Distinct brain networks for remote episodic memory depending on content and emotional experience
Progress in Neurobiology. 2023-04-01; 223: 102422
DOI: 10.1016/j.pneurobio.2023.102422
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Auguste A(1), Fourcaud-Trocmé N(1), Meunier D(2), Gros A(1), Garcia S(1),
Messaoudi B(1), Thevenet M(1), Ravel N(1), Veyrac A(3).
Author information:
(1)UMR 5292 CNRS, INSERM U1028, University Lyon1, Olfaction: From coding to
Memory Team, Lyon Neuroscience Research Center, F-69366 Lyon, France.
(2)University Aix Marseille, Insitut des Neurosciences de la Timone, Marseille,
France.
(3)UMR 5292 CNRS, INSERM U1028, University Lyon1, Olfaction: From coding to
Memory Team, Lyon Neuroscience Research Center, F-69366 Lyon, France. Electronic
address: .
Memories of life episodes are the heart of individual stories. However,
modelling episodic memory is a major challenge in both humans and animals when
considering all its characteristics. As a consequence, the mechanisms that
underlie the storage of old nontraumatic episodic memories remain enigmatic.
Here, using a new task in rodents that models human episodic memory including
odour/place/context components and applying advances behavioural and
computational analyses, we show that rats form and recollect integrated remote
episodic memories of two occasionally encountered complex episodes occurring in
their daily life. Similar to humans, the information content and accuracy of
memories vary across individuals and depend on the emotional relationship with
odours experienced during the very first episode. We used cellular brain imaging
and functional connectivity analyses, to find out the engrams of remote episodic
memories for the first time. Activated brain networks completely reflect the
nature and content of episodic memories, with a larger cortico-hippocampal
network when the recollection is complete and with an emotional brain network
related to odours that is critical in maintaining accurate and vivid memories.
The engrams of remote episodic memories remain highly dynamic since synaptic
plasticity processes occur during recall related to memory updates and
reinforcement.
Copyright © 2023 Elsevier Ltd. All rights reserved.
DOI: 10.1016/j.pneurobio.2023.102422
PMID: 36796748 [Indexed for MEDLINE]
Conflict of interest statement: Declaration of interests The authors declare no
competing interests.