Gut-Brain Axis and Behaviors in a Socially Monogamous Rodent Species

Research on the regulatory role of gut microbiota in clinically relevant behaviors has grown dramatically in recent years. The communication between the gut and the brain, often referred to as the gut-brain axis, can influence underlying neurobiology and resulting health outcomes. Through these research efforts, many have shown that the gut-brain axis is heavily intertwined with the social world across various species. However, the underlying mechanisms remain largely unknown. A socially monogamous rodent species, the prairie vole (Microtus ochrogaster), displays high levels of sociality, providing a unique opportunity to study gut-brain influences on behaviors and the potential underlying mechanisms. Thus, I utilized the prairie vole as an animal model to assess: 1) how manipulation of the gut microbiome via probiotic administration can alter well-studied social circuits in the brain; 2) how manipulation of the social environment alters the gut microbiome, central immune function, and neurochemical circuits, and 3) how impacts of social isolation on the brain and behavior differ between adulthood and adolescence. I found that manipulation of both gut microbes and the social environment alters the gut microbiome, neurochemical circuits in the brain, and relevant behaviors, and these changes are sex-specific in prairie voles. I also found that the prairie vole microbiome is unique from traditional rodent species, with maintained individuality. Through these experiments, I have found that the gut-immune-brain axis plays an integrative role in social and stress-related circuits and resulting behaviors in a socially monogamous rodent model. These data provide both new evidence and a starting foundation for the continued use of the prairie vole model for translational research on the gut-brain axis and the social world.