The authors conclude that downregulation of synaptic proteins NRXN1, CPLX1, neurofilament light chain (NEFL), SYT1, synaptosome-associated protein 25 (SNAP25), and syntaxin 1A (STX1A) in the HC may be linked with synaptic degeneration and the impairment of learning and memory in the brain of AD mice [279] (Figure 8F). Here, CPLX1 is linked to Alzheimer disease.