Rodents' episodic-like memory: concepts, ageing, neurodegeneration, future

Area of Science:

• Neuroscience
• Cognitive Science
• Animal Behavior

Background:

• Episodic memory (EM), the recollection of event details (what, where, when), was historically considered uniquely human.
• Episodic-like memory (ELM) studies in animals use behavioral criteria to investigate memory processes.
• Rodent models offer mechanistic insights into neural circuits and molecular pathways of memory.

Purpose of the Study:

• To review conceptual and methodological advances in episodic-like memory (ELM) research.
• To highlight the role of hippocampal-prefrontal networks in integrating memory dimensions.
• To discuss cellular and synaptic mechanisms underlying memory linking and consolidation.

Main Methods:

• Review of conceptual advances and methodological challenges in ELM research.
• Focus on rodent models for mechanistic insights into neural circuits and molecular pathways.
• Analysis of data on cellular/synaptic mechanisms (tagging-and-capture, ensemble allocation, reactivation) in fear-based ELM.

Main Results:

• Ageing impairs novelty-dependent neuronal ensemble recruitment in the dorsal CA1, affecting memory persistence.
• Cholinergic hypofunction models (relevant to Alzheimer's disease) show severe deficits in object, spatial, and integrated ELM.
• Pharmacological interventions partially reversed memory impairments in cholinergic hypofunction models.

Conclusions:

• ELM paradigms are translationally relevant for modeling age-related memory decline and neurodegeneration.
• ELM research provides tools for studying memory dynamics and informing therapeutic strategies.
• Open questions remain regarding neuromodulation, sex differences, and the aging-Alzheimer's boundary.