Figure 1.
Hypnogram (top) and its respective hypnospectrogram (whole-night time frequency plot of EEG power) (middle) derived from Cz for subject 2.
In hypnogram green dots mark the occurrence of KCs selected for the study and vertical lines the definition of a “cycle” used in Figure 2. MA, microarousal, AW, awake, REM, rapid-eye movement sleep, NR1–4, non-REM sleep stages 1–4. Bottom part: Raw EEG of selected midline electrodes. A K-complex (A) from NREM stage II ending with a spindle (B) is seen (group KC01). Two individual sporadic spindles are also seen (C, D). D is not included in this study because of its proximity to the KC. Sleep staging for all the subjects is provided as a lasagna plot [52] in supplementary figure.
Table 1.
Descriptive Summary of Sleep Patterns.
Figure 2.
All graphs show Spindle Band Power developing over time: Raster images composed of individual time-frequency plots of EEG power near the frequencies of each subject's individual spindle spectral frequency band, for 15 s before and after each event (sporadic spindles in A and KCs in B–D).
Average power change is shown below each raster. A1–2: Spindles as reference events (at time zero). In the y-axis spindle event successive number; all averaged in A2. B1–2: KCs as reference events, spindle data sorted by KC group (from top to bottom: KC00, KC01, KC10, KC11); all averaged in B2. C1–6: KCs as reference events, spindle data sorted by KCs time of occurrence during the night and separated in successive sleep cycles; data from cycles 1–5 averaged in C2–C6 respectively. D1–3: KCs as reference events, spindles data sorted by the amplitude of KCs negative peak. D2 and D3 average data for the relatively larger and smaller KCs respectively. Relative absence of spindles is prominent 2–3 s after the negative peak (B1,C1,D1) and a relative long-term (10–15 s) reduction in their rate of appearance is shown for the about 80 top amplitude-sorted KCs (D1–3). All images, from subject 1.
Figure 3.
Average spectrogram (left), event-related spectral perturbation (middle) and significant changes (right) for a time period 15 s before and 25 s after the negative peak of KCs sorted by group (KC00, KC01, KC10, KC11 in rows 1–4 respectively) and the negative middle peak for sporadic spindles (in 5th row) of subject 1.
Figure 4.
Average spectrogram (left), event-related spectral perturbation (middle) and significant changes (right) as in Fig. 3 but for subject 2.
Figure 5.
Grand average of spindle power changes (dark blue line) ± SD on all KC groups (rows 1–4) and individual spindles (5th row) for all subjects.
The average change is calculated over the individual spindle frequency band for every subject.