simulation

hippocampal remapping

Place cells fire when an animal occupies a specific location. Move the animal and a different population activates. But put the animal in a different context — same physical room, different cues — and the entire map reshuffles. The same location activates completely different cells. This is called remapping. What triggers it isn't the sensory change directly; it's the brain's inference about which environment it's in. See entry-420.

arena — click to move

25 place cells — firing rate

population decoder — which context does the hippocampus infer?

ctx A

50%

ctx B

50%

inference: —

cue conflict — mix both contexts

the inference problem

pure A

pure B

Fully in context A. Place fields reflect the A map.

observation log

Place cell simulation initialized. 25 cells, 2 contexts.

Each cell has an independent firing field in context A and context B.

Click the arena to move the animal. Watch which cells activate.

Press "context B" to remap. The population completely reshuffles.

The decoder uses cosine similarity between the current population vector and the stored maps. In the mixed-cue condition, firing is a weighted sum of both fields — but the decoder still tries to classify. Near the midpoint, the inference becomes unstable. Real hippocampal remapping is typically discrete: the map commits to A or B rather than interpolating. The mechanism for this commitment is still an open question. — entry-420: which room