Article | Published:

Dynamic hidden states underlying working-memory-guided behavior

Nature Neuroscience volume 20, pages 864871 (2017) | Download Citation

Abstract

Recent theoretical models propose that working memory is mediated by rapid transitions in 'activity-silent' neural states (for example, short-term synaptic plasticity). According to the dynamic coding framework, such hidden state transitions flexibly configure memory networks for memory-guided behavior and dissolve them equally fast to allow forgetting. We developed a perturbation approach to measure mnemonic hidden states in an electroencephalogram. By 'pinging' the brain during maintenance, we show that memory-item-specific information is decodable from the impulse response, even in the absence of attention and lingering delay activity. Moreover, hidden memories are remarkably flexible: an instruction cue that directs people to forget one item is sufficient to wipe the corresponding trace from the hidden state. In contrast, temporarily unattended items remain robustly coded in the hidden state, decoupling attentional focus from cue-directed forgetting. Finally, the strength of hidden-state coding predicts the accuracy of working-memory-guided behavior, including memory precision.

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Acknowledgements

We thank E. Spaak, A. Cravo and N. Myers for comments and advice and all our volunteers for their participation. We also thank the Biotechnology & Biological Sciences Research Council (BB/M010732/1 to M.G.S.) and the National Institute for Health Research Oxford Biomedical Research Centre Programme based at the Oxford University Hospitals Trust, Oxford University. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health.

Author information

Affiliations

  1. Department of Experimental Psychology, University of Oxford, Oxford, UK.

    • Michael J Wolff
    • , Janina Jochim
    •  & Mark G Stokes
  2. Department of Experimental Psychology, University of Groningen, Groningen, the Netherlands.

    • Michael J Wolff
    •  & Elkan G Akyürek

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Contributions

M.J.W., M.G.S., and E.G.A. designed the study. M.J.W. and J.J. collected the data. M.J.W. analyzed the data. M.J.W., M.G.S., E.G.A., and J.J. wrote the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Mark G Stokes.

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    Supplementary Text and Figures

    Supplementary Figures 1–4

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    Supplementary Methods Checklist

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    Supplementary Software

    Custom matlab function “mahalTune_func.m” Custom matlab function used for all main analyses

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DOI

https://doi.org/10.1038/nn.4546

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