FIG. 2.

A and B: discharge patterns of individual respiratory neurons from each simulated population and network region (labels on the left) and the integrated population traces for expiratory and phrenic motoneurons and lung volume receptors (3 bottom traces) during “eupneic” respiratory rhythm (A) and following disconnection of lung volume or slowly adapting PSR feedback (B,“vagotomy”—perturbation 1—circled here and in Fig. 1), which produced an increase in the amplitude and duration of phrenic discharge. C: the effect of rostral pons “removal” (inactivation of populations representing the rostral pons; perturbation 2—circled here and in Fig. 1) resulted in an apneustic pattern with prolonged and irregular inspiratory phase durations. D: complete removal of the pons (perturbation 3—circled here and in Fig. 1) led to a gasping-like pattern. See text for details.