<prompt> Rhythm for inspiration started in:-Pneumotaxic centreApneustic centreDRGPre-Botzinger complex  <response>: Ans. d Pre-Botzinger complexRef: Ganongs Review of Medical Physiology 25th Ed; Page No- 656 Pre-Botzinger complex It is called as pacemakers of respiration. Initiates the respiratory rhythm. This complex contains six groups of neurons that functions as central pattern generator for initiation of respiration. Located in the ventrolateral medulla. Rhythmically drives the discharge of phrenic motor neurons that innervates diaphragm. Dorsal respiratory group DRG: are located bilaterally in nucleus of the tractus solitarius NTS. These neurons are primarily concerned with Inspiration. DRG ply an important role in cardio pulmonary reflexes. Pneumotaxic centre: Pneumotaxic centre- Neurons that switch off inspiration. It is located in the upper pons in the nucleus parabrachialias Medialis and the Kolliker-Fuse nucleus. It inhibits inspiration and, therefore, regulates inspiratory volume and respiratory rate. Apneustic centre: It is located in the lower pons. It plays a role in inspiration, producing a deep and prolonged inspiratory gasp apneusis. 