Sleep spindles mediate hippocampal-neocortical coupling during long-duration ripples
- School of Psychology and Centre for Human Brain Health, University of Birmingham, United Kingdom
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Netherlands
- Department of Epileptology, University of Bonn, Germany
Figures
Figure 1
Cortical sleep spindles and hippocampal spindles and SW-Rs.
Top left: heat map illustrating the position of individual contacts across all patients within the hippocampus overlaid on a sagittal slice of the mean structural MRI. Right and bottom insets show …
Figure 2 with 1 supplement
Hippocampal and neocortical spindle activity coincides during SW-Rs.
Statistical maps (t-values) contrasting ripple-locked vs. control TFRs within HIPP (A) and NC (B). Hot colors indicate power increases around SW-Rs, whereas cold colors indicate relative power …
Figure 2—figure supplement 1
Power in the Slow Oscillation (SO) band.
Mean (± SEM) SO power (1–1.5 Hz) averaged across ±1 s around ripples (red) or across matched control events from NREM (dark gray) or REM (light gray) sleep for NC (A) and HIPP (B). Statistical …
Figure 3 with 3 supplements
(Directional) Cortical-hippocampal communication via spindles.
(A) HIPP-NC coherence. The red line depicts the observed coherence between HIPP and NC in the cluster of concurrent increases in spindle power around HIPP SW-Rs (see Figure 2C). Histogram depicts …
Figure 3—figure supplement 1
Mutual cortical-hippocampal connectivity around SW-Rs.
Statistical map (z-scores) contrasting ripple-locked and ripple-free control coherence between NC and HIPP from 1 to 20 Hz and −1 to 1 s around SW-Rs. White contour line outlines the significant …
Figure 3—figure supplement 2
Amplitude- and phase-based cortical-hippocampal connectivity.
(A) Statistical map (z-scores) contrasting ripple-locked and ripple-free control connectivity based on the orthogonalized power correlation. White contour line outlines the significant cluster of …
Figure 3—figure supplement 3
Directed cortical-hippocampal connectivity around SW-Rs.
Statistical map (z-score), masked with positive spectral coherence (Figure 2—figure supplement 1), depicting the difference in PDC between NC->HIPP and HIPP->NC time-locked to ripples in comparison …
Figure 4
Cortical-hippocampal communication is enhanced during long ripples.
(A) Top: histogram of ripple durations pooled across all patients. Red vertical lines indicate the average cut-offs for short (mean ± SEM duration=0.046 ± 0.001 s) and long ripple events (mean ± SEM …
Author response image 1
Time-frequency resolved NC-HIPP coherence obtained for observed ripple events (A) and after shuffling the corresponding NC-intervals and averaged across 100 realizations (B).
(C) HIPP-NC coherence determined for the cluster of concurrent spindle power around HIPP SW-Rs (see Figure 2). The red line depicts the observed coherence, whereas the histogram depicts the …
Tables
Table 1
Sleep architecture.
Mean ± SEM proportion of sleep stages S1, S2, slow wave sleep (SWS) and rapid eye movement (REM) sleep relative to the total time spent asleep.
| Mean | SEM | |
|---|---|---|
| S1 (%) | 22.8 | 4.6 |
| S2 (%) | 44.0 | 3.3 |
| SWS (%) | 16.4 | 2.6 |
| REM (%) | 16.8 | 2.2 |
| Total sleep time (min) | 427.6 | 29.0 |
Table 2
Properties of sleep spindles and sharp-wave ripples.
Patient-specific count and density (events per minute) of algorithmically detected spindles and sharp-wave ripples (SW-Rs) as well as the corresponding mean (± SEM) across participants. Note that …
| Spindle count | Spindle density (per min) | |||||
|---|---|---|---|---|---|---|
| Patient | NC | HIPP | NC | HIPP | SW-R count | SW-R density (per min) |
| 1 | 1440 | 1296 | 6.3 | 6.4 | 135 | 0.7 |
| 2 | 1243 | 571 | 5.5 | 4.3 | 107 | 0.8 |
| 3 | 1703 | 1725 | 5.5 | 5.9 | 116 | 0.4 |
| 4 | 1074 | 978 | 3.0 | 3.1 | 626 | 2.0 |
| 5 | 1427 | 625 | 5.4 | 2.4 | 206 | 0.8 |
| 6 | 1001 | 691 | 4.0 | 3.9 | 153 | 0.9 |
| 7 | 903 | 1975 | 3.3 | 6.7 | 403 | 1.5 |
| 8 | 1004 | 892 | 4.9 | 4.5 | 400 | 2.1 |
| 9 | 2079 | 2038 | 6.2 | 6.0 | 518 | 1.6 |
| 10 | 1120 | 840 | 6.3 | 4.3 | 245 | 1.4 |
| 11 | 494 | 739 | 4.7 | 7.0 | 208 | 2.0 |
| 12 | 448 | 417 | 5.6 | 6.3 | 44 | 0.7 |
| 13 | 1339 | 406 | 5.6 | 2.0 | 45 | 0.2 |
| 14 | 1899 | 1555 | 6.5 | 6.1 | 542 | 2.1 |
| Mean | 1226.7 | 1053.4 | 5.2 | 4.9 | 267.7 | 1.2 |
| SEM | 125.9 | 150.6 | 0.3 | 0.4 | 50.0 | 0.2 |
Table 3
MNI coordinates of the included electrode contacts.
For three patients, no MRI was available.
| MNI coordinates | |||
|---|---|---|---|
| Patient | X | Y | Z |
| 1 | −26 | −29 | -8 |
| 2 | |||
| 3 | |||
| 4 | 26 | −28 | -7 |
| 5 | |||
| 6 | 27 | −29 | -3 |
| 7 | −25 | −28 | 0 |
| 8 | −33 | −33 | -2 |
| 9 | 27 | −31 | -9 |
| 10 | 28 | −35 | -7 |
| 11 | −29 | −38 | -9 |
| 12 | 29 | −31 | 3 |
| 13 | 32 | −30 | -1 |
| 14 | −28 | −34 | -5 |
