For slow wave propagation (Figure 7), we focused on events identified in Fz and in

intracranial recordings of at least three brain structures, although the results were highly robust to the exact detection parameters and to other examinations (Figure S6). To compare timing of unit discharges within MTL (Figure 5F), we defined time zero based on the positive peak of EEG slow waves in parahippocampal gyrus (9/13 subjects) or entorhinal cortex (4/13 subjects). For analysis of local spindles, spectrograms were computed in ± 1 s intervals around peak spindle power, using a short-time Fourier transform with a window of 744 ms and 95% overlap, and normalizing selleck compound power relative to random intervals as in (Sirota et al., 2003). Phased-locked spiking (Figure 3D) was assessed by extracting the instantaneous phase of the depth EEG filtered between 0.5–4 Hz ± 500 ms surrounding slow wave positive peaks via the Hilbert transform, testing for nonuniformity of the phase distribution of spike occurrences using Rayleigh’s test, and determining critical p values using shuffled data to control

for asymmetries in the EEG waveforms (Figure S3). Slow-wave-triggered averaging was conducted for each unit separately using the highest amplitude slow waves in each channel (top 20%). The timing and CCI-779 chemical structure magnitude of firing Ketanserin rate modulations were defined based on the maxima/minima using 20 ms bins. Propagation in unit activities were evaluated across all significantly phase-locked units within a region (Figures 7E and 7F, left; Figure S7F), or for individual units separately using 20 ms bins (Figures 7E and 7F, right). Statistical significance of time differences between spiking activities

of individual units in distinct brain structures (Figures 4E and 4F) was evaluated via bootstrapping by (1) assigning a random anatomical label to each neuron separately (either frontal or MTL for Figure S6G, either PH or HC for “within MTL” analysis in Figure S6H), (2) creating surrogate groups with the same number of units as the real data, and (3) computing the random time offset between the two groups as was done for the real data (Figure S6). In five individuals exhibiting a clear homeostatic decline of SWA during sleep, we analyzed slow waves, K-complexes, and sleep spindle separately in early and late NREM sleep (Figure S1D). Putative K-complexes were detected in Fz recordings as isolated slow waves (within ± 3 s) with peak-to-peak amplitude >75 μV. Classification was performed with a support vector machine using a linear (dot product) kernel, using data from 17 hemispheres of nine individuals in which signals from amygdala and other limbic structures were recorded.