Brain Structure and Function

, Volume 224, Issue 2, pp 883–890 | Cite as

A neuronal population code for resemblance between drug and nondrug reward outcomes in the orbitofrontal cortex

  • Karine GuillemEmail author
  • Serge H. AhmedEmail author
Original Article


The orbitofrontal cortex (OFC) is implicated in choice and decision-making in both human and non-human animals. We previously identified in the rat OFC a mechanism that influences individual drug choices and preferences between a drug and a nondrug (i.e., sweet) outcome that is common across different types of drugs (cocaine and heroin). Importantly, this research also revealed some intriguing drug-specific differences. Notably, the size of non-selective OFC neurons that indiscriminately encode both the drug and the sweet outcomes varies as a function of the drug outcome available (cocaine or heroin). Here we tested the hypothesis that the relative size of the non-selective OFC population somehow represents the degree of resemblance between the drug and nondrug reward outcomes. We recorded OFC neuronal activity in vivo in the same individual rats while they were choosing between two outcomes with varying degrees of resemblance: high (two concentrations of sweet), intermediate (sweet versus heroin) and low (sweet versus cocaine). We found that the percentage of non-selective OFC neurons dramatically increased with the degree of resemblance between choice outcomes, from 26 to 62%. Overall, these findings reveal the existence of a neuronal population code for resemblance between different kinds of choice outcomes in the OFC.


Choice Preference Orbitofrontal cortex Outcome resemblance Cocaine Heroin 



We thank Christophe Bernard, Eric Wattelet, Audrey Durand and Caroline Vouillac-Mendoza for administrative and technical assistance. We also thank Etienne Gontier from the Bordeaux Imaging Center (BIC) for giving us access to his laboratory facility for brain perfusion.


This work was supported by the French Research Council (CNRS), the Université de Bordeaux, and the Fondation pour la Recherche Médicale (FRM DPA20140629788).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

All experiments were carried out in accordance with standard ethical guidelines (European Communities Council Directive 86/609/EEC) and approved by the committee on Animal Health and Care of Institut National de la Santé et de la Recherche (agreement A5012052).


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Institut des Maladies Neurodégénératives, UMR 5293, Université de BordeauxBordeauxFrance
  2. 2.Institut des Maladies Neurodégénératives, UMR 5293, CNRSBordeauxFrance
  3. 3.Institut des Maladies Neurodégénératives, UMR CNRS 5293, Université de BordeauxBordeauxFrance

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