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Updated: Jun 26, 2025

Intracerebroventricular Delivery of Gut-Derived Microbial Metabolites in Freely Moving Mice
Published on: June 2, 2022
Impact of the gut microbiome composition on social decision-making
Marie Falkenstein1, Marie-Christine Simon2, Aakash Mantri2,3
1Control-Interoception-Attention Team, Sorbonne Université, Paris Brain Institute (ICM), Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 47 boulevard de l'Hôpital, 75013 Paris, France.
Abstract:
There is increasing evidence for the role of the gut microbiome in the regulation of socio-affective behavior in animals and clinical conditions. However, whether and how the composition of the gut microbiome may influence social decision-making in health remains unknown. Here, we tested the causal effects of a 7-week synbiotic (vs. placebo) dietary intervention on altruistic social punishment behavior in an ultimatum game. Results showed that the intervention increased participants' willingness to forgo a monetary payoff when treated unfairly. This change in social decision-making was related to changes in fasting-state serum levels of the dopamine-precursor tyrosine proposing a potential mechanistic link along the gut-microbiota-brain-behavior axis. These results improve our understanding of the bidirectional role body-brain interactions play in social decision-making and why humans at times act "irrationally" according to standard economic theory.
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