Project Summary Some of the most interesting and important aspects of behavior and brain function arise from social interactions. The dynamics of dyads or larger groups of animals can be critical for survival, such as development of territories and foraging patterns, building of housing structures such as nests or burrows, and co-parenting to ensure that at least one experienced caretaker is attending to the needs of offspring. Methodological advances in the last five years now enable studies of the neural circuits for social and parental behavior in complex environments in ways not formerly feasible or even possible. Specifically, technical developments in wireless recording, optogenetics for measuring and manipulating certain cell types, algorithms for neural data analysis, methods for quantifying multi-animal behavioral interactions, and the capacity to store and share large data sets have each enabled fundamental discoveries and conceptual breakthroughs relating brain activity to quantitative behavior. In this proposal, we take advantage of each of these advances with an integrated approach to examine social and parental behavior in mice in the lab as well as outdoors. This application is a collaborative effort between the Graham lab at Princeton and the Froemke lab at NYU. For the last several years we have been collaborating, ‘rewilding’ lab mice by placing them outdoors for several weeks at the Stony Ford field station near the Princeton campus. Rewilded mice express many interesting behaviors that we have developed approaches for monitoring and tracking, with multimodal imaging and analysis of behavioral and physiological variables. We believe it is now the time to study these interesting behaviors and interactions, in complex social and spatial environments in conjunction with neural recordings. The central hypothesis is that neurons of the central oxytocin system track the identity and behavior of other animals in a social network, promoting pro-social behaviors to minimize environmental stressors (hunger, hypo- or hyperthermia, crying infants). We will use quantitative behavioral methods based on RFID tracking, video and thermal imaging, combined with neural recordings from hypothalamic neurons including oxytocin neurons. In Aim 1 we examine adult social interactions in same-sex groups of females or males, and in Aim 2 we examine collective parenting by groups of females. Our overall goal is to determine what features of group dynamics emerge in a complex outdoor ecosystem, and how the oxytocin system might enable successful navigation of this socio-spatial environment. These studies will provide direct data towards the central aims of the BRAIN Initiative: quantitative behavioral analysis of interesting multi-animal behaviors in complex environments coupled to neural data collection, to understand essential brain functions related to group survival.