Integrating new memories into the hippocampal network activity space

By investigating the topology of neuronal co-activity, we found that mnemonic information spans multiple operational axes in the mouse hippocampus network. High-activity principal cells form the core of each memory along a first axis, segregating spatial contexts and novelty. Low-activity cells join co-activity motifs across behavioral events and enable their crosstalk along two other axes. This reveals an organizational principle for continuous integration and interaction of hippocampal memories. Gava et al. explore the organization of neuronal co-activity in hippocampus from a graph theoretical perspective to report how new associative memories integrate into the network and restructure the neural patterns representing prior memories.