Events

In humans, hippocampal function is generally recognized as supporting episodic memory, whereas in rats, many believe that the hippocampus creates maps of the environment and supports spatial navigation. How do we reconcile the episodic memory and spatial mapping views of hippocampal function? Here I will discuss evidence that, during learning of what happens where, hippocampal place cells map the locations of events in their spatial context. In addition, I will describe recent findings that, during learning of what happens when in spatial and non-spatial sequences, hippocampal neurons encode specific moments in the course of temporally extended experiences ("time cells", as contrasted with "place cells") and map specific events within their temporal context. These findings support an emerging view that the hippocampus supports episodic memory by creating a "scaffolding" for the organization of events within their spatial and temporal context.