Habitual Preference for the Nondrug Reward in a Drug Choice Setting.

Youna Vandaele,Karine Guillem,Serge H. Ahmed

doi:10.3389/fnbeh.2020.00078

Abstract

For adaptive and efficient decision making, it must be possible to select between habitual alternative courses of action. However, research in rodents suggests that, even in the context of simple decision-making, choice behavior remains goal-directed. In contrast, we recently found that during discrete trial choice between cocaine and water, water-restricted rats preferred water and this preference was habitual and inflexible (i.e., resistant to water devaluation by satiation). Here we sought to test the reproducibility and generality of this surprising finding by assessing habitual control of preference for saccharin over cocaine in non-restricted rats. Specifically, after the acquisition of preference for saccharin, saccharin was devalued and concurrent responding for both options was measured under extinction. As expected, rats responded more for saccharin than for cocaine during extinction, but this difference was unaffected by saccharin devaluation. Together with our previous research, this result indicates that preference for nondrug alternatives over cocaine is under habitual control, even under conditions that normally support goal-directed control of choice between nondrug options. The possible reasons for this difference are discussed.

Highlights

Organisms are constantly choosing between alternatives to select appropriate actions based on prior experience or expected outcomes
In a series of experiments, we have repeatedly shown that when facing a choice between pressing a lever to get a nondrug reward or an alternative lever to receive an intravenous dose of cocaine, most rats prefer the nondrug alternative (Lenoir et al, 2007; Cantin et al, 2010; Augier et al, 2012; Madsen and Ahmed, 2015; Vandaele et al, 2016)
Rats responded more for saccharin than for cocaine during extinction, but this difference was unaffected by any method of saccharin devaluation

Summary

Introduction

Organisms are constantly choosing between alternatives to select appropriate actions based on prior experience or expected outcomes. Evidence indicates that the performance of rewardrelated actions in both rats and humans reflects the interaction of two learning processes (Dickinson and Balleine, 1994; Dickinson, 1994; Balleine and Dickinson, 1998). The balance between goal-directed and habitual processes allows adaptive and efficient decision making. One may intuitively think that habitual course of actions can be selected among other alternatives, research in laboratory animals suggests that, even in the context of the simple choice decision, choice performance is dominated by goal-directed actions, rather than habitual responses (Colwill and Triola, 2002; Holland, 2004; Kosaki and Dickinson, 2010; Halbout et al, 2016).

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