Effects of dopamine on reinforcement learning and consolidation in Parkinson’s disease

  1. John P Grogan  Is a corresponding author
  2. Demitra Tsivos
  3. Laura Smith
  4. Brogan E Knight
  5. Rafal Bogacz
  6. Alan Whone
  7. Elizabeth J Coulthard  Is a corresponding author
  1. University of Bristol, United Kingdom
  2. North Bristol NHS Trust, United Kingdom
  3. University of Oxford, United Kingdom

Abstract

Emerging evidence suggests that dopamine may modulate learning and memory with important implications for understanding the neurobiology of memory and future therapeutic targeting. An influential hypothesis posits that dopamine biases reinforcement learning. More recent data also suggest an influence during both consolidation and retrieval. Eighteen Parkinson’s disease patients learned through feedback ON or OFF medication with memory tested 24 hours later ON or OFF medication (4 conditions, within-subjects design with matched healthy control group). Patients OFF medication during learning decreased in memory accuracy over the following 24 hours. In contrast to previous studies, however, dopaminergic medication during learning and testing did not affect expression of positive or negative reinforcement. Two further experiments were run without the 24-hour delay, but they too failed to reproduce effects of dopaminergic medication on reinforcement learning. While supportive of a dopaminergic role in consolidation, this study failed to replicate previous findings on reinforcement learning.

Article and author information

Author details

  1. John P Grogan

    Institute of Clinical Neurosciences, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
    For correspondence
    john.grogan@bristol.ac.uk
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-0463-8904
  2. Demitra Tsivos

    Clinical Neurosciences, North Bristol NHS Trust, Bristol, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  3. Laura Smith

    Institute of Clinical Neurosciences, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  4. Brogan E Knight

    Clinical Neurosciences, North Bristol NHS Trust, Bristol, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  5. Rafal Bogacz

    Medical Research Council Brain Network Dynamics Unit, University of Oxford, Oxford, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  6. Alan Whone

    Institute of Clinical Neurosciences, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  7. Elizabeth J Coulthard

    Institute of Clinical Neurosciences, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
    For correspondence
    elizabeth.coulthard@bristol.ac.uk
    Competing interests
    The authors declare that no competing interests exist.

Funding

Wellcome (PhD Studentshipt SJ1102)

  • John P Grogan

BRACE (Project grant)

  • John P Grogan
  • Elizabeth J Coulthard

Medical Research Council (MC UU 12024/5)

  • Rafal Bogacz

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

Reviewing Editor

  1. Joshua I Gold, University of Pennsylvania, United States

Ethics

Human subjects: Ethical approval was obtained from the NHS Research Ethics Committee at Frenchay, Bristol (09/H0107/18). All participants gave written consent, in accordance with the Declaration of Helsinki.

Version history

  1. Received: March 14, 2017
  2. Accepted: July 7, 2017
  3. Accepted Manuscript published: July 10, 2017 (version 1)
  4. Version of Record published: July 27, 2017 (version 2)

Copyright

© 2017, Grogan 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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  1. John P Grogan
  2. Demitra Tsivos
  3. Laura Smith
  4. Brogan E Knight
  5. Rafal Bogacz
  6. Alan Whone
  7. Elizabeth J Coulthard
(2017)
Effects of dopamine on reinforcement learning and consolidation in Parkinson’s disease
eLife 6:e26801.
https://doi.org/10.7554/eLife.26801

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https://doi.org/10.7554/eLife.26801

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