FMR1 and fragile X syndrome: To evaluate the functional relevance of elevated ICAM5 expression in FXS, we examined spatial and fear memory and exploratory and anxiety-like behaviors in Fmr1 KO and ICAM5 knock-down (AAV-ICAM5 shRNA-EGFP) Fmr1 KO mice, and compared their performance with WT, ICAM5 knock-down WT, and adenovirus empty vector (AAV-EGFP)-transfected Fmr1 KO and WT mice.