Thesis advisor: Michael Numan / Maternal behavior is a primary social characteristic of mammals. By studying maternal behavior in rats, broader inferences can be made about the neural circuits that influence maternal behavior in other mammals, including humans. Maternal behavior of rats includes nest building, pup grooming, nursing, and pup retrieval. The projections from the medial preoptic area of the hypothalamus (MPOA) to the ventral tegmental area (VTA) of the mesolimbic dopamine system are known to regulate maternal behavior in post-partum rats. The aim of the present study was to examine how inhibition of the basolateral amygdala (BLA), an area that projects to the nucleus accumbens-ventral palldium (NA-VP) circuit of the mesolimbic dopamine system, bilaterally with muscimol (a GABA-A agonist) might interrupt the retrieval of pups by post-partum rats. Females injected with muscimol, but not those injected with saline, displayed significant deficits in retrieval behavior, suggesting that the BLA is a region important for the promotion of maternal behavior. The effects were also reversible, as all females displayed normal maternal behavior 24-hours post-injection. Follow-up studies should use asymmetric neuron-specific lesions of the BLA and the VP to show that the projections from the BLA to the VP are essential for maternal behavior. / Thesis (BA) — Boston College, 2010. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: College Honors Program. / Discipline: Psychology Honors Program. / Discipline: Psychology.