Abstract Social interactions are essential for human health and society. However, the neural circuitry basis for many social behaviors remains uncertain. Beside classical behaviors such as aggression, pair bonding and parenting, recent research has demonstrated that rodents are also capable of behaviors to comfort distressed individuals. To study the neural basis of these prosocial behaviors, we recently adapted a protocol that produces consolation- like behavior in socially monogamous prairie voles to the widely used C57BL/6J mice. Our preliminary experiments indicate an important role for the paraventricular nucleus of the thalamus (PVT) in controlling consolation-like behavior in mice. Comforting a distressed cagemate elicited robust c-Fos expression in the PVT and pharmacogenetic silencing of the PVT dramatically reduced consolation-like behavior. Based on these intriguing results, we propose to (Aim1) perform in vivo electrophysiology recording and optogenetic manipulation of PVT to determine the role of PVT during consolation-like behavior. In comforting mice, there was also strong activation of the prefrontal cortex and ventral subiculum which are major inputs to the PVT. We therefore propose to (Aim2) identify the inputs responsible for PVT activity during prosocial behavior and expand our understanding of the circuitry using viral tracing. The proposed studies defining the prosocial neural circuitry will add to the knowledge base necessary for treating conditions with social deficits.