Serotonergic neurons signal reward and punishment on multiple timescales

  1. Jeremiah Y Cohen  Is a corresponding author
  2. Mackenzie W Amoroso
  3. Naoshige Uchida
  1. Harvard University, United States

Abstract

Serotonin's function in the brain is unclear. One challenge in testing the numerous hypotheses about serotonin's function has been observing the activity of identified serotonergic neurons in animals engaged in behavioral tasks. We recorded the activity of dorsal raphe neurons while mice experienced a task in which rewards and punishments varied across blocks of trials. We 'tagged' serotonergic neurons with the light-sensitive protein channelrhodopsin-2 and identified them based on their responses to light. We found three main features of serotonergic neuron activity: (1) a large fraction of serotonergic neurons modulated their tonic firing rates over the course of minutes during reward versus punishment blocks; (2) most were phasically excited by punishments; and (3) a subset was phasically excited by reward-predicting cues. By contrast, dopaminergic neurons did not show firing rate changes across blocks of trials. These results suggest that serotonergic neurons signal information about reward and punishment on multiple timescales.

Article and author information

Author details

  1. Jeremiah Y Cohen

    Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, Cambridge, United States
    For correspondence
    jeremiah.cohen@jhmi.edu
    Competing interests
    The authors declare that no competing interests exist.
  2. Mackenzie W Amoroso

    Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, Cambridge, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Naoshige Uchida

    Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, Cambridge, United States
    Competing interests
    The authors declare that no competing interests exist.

Ethics

Animal experimentation: All surgical and experimental procedures were in accordance with the National Institutes of Health Guide for the Care and Use of Laboratory Animals and approved by the Harvard or Johns Hopkins Institutional Animal Care and Use Committees.

Reviewing Editor

  1. Timothy Behrens, Oxford University, United Kingdom

Publication history

  1. Received: January 6, 2015
  2. Accepted: February 24, 2015
  3. Accepted Manuscript published: February 25, 2015 (version 1)
  4. Version of Record published: April 8, 2015 (version 2)

Copyright

© 2015, Cohen 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. Jeremiah Y Cohen
  2. Mackenzie W Amoroso
  3. Naoshige Uchida
(2015)
Serotonergic neurons signal reward and punishment on multiple timescales
eLife 4:e06346.
https://doi.org/10.7554/eLife.06346

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