Confidence and psychosis: a neuro-computational account of contingency learning disruption by NMDA blockade.
Mol Psychiatry
; 21(7): 946-55, 2016 07.
Article
en En
| MEDLINE
| ID: mdl-26055423
ABSTRACT
A state of pathological uncertainty about environmental regularities might represent a key step in the pathway to psychotic illness. Early psychosis can be investigated in healthy volunteers under ketamine, an NMDA receptor antagonist. Here, we explored the effects of ketamine on contingency learning using a placebo-controlled, double-blind, crossover design. During functional magnetic resonance imaging, participants performed an instrumental learning task, in which cue-outcome contingencies were probabilistic and reversed between blocks. Bayesian model comparison indicated that in such an unstable environment, reinforcement learning parameters are downregulated depending on confidence level, an adaptive mechanism that was specifically disrupted by ketamine administration. Drug effects were underpinned by altered neural activity in a fronto-parietal network, which reflected the confidence-based shift to exploitation of learned contingencies. Our findings suggest that an early characteristic of psychosis lies in a persistent doubt that undermines the stabilization of behavioral policy resulting in a failure to exploit regularities in the environment.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Trastornos Psicóticos
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Ketamina
/
Aprendizaje
Tipo de estudio:
Clinical_trials
/
Prognostic_studies
Límite:
Adult
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Female
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Humans
/
Male
Idioma:
En
Revista:
Mol Psychiatry
Asunto de la revista:
BIOLOGIA MOLECULAR
/
PSIQUIATRIA
Año:
2016
Tipo del documento:
Article
País de afiliación:
Francia