Figure 2

Representative power spectrum of the RR interval and associated histogram for lung inflation cycles in one toad Rhinella schneideri during normoxia. Spectrum of the RR interval exhibits a less defined ventilatory-related peak that emerges in a more scattered range of frequencies (A). Lung inflation cycles presented as frequency distribution histograms binned into 0.001 Hz width band (B) for comparison purposes with the spectrum of the RR interval (Data represents animal from Fig. 1).