Ablation of Phox2bLC neurons impairs the HCVR. A Schematic diagram illustrating the microinjection of AAV-CAG-DIO-taCasp3-TEVp or AAV-CAG-DIO-mCherry (control virus) into the LC of Phox2b-Cre mice. B Immunofluorescence images showing that the number of Phox2bLC neurons in the Casp3-injected side was significantly reduced compared to the control side of the LC in the same mouse (4 V, fourth ventricle; scale bars, 50 µm). C qPCR results for the levels of Phox2b mRNA in Casp3-transduced mice relative to mCherry-transduced mice (n = 14 samples from 7 mice for mCherry group, n = 10 samples from 5 mice for Casp3 group; ****P < 0.0001, unpaired t test). D–F Effects of bilateral ablation of Phox2bLC neurons on breathing parameters during exposure to different concentrations of CO2 (n = 9 for mCherry group, n = 11 for Casp3 group; *P < 0.05, ***P < 0.001, ****P < 0.0001, two-way ANOVA with Bonferroni’s post hoc test).