Developmental Changes in Sleep Oscillations during Early Childhood

Figure 3

(a) Mean () power density spectra (geometric mean) and (b) event ratios of REM sleep (REMS), light sleep (LightS, NREM sleep stages 1 and 2), and slow-wave sleep (SWS, NREM sleep stages 3 and 4) recorded longitudinally at 2 (blue), 3 (red), and 5 years (orange) of age. The insets in the event ratios are a zoom into the 8–18 Hz range, and the frequency axis of inset and main plot do correspond (e.g., 10 Hz is at the same location in both plots). For a statistical assessment of the longitudinal changes in specific frequency bands, see Figure 4.