Noeud vital for breathing in the brainstem: gasping—yes, eupnoea—doubtful

Abstract

For the past 200 years, various regions of the brainstem have been proposed as a ‘noeud vital’ for breathing—a critical region which, when destroyed, results in an irreversible cessation of breathing and death. Complicating this search for a noeud vital is the extensive network of neurons that comprises the brainstem respiratory control system of pons and medulla. Does a cessation of breathing following ablation of any region reflect the removal of a critical set of neurons whose activity generates the respiratory rhythm or does it reflect the interruption of one component of the neuronal circuit, such that this circuit cannot function, at least temporarily? An additional complication is that in contemporary neuroscience, a number ofin vitropreparations have been introduced for the study of the generation of the respiratory rhythms. However, how are the rhythms that these preparations generate related to normal breathing? Are these rhythms similar to those of gasping, which is recruited when normal, eupnoeic breathing fails, or are these rhythms unique to thein vitropreparation and not related to any breathing patternin vivo?