Our lab studies the brain basis of behavior, integrating ecological, evolutionary and neuroscience perspectives in this work. Our primary research is focused on the neurobiological mechanisms supporting "sociality", a.k.a. life in social groups—using diverse species to assess the universality of specific underlying pathways.

Neural substrates of friendship/peer relationships

What determines whether an organism is solitary or lives in social groups? While decades of research have explored the neurobiology of parental behavior and monogamy, little is known about the biological mechanisms that promote sociality. Our work focuses on the pathways that support affiliation between peers.
Meadow voles are one of our laboratory model of choice because they undergo a predictable transition in social behavior in the field and in the lab. Meadow vole females are territorial during the summer reproductive season, but nest in social groups in the winter (left). The seasonal transition can be recapitulated in the lab by changing photoperiods, allowing us to explore the neurotransmitters, neuropeptides, hormones, and circuits mediating this social transition.
We also study same-sex (peer) affiliation in prairie voles (below) to gain an understanding of how peer relationships are regulated in a monogamous species. Prairie voles are rewarded by contact with mates and in some cases peer "friends", allowing us to probe distinctions between social preference and social motivation.

Sickness and social behavior

Sickness can lead to social avoidance — both on the part of healthy individuals and of sick individuals who may withdraw. But what happens to social behavior in the context of established relationships? We find that prairie voles huddle more with familiar companions when sick, and that sick individuals seek out their companion for huddling. Ongoing studies are examining how and why sickness affects social behavior, and the physiological consequences of these behaviors.

Neuropeptides and sociality

We are examining neurobiological correlates of social behavior in field collected samples from South American rodents. One such effort is comparing the oxytocin receptor systems of social and nonsocial rodents from the genus Ctenomys (tuco-tucos). Tuco-tucos are special because they belong to a species-rich group of social and solitary congeners who share a polygamous mating system. This has allowed us to explore the neural circuits that may be involved in social behavior outside the context of sexual pair-bonding. Initial work focused on two species from similar habitats in the Limay river valley of Argentina. More recently I have extended this analysis to a broad range of tuco-tucos from Argentina, Uruguay, and Peru, as well as degus. Related projects involve Alaskan Taiga voles, Belding’s ground squirrels, and hamster species.

Early life experience/plasticity in the brain

Exposure of rat pups to high or low levels of maternal care-giving in the first few days of life can alter the regulation of stress-reactivity and other phenotypic outcomes into adulthood. These changes in behavior accompany changes in gene expression and DNA methylation. We examined the effects of early life maternal care on social behavior, as well as experience-dependent changes in epigenetic regulation of genes in central and peripheral tissues. In more recent work, we are focusing on how gestational nutritional exposures are linked to later behavior via epigenetic pathways.

Sex bias in subject use, variability and sex

The vast majority of biological research is performed on male animals. There are many important functional differences between male and female organisms, so this sex bias has important negative implications for both scientific understanding and for women’s health. With Dr. Irv Zucker, I published a comprehensive analysis of bias across 10 biological disciplines in 2011. Following on the demonstration that female mice are not more variable than males, we are now undertaking a laboratory study of why and how trait variability is similar across males and females in both cycling and non-cycling species.