A U.S. study suggested that the memory fading with age could be ascribed to the less coordinated brain systems in healthy people, media reported Thursday.

The study conducted by researchers at Harvard University aimed to understand the difference between aging and Alzheimer's disease.

In the study, researchers divided subjects into two groups: the group of subjects aging 60 and over, and the one of subjects aging 35 and younger.

Brain scans were done to detect the presence of amyloid, a chemical typically associated with Alzheimer's disease, to rule out those whose memory declines were disease-related.

The results showed that the disruption of white matter conduits, which carry information between different regions of the brain, only happend in the older group.

The damage of these conduits can disturb the information processing of the brain which causes memory and other cognitive abilities to go soft.

But the researchers said not everyone was impaired to the same degree."Some brains may be better prepared for the assault of Alzheimer's disease," said Randy Buckner, a Harvard professor and Howard Hughes Medical Institute researcher who worked on the study.

This may help explain why some people who develop Alzheimer's disease succumb quickly and others decline more slowly.

(Agencies via Xinhua News Agency December 7, 2007)