Ventral respiratory group
（重定向自Respiration centre）
The (VRG) is a column of neurons located in the ventrolateral region of the medulla, extending from the caudal facial nucleus to -400μm obex. The four cell groups of the VRG are the rostral nucleus retrofacialis, caudal nucleus retroambiguus, nucleus para-ambiguus, and the pre-Bötzinger complex.