1. Neuroscience
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Behavioral evidence for memory replay of video episodes in the macaque

  1. Shuzhen Zuo
  2. Lei Wang
  3. Jung Han Shin
  4. Yudian Cai
  5. Sang Wan Lee
  6. Kofi Appiah
  7. Yong-di Zhou
  8. Sze Chai Kwok  Is a corresponding author
  1. East China Normal University, China
  2. Korea Advanced Institute of Science and Technology, Republic of Korea
  3. University of York, United Kingdom
  4. Shenzhen University, China
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Cite this article as: eLife 2020;9:e54519 doi: 10.7554/eLife.54519

Abstract

Humans recall the past by replaying fragments of events temporally. Here, we demonstrate a similar effect in macaques. We trained six rhesus monkeys with a temporal-order judgement (TOJ) task and collected 5000 TOJ trials. In each trial, they watched a naturalistic video of about 10 s comprising two across-context clips, and after a 2-s delay, performed TOJ between two frames from the video. The data is suggestive of a non-linear, time-compressed forward memory replay mechanism in the macaque. In contrast with humans, such compression of replay is however not sophisticated enough to allow them to skip over irrelevant information by compressing the encoded video globally. We also reveal that the monkeys detect event contextual boundaries and such detection facilitates recall by an increased rate of information accumulation. Demonstration of a time-compressed, forward replay-like pattern in the macaque provides insights into the evolution of episodic memory in our lineage.

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Author details

  1. Shuzhen Zuo

    School of Psychology and Cognitive Science, East China Normal University, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-8917-8352
  2. Lei Wang

    School of Psychology and Cognitive Science, East China Normal University, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-6224-6474
  3. Jung Han Shin

    Program of Brain and Cognitive Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
    Competing interests
    The authors declare that no competing interests exist.
  4. Yudian Cai

    School of Psychology and Cognitive Science, East China Normal University, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  5. Sang Wan Lee

    Department of Bio and Brain Engineering & KAIST Institute for Health Science and Technology, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-6266-9613
  6. Kofi Appiah

    Computer Science, University of York, York, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  7. Yong-di Zhou

    School of Psychology, Shenzhen University, Shenzhen, China
    Competing interests
    The authors declare that no competing interests exist.
  8. Sze Chai Kwok

    School of Psychology and Cognitive Science, East China Normal University, Shanghai, China
    For correspondence
    sze-chai.kwok@st-hughs.oxon.org
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-7439-1193

Funding

National Key Fundamental Research Program of China Grant (2013CB329501)

  • Yong-di Zhou

Ministry of Education of PRC Humanities and Social Sciences Research Grant (16YJC190006)

  • Sze Chai Kwok

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Ethics

Animal experimentation: The experimental protocol was approved by the Institutional Animal Care and Use Committee (permission code: M020150902 & M020150902-2018) at East China Normal University. All experimental protocols and animal welfare adhered with the "NIH Guidelines for the Care and Use of Laboratory Animals".

Human subjects: The experimental protocol was approved by the the University Committee on Human Research Protection (permission code: HR 023-2017) at East China Normal University. . The participants provided informed consent.

Reviewing Editor

  1. Morgan Barense, University of Toronto, Canada

Publication history

  1. Received: December 17, 2019
  2. Accepted: April 20, 2020
  3. Accepted Manuscript published: April 20, 2020 (version 1)
  4. Version of Record published: May 18, 2020 (version 2)

Copyright

© 2020, Zuo 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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