Expression of Hcn mRNA in mouse SGNs. (A and B) Expression of Hcn1–4 in neonatal (A) and adult (B) WT mouse SGNs. qPCR was used to estimate the total mRNA copy number of Hcn genes present in both neonatal (P3) and adult stages (≥P40). Neonatal SGN samples were collected from a pool of 24 whole cochleas. Adult SGN samples were obtained from a pool of 16 whole cochleas. Each preparation was run in triplicate. Results are shown as mean total copies in thousands of Hcn mRNA transcripts per cochlea. Error bars represent SEM.