Brain-derived neurotrophic factor (BDNF) is a key regulator in the synaptic plasticity contributing to the development of cognitive function, whereas in AD pathogenesis, the reduction of BDNF and insulin-like growth factor 1 (IGF-1) levels in the brain is tightly associated with Aβ accumulation and cognitive impairment [80,81]. This evidence concerns the gene IGF1 and Alzheimer disease.