Odor identity coding by distributed ensembles of neurons in the mouse olfactory cortex

  1. Benjamin Roland
  2. Thomas Deneux
  3. Kevin M Franks
  4. Brice Bathellier  Is a corresponding author
  5. Alexander Fleischmann  Is a corresponding author
  1. Collège de France, France
  2. Centre National de la Recherche Scientifique, UPR 3293, France
  3. Duke University, United States
  4. Centre National de la Recherche Scientifique, France

Abstract

Olfactory perception and behaviors critically depend on the ability to identify an odor across a wide range of concentrations. Here, we use calcium imaging to determine how odor identity is encoded in olfactory cortex. We find that, despite considerable trial-to-trial variability, odor identity can accurately be decoded from ensembles of co-active neurons that are distributed across piriform cortex without any apparent spatial organization. However, piriform response patterns change substantially over a 100-fold change in odor concentration, apparently degrading the population representation of odor identity. We show that this problem can be resolved by decoding odor identity from a subpopulation of concentration-invariant piriform neurons. These concentration-invariant neurons are overrepresented in piriform cortex but not in olfactory bulb mitral and tufted cells. We therefore propose that distinct perceptual features of odors are encoded in independent subnetworks of neurons in the olfactory cortex.

Article and author information

Author details

  1. Benjamin Roland

    Center for Interdisciplinary Research in Biology, Collège de France, Paris, France
    Competing interests
    The authors declare that no competing interests exist.
  2. Thomas Deneux

    Unité de Neuroscience, Information et Complexité, Centre National de la Recherche Scientifique, UPR 3293, Gif-sur-Yvette, France
    Competing interests
    The authors declare that no competing interests exist.
  3. Kevin M Franks

    Department of Neurobiology, Duke University, Durham, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-6386-9518
  4. Brice Bathellier

    Unité de Neuroscience, Information et Complexité, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France
    For correspondence
    bathellier@unic.cnrs-gif.fr
    Competing interests
    The authors declare that no competing interests exist.
  5. Alexander Fleischmann

    Center for Interdisciplinary Research in Biology, Collège de France, Paris, France
    For correspondence
    alexander.fleischmann@college-de-france.fr
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-7956-9096

Funding

Marie Curie International Reintegration Grant (IRG 276869)

  • Alexander Fleischmann

Fondation pour la Recherche Médicale (AJE201106)

  • Alexander Fleischmann

European Molecular Biology Organization (ASTF 395 - 2014)

  • Benjamin Roland

LabEx Memolife

  • Benjamin Roland

National Institute on Deafness and Other Communication Disorders (DC009839 and DC015525)

  • Kevin M Franks

Agence Nationale de la Recherche (SENSEMAKER)

  • Brice Bathellier

Human Frontier Science Program (CDA-0064-2015)

  • Brice Bathellier

Marie Curie Program (CIG 334581)

  • Brice Bathellier

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

Ethics

Animal experimentation: This study was performed in strict accordance with French National and INSERM animal care and use committee guidelines (#B750512/00615.02). All surgery was performed under ketamine/xylazine anesthesia.

Copyright

© 2017, Roland 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.

Metrics

  • 1,134
    downloads
  • 125
    citations

Views, downloads and citations are aggregated across all versions of this paper published by eLife.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Open citations (links to open the citations from this article in various online reference manager services)

Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)

  1. Benjamin Roland
  2. Thomas Deneux
  3. Kevin M Franks
  4. Brice Bathellier
  5. Alexander Fleischmann
(2017)
Odor identity coding by distributed ensembles of neurons in the mouse olfactory cortex
eLife 6:e26337.
https://doi.org/10.7554/eLife.26337

Share this article

https://doi.org/10.7554/eLife.26337

Further reading

    1. Neuroscience
    Jakob Rupert, Dragomir Milovanovic
    Insight

    By influencing calcium homeostasis, local protein synthesis and the endoplasmic reticulum, a small protein called Rab10 emerges as a crucial cytoplasmic regulator of neuropeptide secretion.

    1. Neuroscience
    Jian Dong, Mian Chen ... Matthijs Verhage
    Research Article

    Dense core vesicles (DCVs) transport and release various neuropeptides and neurotrophins that control diverse brain functions, but the DCV secretory pathway remains poorly understood. Here, we tested a prediction emerging from invertebrate studies about the crucial role of the intracellular trafficking GTPase Rab10, by assessing DCV exocytosis at single-cell resolution upon acute Rab10 depletion in mature mouse hippocampal neurons, to circumvent potential confounding effects of Rab10’s established role in neurite outgrowth. We observed a significant inhibition of DCV exocytosis in Rab10-depleted neurons, whereas synaptic vesicle exocytosis was unaffected. However, rather than a direct involvement in DCV trafficking, this effect was attributed to two ER-dependent processes, ER-regulated intracellular Ca2+ dynamics, and protein synthesis. Gene Ontology analysis of differentially expressed proteins upon Rab10 depletion identified substantial alterations in synaptic and ER/ribosomal proteins, including the Ca2+ pump SERCA2. In addition, ER morphology and dynamics were altered, ER Ca2+ levels were depleted, and Ca2+ homeostasis was impaired in Rab10-depleted neurons. However, Ca2+ entry using a Ca2+ ionophore still triggered less DCV exocytosis. Instead, leucine supplementation, which enhances protein synthesis, largely rescued DCV exocytosis deficiency. We conclude that Rab10 is required for neuropeptide release by maintaining Ca2+ dynamics and regulating protein synthesis. Furthermore, DCV exocytosis appeared more dependent on (acute) protein synthesis than synaptic vesicle exocytosis.