Data analyses were performed by MATLAB version 9.5 (R2018b, The MathWorks, Inc., Natick, MA; https://www.mathworks.com/products/new_products/release2018b.html) using the EEGlab toolbox 14.1.2b. For removing potential electric power-related noise, 4 Hz bandstop filter was applied centered at 50 Hz and its harmonics up to 400 Hz. For all data and frequency bands a zero-phase Hamming-windowed sinc finite impulse response (FIR) filter implemented in EEGlab (function pop_eegfiltnew contributed by A. Widmann) was used, which automatically calculates the transition bandwidth and filter order for the selected frequency bands. Ripple detection was performed on the basis of the analysis method by Gelinas et al. (2016) within the NREM stages 2 and 3 sleep. For removing potential epileptic activity (IEDs) whole-night ANT and MD LFP signals were band-pass filtered with a 25-80 Hz finite impulse response (FIR) filter. The filtered signal was then rectified and normalized. IEDs were detected as events where the filtered envelope (applying Hilbert transformation) exceeded 2 times the baseline (the mean of the filtered envelope). Those events were then eliminated where the unfiltered signal envelope was 2 times below the baseline. Where two or more IEDs occurred within 1 s, only the one with the largest amplitude was kept. For thalamic ripple detection band-pass filtering of the whole-night ANT and MD LFP signals were performed at 100–200 Hz (FIR filter). The filtered signal was then rectified and normalized. Ripples were then detected as events where the filtered envelope exceeded 5 standard deviations the baseline (the mean of the filtered envelope), and the mean envelope around the detected ripple event for a minimum of 20 ms and a maximum of 100 ms exceeded 2 standard deviation the baseline. Density of the ripples (ripple number per minutes) were calculated for the whole non-artifactual NREM sleep (in stage 2 and 3; defined as ripple(NREM) density) and for sleep spindles (i.e. the density of ripple events occurring during sleep spindle periods; defined as ripple(sp) density). Ripple(NREM) density and ripple(sp) density were compared by two-tailed Student’s t-tests, separately for the ANT and MD. Statistical analyses were performed by STATISTICA 13.1 and JASP 0.15.0.0.