1. Computational and Systems Biology
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Fundamental bound on the persistence and capacity of short-term memory stored as graded persistent activity

  1. Onur Ozan Koyluoglu  Is a corresponding author
  2. Yoni Pertzov
  3. Sanjay Manohar
  4. Masud Husain
  5. Ila R Fiete
  1. University of California, United States
  2. Hebrew University of Jerusalem, Israel
  3. University of Oxford, United Kingdom
  4. The University of Texas at Austin, United States
Research Article
  • Cited 7
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Cite this article as: eLife 2017;6:e22225 doi: 10.7554/eLife.22225


It is widely believed that persistent neural activity underlies short-term memory. Yet, as we show, temporal degradation in such networks behaves differently from human short-term memory performance. We build a more general framework where the memory is viewed as a problem of passing information through noisy channels that represent analog persistent activity networks. Rather than directly storing information, such memory networks might hold information encoded to achieve robustness against noise. We derive a fundamental lower-bound on memory recall precision, which declines with storage duration and number of stored items. We show that human performance, though inconsistent with models involving direct (uncoded) storage in persistent activity networks, can be well-fit by the theoretical bound. This finding is consistent with the view that if the brain stores information in patterns of persistent activity, it might use codes that minimize the effects of noise, motivating the search for such codes in the brain.

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Author details

  1. Onur Ozan Koyluoglu

    Department of Electrical and Computer Science, University of California, Berkeley, United States
    For correspondence
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-8512-4755
  2. Yoni Pertzov

    Department of Psychology, Hebrew University of Jerusalem, Jerusalem, Israel
    Competing interests
    The authors declare that no competing interests exist.
  3. Sanjay Manohar

    Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-0735-4349
  4. Masud Husain

    Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  5. Ila R Fiete

    Center for Learning and Memory, The University of Texas at Austin, Austin, United States
    Competing interests
    The authors declare that no competing interests exist.


National Science Foundation (IIS-1464349)

  • Onur Ozan Koyluoglu

Israeli Science Foundation (1747/14)

  • Yoni Pertzov

National Institute for Health Research (Oxford Biomedical Centre)

  • Masud Husain

Wellcome Trust

  • Masud Husain

National Science Foundation (IIS-1148973)

  • Ila R Fiete

Simons Foundation

  • Ila R Fiete

Howard Hughes Medical Institute (Faculty Scholar Award)

  • Ila R Fiete

MRC Clinician Scientist Fellowship (MR/P00878X)

  • Sanjay Manohar

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


Human subjects: The study reported here conform to the Declaration of Helsinki and all procedures were approved by the ethics committee of the National Hospital for Neurology and Neurosurgery (NHNN) prior to the study commencing. Research Ethics Committee number (ERC) 04/Q0406/60. Personal information about individuals was password protected and saved in compliance to the Data Protection Act 1998 (DPA).

Reviewing Editor

  1. Lila Davachi, New York University, United States

Publication history

  1. Received: October 8, 2016
  2. Accepted: August 25, 2017
  3. Accepted Manuscript published: September 7, 2017 (version 1)
  4. Version of Record published: September 20, 2017 (version 2)


© 2017, Koyluoglu 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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