Comparisons between conditions for the mean estimated frequency.

<p>Mean estimated frequency for the 4–8 Hz component for IC and NC conditions (top left), ANOVA p-values for the 4–8 Hz component (bottom left), mean estimated frequency for the 45–55 Hz component for IC and NC conditions (top right), ANOVA p-values for the 45–55 Hz component (bottom right). Vertical dashed lines denote stimulus onset and horizontal ones denote the 5% significance level.</p

Comparisons between conditions for cross-frequency couplings.

<p>The phase-amplitude (top rows) and phase-phase (bottom rows) couplings were measured with adaptive frequency tracking. Significant intervals are shown in blue (respectively in red) when the coupling strength was higher for the IC (respectively NC) condition. Color intensity denotes significance level of the corresponding permutation test.</p

Pre-processing steps.

<p>EEG signal filtered in the 35–45 Hz band (top), oscillation extracted with the SFT (middle), and its estimated instantaneous frequency (bottom). The estimated frequency is plotted on top of the short-time Fourier transform of the EEG signal. The vertical dashed lines denote stimulus onset.</p

Experimental conditions.

<p>IC condition (left), NC condition (right).</p

Comparisons between datasets for the mean estimated frequency.

<p>Mean estimated frequency for the 1–4 Hz component for real (R) and surrogate (S) datasets (top left), ANOVA p-values for the 1–4 Hz component (bottom left), mean estimated frequency for the 4–8 Hz component for real and surrogate datasets (top right), ANOVA p-values for the 4–8 Hz component (bottom right). Vertical dashed lines denote stimulus onset and horizontal ones denote the 5% significance level.</p

Processing steps used for analyzing the EEG data.

<p>The same features were extracted before and after frequency tracking in order to assess the usefulness of the proposed adaptive algorithm.</p

Comparisons between datasets for the phase-amplitude (PA) couplings.

<p>Coupling strength for real (R) and surrogate (S) datasets was measured using the PLV. Mean PLV for the 1–4 Hz and 4–8 Hz components for real and surrogate datasets (top left), ANOVA p-values for these components (bottom left), mean PLV for the 4–8 Hz and 35–45 Hz components for real and surrogate datasets (top right), ANOVA p-values for these components (bottom right). Vertical dashed lines denote stimulus onset and horizontal ones denote the 5% significance level.</p

Comparisons between conditions for the phase-phase (PP) couplings.

<p>Coupling strength between the 4–8 Hz and 8–12 Hz components was measured using the PLV. Mean PLV with coupling coefficients set to 3∶2 for IC and NC conditions (top left), ANOVA p-values for these coefficients (bottom left), mean PLV with coupling coefficients set to 2∶1 for IC and NC conditions (top right), ANOVA p-values for these coefficients (bottom right). Vertical dashed lines denote stimulus onset and horizontal ones denote the 5% significance level.</p

Comparisons between datasets for cross-frequency couplings.

<p>The phase-amplitude (top rows) and phase-phase (bottom rows) couplings were measured with adaptive frequency tracking. Significant intervals are shown in blue (respectively in red) when the coupling strength was higher for the real (R) (respectively surrogate (S)) dataset. Color intensity denotes significance level of the corresponding permutation test.</p

Original and surrogate EEG signals.

<p>Real EEG signal (top left), surrogate signal (bottom left), amplitude spectrum of the real signal (top right), amplitude spectrum of the surrogate signal (bottom right). Vertical dashed lines denote stimulus onset.</p