Zhao and colleagues44 showed that by taking Nutlin-3, an experimental cancer drug which serves as an inhibitor, mice with FXS lacking the FMRP protein regained their ability to remember what they had seen or smelled in their first study session; this apparent reversal of a memory impairment appeared to specifically relate to reactivation of FMRP affecting neural stem cells and new neurons that they form in the hippocampus. Here, FMR1 is linked to fragile X syndrome.