The right tectal lobe of stage 47 tadpoles was injured and changes in cell division were assessed in the right and left tectal lobes by immunolabeling for phospho-histone H3 (PH3) to identify dividing cells in M phase of the cell cycle over the course of 5 days. Data were analyzed as individual optical sections, but are presented as confocal Z-projections of the tectal lobes, which are outlined. A–J. PH3 labeling of dividing cells in the tectal lobes 24hrs (A,B), 48 hrs (C,D), 3 days (E,F), 4 days (G,H), and 5 days (I,J) after injury in the intact left tectal lobe (A,C,E,G,I) and in the injured right tectal lobe (B,D,F,H,J) of the same animals. K. Total counts of PH3-labeled nuclei in the injured (black line) and intact (gray line) tecta over a 5-day period after injury. N=25 animals total (5 for each time point). *p<0.05, **p<0.01, n.s. = not significant. Scale bars, 100 µm. Data are average ± SEM.