Place field dissociation and multiple maps in hippocampus

When two sets of visual cues move in discordant fashion, the firing fields of hippocampal place cells can dissociate (follow different sets), split (follow both sets), or remap. This conflicts with views of hippocampus as an associative memory that “completes” patterns given a noisy input. We reconcile these views by treating hippocampus as a collection of independent “maplets”. Normally these act in unison, but under the right conditions they can exhibit discordant behavior. The model also accounts for “barrier cells” [B. Rivard, Y. Li, P.-P. Lenck-Santini, B. Poucet, R.U. Muller, Representation of objects in space by two classes of hippocampal place cells, J. Gen. Physiol. 124 (2004) 9–25], and the occasional temporary cessation of firing of some place cells while others remain active.