Cross TF representations between SAPV (S), respiration (R) and HPV (H) from a subject of TTSR data set. (a)–(c) Time-frequency coherence γik(t,f); Ω(γ) is delimited by white contour. The time course of γik(t) is reported below. (d)–(f) Partial TF coherence γik/z(t,f); Ω(γ) is delimited by black contour. The time course of γik/k(t) is reported below.(g)–(i) Phase difference spectra θik(t,f) with. The time course of θik(t) and are reported below.