Figure 5. Relationship between ELM burst and PND absence.

Aa, two types of phrenic cycles. One is a cycle during which the ELM fires with a burst activity (B). The other is a cycle during which no burst activity (NB) is observed. Ab, black dots represent lengths of every B cycle during 1 and 5 Hz SLN stimulation, and grey dots lengths of those NB cycles that are present immediately before the B-cycles. The dashed baseline indicates the cycle length of ventilation at a frequency of 80 cycles min⁻¹. Note that 47/65 B-cycles occur at about twice as long as baseline. Ba, an overlay of five raw traces of rectified PNDs, including one before (black) and four during (grey) stimulation of the SLN. PND_BB is the PND immediately before the burst, and PND_AB is the PND immediately after the burst. The arrow indicates the position of the burst. Bb, open and filled bars represent the sizes of PND_BB and PND_AB respectively, which are normalized to control, as measured from an average of three consecutive PNDs before stimulation of the SLN.