The aging process includes physical changes within our brain that involve structural weakening and process speed decline. The alterations involve a reduction of neural processing in grey matter, and also the deterioration of structural connections in the brain which allow communication between distinct brain regions.
As a result, the ability of the brain to work as a well-wired network system declines — more so among some than others.
A new study among seniors, using magnetic resonance imaging (MRI), measured the moment-to-moment variability in brain activity. As suggested by prior research, investigators focused on the blood oxygenation level-dependent (BOLD) signal.
Scientists at the Lifelong Brain and Cognition Lab at the University of Illinois have observed that a variability in the BOLD signal in the function of certain brain regions may be a good thing, linked to younger age and better cognitive performance.
In fact, greater variability may reflect more flexible or adaptive information processing. However, the association between BOLD variability and structural brain connectivity is not well understood.
Also unknown is the association between brain signal variability and cognitive performance on various tasks such as memory, reasoning, speed, vocabulary, and semantic knowledge.
Researchers collected functional and structural MRI and looked at cognitive performance in 91 elderly, non-demented adults. They found that older adults who had greater variability in neural activity in specific brain regions performed better on fluid ability and memory tasks, and also had better quality of structural white matter connections in the brain.
Their paper is published in the journal PLOS ONE.
“Our study is important as it explores the relationships between moment-to-moment variability in spontaneous brain activity and broadly defined cognitive performance in older adults,” said Agnieszka Burzynska, Ph.D., postdoctoral researcher and author of the study.
“We think that greater variability in brain function in certain regions allows better processing of information, especially during highly demanding memory and reasoning tasks, which require someone to remember information, form associations, or perform abstract mental operations.”
Investigators believe that variability in the brain activity reflects the dynamic use of different brain networks. This study helps to explain brain changes associated with aging.
“In the aging research, there are mixed findings on whether aging is associated with increased or decreased amplitude of neural activity, and looking into variability of the signal gives us a new type of information on how the aging brain works,” said Burzynska.