SYN2 and Alzheimer disease: Namely, these differentially expressed proteins from the 3xTg-AD mice treated with loganin compared to the control mice may directly regulate cognitive deficits of the 3xTg-AD mice via modulating the expression of key molecules (i.e. PAGM1, ENO1, SYN2, Cplx2, and 1433Z), and may be indirectly involved in the regulation of AD pathology and thus affected cognitive impairment of the 3xTg-AD mice.