Figure 1. Specificity of ChETA-eYPF expression in EC of three mouse strains. A–C, Low-magnification microphotographs of EC horizontal sections immunostained for eYFP in a representative CaMKII-Cre (A), PV-Cre (B), or SOM-Cre (C) mouse. D–F, Double immunostaining for YFP (green) and either CaMKII (D), PV (E), or SOM (F, magenta). Bar graphs quantifying the proportion of cells positive for eYFP and the corresponding cell marker are shown in the lower right corner of each panel (n = 3 mice/group; total number of cells counted: CaMKII, 1064; PV, 371; SOM, 325). In CaMKII-Cre mice, 97.0 ± 0.2% of CaMKII neurons expressed ChETA-eYFP, while 1.0 ± 0.9% of eYFP neurons were negative for CaMKII. In PV-Cre mice, 91.0 ± 0.4% of PV interneurons expressed ChETA-eYFP, while 1.5 ± 0.3% of eYFP neurons were negative for PV. In SOM-Cre mice, 83.0 ± 1.9% of SOM interneurons expressed ChETA-eYFP, while 32.5 ± 1.1% of eYFP neurons were negative for SOM. G, Columnar scatter plots comparing the specificity of eYFP expression in the three experimental groups. Each data point (red) represents the proportion of specific viral expression in brain slices obtained from each mouse. The horizontal line in each plot represents the mean and the SEM for the three mice tested from each strain. Note that there was no statistically significant difference in the proportion of eYFP transfection specificity among the three strains (KS test = 5.422, n.s; n = 9). Scale bars: A–C, 200 μm; D–F, 30 μm.