[FHorse]

One can also think of the hippocampus simply as a working memory - short term content addressable memory. If the rat happens to be working on a spatial task, like in a maze, you get place/grid cells. If it happens to be working on a timing task, time cells. The content is simply task dependent.

[sawwit]

Yes, the HC likely plays a role in working memory for associative, declarative and spatial information. Most of the working memory is believed to reside in the (prefrontal) cortex, though; in patterns of synaptic depletion (less than 15-30 seconds) and based on the 'hot potato' principle in which processes in different modules mutually re-activate previous states to manipulate them.