Figure 2 | Scientific Reports

Figure 2

From: Fine Structure of Posterior Alpha Rhythm in Human EEG: Frequency Components, Their Cortical Sources, and Temporal Behavior

Figure 2

Individual examples of two-component structure of alpha rhythm. (A) The amplitude spectrum densities (ASD) of an EEG from posterior electrodes (O1, P1, P5, and TP7 according to the Extended 10/20 System) are presented in the conventional alpha frequency range. (B) The frequency loadings of the two ARCs extracted with PARAFAC1. (C) The normalized source distributions of the ARCs (spatial loadings of the components) are rendered on the average MNI brain (posterior view). Color indicates loading values: the higher the color intensity, the higher the loadings. (D) Temporal loadings of ARC1 (green lines and bars) and ARC2 (red) are shown over representative 3-minute periods (upper row) and as averages over the 4 REC periods (bottom row). The temporal fluctuations of the two components’ loadings are not correlated and both ARCs are well present over the whole EEG session (1.5–2 hours). The dimensionless loading values (y-axes in B and D) are normalized to the maximum value of each loading matrix.

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