(A) Spine density for filopodial spines (defined as spines with spine head width less than 1.5 times the mean width of the spine neck). Spine density was higher in PLX-treated mice (Wilcoxon rank sum test, z = −2.69, p=0.0072). Bars indicate medians across cells (circles). (B) Spine density for mushroom spines (defined as spines with the width of the spine head greater than or equal to 1.5 times greater than the mean width of the spine neck). Spine density was higher in PLX-treated mice (Wilcoxon rank sum test, z = −1.96, p=0.050). Bars indicate medians across cells (circles). (C) Cumulative distribution showing filopodial spine volume. Inset, sampling distributions of the mean filopodial head volume obtained with the hierarchical bootstrap. The mean head volume (dark lines) was not different between groups (hierarchical bootstrap, p=0.72) (D) Cumulative distribution showing mushroom spine volume. Inset, sampling distributions of the mean mushroom head volume obtained with the hierarchical bootstrap. The mean head volume (dark lines) was significantly larger in control mice (hierarchical bootstrap, p=0.036). n = 810 spines from 17 abGCs from three control mice and 1551 spines from 17 abGCs from 4 PLX mice. ns, not significant; *p<0.05; **p<0.01.