RanBP9 overexpression reduces total spine density in the cortex at 12-months of age but not at 6 months. (A), Representative examples of dendrite and spine morphologies of cortical neurons at 6- and 12-monthsof age used for quantitation of spines in different genotypes of mice. (B), Quantitation of Image-pro and NeuronStudio-processed images of 12-month old mice revealed significant reductions in total spines in the RanBP9-Tg (22%), APΔE9 (19%), and APΔE9/RanBP9 (33%) mice compared to WT mice. APΔE9/RanBP9 mice showed further reductions in total spines compared to APΔE9 (14%) mice. The reduction in total spines is due to reduced mushroom spines in the RanBP9-Tg (23%), and APΔE9 (28%) genotypes, while in the APΔE9/RanBP9-Tg genotype the reduction was due to both thin (32%) and mushroom spines (50%). ANOVA followed by post hoc Bonferroni multiple comparison test revealed significant differences. *, p<0.05, **, p<0.01 as indicated compared to WT mice or APΔE9 mice. The data are mean ± SEM, n=5 mice for each genotype.