In the present study, we describe that lower doses than those previously reported [24] of the CB1 receptor antagonist/inverse agonist rimonabant, or a low dose of the CB1 receptor neutral antagonist NESS0327 (0.1 mg/kg), prevent the cognitive deficit in the Fmr1 KO mice measured in the novel object-recognition memory test. Here, FMR1 is linked to Cognitive impairment.