Quantification of total fibers with myelin decompaction and quadrants with decompaction (panels A and C), and g-ratio evaluation (panels B and D), in WT (n= 6 mice), pRsG/+ (n= 3 mice), pRsG/+;pRBPJ (n= 5 mice), and GSI-treated pRsG/+ (n= 6 mice) mice, 1 month post-tamoxifen. A: No significant changes (but a trend toward decrease) were observed in the percent of decompacted fibers in pRsG/+;pRBPJ mutants, as compared to pRsG/+ mice (ns, p=0.091). B: No significant changes were observed in the g-ratio of pRsG/+;pRBPJ mutants, as compared to pRsG/+ mice (ns, p=0.086). C: Significantly decreased percent of decompacted fibers was observed in GSI-treated pRsG/+ mutants, as compared to vehicle-treated pRsG/+ mice (*p=0.011). D: A significant increase in g-ratio was detected in GSI-treated mutants, as compared to pRsG/+ mice (ns, p<0.0001). In all panels; WT values are shown for reference, One-way ANOVA and Tukey's multiple comparisons test were used, and data are presented as the mean ± s.e.m.