Arbitration between model-free and model-based control is not affected by transient changes in tonic serotonin levels.
J Psychopharmacol
; 38(2): 178-187, 2024 02.
Article
em En
| MEDLINE
| ID: mdl-38151862
ABSTRACT
BACKGROUND:
Serotonin has been suggested to modulate decision-making by influencing the arbitration between model-based and model-free control. Disruptions in these control mechanisms are involved in mental disorders such as drug dependence or obsessive-compulsive disorder. While previous reports indicate that lower brain serotonin levels reduce model-based control, it remains unknown whether increases in serotonergic availability might thus increase model-based control. Moreover, the mediating neural mechanisms have not been studied yet.AIM:
The first aim of this study was to investigate whether increased/decreased tonic serotonin levels affect the arbitration between model-free and model-based control. Second, we aimed to identify the underlying neural processes.METHODS:
We employed a sequential two-stage Markov decision-task and measured brain responses during functional magnetic resonance imaging in 98 participants in a randomized, double-blind cross-over within-subject design. To investigate the influence of serotonin on the balance between model-free and model-based control, we used a tryptophan intervention with three intervention levels (loading, balanced, depletion). We hypothesized that model-based behaviour would increase with higher serotonin levels.RESULTS:
We found evidence that neither model-free nor model-based control were affected by changes in tonic serotonin levels. Furthermore, our tryptophan intervention did not elicit relevant changes in Blood-Oxygenation-Level Dependent activity.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Triptofano
/
Transtorno Obsessivo-Compulsivo
Limite:
Humans
Idioma:
En
Ano de publicação:
2024
Tipo de documento:
Article