Fig. 1 | Nature Communications

Fig. 1

From: Local hippocampal fast gamma rhythms precede brain-wide hyperemic patterns during spontaneous rodent REM sleep

Fig. 1

REM sleep is characterized by massive brain-wide hyperemia. a Typical fUS-EEG recording during sleep subsequent to a track-running task. Sleep scoring is performed by using neck electromyogram (EMG), head acceleration (ACC), and hippocampal local field potential (LFP) to discriminate between quiet wake (QW), active wake (AW), non-REM sleep (NREMS), and REM sleep (REMS). REMS periods are characterized by high theta/delta ratio, low ripple content and elevated cerebral blood volume (CBV). Scale bar: 5 min (Top) Four typical Power Doppler images (CBV, voxel resolution: 100 × 100 × 400 μm) for each state and corresponding 5-s LFP trace. Scale bar: 1 s. Note the similarity in the EEG patterns (theta activity) between AW and REMS, contrasted by the discrepancy in the vascular patterns. b Regional hemodynamics during a transition between NREMS to REMS. (Top) High-amplitude vascular patterns are present in almost all brain regions and more sustained in the dorsal thalamus and hippocampus. (1–2) Auditory cortex, left and right, respectively; (3–4) Primary somatosensory barrel field cortex; (5–6) Lateral parietal association cortex; (7–8) Retrosplenial cortex; (9–10) CA1 region; (11–12) CA2 region; (13–14) CA3 region; (15–16) Dentate gyrus; (17–18) Dorsal thalamus; (19–20) Post-thalamic nuclear group; (21–22) Ventral posteromedial thalamic nucleus; (23–24) Whole thalamus; (25–26) Hypothalamic region. Scale bar: 20 s. (Bottom) Phasic vascular events (vascular surges) are detected when the proportion of active voxels (gray curve) crosses 50% of total voxel amount. A pixel is «active» when its value is higher than one standard-deviation above active wake levels

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