Summer Research Opportunity in Neuroendocrinology:
Davis Laboratory
What do we study?
My lab bridges the great physiological/ecological divide, by asking questions about both physiological and neural mechanisms of behavior as well as about the adaptive value of behavior. Ideally, answers to both types of questions are synthesized to yield a much more informative picture. Most broadly, I study the biology of aggression, and currently have two major lines of research.
The first is the study of forced copulation, which is a form of sexual coercion that occurs in many species, from insects to humans. It is behavior that generally is considered to be adaptive, although this idea is extremely controversial in humans, but virtually nothing in known of its biological underpinnings. I seek to answer questions of the role of forced copulations in the mating systems of vertebrates, and to uncover some of the physiological, neural and behavioral mechanisms involved. The model system I use is, well, ducks. Forced copulation is widespread and common in waterfowl, and the mallard in particular is an excellent species in which to study these questions in a captive situation.
The second line of study is concerns the neural and hormonal mechanisms involved in changes in aggression. It is a well known phenomenon that experience can influence the expression of aggression in the future. Specifically, animals that have a winning experience are more likely to be aggressive and win in the future, and conversely, animals that are trained with a losing experience are more likely to lose future encounters. What physiological and neural changes lead to these behavioral changes? This is work that I have been doing in Peromyscus mice.
What might the summer experience be like?
At this point in my research, there is a great deal of ground work that needs to be laid, the most obvious of which is the mapping of the mallard brain and the production of a useable brain atlas of the mallard. Although the brain is well mapped for mammalian species such as humans, mice and rats, there is substantially less to go on in the avian world. I anticipate spending much of this summer, slicing and staining mallard brains, and creating and labeling sketches of the brain slices. Depending on how well this goes, this work should result in a publication for all who work on the project.
I hope also to conduct a pilot study on female mallards to demonstrate that forced copulation is just that – forced. One difficulty in studying this behavior in some species is knowing when a copulation is consensual and when it is forced. Although behaviorally, this seems quite clear in waterfowl, it is still helpful to devise more objective ways of demonstrating this difference. To that end, I seek to show that females subjected to the stress of forced copulation exhibit physiological evidence of stress. Specifically, one of the steroid hormones, corticosterone (cortisol in primates) is frequently used as a marker for acute stress. Also, brain areas involved in stress response will show activity following that stressor. I hope to look at c-fos, which is a marker for neural activation, in stressed females to determine areas of the mallard brain involved in the stress response. In this pilot study, the stressor will simply be the stress of capture.
Another possible project would be in looking at some of the neural changes in arginine vasopressin (AVP) levels in male mice following a variable number of wins. AVP is a neurohormone that has been shown to be involved in the expression of aggression social interactions in a wide array of species. Do levels of this brain chemical increase as an individual has an increasing number of winning experiences? The behavioral work has been done, and the brains sit in the freezer, awaiting this assay.
Research Papers