eLife assessment
This important study advances our understanding of the composition and circuit organization of the preBötzinger complex (preBötC)-the brainstem region that generates the respiratory rhythm and coordinates breathing with different motor and physiological behaviors in mammals. The reviewers agreed that the evidence supporting the conclusion that the preBötC is composed of a segregated subgroup of output neurons that modulates orofacial muscle activity is compelling and based on technically elegant, state-of-the-art combinatorial dual viral transgenic and optogenetic approaches in rats. After the cytoarchitectonic analyses are strengthened, the work will be of interest to neuroscientists and physiologists working on the neural control of breathing and other motor systems.