Parabrachial Foxp2-expressing neurons are necessary for sustaining core body temperature in the cold

Cold environmental temperature is a threat to survival. Sustaining core body temperature in the cold requires a dynamic set of adaptive responses known as "cold defense," but the neural circuitry orchestrating these responses remains unclear. We identified a cluster of Atoh1-derived, Foxp2-expressing glutamatergic neurons in the lateral parabrachial nucleus (PB) that are activated by exposing mice to cold environmental temperature. Eliminating Foxp2-expressing PB neurons caused body temperature to plummet in the cold. Mice lacking these neurons had normal wakefulness, movement and appetite at room temperature, and their autonomic cold-defense responses remained intact. However, these mice had reduced metabolism and locomotor activity in the cold, and thermal discrimination was impaired. Our results indicate that thermosensory information relayed through Foxp2-expressing PB neurons is essential for sensing and surviving a cold environment.