To test the use of our approach in a disease model, we monitored PNNs in vivo in a mouse model of fragile X syndrome [i.e., Fmr1-knockout mice; Figs. 1(h) and 1(i)] and found considerably less PNNs in these animals (p=0.0277), similar to previously described results from ex vivo experiments4 highlighting the use of our method to study in vivo this and other pathologies related to PNNs. This evidence concerns the gene FMR1 and fragile X syndrome.