Further, overexpression of HDAC3 in the hippocampus of AD model mice increases Aβ levels and decreases dendritic spine density (Zhu et al., 2017), and multiple studies report that inhibition of HDACs in AD mouse models improves learning and memory deficits (Guan et al., 2009; Rumbaugh et al., 2015; Volmar et al., 2017; Zhu et al., 2017). This evidence concerns the gene HDAC3 and Alzheimer disease.