The role of the dorsal premammillary nucleus and its main targets in the neuroendocrine and behavioral responses observed after social defeat

Abstract

Previous studies from our laboratory have shown that the dorsal premammillary nucleus (PMD) is critically involved in mediating fear responses of intruders exposed to dominant males during social defeat. Conversely, during predator exposure, the PMD is also known to influence contextual memory processing to environmental cues previously associated with a predator. While fear responses are likely to depend upon PMD projections to the PAG, PMD projections to the ventral part of the anteromedial thalamic nucleus appear to mediate mnemonic processing to aversive events. In the present work, we are going to investigate the role of the PMD and its main targets (i.e., the AMv and PAG) in the behavioral and neuroendocrine response observed during the social defeat and in the situation of the post-defeat during exposure to an environment previously associated with the social defeat. Next, we will study the putative neural circuits underlying the pos-defeat behavioral and neuroendocrine changes, and how previous inactivation of the PMD or its main targets, during the encounter with the dominant male, will affect the circuits mobilized in the post-defeat phase. (AU)