Figure 3.

Length and density of protrusions develop normally in Fmr1 KO mice. A, High-resolution images of dendritic protrusions at different postnatal ages (best projections; ∼8–12 optical sections, 1 μm apart). Compared with WT mice (gray bars), dendrites in mutant mice (blue circles) appeared to have an abundance of thin protrusions (arrows) and fewer mushroom spines with heads (arrowheads) (for detailed quantification of this phenotype, see also Fig. 5). The asterisks point to large knobby protrusions that are usually seen in WT mice at P7–P8. B, C, Density and length of dendritic protrusions at different postnatal ages. Each blue circle indicates a different dendrite from a KO mouse. Control values from WT mice are indicated by gray box-and-whisker plots that show the average (+) and the median (horizontal line). The whiskers represent the 10 and 90 percentile boundaries. *p < 0.05, one-way ANOVA followed by Tukey's test. There were no significant differences between WT and Fmr1 KO mice.