Double immunofluorescence for β-galactosidase and neuron-specific nuclear protein revealed that the GFAP-Cre transgenic line mediates recombination in 98% of neurons in cortical layers II/III and hippocampal area CA1 (Figure 2A, C), while the CaMKII-Cre line mediates recombination in 80% of cortical layers II/III and 75% of hippocampal CA1 neurons (Figure 2B, D).