RT Journal Article SR Electronic T1 A Locus Coeruleus- dorsal CA1 dopaminergic circuit modulates memory linking JF bioRxiv FD Cold Spring Harbor Laboratory SP 2021.10.27.466138 DO 10.1101/2021.10.27.466138 A1 Ananya Chowdhury A1 Alessandro Luchetti A1 Giselle Fernandes A1 Daniel Almeida Filho A1 George Kastellakis A1 Alexandra Tzilivaki A1 Erica M Ramirez A1 Mary Y Tran A1 Panayiota Poirazi A1 Alcino J Silva YR 2021 UL http://biorxiv.org/content/early/2021/10/28/2021.10.27.466138.abstract AB Individual memories are often linked so that the recall of one triggers the recall of another. For example, contextual memories acquired close in time can be linked, and this is known to depend on temporary increase in excitability that drive the overlap between dorsal CA1 (dCA1) hippocampal ensembles encoding the linked memories. Here, we show that the Locus Coeruleus (LC) cells projecting to dCA1 have a key permissive role in contextual memory linking, without affecting contextual memory formation, and that this effect is mediated by dopamine and not by noradrenaline. Additionally, we found that LC to dCA1 projecting neurons modulate the excitability of dCA1 neurons, and the extent of overlap between dCA1 memory ensembles, as well as the stability of coactivity patterns within these ensembles. This discovery of a neuromodulatory system that specifically affects memory linking without affecting memory formation, reveals a fundamental separation between the brain mechanisms that modulate these two distinct processes.Competing Interest StatementThe authors have declared no competing interest.