The silent mPFC engram cells gradually mature into active engram cells (activatable by natural recall cues) during the weeks after learning and this maturation process requires post-training input from the hippocampal engram cells. Thus, we propose that SCM occurs in two major steps: the rapid generation of a silent engram in the mPFC during learning and the slow functional maturation of these engrams aided by input from hippocampal engram cells during the post-training period lasting a few weeks in rodents.