Super-ager brain: What to know

Older adults who remain cognitively sharp as they age have a genetic advantage over their peers, a new study finds.

Scientists at the University of Illinois College of Medicine at Chicago have found that so-called super-elders generate twice as many new neurons in the hippocampus – a part of the brain essential for learning and memory – as typical older adults. Their research was published Wednesday in the journal Nature.

“This discovery means that super-ages have a molecular capacity that allows them to perform higher. [cognitive] “Neurogenesis is one of the most profound forms of brain plasticity.”

In other words, she says, super-aged brains are more “accommodating.”

A super-ager is a person 80 or older who has the memory capacity of someone at least two to three decades younger, determined by delayed word recall tests, according to Dr. M. Marsel Mesulam, founder of the Mesulam Institute for Cognitive Neurology and Alzheimer’s Disease at Northwestern University’s Feinberg School of Medicine, who coined the term.

In the new study, Lazarov and his colleagues studied 38 brains from five groups of deceased adults: healthy adults aged 40 and younger, healthy older adults, people in the early stages of cognitive decline, people with Alzheimer’s disease, and older adults. The six super-aged brains were donated by Northwestern’s SuperAging program, which celebrated its 25th anniversary last year.

The researchers examined neurons at different stages of development in brain tissue samples. The study showed that super-aged people had twice as many new or “immature” neurons as healthy older people. Compared to people with Alzheimer’s disease, super-aged people had two and a half times more.

In the mid-20th century, it was thought that mammals were born with a fixed number of neurons in their brains. Scientists then discovered adult neurogenesis in rodents and primates in the 1960s and 1970s.

Although studies have since recognized this phenomenon in humans – in a part of the hippocampus called the dentate gyrus – the evidence is mixed and the process poorly understood.

“We established the presence of this process and its roles in learning and memory in rodents and primates,” Lazarov said. “Whether the human brain works in the same way is a very crucial question for us.”

Lazarov’s research suggests that adult human brains are not only capable of generating new neurons, but that they do so as a function of age and cognitive state.

Super-age brains showed a “signature of resilience,” Lazarov said. “They are able to cope with aging and perform well in terms of cognition.”

Additionally, his team discovered that changes in two cell types, astrocytes and CA1 neurons, help regulate memory and cognition in the aging hippocampus.

Still, the study had limitations, the authors said: It had a small sample size, and high variability among human brain samples is typical.

Super-ages offer more than 25 years of cognitive clues

This research marks the first discovery of a genetic difference between super-aged and typical older adults, according to the Northwestern SuperAging program.

“These people are in their 80s and 90s, and all of a sudden you see they still have immature neurons that are rewiring,” said Tamar Gefen, co-director of the program and co-author of the study. “There is no doubt that their seahorses [are] completely different from that of other human beings, period.

The program has made other discoveries related to exceptionally healthy older brains, ranging from personality traits to neurological abnormalities. For one thing, Gefen said, super-aged people typically describe themselves as extroverts. They also have more von Economo neurons, which are nerve cells linked to social behavior.

“We’ve heard time and again how important socialization is to healthy aging, and on the other hand, how detrimental isolation is to older adults,” she said.

Super-aged people also tend to go with the flow and remain open to new experiences, with low levels of self-reported neuroticism, Gefen added.

Healthy human brains shrink with age, a progression made worse by Alzheimer’s disease. However, in a 2017 study published in the Journal of the American Medical Association, Northwestern researchers found that the brains of super-aged people shrank more slowly than those of their peers.

In 2021, Gefen and colleagues published research in the journal Cerebral Cortex showing that super-agers are resistant to neurofibrillary tangles, or tau, which are abnormal accumulations of proteins linked to Alzheimer’s disease.

When it comes to immunity, super-aged people have as many questions as answers. The brain is home to immune cells called microglia, which are activated in people with neurodegenerative diseases. In a 2019 study published in the journal Frontiers in Aging Neuroscience, Gefen’s team found that super-aged people not only had fewer activated microglia than people with dementia, but also had a similar amount to people 30 to 40 years younger.

You don’t have to be a super-adult to stay alert

In a sense, the new study suggests that super-aged people have won the genetic lottery.

“I guess we’re lucky,” said Sel Yackley, a participant in Northwestern’s SuperAging program. “We are creating new neurons.”

The 86-year-old Chicagoan joked that she was fulfilling her “super-adult duties.” Meaning, she knits, goes to the gym, makes jewelry, sings in choir, and loves checking things off her daily to-do list. Yackley isn’t able to socialize in person much these days, but prioritizes staying in touch with friends via phone, email and Zoom.

Yackley said she’s proud to be a super-ager, but she’s not immune to the cognitive hurdles that come with aging.

“There are some things I remember like it was yesterday, but there are other things I forget,” she said.

Even if a person is not very old, there are many things they can do throughout adulthood to support their brain health, said Dr. Jennifer Pauldurai, medical director of the Inova Brain Health and Memory Disorders Program in Northern Virginia. It’s time to prioritize cognitive well-being, she said, long before natural decline or dementia sets in.

“I like the concept of superaging because it gives us a lot of control back. Rates of dementia and Alzheimer’s are only increasing. We’re living longer, and that means things are falling apart,” said Pauldurai, who was not involved in the study. “But if there’s an opportunity for us to make this crisis a little less intense, we should talk about it.”

This latest research demonstrates the malleability of the brain and Pauldurai recommends thinking of the organ as a piece of clay. Some people may be born with better quality clay than others, but it can still be shaped throughout life to build and maintain neural pathways.

However, a neglected piece of clay will harden and become difficult to work with.

“It’s similar to what happens to our brains if we don’t actively use it, if we don’t stay fit and cognitively engaged, if we’re not physically active throughout our lives,” Pauldurai said.

Maintaining your overall health is also vital for a flexible brain, she said, noting that factors such as poorly managed chronic illness or untreated mental trauma can impact neuron growth.

“It’s much easier to talk about preventative health care and brain health before there are many cracks in the system. [clay] pot,” she said. “I’d rather talk about that than the fact that I don’t have a cure for Alzheimer’s yet.”

Yackley, a former journalist, attributes her cognitive resilience in part to her career path.

“I had an inquisitive mind,” she says. “I’ve followed a lot of stories and interviewed a lot of people – it may have something to do with my neurons.”

Her advice to non-super-agers: stay not only busy, but engaged.

“Don’t worry about the years,” Yackley said. “Just stay active, mentally and physically. »