Aging Brains Get Out of Sync

By Steven Reinberg
HealthDay Reporter
Thursday, December 6, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

WEDNESDAY, Nov. 5 (HealthDay News) -- In a finding that uncovers the biological underpinnings of "senior moments," new research shows that communication between different parts of the brain begins to break down as a person grows older.

"We wanted to see how the brain changes in cognition in normal aging," said lead researcher Randy Buckner, a professor of psychology at Harvard University. "We were interested in normal aging, aging that isn't accompanied by even the earliest signs of Alzheimer's disease."

Buckner noted that it's sometimes tough even for neurologists to understand the difference between normal aging and Alzheimer's. "There are subtle changes in how brain areas communicate and coordinate with each other," he said. "As we age, we see that communication between these areas changes."

The report appears in the Dec. 6 issue of Neuron.

In the study, Buckner's team used a brain-imaging technique called functional magnetic resonance imaging (fMRI) to study the brains of 55 adults aged 60 and over, and 38 adults aged 35 and younger. To guarantee that none of the older subjects were in the early stages of Alzheimer's, the researchers checked for the presence of amyloid in the brains of those volunteers. If that telltale sign was detected, the person was not included in the study.

Among the adults they observed, they found that in the younger people, regions of their brains communicated easily with one another. However, this was not so with the older people.

In older people, the white matter of the brain that connects various brain areas had started to deteriorate, a chemical fact that would account for the lack of communication that affects cognitive function, Buckner said.

When these changes start isn't clear, Buckner said. "They appear to start slowly in the seventh and eighth decade of life," he said. "We also don't know what factors cause these changes to accelerate."

The cognitive changes caused by deterioration of white matter are subtle, Buckner said. "The changes in the crosstalk of brain regions are correlated with mild cognitive changes," he said. "People who have these changes are aging gracefully."