2. Develop biomarkers and imaging techniques to monitor early effects of new disease-modifying therapies. Methods are needed that can reliably detect relevant changes in the turnover of Aβ, tau and α-synuclein. In the present study one focus will be to study the annual change in the retention of Tau PET ligands during both the prodromal and dementia stages of AD. Further, we need biomarkers that detect the intensity of ongoing synaptic/neuronal degeneration. Imaging methods revealing the functional and structural integrity of different brain networks might also be relevant.