Publication Date

2014

Document Type

Honors Thesis

Department

Neuroscience

Keywords

Neurosciences, Socioendocrinology, Corticosterone, Voles-Behavior, Attachment behavior, Stress (Psychology)-Animal models, Hormones, Behavior, Stress, Voles, Social attachment

Abstract

Stress research has become of particular importance across many disciplines for various reasons related to organismal health and physiology. In addition to having an effect on mammalian physiology, the HPA axis can exert its effects in a broader sense to affect an organism's sociality. Social behavior has been well studied in the laboratory in the context of attachments between mates, but very little is known about the mechanisms underlying peer social relationships. The goal of this study was to elucidate the relationship between the HPA axis and its products, stress reactivity, and their effects on social behavior using female meadow voles, which are an emerging model for peer social relationships due to their unique seasonal shift in behavior. In a series of three experiments, we 1) characterized the seasonal variation in corticosterone (CORT) levels, 2) examined the effect of a stressor on partner preference formation, and 3) monitored the pattern of CORT following a stressor over a 24-hour period. We found that there are seasonal differences in CORT levels for female meadow voles, and interestingly that the effect was reversible by the use/omission of steroid displacement agents during the assay, which remove CORT from binding globulins. In examining the effects of stress on partner preference formation, there was a trend of swim stress decreasing the number of animals forming partner preferences and huddling time (but were no significant differences between the swim stress and no swim treatment groups). Finally, in the preliminary time course pilot it was found that CORT was indeed elevated following swim treatment vs. no swim treatment, but further data points must be added to be conclusive. From the present data it is clear that there are seasonal differences in CORT (and by extension, in the activation of the HPA axis) for female meadow voles. Further work must be done to determine what exact mechanisms are influencing these differences. Furthermore, as it stands stress and the HPA axis do not affect same sex partner preferences in the same ways they affect opposite sex partner preferences; which is plausible given the neural circuitry between opposite sex and same sex attachments are very distinct from one another. Again, further work is needed to determine if stress can exert effects on the formation of same sex partner preferences, and to fully characterize how the CORT levels elicited by a stressful stimulus are related to the formation of preferences in the first 24 hours of cohabitation

Language

English

Comments

51 pages : color illustrations. Honors Project-Smith College, 2014. Includes bibliographical references (pages 48-51)

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