Fig. 2: LC stimulation of adrenergic activity switched small Ca²⁺ signaling to large waves.

A Typical fluorescent images show that LC stimulation can induce large Ca²⁺ increases after LC stimulation. Scale bar = 20 µm. B A schematic illustrates projections from LC stimulation (red dashed line) and whisker stimulation (green solid line and blue dashed line) to the barrel cortex. LC stimulation was generated using bipolar concentric electrodes, while whisker stimulation was generated through air puffing. C Typical traces show the changes in Ca²⁺ transients and LFP EPSPs. Upper traces (blue trace is from sleeping state, while the red trace is after LC stimulation) are relative changes of Ca²⁺ (ΔF/F₀) in an astrocytic process located close to the recording electrode. Lower traces are LFPs recorded by the recording electrode. D Analysis shows comparisons of the relative changes in Ca²⁺ (ΔF/F₀) in astrocytic processes upon whisker stimulation (**P < 0.001, paired t-test for the first two pair of groups, n = 42 for before and after LC stimulation; n = 58 for before and after NE application. For other groups, one-way ANOVA was used, F (4,296) = 227.373, P < 0.001, spots show the average in each mouse, n = 5–6 mice, data are shown as the mean ± SD). E Analysis shows comparisons of the relative changes in LFP EPSPs upon whisker stimulation (**P < 0.01, one-way ANOVA, n = 5–6 mice, data are shown as the mean ± SD). The x-axis labels indicate the type of stimulation used. Additional abbreviations used are as follows: TER, α1-antagonist terazosin; MPEP, mGluR5 antagonist. F A cartoon shows the possible mechanism of two different effects of Ca²⁺ during sleep and waking, and NE is a switch between these two states.