Microglial TNFα modulates slow waves during NREMS. (a) Amounts of vigilance states over 24 h reported by 2-h segments. Wake, NREMS, and REMS are not significantly different between tCTL and micTNFα-KO mice (n = 15 mice per group; two-way RM-ANOVA, P = 0.1490; P = 0.2784, P = 0.6838 respectively). (b) Left: Average spectral density (top) of tCTL and micTNFα-KO (lines: means; shaded area: SEM). Right: Ratio between power in faster delta frequencies (δ2, waves from 2.5 to 3.5 Hz) and slower delta frequencies (δ1, waves from 0.75 to 1.75 Hz) in NREM sleep (Mann-Whitney W = 169, P = 0.0043). (c) Left: Examples of EEG and 0.1–4 Hz filtered EEG during NREMS from a transgenic control tCTL; the positive and negative peaks of the delta-filtered signal are indicated by orange and blue points, respectively. Ticks on gray lines indicate large positive deflections corresponding to slow waves (SW). Right: Grand average SW for tCTL (black) showing duration (d) and maximum slope (s), and micTNFα-KO (green). (d) Characteristics of SW in a 24-h time period. micTNFα-KO mice exhibit significantly shorter peak onset slopes and longer SW duration than tCTL mice. Mann–Whitney W = 42 P = 0.005 and W = 153, P = 0.37 respectively. n = 14 tCTL and 15 micTNFα-KO respectively. (b [right] and d) Results are presented as minimum to maximum boxplots with the individual values of each mouse represented as datapoints.