Rhythm for inspiration started in:-

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).