The parastrial nucleus (PS) is a lenticular formation located beneath the anterior commissure in the preoptic area. Anatomic and physiologic studies have demonstrated: 1) a direct projection from PS neurons to the dorsomedial hypothalamus (DMH), 2) increased cold-evoked Fos expression in PS, and 3) infected neurons in PS after injection of Pseudorabies virus into the interscapular brown adipose tissue (iBAT). However, it has not been assessed whether a specific population of PS neurons projecting to DMH is involved in the modulation of iBAT thermogenesis. We aim to determine if PS projecting neurons to DMH are selectively responsive to cold or warm stimuli, and if pharmacologic manipulation of these neurons activates iBAT thermogenesis.