Figure 2.

Cortical cooling eliminated silent states in lightly anesthetized mice and disrupted slow waves in deeply anesthetized mice. A, Drawing indicates the positions of the cooling plate and electrodes. B, The examples of EEG and LFP activity recorded during deep (left) and light (right) anesthesia. C, Cortical cooling during deep anesthesia decreased the amplitude of slow-wave activity and evoked LFP spikes (C1, left). C1, LFP and the absolute value of gamma LFP (bottom trace) activities in control and during cooling in deeply anesthetized mouse. The black curve represents the smoothed absolute value of gamma LFP. Cooling disrupted cortical slow waves and evoked fast LFP spikes. C2–C4, Grouped data: three mice, two times. C2, Autocorrelations of LFP signal plotted in control, during cooling, and recovery (deep anesthesia). Autocorrelation (C3) and distribution (C4) of smoothed absolute value of gamma signal in control, during cooling, and recovery (deep anesthesia). D, Cortical cooling during light anesthesia evoked persistent activity (the shown example was obtained from the same mouse as in C). D1, LFP and the absolute value of gamma LFP activities (bottom trace) in control and during cooling (light anesthesia). The black curve represents the smoothed absolute value of gamma LFP. Cooling eliminated cortical silent states and evoked persistent activity. D2–D4, Grouped data: three mice, three times. D2, Autocorrelations of LFP activity plotted in control, during cooling, and recovery (light anesthesia). Autocorrelations (D3) and distributions (D4) of smoothed absolute value of gamma activity (right) plotted in control, during cooling, and recovery (light anesthesia). Dashed red line in D4 shows a distribution of absolute value of gamma activity in lightly anesthetized mice during periods of spontaneous EEG activation. In all the panels, the positive part of SEM is shown with gray (negative part is not shown).