The primary focus of our laboratory is the general area of “ecological physiology.” Specifically, we study the interactions among the nervous, endocrine and immune systems and behavior in a variety of ecologically-relevant environmental contexts using the Siberian hamster (Phodopus sungorus) as our model system.
Microbiome Influences on the Neuroendocrine Regulation of Social Behavior
The large intestine of the mammalian gastrointestinal tract contains approximately 100 trillion microorganisms, an amount ten times greater than the total number of cells in the body. This diverse group of symbiotic bacteria, called the gut microbiome, is critical for mammalian survival and exerts a surprisingly powerful influence on the brain and behavior. Interestingly, microbiota can be transmitted from mother to offspring and, thus, alter offspring neurobehavioral development. Our lab is interested in elucidating the physiological mechanisms by which the gut microbiome shapes the development of social behaviors. Currently, we are investigating the consequences of altered maternal microbiome on the neural, endocrine, immune, and behavioral responses of offspring.
Neuroendocrine Mechanisms of Seasonal Aggression
Many non-tropical mammals, such as Siberian hamsters, undergo seasonal changes in a wide array of physiological and behavioral responses. Specifically, some animals regress their reproductive systems and exhibit decreased circulating levels of androgens during the winter non-breeding season, but “re-grow” their reproductive organs and elevate circulating gonadal steroid levels in time for the impending summer breeding season. Interestingly, some species exhibit equivalent or increased levels of territorial aggression outside of the breeding season. Previous work from our lab has provided evidence that Siberian hamsters undergo a “seasonal switch” in neuroendocrine mechanisms between the breeding and non-breeding seasons, in which the adrenal hormone precursor dehydroepiandrosterone (DHEA) facilitates increased territorial aggression during the non-breeding season. Currently, we are continuing our work on the neuroendocrine mechanisms underlying seasonal aggression by examining the role of adrenal DHEA as a precursor of neurally-derived steroids in breeding and non-breeding hamsters.