Inflexible habitual decision-making during choice between cocaine and a nondrug alternative

Abstract

The concept of compulsive cocaine-seeking habits is difficult to reconcile with other evidence showing that humans and even rats remain able to shift their choice away from the drug and toward an alternative nondrug reward, when available. This paradox could dissolve if preference for the nondrug option reflected in fact inflexible habitual decision-making (i.e., fixed in a habitual control mode, with no return to a goal-directed control mode). Previous research in rats has shown that prior drug use can favor habit formation, but whether the resulting habits are inflexible or not is largely unknown. Here we addressed this question by manipulating the value of water in rats that chose between water and cocaine in a discrete-trials procedure. Rats preferred water when thirsty and maintained this preference despite water devaluation by satiation. Only with repeated daily testing under water satiation did they progressively reverse their preference toward cocaine. Additional evidence showed that this progressive reversal of preference reflected in fact new interoceptive discrimination learning. Overall, this study suggests that rats seem to be stuck in a habitual decision-making mode, unable to return to a goal-directed mode upon experiencing a change in options value. It also reveals that inflexible decision-making does not necessarily promote drug choice, but can also under some circumstances favor abstinence.

Addiction is driven by excessive goal-directed drug choice under negative affect: translational critique of habit and compulsion theory

“…This manipulation immediately reduced performance of the seeking response tested in extinction (in the absence of the taking lever), suggesting the seeking response was controlled by a goal-directed expectation of access to cocaine, rather than an S−R association. So although drug seeking can be goal-directed (see also [69][70][71]), as noted in the habit section, most animal studies suggest it is habitual (see also [72]). It remains unclear what the optimal parameters are for detecting goaldirected vs. habitual drug-seeking behaviour [73].…”

Fractionating the all‐or‐nothing definition of goal‐directed and habitual decision‐making

“…Similarly, a recent animal study trained rats to solve different puzzles daily for access to cocaine, and found that these animals were quite sensitive to the changing contingencies, but displayed typical hallmarks of addiction including escalation and (in a subset of animals) resistance to shock‐induced reductions in cocaine seeking (Singer et al, ). Interestingly, a recent study found cocaine‐induced facilitation of inflexible, habitual responding specifically for choice of a non‐drug reward, highlighting the complex effect habitual facilitation may have (Vandaele, Vouillac‐Mendoza, & Ahmed, ). Drug‐induced facilitation of habitual responding is not always observed (Halbout et al, ; Singer et al, ), and it is important to note that certain forms of instrumental training may prevent the emergence of habitual control.…”

Habitual Preference for the Nondrug Reward in a Drug Choice Setting

“…These results suggest that preference remains sensitive to instrumental and environmental contingencies, and may thus be under goal-directed control. However, we recently showed that this is, in fact, not the case (Vandaele et al, 2019b). Specifically, rats persisted to choose water, their preferred nondrug option when thirsty, even after devaluation by satiation and even if they consumed little of it upon delivery.…”