Using the data of a cohort including cognitively healthy (HC) older adults, and individuals with SCD, MCI, or AD, we hypothesized that (1) MRI‐derived markers of neurodegeneration and connectivity predominantly in areas of early amyloid (frontal/parietal) and tau (medial temporal lobe) accumulation are reflected by changes of plasma Aß42/40 and p‐tau181, respectively; and (2) MRS‐derived biochemical brain changes related to neuroinflammation (myo‐inositol) and neuronal integrity (NAA) are reflected by changes of plasma GFAP and NfL, respectively. Here, GFAP is linked to Schnyder corneal dystrophy.