Figure 2.

Topographical distribution of slow wave activity (EEG power between 0.75 and 4.5 Hz) during the first hour of NREM sleep for individuals within defined age-groups. Black dots represent all 109 EEG electrodes included in this analysis. Values are color coded (red: maxima, blue: minima). Numbers plotted on the right side of each map depict the maximal (red) and minimal (blue) value within each map. Topographical maps are proportionally scaled and missing electrode values were interpolated. Representative subjects up to 24 years were selected from the study by Kurth et al. (2010). Topographical plots of healthy control subjects older than 60 years from Neumann et al. (unpublished data) (A) Maturation of slow wave topography illustrated for 4- to >60-year-old subjects. Each plot includes data of one representative subject. (B) Each column represents the SWA maps of two different sleep sessions (at least 1 week apart) for one subject. The two maps of each subject illustrate the topographical “fingerprint” of the power distribution in the SWA range.