Also related, but not yet confirmed: "Time cells", which are also located in the hippocampus: http://www.nature.com/nrn/journal/v15/n11/abs/nrn3827.html

One can possibly think of the hippocampus as a 'space-time integrator' that continuously indices high-level activation patterns from the cortex and stores them much like a log book. Memories in the hippocampus last minutes to months, after which they are either transferred to long-term memory in the cortex or lost.