Figure 5. Median (A) and individual phase coherences (B) between skin and muscle sympathetic nerve activities for all subjects.

The heavy black lines indicate median (A) and individual (B) phase coherences; the grey lines indicate average surrogate values (see Methods), and the red areas indicate coherence which was significantly different (greater than 2 standard deviations above) from the surrogate values. The asterisks indicate frequency ranges within which skin and muscle coherences were significant. In all subjects, skin and muscle sympathetic nerve activities were significantly coherent over a broad range, including cardiac frequencies (extreme right of individual data panels). The group median data (A) obscure the significant narrow frequency ranges over which skin and muscle sympathetic nerve activities are coherent in individuals.