Analysis of new cell identities 7 days post-PTBI. To determine what types of new cells are generated in the first 7 days post-PTBI, we used pulse-chase experiments with EdU in combination with the glial marker anti-Repo and the neuronal marker anti-Elav. At 7 days post-PTBI, we found four classes of cells resulting from proliferation: EdU+ and without either Repo or Elav (A–A’’’; Class I); Cells that were EdU+ and Repo+ (B–B’’’; Class II); EdU+ and Elav+ (C–C’’’; Class III); and EdU+, Repo+, Elav+ (D–D’’’; Class IV). Arrowheads indicate representative cells in each class. The nuclear dye DAPI is in blue. We then measured the changing ratios of these cell types over time in control (E) and PTBI brains (F). For controls, 11 brains and 28 PH3+ cells were analyzed at 24 hours, 9 brains and 15 EdU+ cells were analyzed at 7 days, and 2 brains and 3 EdU+ cells were analyzed at 14 days. For PTBI samples, 17 brains and 181 PH3+ cells were analyzed at 24 hours, 15 brains and 172 EdU+ cells were analyzed at 7 days, and 8 brains and 278 EdU+ cells were analyzed at 14 days.