Reward-specific satiety affects subjective value signals in orbitofrontal cortex during multicomponent economic choice

Alexandre Pastor-Bernier,Wolfram Schultz,Arkadiusz Stasiak

doi:10.1073/pnas.2022650118

Alexandre Pastor-Bernier, Wolfram Schultz + Show 1 more

Open Access

https://doi.org/10.1073/pnas.2022650118

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Abstract

Sensitivity to satiety constitutes a basic requirement for neuronal coding of subjective reward value. Satiety from natural ongoing consumption affects reward functions in learning and approach behavior. More specifically, satiety reduces the subjective economic value of individual rewards during choice between options that typically contain multiple reward components. The unconfounded assessment of economic reward value requires tests at choice indifference between two options, which is difficult to achieve with sated rewards. By conceptualizing choices between options with multiple reward components ("bundles"), Revealed Preference Theory may offer a solution. Despite satiety, choices against an unaltered reference bundle may remain indifferent when the reduced value of a sated bundle reward is compensated by larger amounts of an unsated reward of the same bundle, and then the value loss of the sated reward is indicated by the amount of the added unsated reward. Here, we show psychophysically titrated choice indifference in monkeys between bundles of differently sated rewards. Neuronal chosen value signals in the orbitofrontal cortex (OFC) followed closely the subjective value change within recording periods of individual neurons. A neuronal classifier distinguishing the bundles and predicting choice substantiated the subjective value change. The choice between conventional single rewards confirmed the neuronal changes seen with two-reward bundles. Thus, reward-specific satiety reduces subjective reward value signals in OFC. With satiety being an important factor of subjective reward value, these results extend the notion of subjective economic reward value coding in OFC neurons.

Highlights

Sensitivity to satiety constitutes a basic requirement for neuronal coding of subjective reward value
As animals may not choose a sated single reward when a nonsated alternative is available [15,16,17] and fail to achieve choice indifference, we studied bundles that each contained the same two rewards on which the animals sated to different degrees
This study investigated whether the reward responses of orbitofrontal cortex (OFC) neurons reflected reductions of subjective economic reward value induced by satiety for specific rewards, using stringent tests based on formal concepts of economic decision theory

Summary

Introduction

Sensitivity to satiety constitutes a basic requirement for neuronal coding of subjective reward value. Satiety reduces the subjective economic value of individual rewards during choice between options that typically contain multiple reward components. The unconfounded assessment of economic reward value requires tests at choice indifference between two options, which is difficult to achieve with sated rewards. Choice indifference becomes feasible when an added amount of unsated reward can compensate for the value loss of the sated reward Such tests require reward options with two reward components (“bundles”). The coffee has lost more value for us than water Such value loss is often referred to as sensory-specific satiety (or, more appropriately here, reward-specific satiety) and contrasts with general satiety that refers indiscriminately to all rewards [4, 5].

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