It has been reported that the phosphorylation of ERK1/2 (activation of MAPK pathway) can be significantly inhibited by β-amyloid in organotypic hippocampal slice cultures and neuronal cell lines, as well as in AD animal models, as shown in Figure 5 (Daniels et al., 2001; Bell et al., 2004; Ma et al., 2007). Here, MAPK3 is linked to Alzheimer disease.