Figure 2 | Scientific Reports

Figure 2

From: A set of composite, non-redundant EEG measures of NREM sleep based on the power law scaling of the Fourier spectrum

Figure 2

Examples for spectral peaks over the antero-posterior cortical axis in one of the subjects. Upper part: periodograms in the double natural logarithmic plane characterized by a combination of linear trends and spectral peaks. Middle panel: whitened power by subtracting the fitted linears: ln P − (ln C + α ln f); note the uniform baseline power (~ 1) and the spectral peaks. Lower panel: enlarged spectral peaks in the spindle frequency range, characterized by lower frequency maxima in the anterior as compared to the posterior recording locations (see colour-coded arrows); maximal antero-posterior shifts in peak frequency emerged between the frontal and central recording sites, demarcating slow-anterior and fast-posterior sleep spindle-related spectral peaks.

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