EE leads to elevated levels of mature NGF and BDNF in AD, which activate the protein kinases/extracellular signal-regulated kinase (MAPK/ERK) and phosphoinositide-3kinase/protein kinase B (PI3k-AKT) signaling pathways, thereby enhancing hippocampal neurogenesis and synaptic plasticity, among other effects [127]. Here, NGF is linked to Alzheimer disease.