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. 2017 Jun 14;118(4):2344–2357. doi: 10.1152/jn.00913.2016

Fig. 7.

Fig. 7.

Ratio of phasic to tonic ipsilateral phrenic nerve activity following C4 and T2 HF-ES. Shown are the average “signal-to-noise ratios” of phasic to tonic ipsilateral phrenic nerve activity at baseline and following each bout of HF-ES delivered to either the C4 (A) or T2 (B) spinal cord at 2 and 12 wk postinjury. A dose-dependent reduction in this ratio was observed following both C4 and T2 stimulation (*P < 0.05, different from 1,000 µA) across all outcomes (phasic, tonic, and total nerve activity), with the greatest reductions in this ratio occurring following the highest stimulation intensities. No significant time-dependent group differences were observed, although this ratio was consistently lower in the chronic postinjury time point, a finding that is consistent with increased baseline tonic activity in chronically injured rats. Data were evaluated using 2-way repeated-measures ANOVA with Holm-Sidak post hoc tests for individual comparisons (groups: 2-wk C4, n = 8; 12-wk C4, n = 8; 2-wk T2, n = 7; 12-wk T2, n = 7).