Lab 2017 Spring 

Lab Spring 2015 with guest Norbert Sachser

Lab Fall 2015 with guest Fadao Tai

Basic Studies

Who we are and how we develop are determined largely by the challenges we face and the resources we have to meet those challenges. Many of these challenges and resources are social in nature. Our companions can “buffer” the impact of environmental challenges, or “stressors”, and the loss of close companions can be a severe stressor itself. Our laboratory is focused on understanding the mechanisms underlying these effects, and how they shape behavioral and biological development.

In a natural environment, the social stressors an animal faces in early life can help prepare it for the challenges it is likely to encounter at older ages. But, early stress can also have negative, even devastating, consequences. In humans, early social stressors such as abuse, neglect, and separation from the mother have been linked to a greater propensity to develop psychopathology such as major depression in adolescence and adulthood. These effects appear to involve complex interactions between the brain, hormones, and aspects of the immune system.

Although depression is a uniquely human condition, basic processes underlying depression and its development can be studied in animals. Much of our work focuses on guinea pigs. Although not closely related to humans, guinea pigs exhibit an intricate social system, with social interactions and their absence affecting many of the same behavioral, neural, hormonal, and immune processes as in humans. In collaboration with colleagues at the California National Primate Research Center, we also test how well our results extend to nonhuman primates. The following papers provide some examples of our basic research.

Hennessy, M.B., Schreibeis, A.D., Schiml, P.A., & Deak, T. (2017). Maternal separation increases later immobility during forced swim in guinea pig pups: Evidence for sensitization of a depressive-like state. Developmental Psychobiology, 59, 128-132.

Hennessy, M.B., Chun, K., & Capitanio, J.P. (2017). Depressive-like behavior, its sensitization, social buffering and altered cytokine responses in rhesus macaques moved from outdoor social groups to indoor housing. Social Neuroscience, 12, 65-75.

Zimmerman, T., Kaiser, S., Hennessy, M.B., & Sachser, N. (2017). Adaptive shaping of the behavioural phenotype during adolescence. Proceedings of the Royal Society B: Biological Sciences, 284, 20162784

Applied Studies

In our applied work, we are using principles derived from our and other’s basic research to find ways to reduce neuroendocrine and behavioral stress responses of dogs confined in animal shelters. One goal is to improve the welfare of these dogs. Even in well-run, modern animal shelters, dogs are confronted with an array of psychological stressors known to elevate stress hormone levels. Therefore, with the help of local shelters, we are studying ways that interventions might moderate hormonal and behavioral responses to stress. A second goal is to improve adoption success. Dogs adopted from shelters often exhibit behavioral problems such as “separation anxiety”. Behavior problems frequently result in dogs being returned to the shelter. We hypothesize that many of these problems stem from stressful experiences inherent in confinement. We, therefore, hope to improve adoption success by reducing the stressfulness of the shelter for dogs that find themselves there. The following papers are examples of this work. 

Willen, R.M., Mutwill, A., MacDonald, L. J., Schiml, P.A., & Hennessy, M.B. (2017). Factors determining the effect of human interaction on the cortisol levels of shelter dogs. Applied Animal Behaviour Science, 186, 41-48.

Dudley, E.S., Schiml, P.A., & Hennessy, M.B. (2015). Effects of repeated petting sessions on leukocyte counts, intestinal parasite prevalence, and plasma cortisol concentration of dogs housed in a county animal shelter. Journal of the American Veterinary Medical Association, 247, 1289-1298.

Student Assistants

Student assistants in the lab are typically undergraduate psychology (behavioral neuroscience concentration) or biology majors, or are graduate students in interdisciplinary Biomedical Sciences Ph.D. program or the Department of Neuroscience, Cell Biology and Physiology’s master’s program in anatomy.