The purpose of this study is to develop imaging techniques that can distinguish functional brain changes in people at high risk for dementia years prior to onset of clinical memory problems from those with normal changes of aging.

The overall goals of this project are to identify consistent patterns of variance in brain function in patients at risk for Alzheimer's Disease by using APOE ε4 as a marker for disease risk. The activation Blood Oxygen Level Dependency (BOLD) signal will be compared to both resting and activation perfusion signals to assess the variability of cerebral blood flow as it relates to the BOLD signal. Each participant will be imaged on a 3T MRI scanner while performing an associate episodic memory task.

A total of 90 individuals will be recruited for this study. Participants will be non-demented, right handed, adults with or without at least one APOE ε4 allele. Groups will be split as follows: A) ages 25-39: non-ε4 (n=15); B) ages 25-39: +ε4 (n=15); C) ages 40-49: non-ε4 (n=15); D) ages 40-49: +ε4 (n=15);.E) ages 50-65: non-ε4: F) ages 50-65: +ε4 (n=15). These groups will be matched for mean age, mean years of education, gender distribution, as well as the presence or absence of a family history of AD in a first degree relative.

There will be 2 scanning sessions for each participant. Scan session #1 and Scan session #2 will be acquired within 2 weeks of each other and will take approximately one hour each.

Inclusion Criteria:

• Right-handed

Exclusion Criteria:

• Major medical illnesses
• History of significant head trauma with residual cognitive deficits
• Other neurological or major psychiatric disorders such as schizophrenia, bipolar disorder, developmental learning disorder, and alcohol or substance abuse
• MRI contra-indications

healthy adults from the community