Adults show cognitive impairment, and better well-being with age

A UCSD study identifies the neural mechanisms that contribute to cognitive impairment in aging adults; Findings may inspire new clinical interventions

Senior author Jyoti Mishra, director of the NEATLabs Institute and associate professor of psychiatry at the University of California, San Diego School of Medicine, said.

The study collected samples from 62 younger healthy adults in their 20s and 54 healthy older adults over the age of 60. The researchers assessed the participants’ mental health, surveying symptoms of anxiety, depression, loneliness, and overall mental health. Participants also performed several demanding cognitive tasks while measuring brain activity using electroencephalography (EEG).

The results showed significantly worse symptoms of anxiety, depression, and loneliness in young adults and increased mental health in older adults. However, when it came to cognition, task performance was significantly lower in older adults.

EEG recordings revealed that during the tasks, older adults showed greater activity in the frontal parts of the brain’s default mode network. This group of brain regions is usually active when an individual is ruminating, daydreaming, or mind-wandering, and is usually suppressed during goal-directed tasks.

“The default mode network is useful in other contexts, helping us process the past and imagine the future, but it gets distracting when you’re trying to focus on the present to tackle a challenging task quickly and accurately,” Mishra said.

While the default mode network appears to interfere with cognition, many other areas of the brain appear to improve it. Better task performance in younger adults was associated with greater activity in the dorsolateral prefrontal cortex, part of the brain’s executive control system. However, in the elderly, those with better cognitive performance showed greater activity in the inferior frontal cortex, an area that helps direct attention and avoid distractions.

The dorsolateral prefrontal cortex is known to degrade with age, so researchers suggest that increased inferior prefrontal cortex activity may be a way for older adults to compensate during these tasks.

The team is now looking at therapeutic interventions to strengthen these frontal networks, such as brain stimulation methods, while also suppressing the default mode network through mindfulness meditation or other practices that direct individuals to the present.

“These findings may provide new neurological markers to help monitor and mitigate cognitive decline in aging, while at the same time maintaining well-being,” Mishra said.

The study may also inspire new ways to address the mental health of younger adults. “We tend to think of people in their twenties as being at their peak cognitive functioning, but it’s also a very stressful time in their lives, so when it comes to mental health there may be lessons to be learned from older adults,” Mishra said.

Study co-authors include Gillian Grennan, Pragathi Priyadarsini Balasupramani, Naseem Waheedi, Dakshin Ramanathan and Dilip V Jesty, all at the University of San Diego.

Funding for the study came, in part, from the National Institute of Mental Health (grant T32-MH019934), NeuroAIDS Interdisciplinary Research Fellowship grant (grant R25MH081482), the Stein Institute for Research on Aging at UCSD, the Brain Behavior Research Fund, the Kavli Foundation, and the Burroughs Wellcome Award Fund Career for Medical Scientists and the Sanford Institute for Compassion and Compassion.

The full study: https://doi.org/10.1037/pag0000710
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