The main focus of research in my lab is on the mechanisms through which the neuropeptide vasotocin influences social behavior in goldfish. Vasotocin is the evolutionary precursor to vasopressin, which is found in the brains of mammals, including humans. However, the fish vasotocin system is less specialized than are the vasotocin systems found in other non-mammalian vertebrates or the vasopressin systems found in mammals, which facilitates our efforts to understand the fundamental ways through which these peptides influence social behavior in vertebrates. We have found that vasotocin infusions into the brain inhibit social approach behavior in goldfish, potentially by affecting brain systems involved in the regulation of anxiety. We have also been trying to determine where within the brain that vasotocin exerts such behavioral effects, and in so doing have identified a very well developed pattern of vasotocin terminal fibers in the hindbrain that could influence social behavior through autonomic regulatory mechanisms. Future work will use combined behavioral, neuroanatomical and molecular approaches to identify the precise brain circuits associated with vasotocin's behavioral actions in this species.
Although most of our work has focused on non-mammalian systems, we have also begun to investigate how vasopressin influences functions related to social communication in humans. The fact that vasotocin and vasopressin influence various social behaviors in many species from diverse vertebrate groups suggests that functions related to social regulation have, in general, been highly conserved during evolution, but nobody had tested whether or not vasopressin has any effects on social behavior in humans. Using psychophysiological techniques, a former student and I found that intranasal vasopressin administration affects facial muscle activity patterns related to social communication. Specifically, it prompts men to respond to emotionally neutral social stimuli as if they were threatening. We are currently repeating those studies in men and women to see if vasopressin similarly affects how both sexes perceive social stimuli.
Since coming to Bowdoin I have also begun to collaborate with Patsy Dickinson in the biology department to conduct electrophysiological studies measuring pheromone effects on brain processes in newts. Our students have collected data showing that sex pheromones enhance the processing of female tactile stimuli that takes place in the male's hindbrain, potentially by inducing local vasotocin release within this part of the brain. Two students currently working with me and Prof. Dickinson are continuing these electrophysiological studies. Additionally, they are trying to use neuroanatomical methods to identify the vasotocin circuits mediating such sensory system interactions.
2-3 students typically work in Rick's lab every summer, supported through grant funds or college fellowships. Many have gone on to present their data at conferences and some have even been co-authors on papers describing the work.
Joseph Adu '07
Peripheral Influences on Social Behavior in Goldfish
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