We examine Alzheimer's disease in the context of the aging brain. Our work is focused on developing new methods to investigate the earliest brain regions affected in Alzheimer's disease and use this knowledge to improve early detection and to evaluate novel non-invasive interventions to delay cognitive decline. We combine neuroimaging methods (3T, 7T and 9.4T MRI, PET, EEG), biofluids, wearables, physiological, behavioural and cognitive measures, and non-invasive neurostimulation methods.