Fig. 5.

Wavelet phase coherence and windowed wavelet phase coherence from one subject. B: a contour plot documents phase coherence between breathing and diastolic pressure during both spontaneous breathing and the first (fast-to-slow) ramped-frequency breathing period. The time-averaged wavelet phase coherences (A and C) indicated that significant coherence (red) was limited primarily to the usual breathing frequency range. Significant breathing and muscle sympathetic nerve wavelet phase coherence was limited to a narrow frequency range during spontaneous breathing (D). Phase coherence between diastolic pressure and muscle sympathetic nerve oscillations (G and I) was significant over a wide frequency range and seemed to be uninfluenced by the breathing mode. For the analyses depicted in this figure and Fig 6, we did not test for significance above 0.5 Hz (the Nyquist frequency of R-R interval, systolic, and diastolic pressure signals; see methods).