The purpose of this study is to better understand how vascular (blood vessels) health and abnormal white matter signals in the brain affect thinking. White matter is brain tissue made up of nerve fibers that allow brain cells to quickly send and receive messages. White matter hyperintensities (WMH) can show that there is damage to the blood vessels in the brain (vascular brain injury). This can result in vascular cognitive impairment and dementia (VCID). Results from this study will improve understanding of how poor vascular health causes WMH and VCID. Researchers hope that these findings will lead to treatments aimed to reduce VCID. Participants are 65-90 years old, have African American, Hispanic/Latino, or European ancestry, and note a decline in memory or thinking over the last 3 years. Study procedures include physical, neurological, and cognitive examinations, blood draws, and brain magnetic resonance imaging.