Cell division dynamics in the normal and regenerating RNC. (A) BrdU labeling paradigm employed to quantify cell division. (B) Diagram showing the percentage of all BrdU-incorporating cells (irrespective of their phenotype) normalized to the total number of cells in the tissue. (C) Diagram showing how many of the BrdU-incorporating cells are ERG1-positive glial cells. (D) Diagram showing how many of the ERG1-positive glial cells incorporate BrdU. Results are represented as mean (percentage) ± standard error. *P < 0.05, **P < 0.01, ***P < 0.001. ‡ indicates that the value is missing because BrdU-incorporating cells were absent in three of the four animals. The the ratio of the number of BrdU+ ERG1+ cells divided by the total number of BrdU+ cells is impossible to define in these animals (division of zero by zero). Therefore, neither mean value nor standard error were calculated. In the fourth animal, there were only two BrdU+ cells in the hyponeural neuroepithelium, one of them was BrdU+ ERG1+, whereas the other was BrdU+ ERG1-.