Figure 2.

Developmental conditions: average power density spectra (first 27 min of artefact-free epochs of non-rapid eye movement (NREM) sleep, which is the common maximal duration across recordings and subjects) for absolute (top row) and relative data (bottom row, calculated relative to 2 years). Markers at bottom of subplots refer to significant differences between age groups (2, 3, 5 years).