Extended Data Fig. 8: [Cl⁻]_i regulation underlies local low-frequency cortical oscillations in the sleep-deprived awake state.

Data from Fig. 6 is replotted by normalizing the LFP and EEG spectral power in the 3^rd hour of the sleep-deprived awake state, to the preceding 12 h baseline. Continuous awake LFP and EEG recordings were used to monitor local and global spectral power, respectively. Mice experienced a 3-hour SD protocol at the beginning of the light period (ZT0 to ZT3), during which [Cl⁻]_i was manipulated by locally infusing blockers of NKCC1 or KCC2 into S1. a. The awake LFP normalized to 12 h baseline (left) revealed an increase in low-frequency cortical oscillations (2–6 Hz; black: 15 animals). The level of low-frequency oscillations was reduced by local infusion of bumetanide (blue versus black, *p = 0.0116, paired t-test; t = 3.582; df = 6; d = 1.35; blue: 7 animals, black: 7 animals) and increased by VU (red versus black, **p = 0.0078, Wilcoxon matched-pairs signed-ranks test; d = 0.89; red: 8 animals, black: 8 animals,). These manipulations did not affect the frontal EEG (right; blue versus black, p = 0.5122, paired t-test; t = 0.6965; df = 6; d = 0.26; blue: 7 animals, black: 7 animals; red versus black, p = 0.4467, paired t-test; t = 0.8255; df = 5; d = 0.34; red: 6 animals, black: 6 animals). b. To test the relationship of the low-frequency oscillations to activity-dependent processes during SD, whiskers were trimmed unilaterally just before the animal experienced the 3-hour SD protocol. Either vehicle control (Veh) or VU was infused unilaterally during SD. The awake LFP normalized to 12 h baseline (left) revealed that whisker trimming prevented the increase in local low-frequency cortical oscillations (blue versus black, ***p = 0.0007, paired t-test; t = 6.452; df = 6; d = 2.44; blue: 7 animals, black: 7 animals). This effect could be rescued by VU infusion into S1 (red versus blue, *p = 0.0122, unpaired t-test with Welch correction; t = 3.541; df = 6; d = 1.4; red: 7 animals). Neither whisker trimming nor S1 infusion affected the increase in low-frequency oscillations detected in the frontal EEG (right; blue versus black, p = 0.0873, paired t-test; t = 2.041; df = 6; d = 0.77; red versus blue p = 0.6495, unpaired t-test; t = 0.47; df = 12; d = 0.9). Data represent mean ± sem. All tests are two sided.

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