Time, Cells, and Memory

Memory for specific life experiences is characterized by recollection of the flow of events in time and space that compose specific episodes, and this ability depends on the hippocampus. For some time we have known about “place cells” in the hippocampus that may code the places where events within episodes occur. Here I will describe recent complementary evidence of “time cells” in the hippocampus that encode sequential moments in temporally structured experiences. Furthermore, ensembles of time cells represent the temporal organization of specific memories and predict memory success. In addition, we have traced the origin of timing signals to a cortical area that also carries signals about space to the hippocampus. Taken together, these findings support of an emerging view that the hippocampal system serves memory by mapping the organization of events within their temporal and spatial context.