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Arbitration between model-free and model-based control is not affected by transient changes in tonic serotonin levels.
- Source :
- Journal of Psychopharmacology; Feb2024, Vol. 38 Issue 2, p178-187, 10p
- Publication Year :
- 2024
-
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. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 02698811
- Volume :
- 38
- Issue :
- 2
- Database :
- Complementary Index
- Journal :
- Journal of Psychopharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 175415673
- Full Text :
- https://doi.org/10.1177/02698811231216325