what is eupnea respiratory neuronal networks in vertebrates appear to be able to generate a variety of rhythmic patterns in vivo leading to the biological diversity of eupneic patterns as well as to lifethreatening dyspneic patterns eupnea is best viewed as the collection of respiratory strategies preventing potential dyspneas the major and perhaps the only criterion for a definition being that eupnea allows survival specific criteria can then be derived from the physiological identification of neurobiological mechanisms underlying identified dyspneic patterns by exaggerating prodyspneic mechanisms or suppressing them antidyspneic mechanisms because eupnea is vital and one of the major targets of evolutionary pressure identification of dyspnearelated neuronal systems seems to be important to understand the normal biological organization of the respiratory neuronal system