Hippocampal sharp wave-ripples and the associated sequence replay emerge from structured synaptic interactions in a network model of area CA3
- Institute of Experimental Medicine, Hungary
- Alfréd Rényi Institute of Mathematics, Hungary
Abstract
Hippocampal place cells are activated sequentially as an animal explores its environment. These activity sequences are internally recreated ('replayed'), either in the same or reversed order, during bursts of activity (sharp wave-ripples; SWRs) that occur in sleep and awake rest. SWR-associated replay is thought to be critical for the creation and maintenance of long-term memory. In order to identify the cellular and network mechanisms of SWRs and replay, we constructed and simulated a data-driven model of area CA3 of the hippocampus. Our results show that the chain-like structure of recurrent excitatory interactions established during learning not only determines the content of replay, but is essential for the generation of the SWRs as well. We find that bidirectional replay requires the interplay of the experimentally confirmed, temporally symmetric plasticity rule, and cellular adaptation. Our model provides a unifying framework for diverse phenomena involving hippocampal plasticity, representations, and dynamics, and suggests that the structured neural codes induced by learning may have greater influence over cortical network states than previously appreciated.
Data availability
The source code to build, run and analyze our model is publicly available on GitHub: https://github.com/KaliLab/ca3net
Article and author information
Author details
Funding
Hungarian Scientific Research Fund (K83251)
- Maria Rita Karlocai
- Attila I Gulyás
- Szabolcs Káli
Hungarian Scientific Research Fund (K85659)
- Orsolya Steinbach-Németh
- Norbert Hájos
Hungarian Scientific Research Fund (K115441)
- Attila I Gulyás
- Szabolcs Káli
Hungarian Brain Research Program (2017-1.2.1-NKP-2017-00002)
- Norbert Hájos
European Commission (ERC 2011 ADG 294313)
- Tamás Freund
- Attila I Gulyás
- Szabolcs Káli
European Commission (FP7 no. 604102,H2020 no. 720270,no. 785907 (Human Brain Project))
- Tamás Freund
- Attila I Gulyás
- Szabolcs Káli
Hungarian Ministry of Innovation and Technology NRDI Office (Artificial Intelligence National Laboratory)
- Szabolcs Káli
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: Experiments were approved by the Committee for the Scientific Ethics of Animal Research (22.1/4027/003/2009) and were performed according to the guidelines of the institutional ethical code and the Hungarian Act of Animal Care and Experimentation. Experiments were performed in acute brain slices; no animal suffering was involved as mice were deeply anaesthetized with isoflurane and decapitated before slice preparation. Data recorded in the context of other studies were used for model fitting, and therefore no additional animals were used for the purpose of this study.
Copyright
© 2022, Ecker et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Hippocampal sharp wave-ripples and the associated sequence replay emerge from structured synaptic interactions in a network model of area CA3
eLife 11:e71850.
https://doi.org/10.7554/eLife.71850
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