14 DAY TRIAL // Adults find it more difficult to screen out irrelevant information and to concentrate in busy environments than younger people. A new study reveals what happens with the brain as people get older and explains why our "multi-tasking" abilities lessen with age.
"It's known that older adults are more easily distracted. We think we've found a mechanism in the brain to explain this and generated new insight into when in the lifespan these brain changes begin to occur," says Dr. Cheryl Grady.
The researchers have used functional magnetic resonance imaging (fMRI) to look at how brains function in young adults (20-30 years), middle-aged adults (40-60 years) and older adults (65-87 years). Investigators administered a series of memory tasks to the three age groups and monitored what brain areas "light up". Scientists wanted to know whether the age-related changes in brain function are task-specific, or generalized across a number of regions during memory tasks.
They have found that the ability of inhibiting distracting information in connected to two regions in the frontal lobes. One area, the dorsolateral prefrontal cortex, is involved in dealing with tasks requiring concentration, such as reading. The other area, the medial frontal and parietal regions, is associated with non-task related activity in a resting state, such as thinking about yourself, what you did last night, and monitoring what's going on around you.
In case of young adults, during the execution of a certain task the activity in first area increases and the activity in the second area decreases.
However, starting in middle age (40-60 years), Dr. Grady's team noted that this up and down pattern of the two brain areas begins to break down during performance of memory tasks. Activity in the second area stays turned on while activity in the first decreases. In case of older adults (65+), this imbalance becomes even more pronounced, which explains their reduced ability to ignore distracting or irrelevant information.
"Our fMRI scanning reveals that middle age represents the transition between the patterns observed in youth to that found in old age. The seesaw imbalance in the two frontal lobe areas is not as significant as in older adults, but the functional changes are detectable by middle age."
Overall, findings confirmed that age-related changes in brain function are happening across various memory tasks and progress in a linear fashion as adults age.
According to Dr. Grady the study reinforces a cautionary message to aging adults: "Older adults should try to reduce distractions in their environment and concentrate on one key attentional task at a time. It may be as easy as turning down the radio when reading, or staying off the cell phone when driving a car."