The study principle investigator left the institution.

The purpose of this study is to assess the effects of non-invasive brain stimulation on memory in cognitively unimpaired older adults and in patients amnestic mild cognitive impairment (aMCI) due to Alzheimer's disease (AD). This study will use repetitive Transcranial Magnetic Stimulation (rTMS) to stimulate nodes of the Default Mode Network (DMN)- which is thought to support episodic memory and to be affected by Alzheimer's pathology.

We will use functional connectivity MRI (fcMRI) to assess changes in functional network architecture following the stimulation. We will also assess putative cognitive improvements resulting from the stimulation by in-depth memory testing.

Inclusion Criteria:

1. Between the ages of 60-85
2. All participants will be native English speakers
3. Willing and able to consent to the protocol and undergo imaging and neuropsychological testing at the specified time points
4. Participants with aMCI will be asked to bring a study partner to all visits
5. Only patients with very mild or mild cognitive impairment (CDR 0.5 or CDR 1) will be included in the prodromal AD cohort

Exclusion Criteria:

1. History of head trauma involving loss of consciousness or alteration in consciousness
2. Another major neurologic or psychiatric condition
3. Known presence of a structural brain lesion (e.g. tumor, cortical infarct)
4. Any contraindication to MRI, such as presence of pacemakers, aneurysm clips, artificial heart valves, ear implants, metal fragments, or foreign objects in the eyes, skin, or body
5. Longstanding premorbid history (i.e. longer than 10 years) of alcohol or substance abuse with continuous abuse up to and including the time that the symptoms leading to clinical presentation developed
6. Any significant systemic illness or unstable medical condition which could lead to difficulty complying with the study protocol.
7. Unwilling to return for follow-up, undergo neuropsychological testing, TMS, and MR imaging

There is no plan to share IPD with researchers outside of this protocol.

All participants will undergo SHAM stimulation as a control condition. They will be blinded as to whether they are receiving active or SHAM stimulation.