The goal of this study is to investigate whether Low Intensity Focused Ultrasound Pulsation (LIFUP) targeting a part of the brain involved in memory will have an affect on brain activity and whether it may improve memory in people with Mild Cognitive Impairment and Mild Alzheimer's Disease. The main questions the study seeks to answer are: 1. Can LIFUP increase brain activity in the targeted area? 2. Can LIFUP improve memory in people with MCI and mild AD? 3. Can LIFUP improve connectivity of memory networks in the brain? Participants in this study will complete MRIs and memory testing, and receive Low Intensity Focused Ultrasound to a part of their brain involved in memory (the entorhinal cortex).