Organotypic cultures were produced from P12 mice and grown for 12 days. a,b. Representative images of γH2ax and 53bp1 foci in Atmf/f cultures, 30 min after irradiation with 2 Gy of IR. c,d. Quantification of γH2ax nuclear foci (c) or 53bp1 foci (d) in PCs from Atm-KD-CNS mice. e,f. Similar data obtained from Atm-KD-PC mice. The results represent the average counts in 90 PCs at each time point in 3 separate experiments. Standard error is as shown. Two-tail t-test was used to determine statistical significance between pairs of mice with different genotypes. * p < 0.05, ** p < 0.005, *** p < 0.0005. Non-underlines asterisks refer to the significance of the differences between the Atmfl/fl and Atm-KO-CNS or Atm-KD-CNS genotypes; underlined asterisks refer to the significance of the differences between Atm-KO-CNS and Atm-KD-CNS.