<prompt> Pacemaker regulating the rate of respiration isPneumotaxic centreNucleus tractus solitariusApneustic centrePre-Botzinger complex  <response>: Pre-Botzinger complex initiates the respiratory rhythm, consists of six group of neurons that functions as central pattern generator for initiation of respiration. Located in the ventrolateral medulla. Ref: Ganong 25th edpage 655 