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Nat Commun. 2018 Aug 29;9(1):3498. doi: 10.1038/s41467-018-05873-3.

Reconciling persistent and dynamic hypotheses of working memory coding in prefrontal cortex.

Author information

1
Sobell Department of Motor Neuroscience, University College London, London WC1N 3BG, UK. sean.cavanagh.12@ucl.ac.uk.
2
Sobell Department of Motor Neuroscience, University College London, London WC1N 3BG, UK.
3
Department of Psychology, University of California at Berkeley, Berkeley, CA 94720, United States.
4
Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, CA 94720, United States.
5
Max Planck-UCL Centre for Computational Psychiatry and Aging, University College London, London WC1B 5EH, UK.
6
Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford OX37JX, UK.
7
Sobell Department of Motor Neuroscience, University College London, London WC1N 3BG, UK. s.kennerley@ucl.ac.uk.
8
Department of Psychology, University of California at Berkeley, Berkeley, CA 94720, United States. s.kennerley@ucl.ac.uk.
9
Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, CA 94720, United States. s.kennerley@ucl.ac.uk.

Abstract

Competing accounts propose that working memory (WM) is subserved either by persistent activity in single neurons or by dynamic (time-varying) activity across a neural population. Here, we compare these hypotheses across four regions of prefrontal cortex (PFC) in an oculomotor-delayed-response task, where an intervening cue indicated the reward available for a correct saccade. WM representations were strongest in ventrolateral PFC neurons with higher intrinsic temporal stability (time-constant). At the population-level, although a stable mnemonic state was reached during the delay, this tuning geometry was reversed relative to cue-period selectivity, and was disrupted by the reward cue. Single-neuron analysis revealed many neurons switched to coding reward, rather than maintaining task-relevant spatial selectivity until saccade. These results imply WM is fulfilled by dynamic, population-level activity within high time-constant neurons. Rather than persistent activity supporting stable mnemonic representations that bridge subsequent salient stimuli, PFC neurons may stabilise a dynamic population-level process supporting WM.

PMID:
30158519
PMCID:
PMC6115433
DOI:
10.1038/s41467-018-05873-3
[Indexed for MEDLINE]
Free PMC Article

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