<qa>  What is the name of the study that will be performed by the subject?Healthy aging and aging human subjects with mild cognitive impairment and mild Alzheimers disease from the TARCC cohort and South Texas will be studied using a double-blind, placebo-controlled design. After informed consent and familiarity with the tasks and the MRI environment, the subject will enter an MRI scanner and perform the following 6 tasks. 