Figure 15.

Network links of interaction between muscle tone frequency bands and cortical rhythms. Histograms of group-averaged network links as measured by the TDS method (Materials and Methods section 2.3) representing strength of interaction between each EMG frequency band of (A) chin and (B) leg muscle tone and brain cortical rhythms (δ, θ, α, σ, β, γ₁, γ₂ from the Frontal Fp1 area) for different sleep stages. Links are grouped to present the interaction of each EMG band with all cortical rhythms at the Fp1 channel location. Each figure panel corresponds to the links strength interaction profile of all EMG bands with the Fp1 cortical area (shown in Figures 12, 14) for a given sleep stage—the average links strength of each group in a panel is presented as a separate bar in the Fp1 profile in Figures 12, 14. Histograms show inhomogeneous distribution of links strength, where all EMG bands of both chin and leg muscle tone exhibit dominant interactions with the high-frequency γ₁ and γ₂ cortical rhythms during wake (one-way ANOVA for each separate group gives p ≤ 0.001), while REM, light and deep sleep are characterized by stronger same-frequency coupling of EMG bands with the corresponding cortical rhythms (δ_EEG-δ_EMG, θ_EEG-θ_EMG, etc.), a behavior more pronounced for chin-brain compared to leg-brain interactions (Method 2.6). Results are consistent for all brain areas (EEG channel locations), indicating universal patterns in cortical rhythm and muscle tone network interactions.