Neuronal release of BDNF can alter anxiety-like behaviors in mice (Berton et al., 2006; Chen et al., 2006) and age-dependent changes in the expression of BDNF observed in the brain of Fmr1 KO mice (Uutela et al., 2012) could at least partially explain the alterations seen in the anxiety phenotype in different studies. This evidence concerns the gene BDNF and Anxiety.