A new DARPA research program called Restoring Active Memory Replay (RAM Replay) aims to investigate the role of neural “replay” in the formation and recall of memory.

The goal is to help individuals better remember specific episodic events and learned skills. The military application is to improve rehabilitation and recovery for injured warfighters challenged by impaired memory.

The program is designed to develop “novel, rigorous computational methods to help investigators determine which brain components matter in memory formation and recall, and how much they matter.”

“Military personnel carry a growing responsibility to recount, report and act upon knowledge gleaned from previous experiences, and how well those experiences are recalled can make all the difference in how well these individuals perform in combat and other challenging situations,” said Justin Sanchez, PhD, DARPA program manager.

Memories are repeatedly reactivated, not fixed

Stored memories are not inert, Sanchez noted, and are subject to subtle forces over time. “The timeframe between a given experience and subsequent reporting or use of the memory can range from hours to months to years. During this time, physiological, environmental and behavioral factors can affect the process by which an individual’s representation of the experience is consolidated into memory, potentially affecting the accessibility and accuracy of the memory and one’s ability to make use of ‘lessons learned’ later on.”

Studies have suggested that memory representations in the brain are are not fixed; they are repeatedly “reactivated” (often unconsciously) following initial encoding, during both wakefulness and sleep. And memory reactivation has been linked to the process of neural replay, during which patterns of neural activity reflect the patterns of activity that had occurred during initial encoding of the memory. (See “Neurons constantly rewrite their DNA to store information.”)

Some human studies have investigated ways to improve memory recall by presenting sensory cues or transcranial stimulation during specific phases of sleep. KurzweilAI has covered a large number of such studies.

“In the long run, we hope RAM Replay will identify core memory-strengthening mechanisms and give rise to a generalizable set of solutions applicable to the challenge of memory reliability in an increasingly information-dense world,” said Sanchez. “That could benefit civilians and Service members alike in areas as diverse as general education, job retraining, and battlefield awareness.”