Functional heterogeneity within the rodent lateral orbitofrontal cortex dissociates outcome devaluation and reversal learning deficits.

Marios C Panayi,Simon Killcross

doi:10.7554/elife.37357

Abstract

The orbitofrontal cortex (OFC) is critical for updating reward-directed behaviours flexibly when outcomes are devalued or when task contingencies are reversed. Failure to update behaviour in outcome devaluation and reversal learning procedures are considered canonical deficits following OFC lesions in non-human primates and rodents. We examined the generality of these findings in rodents using lesions of the rodent lateral OFC (LO) in instrumental action-outcome and Pavlovian cue-outcome devaluation procedures. LO lesions disrupted outcome devaluation in Pavlovian but not instrumental procedures. Furthermore, although both anterior and posterior LO lesions disrupted Pavlovian outcome devaluation, only posterior LO lesions were found to disrupt reversal learning. Posterior but not anterior LO lesions were also found to disrupt the attribution of motivational value to Pavlovian cues in sign-tracking. These novel dissociable task- and subregion-specific effects suggest a way to reconcile contradictory findings between rodent and non-human primate OFC research.

Highlights

The orbitofrontal cortex (OFC) in rodents and primates is critical for updating behaviour flexibly when outcome contingencies change (Murray et al, 2007)
Rats were trained to lever press for either pellet or liquid sucrose rewards on a random interval 30 s schedule (RI30), and were exposed to the alternative reward non-contingently in a separate session on each day of training
We directly confirmed the dissociable role of the rodent OFC in Pavlovian but not instrumental behavioural flexibility following outcome devaluation (Gallagher et al, 1999; Ostlund and Balleine, 2007a)

Summary

Introduction

The orbitofrontal cortex (OFC) in rodents and primates is critical for updating behaviour flexibly when outcome contingencies change (Murray et al, 2007). OFC lesions do not impact initial acquisition of rewarded and non-rewarded cues or actions, they significantly disrupt the flexible updating of behaviour following the reversal of these contingencies (Boulougouris et al, 2007; Murray et al, 2007; Schoenbaum et al, 2003). Both outcome devaluation and reversal learning require flexibly tracking changes in learned contingencies and updating behaviour appropriately when contingencies or outcome values change, and both procedures are disrupted by damage to the OFC

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Conclusion