Fig. 9.

Representative examples of phrenic motoneurons that burst during inspiration (A) or tonically across the entire respiratory cycle (B). Sorted waveforms (i.e., spikes) and raw unit bursting, along with the phrenic neurograms (∫Phr), are presented in the left column. The middle column shows waveform overlay plots and cycle-triggered histograms for each cell. The η² values (see materials and methods) are provided above the histogram. The panels on the right provide the output of STA of the integrated phrenic neurogram (∫Phr, top) and raw phrenic neurogram (Phr, bottom). The phasic cell that is shown in A displays strong inspiratory-related modulation (see cycle-triggered histogram) and has an accordingly high η² value. In contrast, the tonic phrenic motoneuron shows no evidence for respiratory modulation and the η² value is close to zero. Nevertheless, both of these cells display a distinct latency peak in the phrenic spike-triggered average that can be observed in both the raw and integrated phrenic signal.