Fig. 5. Scopolamine disrupts phase synchrony in the theta band.

a Top-down: 6–8 Hz filtered traces, phases, phase differences, and circular histograms showing the phase differences between a right and left hippocampal electrode pair during an example trial in the placebo and scopolamine conditions for subject 4. b Top: Time-frequency spectrogram showing the phase-locking values (PLVs) for a hippocampal electrode pair from subject 4 during encoding for the placebo and scopolamine sessions. Warmer colors indicate greater PLV (synchrony). Bottom: Mean PLV as a function of frequency for the spectrogram shown above. Bars indicate frequency windows where statistical significance was present (blue = Plac. > Scop., red = Scop. > Plac., p < 0.05, two-sided Wilcoxon rank-sum test). c Top: Time-frequency spectrogram showing the PLVs for a hippocampal electrode pair from subject 5 during encoding for the placebo and scopolamine sessions. Warmer colors indicate greater PLV (synchrony). Bottom: Mean PLV as a function of frequency for the spectrogram shown above. Bars indicate frequency windows where statistical significance was present (blue = Plac. > Scop., red = Scop. > Plac., p < 0.05, two-sided Wilcoxon rank-sum tests). d Percentage of electrodes showing significant increases in synchrony at each frequency for placebo (left; blue) and scopolamine (right; red) conditions (p < 0.05, Wilcoxon rank-sum test). Dotted lines indicate the percentage of electrodes showing significant increases in synchrony during the baseline periods for placebo (left) and scopolamine (right) (see Methods). e Bar plot showing differences in the percentage of electrodes with significant increases in slow (2–4 Hz) and fast (4–10 Hz) theta-band synchrony for placebo and scopolamine (slow theta: z = −2.87, p = 4.06 × 10⁻³, fast theta: z = −2.09, p = 0.04, two-sided two-proportion z-tests). Source data are provided as a source data file.