The Synapse Project

Inclusion Criteria: * Cognitively unimpaired adults- * Aged 55 - 89 * Normal cognition (results of most recent testing with the source cohort indicate the participant is cognitively unimpaired as judged by consensus or expert review) * In good general health with no conditions/medications affecting cognition or imaging * Willing to undergo \[C-11\]UCB-J, \[C-11\]PiB, and \[F-18\]MK6240 PET scans * An adequate MRI exam within 12 months prior to baseline. An MRI will be performed if not already available. * Mild dementia and amnestic Mild Cognitive Impairment- * Aged 50 years or older * Abnormal cognitive status of MCI or dementia as judged by consensus or expert review using NIA-AA 2018 criteria * MCI's must be affected in the memory domain but may also have other affected domains * Willing to undergo \[C-11\]UCB-J, \[C-11\]PiB, and \[F-18\]MK6240 PET scans * An adequate MRI exam within 12 months prior to baseline. This MRI exam will come from ADRC/WRAP studies. Clinical MRI's (ones obtained outside of the research program) will not be adequate. An MRI will be performed if not already available from within the research program. Exclusion Criteria: * For women, pregnant, lactating or breastfeeding, or intention to become pregnant * Evidence of unstable or untreated clinically significant gastrointestinal, cardiovascular, hepatic, renal, hematological, neoplastic, endocrine, alternative neurological, immunodeficiency, pulmonary, or other disorder or dise…