Interestingly, knockdown Fmr1 GC had more mature glutamatergic synaptic sites and accordingly received more glutamatergic inputs than control GCs (Scotto-Lomassese et al., 2011), which recapitulates the hyperexcitability phenotype found in other brain regions in FXS (Contractor et al., 2015; Ethridge et al., 2017). This evidence concerns the gene FMR1 and fragile X syndrome.