Ronald J. Barfield - US grants

Broadly stated, the objectives of the research presented here are to elucidate neuroendocrine mechanisms underlying reproductive behavior and to analyze the communicative role of ultrasonic vocalizations in the social integration of reproduction. Research proposed on neuroendocrine factors will be concerned primarily with sites and mechanisms of steroid hormone action in the regulation of sexual behavior. To accomplish this goal hormonal and other agents will be implanted directly at the sites of populations of target cells in the central nervous system in male anf female rats. Research on ultrasonic vocalizations will be focused on the nature of the message conveyed by 50 kHz vocalizations of males and females and by the 22 kHz postejaculatory vocalization of the male. Techniques including surgical devocalization and playback of recorded vocalizations will provide experimental control over these signals. Research proposed here should extend our understanding of funamental neuroendocrine mechanisms underlying reproductive processes in mammals in general (including humans). In addition, expansion of our understanding of the dynamics of social communication in reproductive activity of rats will make this species an even more valuable model system for the study of reproductive processes in general.

Complex social interactions involve communication through auditory, postural, visual and olfactory signals. In nature, Norway rats possess a complex social system which includes reproductive, territorial and agonistic behavior. Rats, like many other mammalian species including humans, utilize several channels of communication in the integration of their social activities. While it is clear that this species rely heavily on olfaction and tactile in their social communication, acoustical communication plays an important role as well. Rats communicate acoustically with ultrasonic vocalizations which are only audible by sophisticated instrumentation. Dr. Barfield has defined several different ultrasonic vocalizations that occur during different phases of reproductive activity. He will now elucidate the role of these ultrasonic calls in coordinating reproductive activity between males and females. The role that vocalizations by males play in facilitating impregnation and fertility in females will also be investigated. Rats serve as an important model system for mammalian reproductive physiology and behavior. An appreciation of the role of vocal communication in rat reproduction will enhance our general understanding of reproductive coordination. The questions proposed by Dr. Barfield are of theoretical importance and immediate relevance to research in the field of behavioral neuroendocrinology.