Parabrachial -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 -derived, -expressing glutamatergic neurons in the lateral parabrachial nucleus (PB) that are activated by exposing mice to cold environmental temperature. Eliminating 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 -expressing PB neurons is essential for sensing and surviving a cold environment.