Grant: Operating Grant

Alzheimer's Disease (AD) is the most common single cause of dementia. Progress towards new treatments for AD has led to an effort to find biological markers of the disease, which may aid in diagnosis, tracking, and predicting response to drug treatment. Functional brain imaging, where measures of brain activity are recorded while performing a task, has been used for this important goal, with promising results. There is evidence that patients show greater activity than healthy participants in some brain regions, which correlates with better cognitive status. However some studies fail to find these changes, and the interacting effects of structural changes (i.e., changes in volume and integrity of grey and white matter), medication and task difficulty on these findings are unknown. Our study aims to identify the impact of structural degeneration and medication status on cortical activation, using a simple activation task that patients can easily perform. We focus on an area important to face perception, the face-selective fusiform gyrus (FG). The FG is implicated in these activity changes, is structurally affected, and may show changes in activation following treatment. Brain activity will be measured with functional MRI while patients and healthy older adults view faces, and measure brain structure with structural MRI and diffusion tensor imaging. We will scan patients once before beginning drug treatment with a cholinesterase inhibitor (ChEI) and once after 6 months of treatment. We hypothesize that patients will show significant differences in FG activity compared to healthy controls, the degree of which will be related to structural integrity. Further, we predict that drug treatment will increase FG activity, and the degree of this increase will predict clinical response to the drug. This study may help doctors predict which patients will be helped by treatments, and identify patients likely to do well or less well over time.