How memories are encoded in human hippocampal neurons?
The hippocampus plays a crucial role in episodic memory, with ongoing debate on how this is implemented at the level of single neurons.
Concept neurons encoding specific elements (e.g., a specific person) and index neurons that encode the conjunction of elements within an entire episode represent two primary theories in hippocampal coding.
Here, the researchers reconcile these two frameworks by leveraging the discovery made in engram research that neurons are allocated to a memory trace based on excitability.
Based on this premise, the authors argue that, through the successive consolidation of episodes that share common elements, a subset of index neurons allocated to all these episodes would evolve into concept neurons tuned to this common element.
They suggest a focus on shared computational principles over the identification of discrete neural labels, as this approach allows a more productive discourse between researchers studying different species.
https://www.cell.com/trends/cognitive-sciences/fulltext/S1364-6613(25)00031-2
