Activity of Cerebral Networks, Amyloid and Microglia in Aging and Alzheimer's Disease

Inclusion Criteria: * Informed consent for the additional examinations, written declaration of consent * Constant pharmacotherapy in a period of one week before the MRI/EEG/PET examination Exclusion Criteria: * Existence of legal guardianship/restricted capacity to consent * Other severe concomitant psychiatric illnesses, e.g. schizophrenia, bipolar affective disorder * Clinically relevant depressive symptoms (Beck Depression Inventory, BDI, score \> 17/GDS \> 5) * Acute suicidal tendencies * Drug, medication or alcohol abuse at the time of the study * Severe traumatic brain injury (\> 2nd degree TBI) in the medical history or 1st degree within the last 3 months. * Evidence of structural damage to the basal ganglia or brainstem * Severe neurological diseases (such as disc prolapse in the last 6 months, sensory, motor or autonomic polyneuropathies) * Severe internal diseases (such as manifest arterial hypertension, severe heart disease, pacemaker, respiratory insufficiency) * Any electronic implants (e.g. pacemakers) or other MRI and/or PET contraindications * Malignant diseases of any kind in the last 5 years, severe active infectious diseases, chronic and systemic skin diseases * Bone diseases (such as Paget's disease, osteoporosis with spontaneous fractures, recent fractures) * Other circumstances which, in the opinion of the investigator, speak against the patient's participation in this study * Occupational or other radiation exposure \>15 mSv/a