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Impairments in reinforcement learning do not explain enhanced habit formation in cocaine use disorder

RATIONALE: Drug addiction has been suggested to develop through drug-induced changes in learning and memory processes. Whilst the initiation of drug use is typically goal-directed and hedonically motivated, over time, drug-taking may develop into a stimulus-driven habit, characterised by persistent...

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Detalles Bibliográficos
Autores principales: Lim, T. V., Cardinal, R. N., Savulich, G., Jones, P. S., Moustafa, A. A., Robbins, T. W., Ersche, K. D.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Berlin Heidelberg 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6695345/
https://www.ncbi.nlm.nih.gov/pubmed/31372665
http://dx.doi.org/10.1007/s00213-019-05330-z
Descripción
Sumario:RATIONALE: Drug addiction has been suggested to develop through drug-induced changes in learning and memory processes. Whilst the initiation of drug use is typically goal-directed and hedonically motivated, over time, drug-taking may develop into a stimulus-driven habit, characterised by persistent use of the drug irrespective of the consequences. Converging lines of evidence suggest that stimulant drugs facilitate the transition of goal-directed into habitual drug-taking, but their contribution to goal-directed learning is less clear. Computational modelling may provide an elegant means for elucidating changes during instrumental learning that may explain enhanced habit formation. OBJECTIVES: We used formal reinforcement learning algorithms to deconstruct the process of appetitive instrumental learning and to explore potential associations between goal-directed and habitual actions in patients with cocaine use disorder (CUD). METHODS: We re-analysed appetitive instrumental learning data in 55 healthy control volunteers and 70 CUD patients by applying a reinforcement learning model within a hierarchical Bayesian framework. We used a regression model to determine the influence of learning parameters and variations in brain structure on subsequent habit formation. RESULTS: Poor instrumental learning performance in CUD patients was largely determined by difficulties with learning from feedback, as reflected by a significantly reduced learning rate. Subsequent formation of habitual response patterns was partly explained by group status and individual variation in reinforcement sensitivity. White matter integrity within goal-directed networks was only associated with performance parameters in controls but not in CUD patients. CONCLUSIONS: Our data indicate that impairments in reinforcement learning are insufficient to account for enhanced habitual responding in CUD. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s00213-019-05330-z) contains supplementary material, which is available to authorized users.