Fig. 4: Disruption of PPT1-GABA_AR interaction enhances theta and gamma oscillation power but impairs theta phase coupling in CA1 region.

FP signals recorded in the CA1 region of WT (A), PPT1-KI (B), PPT1-KI treated with BuHA (C), and Gabra1^em1 mice (1 to 2 months old) (D). Lower traces show filtered theta (3–8 Hz) and gamma oscillation (30–80 Hz) from the FP signals. Spectrograms of the FP signals recorded from WT (E), PPT1-KI (F), BuHA-treated PPT1-KI (G), and Gabra1^em1 (H) mice. I PSD of FP recorded from WT (black), PPT1-KI (red), BuHA-treated PPT1-KI (blue), and Gabra1^em1 (green) mice. Analysis of the theta (J) and gamma (K) PSD. WT: n = 8 mice; PPT1-KI: n = 8 mice; PPT1-KI treated with BuHA: n = 8 mice; Gabra1^em1: n = 6 mice; one-way ANOVA, ***P < 0.001. Sample traces show theta phase locking in the CA1 region. Peri-event raster (upper panel) and histogram (lower panel) displaying phase coupling of spike units and theta waves recorded from WT (L), PPT1-KI (M), BuHA-treated PPT1-KI (N), and Gabra1^em1 (O) mice. Tips display the timestamps of the spike units. Dotted lines indicate valleys of theta waves. Bin width is 2 ms. Circular distribution of mean-spike theta phase angles (15° bin width) (upper panel) recorded from the CA1 area of WT (P), PPT1-KI (Q), BuHA-treated PPT1-KI (R), and Gabra1^em1 (S) mice. The red bars represent the direction and magnitude (length) of the MRL of the population. T Comparison of mean MRL values between multiple groups. WT: n = 31 neurons from 6 mice; PPT1-KI: n = 35 neurons from 5 mice; BuHA-treated PPT1-KI: n = 29 neurons from 5 mice; Gabra1^em1: n = 40 neurons from 6 mice. Kruskal–Wallis test, ***P < 0.001. Data are represented as mean ± SEM.