Oxytocin neurons signal state-dependent transitions from rest to thermogenesis and behavioral arousal

Core body temperature (Tb) is defended within narrow limits through thermoregulatory behaviors like huddling, nesting, and physical activity, as well as autonomic responses like brown fat thermogenesis. While Tb displays regulated fluctuations across different behavioral states and rest/arousal cycles, the neural control of these transitions remains poorly understood. Here, we investigate the relationship between oxytocin neurons of the paraventricular hypothalamus (PVN^OT) and behavioral and autonomic thermoeffector pathways across physiological states in mice. First, we show that PVN^OT neurons are activated during social thermoregulation. We then demonstrate that in vivo PVN^OT calcium dynamics align with transitions from rest to thermogenesis and behavioral arousal. Counter to our initial hypothesis, these dynamics were observed in both social and non-social contexts. Using a computer vision model to track thermoeffector pathways, we demonstrate that precisely timed stimulation of PVN^OT neurons during low-Tb resting states increases thermogenesis followed by behavioral arousal. We therefore suggest a model in which PVN^OT neurons facilitate homeostatic state-dependent transitions in thermo-behavioral states.