When I first learned about place cells and grid cells, I felt a dopamine reward, believing that I understood something about brain structure and function. Finally, an unambiguous connection between neurons and behavior! Leutgeb’s talk and the papers related to cognitive maps made me realize that place cells and grid cells may be flexible, opportunistic, and more complicated than they seemed at first. They don’t represent a topographic map of the environment. Our efforts to reduce and simplify for the sake of understanding are in continuous negotiation with reality.
Here are some cool visualizations of grid cell activity:
http://www.scholarpedia.org/article/Grid_cells
Here are some good thoughts, even if you just read the abstract and the final paragraph:
http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1692339&blobtype=pdf
(O’Keefe, Burgess, Donnett, Jeffery, Maguire, 1998)