A timely glimpse of memories to come

Research in the last century has provided insight into the systems, cellular, and molecular processes involved in the formation, storage, recall, and update of memory engrams - the physical manifestation of the long sought-after philosophical and psychological concept of memory traces. Recent technologies allow scientists to visualize the key molecular players involved in segregating, ordering, and linking memories close in time, for future treatment of "disorders of the engram" where memory linking is deficient (e.g., cognitive aging or Alzheimer's) or excessive (e.g., PTSD).