Phasic bursting in the hypoglossal nerve (HN) can be uncoupled from phrenic bursting by application of positive end-expired pressure (PEEP). We wished to determine if similar uncoupling can also be induced in other respiratory-modulated upper airway (UAW) motor outputs. Discharge of the facial, hypoglossal, superior laryngeal, recurrent laryngeal and phrenic nerves was recorded in anesthetized, ventilated rats during stepwise changes in PEEP with a normocapnic, hyperoxic background. Application of 3-6 cmH₂O PEEP caused the onset inspiratory UAW nerve bursting to precede the phrenic burst, but did not uncouple bursting. In contrast, application of 9-12 cmH₂O PEEP uncoupled UAW neurograms such that rhythmic bursting occurred during periods of phrenic quiescence. Single fiber recording experiments were conducted to determine if a specific population of UAW motoneurons is recruited during uncoupled bursting. The data indicate that expiratory-inspiratory (EI) motoneurons remained active while inspiratory (I) motoneurons did not fire during uncoupled UAW bursting. Finally, we examined the relationship between motoneuron discharge rate and PEEP during coupled UAW and phrenic bursting. EI discharge rate was linearly related to PEEP during pre-inspiration, but showed no relationship to PEEP during inspiration. Our results demonstrate that multiple UAW motor outputs can be uncoupled from phrenic bursting, and this response is associated with bursting of EI nerve fibers. The relationship between PEEP and EI motor neuron discharge rate differs during Pre-I and I periods; this may indicate that bursting during these phases of the respiratory cycle is controlled by distinct neuronal outputs.