Fig. 3. Cortical [Cl^-]_i regulation determines the level of local SWA during NREM sleep.

a. An LFP electrode coupled to an infusion cannula was targeted to L5 of left S1 and frontal EEG screws were positioned over the right hemisphere. Continuous LFP and EEG recordings were used to monitor local and global spectral power, respectively. b. SWA (black triangle) is most intense at sleep onset (coincident with light onset), when sleep pressure is high, and lessens over the course of sleep. [Cl^-]_i was manipulated at different points during NREM sleep by locally infusing blockers of NKCC1 or KCC2. c. LFP in a mouse that received vehicle (top) or bumetanide (bottom) during early NREM sleep, on different days. Expanded traces (right) are from the boxed regions. d. Bumetanide infusion during early NREM sleep reduced local spectral power in the SWA range (left; **p=0.0027, paired t-test; t=5.508; df=5; d=2.25; 6 trials, 5 animals), without affecting frontal EEG (right; p=0.3989, paired t-test; t=0.9219; df=5; d=0.38; 6 trials, 5 animals). e. LFP in a mouse that received either vehicle (top) or bumetanide (bottom) during later NREM sleep, when levels of SWA have reduced. f. Bumetanide infusion during later NREM sleep did not affect local spectral power in the SWA range (left; p=0.8006, paired t-test; t=0.2663; df=5; d=0.11; 6 trials, 5 animals), or frontal EEG (right; p=0.972, paired t-test; t=0.0368; df=5; d=0.01; 6 trials, 5 animals). g. LFP in a mouse that received infusion of vehicle (top) or VU (bottom) during later NREM sleep. h. VU infusion during later NREM sleep increased local spectral power in the SWA range (left; **p=0.0073, paired t-test; t=4.366; df=5; d=1.78; 6 trials, 4 animals), without affecting frontal EEG (right; p=0.355, paired t-test; t=1.019; df=5; d=0.42; 6 trials, 4 animals). Data represent mean ± sem. All tests are two sided.