Fig. 2: Example transition episodes in humans.
From: Aspects of tree shrew consolidated sleep structure resemble human sleep
a Top, spectrograms of example episodes of human sleep from three subjects. Bottom panel, corresponding traces of delta (0.5–4 Hz) and theta-alpha (4–12 Hz) power in red and blue respectively. Red patches highlight transition segments from NREM with high delta power to REM sleep with low delta power. b Delta power vs. theta-alpha power is shown for six example transitions. Title numbers corresponding to transitions with the same numbers from (a). Note theta-alpha power increases over the time course of a few transitions (see transition 1 and 7) in comparison to other transitions in which a simultaneous decrease of delta and theta-alpha power is observable. Color bars reflect Fourier power in arbitrary units.
