In animal models of AD, occupancy of HDAC2 in the promoter region of Bdnf exon IV contribute to the reduction of BDNF in APP/PS1 mice (Hsiao et al., 2017) and infusion of amyloid fibrils into the hippocampus of rats induces HDAC2 occupancy at promoter VI of Bdnf and thus decreases Bdnf expression (Hendrickx et al., 2014). Here, BDNF is linked to Alzheimer disease.