Besides measuring attentional performance and inhibitory control in Fmr1-KO and WT mice under standard task conditions, we tested the effect of a metabotropic glutamate receptor 5 (mGluR5) inverse agonist 6-Methyl-2-(phenylethyny)pyridine (MPEP), a therapeutic candidate for FXS, upon performance in this attentional paradigm. This evidence concerns the gene GRM5 and fragile X syndrome.