Functional properties of the paraFacial Respiratory group within the brainstem respiratory network

呼吸活动是由位于下脑干（髓质）的节律性活跃的神经细胞（神经元）产生的;这些神经元控制呼吸肌从出生到生命的最后一次呼吸的连续节律性收缩。多年来，前伯青格复合体（preBötC），一组延髓中的吸气神经元，一直被认为是呼吸的唯一基础系统。在该模型中，吸气是呼吸循环的活跃阶段。然而，最近的证据表明，第二个区域，旁面部呼吸群（paraFacial Respiratory Group，pFRG），也可能在呼吸节律发生中起关键作用，该区域被特别提出在产生呼气活动（呼气肌的主动募集）中起关键作用，而preBötC是吸气所必需的。

Respiratory activity is generated by rhythmically active nerve cells (neurons) located in the lower brainstem (medulla); these neurons control the continuous rhythmic contraction of respiratory muscles from birth until the last breath of life. For a number of years, the preBötzinger Complex (preBötC), a group of inspiratory neurons in the medulla, has been thought to be the only system that underlies respiration. In this model, inspiration is the active phase of the respiratory cycle. Recent evidence, however, has shown that a second region, the para Facial Respiratory Group (pFRG), may also have a key function in respiratory rhythmogenesis and this area has been specifically proposed to have a critical role in the generation of expiratory activity (active recruitment of expiratory muscles), whereas preBötC is necessary for inspiration.