episodic memories across the dorsolateral prefrontal cortex, which can lead to persistent and overwhelming fear linked to associative cues. This idea opens new avenues for PTSD interventions by targeting the brain’s ability to integrate episodic memories after trauma.

“Our results reveal a previously unknown phenomenon in how the brain prioritizes and processes fear memories,” said lead author Dr. Aurelio Cortese of the Advanced Telecommunications Research Institute (ATR). “This time-dependent rebalancing between brain regions may explain why some people develop post-traumatic stress disorder while others do not,” explained final author Dr. Ai Koizumi of Sony Computer Science Laboratories , Inc.

The study findings have the potential to reshape our understanding of PTSD and fear memory processing, providing new insights for developing more effective interventions.

Provided by the ATR Brain Communication and Information Research Laboratory Group