Circuit locus of hippocampal attractor dynamics for pattern separation and completion

Ascertain whether the attractor dynamics supporting pattern completion and pattern separation in hippocampal memory retrieval are implemented by the recurrent hippocampal–entorhinal loop or occur entirely within the hippocampus, specifically with pattern separation in dentate gyrus and pattern completion in CA3.

Background

To support error-correcting retrieval, hippocampal keys are hypothesized to engage attractor dynamics that map noisy inputs to appropriate episodic memory states (pattern completion) while separating distinct episodes (pattern separation). Competing proposals place these dynamics in the recurrent hippocampal–entorhinal circuit or within specific hippocampal subfields (dentate gyrus and CA3).

Resolving the circuit-level origin of these dynamics would clarify how episodic indexing and retrieval are implemented and inform models connecting neurobiology to key–value memory architectures.

References

It remains to be seen if such attractor dynamics are implemented by the recurrent hippocampal-entorhinal loop \citep{chandra23} (Box 1) or by the proposal that both occur within hippocampus, with pattern separation by dentate gyrus and pattern completion by area CA3 \citep{rolls13}.

— Key-value memory in the brain (2501.02950 - Gershman et al., 6 Jan 2025) in Section: Evidence from psychology and neuroscience > Distinct representations of keys and values (final paragraph on attractor dynamics)