While low levels of BDNF are associated with cognitive deficits and impaired memory and learning (Capsoni et al., 2000; Heldt et al., 2007), increasing BDNF levels in AD animals prevents neuronal loss and improves cognitive performance (Nagahara et al., 2009, 2013; Jiao et al., 2016; Gao et al., 2022). This evidence concerns the gene BDNF and Alzheimer disease.