Primate memory, from simple associations to abstract concepts

The hippocampus is a neural structure central to the formation of memories and wayfinding. To understand the neural mechanisms at work during memory formation over multiple episodes, Electrophysiological recordings show that neurons in the macaque hippocampus encode complex conjunctions of traits relevant to the navigational task during virtual navigation. While a majority encode environment-specific cues, about one third exhibit correlated firing across different environments sharing the same spatial structure. The similarity of firing appeared to encode the logic of the task in a way akin to a schema. The existence of the schema cells offers a foundation for abstraction in the monkey and suggests that memory storage in the primate could proceed in a similar way from simple cue associations up to conceptual thinking.