CNO administration (compared to Veh administration) to mice micro-infused with hM4Di-mCherry in ACC or CA1 region of dorsal hippocampus did not alter (a) ripple amplitude (Veh n = 16, ACC-CNO n = 8, CA1-CNO n = 8; two-way repeated measures ANOVA pre-training versus post-training x Veh versus ACC-CNO versus CA1-CNO; pre-training versus post-training F1,29 = 13.42, p=0.001; Veh versus ACC-CNO versus CA1-CNO F2,29 = 0.63, p=0.54; interaction F2,29 = 0.64, p=0.54), or (b) spindle amplitude (Veh n = 16, ACC-CNO n = 8, CA1-CNO n = 8; Kruskal-Wallis test Veh versus ACC-CNO versus CA1-CNO p=0.056; Wilcoxon signed rank test pre-training versus post-training p=0.027). No differences in (c) power spectrum (between 2–200 Hz) before (pre-training) and after (post-training) CNO treatment in mice micro-infused with virus in ACC (left, % total ACC power, n = 8) or CA1 (right, % total CA1 power, n = 8), or (d) % total power (between 1–100 Hz) as quantified from (c), in delta (1–4 Hz), theta (4–12 Hz), alpha (12–20 Hz), beta (20–40 Hz) or gamma (40–100 Hz) frequency bands in mice micro-infused with hM4Di-mCherry virus in ACC (left, two-way repeated measures ANOVA pre-training versus post-training x five frequency bands; pre-training versus post-training F1,7 = 0.47, p=0.52; frequency bands F4,28 = 17.88, p<0.0001; interaction pre-training versus post-training x frequency bands F4,28 = 1.74, p=0.17), or CA1 (right, two-way repeated measures ANOVA pre-training versus post-training x five frequency bands; pre-training versus post-training F1,7 = 0.001, p=0.97; frequency bands F4,28 = 16.30, p<0.0001; interaction F4,28 = 0.64, p=0.64). No differences in Veh- or CNO-treated mice micro-infused with virus in ACC or CA1 in (e) non-REM (NREM) ratio during recording sessions, (ACC, left, n = 8 per group; two-way repeated measures ANOVA pre-training versus post-training x Veh versus CNO; pre-training versus post-training F1,14 = 3.46, p=0.084; Veh versus CNO F1,14 = 1.12, p=0.31; interaction F1,14 = 0.40, p=0.55; CA1, right, n = 8 per group; Mann-Whitney test p=0.84, Wilcoxon signed-rank test Veh pre-training versus post-training p=0.74, CNO pre-training versus post-training p=0.55), or (f) NREM bout duration (ACC, left, n = 8 per group; Mann-Whitney test p=0.15, Wilcoxon signed-rank test Veh pre-training versus post-training p>0.99, CNO pre-training versus post-training p=0.55; CA1, right, n = 8 per group; Mann-Whitney test p=0.75, Wilcoxon signed-rank test Veh pre-training versus post-training p=0.95, CNO pre-training versus post-training p=0.38). (g) Learning-induced increases in cross-correlation between spindle and ripple events in Veh-treated mice micro-infused with hM4Di-mCherry in ACC or CA1 was prevented in CNO-treated mice. (h) Pre-training-normalized peak correlation coefficients in mice micro-infused with virus in ACC (n = 8 per group; Welch’s t-test t8.07 = 2.46, p=0.023; Veh versus one one-sample t-test t7 = 1.93, p=0.095; CNO versus one one-sample t-test t7 = 3.49, p=0.01), or CA1 (n = 8 per group; Welch’s t-test t8.73 = 2.49, p=0.036; Veh versus one one-sample t-test t7 = 2.18, p=0.066; CNO versus one one-sample t-test t7 = 1.29, p=0.24). (i) Pre-training-normalized ripple-spindle joint occurrence rate in mice micro-infused with virus in ACC (n = 8 per group; Welch’s t-test t9.66 = 3.67, p=0.005; Veh versus one one-sample t-test t7 = 2.66, p=0.033; CNO versus one one-sample t-test t7 = 3.05, p=0.020), or CA1 (n = 8 per group; Welch’s t-test t7.88 = 2.35, p=0.047; Veh versus one one-sample t-test t7 = 2.08, p=0.077; CNO versus one one-sample t-test t7 = 1.40, p=0.21). Data are individual mouse, or mean ±s.e.m. (a.u.: arbitrary unit, *p<0.05, **p<0.01).