This project will examine the structure and neurochemistry of neural circuitry underlying parental behavior in the prairie vole (Microtus ochrogaster). Prairie voles have a gregarious social system in which males and females pair-bond and share in the care of offspring. Because of the male?s extensive involvement in raising the offspring, the prairie vole is an ideal model for examining the neural circuitry underlying male parental care and for contrasting it with the circuitry used by females. Based on studies of neural activation following pup exposure, the lateral septum (LS) and principal nucleus of the bed nucleus of the stria terminalis (pBNST) have been singled out as brain areas likely to be involved in parental behavior. First, the importance of these areas for parental behavior will be determined using excitotoxic lesions. Next, the connections of the cells that are activated during parental behavior will be determined using anatomical tract tracing along with staining for a marker of neuronal activity, Fos. The importance of areas receiving projections from the pBNST and LS will be determined using excitotoxic lesions. If time permits, we will identify the neurotransmitter content of these projections, which will enable us to test with pharmacological means the specific contributions of projections of the pBNST and LS to parental behavior.