The purpose of this research study is to understand the association between heart and brain health in a population of 40-75 year olds. In this study, we will work to better understand blood vessel stiffness and brain function in African American and non-Hispanic white individuals. You will be asked to give blood during the study visit. Additional information will be obtained to help the researcher better understand the blood vessel and brain function data collected. There is only one study visit that last roughly 2 hours and compensation will be available.