Attractor Dynamics in the Hippocampal Representation of the Local Environment

TLDR

Memories are hypothesized to be attractor states in the hippocampus, yet direct evidence is lacking because place cell representations have previously shown continuous, shape‑dependent responses. Exposure to novel square and circular environments induces abrupt, simultaneous switching of place cell representations, demonstrating attractor dynamics that may underlie distinct contextual memory formation.

Abstract

Memories are thought to be attractor states of neuronal representations, with the hippocampus a likely substrate for context-dependent episodic memories. However, such states have not been directly observed. For example, the hippocampal place cell representation of location was previously found to respond continuously to changes in environmental shape alone. We report that exposure to novel square and circular environments made of different materials creates attractor representations for both shapes: Place cells abruptly and simultaneously switch between representations as environmental shape changes incrementally. This enables study of attractor dynamics in a cognitive representation and may correspond to the formation of distinct contexts in context-dependent memory.