Dementia and Neurodegeneration have devastating consequences. My work aims to protect brain function in those at risk of dementia, and restore brain function in those with symptoms. My program has four pillars: 1. to define cognitive processes that are affected by dementia and ageing, and individual differences in cognition. 2. to determine mechanisms of individual differences, and prognosis, in terms of underlying cognitive processes (cognitive models); genetics; neural circuits and connectivity (MEG, EEG, fMRI or DWI); neurochemistry; and neuropathology (in vivo PET; and post mortem). 3. to predict the trajectory of brain function across the lifespan (CamCAN), in people at risk of dementia (eg. GENFI, PROSPECT, ICICLE-PD, D&F-Phenotyping studies), and those with symptoms (eg. PiPPIN). 4. to use new drugs to protect the brain, or restore brain function, in experimental medicines studies using precision-biomarkers in precisely-characterised clinical populations.