As young people our brains are able to switch from one mental activity to another. As we get older we tend to have a more difficult time getting rid of distractions and getting back to what we were doing before. This process involves our working memory, the area of the brain that holds short-term memory, and could be the root of such memory diseases as Alzheimer’s.
New research into the brain functions of older adults may explain why seniors have a harder time keeping their train of thought, or juggling more than one activity at a time. From research, seniors seem to be unable to switch between function networks in the brain as quickly as they used to. These findings, published in the Proceedings of the National Academy of Sciences, (April 12, 2011) show that it’s not lack of paying attention that is causing the inability; it’s the slow reflexes to return to what they were doing once they were distracted.
The study, led by University of California at San Francisco neuroscientist Adam Gazzeley, scanned and compared the brains of 20 young adults who’s average age was 25, to 20 elderly people who’s average age was 69.
During their fMRI scan each subject was shown a landscape photo and asked to keep it in mind. A few seconds later they were shown a portrait of a face and asked to answer several questions about it. A few seconds later they were shown a different landscape picture and asked to compare it to the first.
Prior research by Gazzaley and other scientist described how elderly people tended to have trouble switching between tasks. Exactly why this was happening was a puzzle. By using fMRI in the new study, Gazzaley and his colleagues were able to see a somewhat clearer picture of the brain processes.
Gazzaley had at first believed that elderly people were focusing too much on distractions, but found instead that their brain activity was not much different from their younger counterparts when presented with the face portrait. Where the differences took place was when the face portrait was removed. The face lingered in the minds of the elderly subjects, while the younger subjects were able to push it out of the mind almost immediately. When presented with the second landscape the elderly brains were slow to pick up.
According to Grazzaley, “The paper is a snapshot. It raises many more questions than answers, and resolves few.”
The question is, does the reaction of the older adults come from the culture they were raised in, where there were less distractions like cell phones and iPads than there are today — or is it due to their brains becoming less flexible over time? If it’s due to aging, when does the deterioration begin to take place? And, if so, is it possible to strengthen the plasticity?
Hopefully additional studies will find out what causes the plasticity of our brains to change as we age, and when they do they could unravel the secrets to uncovering the reason behind Alzheimer’s disease and other neurodegenerative diseases.
From the Desk of Ron White
AARP – Multitasking ‘Switch’ Doesn’t Work as Well in Older Brains
Age affects short-term memory, attention to new task: http://www.aarp.org/health/brain-health/info-05-2011/multitasking-switch-in-older-brains.html
Wired Science — Brain Scans Show How Multitasking is Harder for Seniors: http://www.wired.com/wiredscience/2011/04/multitasking-brains/