<P> The pneumotaxic center regulates the amount of air that can be taken into the body in each breath . The dorsal respiratory group has rhythmic bursts of activity that are constant in duration and interval . When a faster rate of breathing is needed the pneumotaxic center signals the dorsal respiratory group to speed up . When longer breaths are needed the bursts of activity are elongated . All the information that the body uses to help respiration happens in the pneumotaxic center . If this was damaged or in any way harmed it would make breathing almost impossible . </P> <P> One study on this subject was on anesthetized paralyzed cats before and after bilateral vagotomy . Ventilation was monitored in awake and anesthetized cats breathing air or CO2 . Ventilation was monitored both before and after lesions to the pneumotaxic center region and after subsequent bilateral vagotomy . Cats with pontine lesions had a prolonged inhalation duration . In cats, after anaesthesia and bivagotomy, pontine transection has been described as evoking a long sustained inspiratory discharges interrupted by short expiratory pauses . In rats on the other hand, after anaesthesia, bivagotomy and pontine transection, this breathing pattern was not observed, either in vivo or in vitro . These results suggest interspecies differences between rat and cat in the pontine influences on the medullary respiratory center . </P> <P> The apneustic center of the lower pons appears to promote inhalation by a constant stimulation of the neurons in the medulla oblongata . The apneustic center sends signals to the dorsal group in the medulla to delay the' switch off', the inspiratory off switch (IOS) signal of the inspiratory ramp provided by the pneumotaxic centre . It controls the intensity of breathing, giving positive impulses to the neurons involved with inhalation . The apneustic center is inhibited by pulmonary stretch receptors and also by the pneumotaxic center . It also discharges an inhibitory impulse to the pneumotaxic center . </P> <P> Breathing is the repetitive process of bringing air into the lungs and taking waste products out . The oxygen brought in from the air is a constant, on - going need of an organism to maintain life . This need is still there during sleep so that the functioning of this process has to be automatic and be part of the autonomic nervous system . The in - breath is followed by the out - breath, giving the respiratory cycle of inhalation and exhalation . The number of cycles per minute is the respiratory rate . The respiratory rate is set in the respiratory center by the dorsal respiratory group, in the medulla, and these neurons are mostly concentrated in the solitary nucleus that extends the length of the medulla . </P>

Chemosensitive areas of the respiratory center are located