Work

Hippocampal ripple diversity organizes neuronal reactivation dynamics in the offline brain

Year: 2025

Type: article

Abstract: Hippocampal ripples are highly synchronized neuronal population patterns reactivating past waking experiences in the offline brain. Whether the level, structure, and content of ripple-nested activity are consistent across consecutive events or are tuned in each event remains unclear. By profiling individual ripples using laminar currents in the mouse hippocampus during sleep/rest, we identified ripples in stratum pyramidale that feature current sinks in stratum radiatum (Rad sink ) versus stratum lacunosum-moleculare (LM sink ). These two ripple profiles recruit neurons differently. Rad sink ripples integrate recent motifs of waking coactivity, combining superficial and deep CA1 principal cells into denser, higher-dimensional patterns that undergo hour-long stable reactivation. By contrast, LM sink ripples contain core motifs of prior coactivity, engaging deep cells in sparser, lower-dimensional patterns that undergo a reactivation drift to gradually update their pre-existing content for recent wakefulness. We propose that ripple-by-ripple diversity supports parallel reactivation channels for integrating recent wakefulness while updating prior representations.

Source: Neuron

DOI: 10.1016/j.neuron.2025.09.012

Authors: Manfredi Castelli, Vítor Lopes-dos-Santos, Giuseppe P. Gava, Renaud Lambiotte, David Dupret

Institutions: University of Oxford, MRC Brain Network Dynamics Unit

Language: English

Topic: Memory and Neural Mechanisms

Subfield: Cognitive Neuroscience

Field: Neuroscience

Domain: Life Sciences

Open Access status: hybrid

Estimated APC paid: $10,400

Funders: Medical Research Council, Engineering and Physical Sciences Research Council