Evolution is certain to have ensured optimal strategies to drive inspiratory muscles to produce pulmonary ventilation, a function which is essential for survival. However, the neural underpinnings for such strategies are little studied. We have examined the recruitment of single human motoneurones in obligatory inspiratory muscles, particularly the diaphragm and inspiratory intercostal muscles (e.g. Butler & Gandevia, 2008), in an attempt to find common strategies that may underlie their recruitment in different tasks. These include volitionally-driven inspiration and inspiration driven by chemical drive, presumably from pontomedullary respiratory centres. During quiet breathing, inspiratory activity in the parasternal intercostal muscles is measured for populations of single units. There is earlier and greater activity in those muscle portions with a greater mechanical advantage for inspiration (e.g. De Troyer et al 2005; Gandevia et al 2006). This ensures efficient matching between neural drive and ventilation. This principle of ‘neuromechanical matching’ represents a recruitment strategy superimposed on the well-known Henneman size principle. During highly volitional breathing this strategy is preserved in the intercostal muscles (Hudson et al 2011). We have proposed that this common neuromechanical matching is mediated at a premotoneuronal level via a ‘spinal distribution network’ for inspiratory drive. Unfortunately, the human studies do not reveal whether such a network exists at a spinal level, or whether pontomedullary, or even motor cortical circuits are involved. However, recent studies in dogs spinalised at C2 show that intercostal motor unit firing preserves the usual neuromechanical matching of spontaneous breathing even when ventilation is evoked by thoracic spinal cord stimulation (DiMarco & Kowalski, 2010; 2011). This represents evidence for a spinal distribution network which can impose neuromechanical matching on intercostal motor output. There is also other evidence for respiratory propriospinal neurones (e.g. Saywell et al 2011). A spinal distribution network makes sense from an evolutionary perspective: axial muscles would first have been driven by reticulospinal paths, then also by bulbospinal paths as lung breathing developed, and then finally by corticospinal paths. Such a network would ensure efficient muscle use with a range of descending drives for different tasks.