Fig. 3

Images showing the absence of Ki-67 immunostaining in the SG and IG layers in a 28 wk NTD (A, B) and a 31 wk DS (C, D). Photos of DCX- immunoreactivity in cortical SG and IG layers in NTD aged 28 (E, F), 44 (I, J) and 174 wk (M, N) and DS aged 33 (G, H), 44 (K, L), and 196 (O, P) wk subjects. Note that DCX immunostaining decreased with age and was absent in the oldest cases in both groups (M–P). Small undifferentiated cells were DCX positive in 28–44 wk NTD (E, F, I, J) and 33–44 wk DS (G, H, K, L) cases. Note many more DCX positive cells in SG and IG layers at DS 44 wk compared to a NTD 44 wk suggesting a delay in neuronal migration/neurogenesis in DS. Boxplot showing a significantly greater number of DCX positive cells in SG compared to IG in both NTD (n = 9) and DS (n = 10) (Q) (Wilcoxon signed rank test, NTD p = 0.008; DS p = 0.008), while no significant differences were found in the SG and IG layers between groups (Mann–Whitney rank sum test). *p < 0.05. Scale bars: D = 50 µm applies to A–C; F = 50 µm applies to E; H = 50 µm applies to G; J = 50 µm applies to I; L = 50 µm applies to K; N = 50 µm applies to M; and P = 50 µm applies to O