Furthermore, the expression of NgR and downstream signaling proteins are elevated in patients with AD and aged rats with deficits of spatial cognition (VanGuilder & Sonntag, 2013; Zhu & Guo, 2007), and neuronal overexpression of NgR impairs cognitive function in APP/PS1 mice (Karlsson et al., 2013). Here, PSEN1 is linked to Alzheimer disease.