It is noteworthy that intranasal infusion of the most potent cholinotrophic substance nerve growth factor (NGF) prevented memory deficits in AD mice (Capsoni et al., 2012), or ameliorated Aβ deposition (Tian et al., 2012) or attenuated tau phosphorylation (Lv et al., 2014). Here, NGF is linked to Alzheimer disease.