Tonic and phasic drive to medullary respiratory neurons during periodic breathing

Highlights ► Diaphragmatic activity was increased and phasic during the waxing phase and was decreased and tonic during the waning phase. ► Expiratory and inspiratory neural activity was increased and phasic during the waxing phase but was decreased and more tonic during the waning phase. ► During apneas associated with PB, diaphragmatic activity was silent and most, but not all, inspiratory cells were inactive while the activity of most expiratory cells was decreased but remained tonically active.