Eighty-year-olds produce twice as many new neurones than their counterparts.

Even in their 80s, some people are still able to think clearly and quickly as they would have decades ago. According to a recent study, their brains may be producing more new neurones than the majority of their classmates.

According to the same study, there was hardly any evidence of new neurone growth in the memory hub of the brains of individuals with Alzheimer's disease. Researchers from Northwestern University, the University of Washington, and the University of Illinois Chicago (UIC) produced the work.

Neurogenesis indicators

The group concentrated on the hippocampus, a part of the brain that plays a major role in remembering. They discovered that the most active indicators of adult neurogenesis—the process by which new neurones are created during adulthood—were identified in "superagers," or persons in their 80s with exceptionally good memories.

Orly Lazarov, a professor at UIC, stated, "This is a big step forward in understanding how the human brain processes cognition, forms memories, and ages." Researchers can develop treatments for cognitive resilience, healthy ageing, and the prevention of Alzheimer's disease and associated dementia by figuring out why some brains age more healthily than others.

Is it true that adults develop new neurones?

The fundamental building blocks of the neurological system are neurones. They are essential to every action, feeling, and thinking. Many scientists thought for a long time that you were born with all of your neurones and gradually lost them.

When researchers discovered that new neurones can develop throughout life in at least one area of the brain—the hippocampus—in the late 20th century, that perspective began to change.

For years, there was doubt regarding the extent to which adult neurogenesis actually occurred in adult humans, despite the fact that the concept was well known in rats.

The idea gained support from research on monkeys, which connected neurogenesis to better memory and healthier brain ageing. However, due in part to the difficulty of directly studying real human brain tissue, the matter has remained unexpectedly contentious in humans.

A compelling piece of evidence is added by this latest study. It bolsters the notion that adult neurogenesis does happen in people and raises the possibility that it is connected to cognitive resilience, the uncommon capacity to maintain mental acuity far into old life.

Adult neurogenesis stages

Five groups of donated human brain samples were examined by the team. Young adults and older persons in good health were present, as were those with mild or early dementia, Alzheimer's disease patients, and older adults with superager-like memory.

The superager samples were acquired from Northwestern University and were from donors who were 80 years of age or older and had remarkable memory abilities. The University of Washington provided the other samples.

The researchers searched for several steps of the hippocampal neuron-building pipeline rather than a single "new neurone" marker. They looked for immature neurones that were on the verge of becoming fully functional, neuroblasts that were farther along in the process, and stem cells that might develop into neurones.

Lazarov suggested comparing the stages of adult neurogenesis to those of a newborn, toddler, and adolescent. "All of these indicate that new neurones are developing in these hippocampuses."

This is significant because a complete developmental trail is more difficult to dispute than a single marker that could be constructed in a variety of ways.

The most reproductive people were superagers.

The pattern was fairly noticeable across the groups. The hippocampal formation of new neurones was demonstrated in healthy people. Superagers, however, were particularly active. Compared to normal older adults, their hippocampus displayed greater neuron synthesis, which the researchers describe as a type of biological "resilience signature."

According to Lazarov, "superagers had twice the neurogenesis of the other healthy older adults." They have a better memory because of something in their brains. The evidence supports my theory that the key component is hippocampus neurogenesis.

On the other end of the range, very little neurogenesis was seen in the brains of individuals who were already in the first discernible stage of cognitive impairment. Additionally, hardly none were found in the brains of Alzheimer's patients.

It's difficult to overlook the difference: the most dysfunctional brains were almost "silent" on the creation of new neurons, whilst the top-performing older brains were the most active.

Beyond the quantity of newly formed neurones

Another finding that might be equally significant was that the new neurones had distinct epigenetic signatures based on the individual's cognitive state.

The set of instructions that instructs genes on when to turn on or off is commonly referred to as epigenetics. It can affect how cells react to stress, inflammation, food, and other cues. It is influenced by both life events and the environment.

The researchers discovered that each group had different "blueprints" linked to new neurones. This suggests that neurogenesis involves more than just quantity.

What distinguishes resilient brains from fragile ones may also have to do with the calibre and flexibility of those cells—how they react to shifting circumstances.

Why this is important for ageing

The study comes at a time when life expectancy is higher than it has ever been. However, living well does not equate to living longer. Many families are familiar with the agony of witnessing personality and memory changes brought on by dementia.

According to Jalees Rehman, a professor at UIC and co-lead author, "life expectancy is higher now than ever before because modern medicine has revolutionised health care."

"We must make sure that a high quality of life, including cognitive health, is accompanied by this overall increase in life expectancy."

In order to help more people keep their memory and cognitive abilities as they age, it is hoped that a better understanding of why superagers sustain neurogenesis may lead to treatments or lifestyle changes.

What follows

The study makes no claims about how increasing neurogenesis can prevent Alzheimer's. Alzheimer's comprises several disease stages, and human brains are complex. However, the results do imply that neurogenesis might be one significant aspect of the narrative, and possibly one that is modifiable.

The next step, according to Rehman, is to investigate lifestyle and environmental factors including inflammation, exercise, and diet that may have an impact on neurogenesis. Additionally, the team hopes that the work would inspire hope in the public.

Ahmed Disouky, the study's first author, stated, "What's exciting for the public is that this study shows the aging brain is not fixed or doomed to decline." More adults may be able to keep their memory and cognitive health as they age if we can better understand how certain people naturally maintain neurogenesis.

The most straightforward conclusion for now is that some elderly brains continue to develop. The way we think about cognitive aging and what "healthy aging" might actually look like in the future may change if researchers can understand how superagers achieve it and why Alzheimer's brains don't.