Impaired development of the cortical plate in the prh mutant and ameliorative effect by bindarit in Layers II–IV. A, Cortical layer-specific markers SATB2 (II–IV), CTIP2 (V), and TBR1 (VI) are used to stain layer-specific cortical neurons in veh-/bin- WT and prh (scale bars: 100 μm). (B, top row) The thickness of cortical Layer II through IV is significantly reduced in veh-prh, and this defect is improved in bin-prh cortex (††††p < 0.0001 vs veh-WT, ‡p = 0.0264, ‡‡‡‡p < 0.0001 vs bin-WT, *p = 0.0110 vs veh-prh; two-way ANOVA followed by Tukey's test, n = 9–10 in each group; left top). B, bottom row, The cell density of SATB2⁺ neurons in cortical Layers II–IV are not significantly changed between groups (left bottom). CTIP2⁺ cortical Layer V thickness is reduced in prh (§§§p = 0.0005, prh vs WT) and not recovered by bindarit (p = 0.9869, bin-prh vs veh-prh, two-way ANOVA followed by Tukey's test, n = 9–10 in each group; middle top). TBR1⁺ Layer VI thickness (right top), as well as the cell density of CIPT2 (middle bottom)/TBR1 (right bottom) positive Layer V/VI neurons are not significantly altered in prh mutants.