NGF and Alzheimer disease: Several studies have shown the ability of NGF to support the maintenance and survival of the cholinergic neuronal system (Allen et al., 2013) and to contribute to the survival and regeneration of cholinergic neurons in age-related diseases, such as AD (Mitra et al., 2019), suggesting that an increase in NGF in the brain of Gdnfwt/hyper mice may contribute to the preserved cholinergic function upon aging.