Fig. 1
From: Bidirectional prefrontal-hippocampal dynamics organize information transfer during sleep in humans
Sleep architecture and coupled NREM oscillations. a Top: hypnogram of a single subject (MT = movement time). Bottom: corresponding multi-taper spectrogram with superimposed number of detected SO and sleep spindle events (white solid lines; 5 min averages). b Top: normalized circular histogram of detected spindle events relative to the SO phase. Note the peak around 0° (circular mean = 15.27°, i.e. after the SO peak). Bottom: peak-locked sleep spindle average across all detected events in NREM sleep (black). Low-pass filtered events (red) highlight that the sleep spindles preferentially peaked during the SO ‘up-state’. c Peak-locked spindle grand average (black; N = 18; scalp EEG) superimposed with the SO low-pass filtered signal (red). Inset: spindles were significantly nested in the SO peak (V-test: p = 0.0050; red dots depict individual subjects). d Directional SO-spindle coupling as measured by the phase-slope index (PSI; mean ± SEM). SO phases significantly predicted spindle amplitudes (one-tailed t-test: p = 0.0436). Red dots depict individual subjects
