I've been quite recently visiting a friend of us at the university. He is doing a lot of research on brains over there. So I have seen a rat with a brain transplant in RL

.
Appearantly, they have made a small breakthrough over there by graphing the position of the rat where a brain cell activates, leading to this:

A really nice pattern with clear hexagons where the brain cells mostly activate. Although they had a poster there which showed one that was a far better one than this, but you get the idea.
See also:
http://en.wikipedia.org/wiki/Grid_cell
Generally really interesting stuff!