The study could offer incites into delaying the onset of dementia.
New research from UC San Diego, which incorporates key areas in healthy brain aging, pits younger adults against their elderly counterparts to compare intelligence and well-being. Results consolidating brain-imaging and psychological evaluation indicated that even though older participants scored considerably lower in cognitive tests than their younger counterparts–they are far healthier mentally.
The work centers around what is known as ‘senior moments,’ where an older friend or family member forgets a word or misplaces their keys. And even though studies have firmly established that these mild declines in cognition are perfectly normal as the brain changes with age: dementia is not.
In fact, in up to forty percent of these cases, people can prevent or delay mild cognitive decline making it essential to understand which areas of the brain are affected in the normal aging process – by doing this, researchers hope to see how they differ in abnormal decline while training and improving them.
The study, recently published in Psychology and Aging, saw sixty-two participants in their twenties and fifty-four healthy older adults over 60 undergo a gauntlet of cognitive tests. At the same time, scientists measured their brain activity using electroencephalography (EEG) to discern whether the two groups were using different areas of the brain for each task due to their age.
Results showed that each group was indeed using different connections to perform the task, with the elderly contingent scoring significantly worse than their younger peers. However, when researchers interviewed both cohorts to evaluate their mental state: younger participants exhibited markedly worse mental well-being than their far happier elderly competitors.
Lead author Jyoti Mishra, associate professor of psychiatry at UC San Diego, explains, “We wanted to better understand the interplay between cognition and mental health across aging, and whether they rely on activation of similar or different brain areas.”
Mapping cognitive decline
According to past studies, on average, our mental agility appears to peak around thirty years of age. And even though these subtle declines in cognition are normal, they can lead to a condition known as mild cognitive impairment (MCI) – where difficulties with recall and speech become more noticeable. In turn, MCI may increase the risk of dementia-including Alzheimer’s disease-involving the deterioration of memory, language, reasoning, and judgment severe enough to interfere with daily life.
Despite this, some people with MCI might never develop dementia or even get better due to certain lifestyle changes. Subsequently, if scientists could identify the processes involved in normal brain aging, they could find ways to improve them – making inroads in the fight against MCI and dementia.
The team set out to discern which brain areas decline or become more active with age by comparing young and old participants’ cognitive abilities and mental health. They began by hooking the volunteers up to an EEG while they all underwent cognitive tests. In this way, the team could glean which brain areas were active or no longer used in specific tasks depending on the person’s age.
For instance, in the younger volunteers, EEG data showed that higher cognitive scores were achieved by those who exhibited more activity in the dorsolateral prefrontal cortex: part of the brain’s executive control system known to degrade as we age. However, during the same tasks, the elderly contingent showed increased activity in anterior portions of the brain’s Default Mode Network (DMN): a brain region usually active when an individual is in deep contemplation or daydreaming and inhibited during tasks denoting honed concentration. In this case, overactivity in this area may explain why they scored so much lower than their younger competitors.
“The default mode network is useful in other contexts, helping us process the past and imagine the future, but it’s distracting when you’re trying to focus on the present to tackle a demanding task with speed and accuracy,” said Mishra.
But all was not lost for this cohort – activity in an area that helps guide attention and avoid distractions, known as the inferior frontal cortex, was increased, kicking in to improve scores in the older sample. Excitingly, taken together, these results validate the group’s premise that different brain areas are being activated and suppressed during brain aging as opposed to the regions used by young people.
After all the volunteers had completed these tests, the team used a verified survey to gain insight into their mental states. They found significantly more symptoms of anxiety, depression, and loneliness in young people and, in contrast, greater mental well-being in older adults.
For this reason, Jyoti feels their study could also inspire new ways of addressing the mental health of younger adults. “We tend to think of people in their twenties as being at their peak cognitive performance, but it is also a very stressful time in their lives, so when it comes to mental well-being, there may be lessons to be learned from older adults and their brains,” she adds.
The team is now looking into therapeutic interventions to strengthen these frontal networks, such as brain stimulation methods while suppressing the DMN through mindfulness meditation or other practices that orient individuals to the present.
“These findings may provide new neurological markers to help monitor and mitigate cognitive decline in aging, while simultaneously preserving well-being,” concludes Mishra.
