Older adults appear more easily distracted by irrelevant information than younger people when they experience stress or powerful emotions — and a specific network in the brain recently identified as the epicenter for Alzheimer’s and dementia may be to blame.
A USC-led study finds that seniors’ attention shortfall is associated with the locus coeruleus, a tiny region of the brainstem that connects to many other parts of the brain. The locus coeruleus helps focus brain activity during periods of stress or excitement.
Increased distractibility is a sign of cognitive aging, said senior author Mara Mather, an expert on memory and professor at the USC Leonard Davis School of Gerontology. The study found that older adults are even more susceptible to distraction under stress, or emotional arousal, indicating that the nucleus’s ability to intensify focus weakens over time.
“Trying hard to complete a task increases emotional arousal, so when younger adults try hard, this should increase their ability to ignore distracting information,” said Mather, who is also a professor with the USC Dornsife College of Letters, Arts and Sciences. “But for older adults, trying hard may make both what they are trying to focus on and other information stand out more.
“For instance, if an older adult is taking a memory test in a clinician’s office, he or she may be trying hard to focus but will be more easily distracted than a younger adult by other thoughts or noises in the background.
Previous research led by Mather, director of the USC Emotion and Cognition Laboratory, has highlighted the locus coeruleus and its roles in cognition and memory. Currently, Mather is focused on studying how locus coeruleus function changes during aging and Alzheimer’s disease.
The locus coeruleus appears to be one of the earliest sites of tau pathology, the tangles that are a hallmark of Alzheimer’s disease. An estimated 5.7 million Americans have Alzheimer’s, which is the nation’s the sixth-leading cause of death.
“Initial signs of this pathology are evident in the locus coeruleus in most people by age 30,” Mather said. “Thus, it is critical to better understand how locus coeruleus function changes as we age.”
Mather is among more than 70 researchers at USC who focus their research on the prevention, treatment and potential cure of Alzheimer’s disease.
The study was published on May 7 in Nature Human Behavior.