Diabetes( mainly type II diabetes )lead to the central nervous system (CNS) function impairment, especially the mild cognitive impairment that increased the risk of progression to dementia.The primary objectives are defined according to a hierarchical design: i) to tailor and apply multi-parametric, functional MRI techniques to identify cerebral abnormalities (cerebral biomarkers) in type 2 diabetes mellitus and prodromal diabetes mellitus ; ii) to assess whether these cerebral biomarkers are associated with cognitive decrements;iii) to follow up with the putative prediabetic condition patients to verify whether they can transform into diabetes.