In newly published research, scientists identified two types of neurons in the medial temporal lobe, boundary (especially the beginning of a new memory) and event cells (the "title" of the event) that serve as a "filing system" for memories. This system apparently aids in mental time travel, or episodic memories, by helping us to specifically recall memories. Here is the new article: https://www.statnews.com/2022/03/07/newly-discovered-brain-cells-may-be-memory-filing-system-study-suggests/, and here is the research publication: https://www.nature.com/articles/s41593-022-01020-w.