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Hippocampal awake replay in fear memory retrieval

Nature Neuroscience volume 20, pages 571580 (2017) | Download Citation

Abstract

Hippocampal place cells are key to episodic memories. How these cells participate in memory retrieval remains unclear. After rats acquired a fear memory by receiving mild footshocks in a shock zone on a track, we analyzed place cells when the animals were placed on the track again and displayed an apparent memory retrieval behavior: avoidance of the shock zone. We found that place cells representing the shock zone were reactivated, despite the fact that the animals did not enter the shock zone. This reactivation occurred in ripple-associated awake replay of place cell sequences encoding the paths from the animal's current positions to the shock zone but not in place cell sequences within individual cycles of theta oscillation. The result reveals a specific place-cell pattern underlying inhibitory avoidance behavior and provides strong evidence for the involvement of awake replay in fear memory retrieval.

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Acknowledgements

We thank all the members of the Ji lab for helpful discussions. This study was supported by grants from National Institutes of Health (R01MH106552) and Simons Foundation (#273886) to D.J.

Author information

Affiliations

  1. Neuroscience PhD Program, Baylor College of Medicine, Houston, Texas, USA.

    • Chun-Ting Wu
  2. Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA.

    • Chun-Ting Wu
    • , Daniel Haggerty
    •  & Daoyun Ji
  3. Department of Electrical and Computer Engineering, Rice University, Houston, Texas, USA.

    • Caleb Kemere
  4. Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA.

    • Daoyun Ji

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Contributions

D.J. and C.-T.W. conceived the project. D.J. and C.-T.W. designed the experiments. C.-T.W. performed the experiments and collected the data. C.-T.W., D.J. and C.K. analyzed the data. D.H. performed the histology. C.-T.W., D.J. and C.K. wrote the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Daoyun Ji.

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DOI

https://doi.org/10.1038/nn.4507

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