Research report The medial orbitofrontal cortex encodes a general unsigned value signal during anticipation of both appetitive and aversive events Elise Metereau and Jean-Claude Dreher * Neuroeconomics Laboratory: Reward and Decision Making, Cognitive Neuroscience Center, Unit e Mixte de Recherche 5229, Centre National pour la Recherche Scientifique (CNRS), Bron, France article info Article history: Received 29 January 2014 Reviewed 24 March 2014 Revised 27 May 2014 Accepted 5 August 2014 Action editor Sarah MacPherson Published online 28 August 2014 Keywords: Appetitive conditioning Aversive conditioning fMRI Orbitofrontal cortex Expected value abstract The medial orbitofrontal cortex (mOFC)/ventromedial prefrontal cortex (vmPFC) has been proposed to signal the expected value of rewards when learning stimuli-rewards associ- ations. Yet, it is still unclear whether identical or distinct orbitofrontal cortex regions encode expected rewards and punishments at the time of the cue during appetitive and aversive classical conditioning. Moreover, it is unknown whether anticipation of different types of positive and negative reinforcers differentially influence specific orbitofrontal cortex regions. To answer these questions, this study investigated whether the human mOFC/vmPFC region encodes a general unsigned anticipatory value signal for different types of rewards and punishments (responding in a positive fashion in anticipation of both appetitive and aversive events) or a signed expected value signal (responding positively in anticipation of rewards and negatively in anticipation of punishments) when learning cue- outcomes associations. Using a model-based fMRI approach implementing a reinforcement learning model to compute the expected values of two types of rewards (pleasant juice, monetary gain) and two types of punishments (aversive juice, aversive picture), we found that mOFC/vmPFC activity correlated positively with the expected value of the cues, in anticipation of both rewards and punishments. This finding indicates that the mOFC/ vmPFC encodes a general unsigned anticipatory value signal, regardless of reinforcers valence (positive/negative) and types (gustatory, visual). © 2014 Elsevier Ltd. All rights reserved. 1. Introduction The orbitofrontal cortex has been proposed to signal outcome expectancies, i.e., to signal the expected characteristics and value of specific outcomes that the animal expects (Rushworth & Behrens, 2008; Schoenbaum, Roesch, Stalnaker, & Takahashi, 2009; Schoenbaum, Saddoris, & Stalnaker, 2007). Direct evidence supporting this hypothesis comes from ro- dents' OFC neuronal recordings directly demonstrating * Corresponding author. CNRS UMR 5229, Cognitive Neuroscience Center, Reward and Decision Making Group, 67 Bd Pinel, 69675 Bron, France. E-mail address: dreher@isc.cnrs.fr (J.-C. Dreher). Available online at www.sciencedirect.com ScienceDirect Journal homepage: www.elsevier.com/locate/cortex cortex 63 (2015) 42 e54 http://dx.doi.org/10.1016/j.cortex.2014.08.012 0010-9452/© 2014 Elsevier Ltd. All rights reserved.