RTN4R and Alzheimer disease: Depletion of PSD95 can lead to neuronal cell death in hippocampus has been previously reported [35, 36] and in conjunction, our results indicate that increased level of PSD95 may protect the normal function of the hippocampal neurons in the AD model mice, which further points out that the NgR caused the neuronal dysfunction through the postsynaptic proteins not presynaptic proteins (Figure 4).