The goal of this pilot study is to determine whether a high-dose form of non-invasive brain stimulation is a promising and safe treatment for Mild Cognitive Impairment. Transcranial magnetic stimulation (TMS) is an FDA approved treatment for depression. In studies of TMS for depression and other disorders, individuals have experienced improved cognitive function. Thus, the current study is testing whether TMS is safe, feasible and effective in improving cognition in individuals with Mild Cognitive Impairment.

The purpose of this study is to use neuroimaging to understand how networks in the brain change over time. Although the single most significant risk factor for developing Alzheimer's disease (AD) is age, the neurobiological processes underlying the transition from normal aging to AD are not well understood. Our group of researchers has developed ways to use MRI to detect small changes in certain parts of the brain. We will use neuroimaging to understand how the connections in the brain change over time in healthy aging. The goal is to discover which brain changes are present in healthy aging so that future studies can assess the risk for developing Alzheimer's Disease.

Participants will have two study visits (about 2 years apart) where they will undergo tests to assess mental function, fill out questionnaires, and undergo a blood draw, brain MRI and PET scan. At the second visit, participants will not repeat the blood draw and a PET scan.

Participants are required to have a Co-Participant accompany them for the first portion of each visit. This individual must be a reliable informant that has contact with the participant at least once per week.