By using functional MRI brain imaging, the researchers found that these symptomless carriers of the APOE-4 gene demonstrated significantly reduced functional brain connectivity between the hippocampus and the posterior cingulated cortex, two important brain structures for memory processing.
These structures are relevant for information acquisition, filtering and sorting
Led by Shi Jiang Li, Ph.D., professor of biophysics, this study was conducted at Froedtert Hospital.
"Just as if cancer could be detected when there were only a few cells, decades before it was evident, the advantage of identifying those at great risk for having Alzheimer's would be of tremendous value in development of interventional therapies," said Dr. Li.
In the study, the researchers examined 28 neurologically-normal subjects, between ages 45 and 65. Out of these, 12 carried the APOE-4 gene and 16 did not.
No significant difference in age, educational level, or neuropsychological performances was seen in the two groups. All subjects received fMRI scans. For each subject, functional connectivity between the two brain structures was measured in a resting state.
It was revealed that functional connectivity in the non APOE-4 carriers was approximately 65 percent better than that of the carriers.
The study was presented at the Alzheimer's Association International Conference on Alzheimer's disease in Chicago.