Jerusalem Post
ByDORON KUPERSTEIN
A new study found that eighty-year-olds with particularly sharp memory have a significantly higher number of young nerve cells in the hippocampus region of the brain.
Most people experience a gradual decline in cognitive abilities with age. The brain accumulates damaged proteins, nerve cells die, and memory and thinking weaken. However, there is a small and unusual group of people aged eighty and over whose memory is almost as sharp as it was at fifty. They are called super-agers, and a new study now attempts to explain what is behind the phenomenon.
The study, published in the journal Nature, focuses on one of the most controversial questions in neuroscience: Whether the human brain is capable of producing new nerve cells even at an older age. This process is called neurogenesis, and for years researchers have been divided on whether it occurs in adults.
Twice as many young nerve cells
As part of the study, researchers examined brain samples collected after death from people of different ages. They focused on the hippocampus, a region of the brain that is essential for learning and memory and is considered a central site for the creation of new nerve cells.
First, the researchers looked for genetic markers of three types of cells in samples from the brains of young people aged twenty to forty with normal cognitive function. The three types included neural stem cells, neuroblasts, and immature nerve cells. The presence of all three types together suggests an active process in which stem cells gradually develop into mature nerve cells.
The researchers then compared four groups of adults: Those of the same age with normal cognition, people with mild cognitive impairment, Alzheimer’s patients, and super-agers. All groups contained the three types of cells, but the quantities differed dramatically.
Among the super-agers, nearly twice as many immature nerve cells were found compared to their peers with normal memory, and two and a half times more than in Alzheimer’s patients. Surprisingly, they even had more young cells than people aged twenty to forty.
Genetic programming that protects the brain
Beyond the high number of young nerve cells, the researchers found that these cells had unique genetic and epigenetic characteristics, which may give them resistance to aging processes. According to one of the researchers, it is possible that super-aging is not only due to a large number of young cells, but also to a genetic program that allows their preservation over time.
Other researchers in the field note that neurogenesis may also explain additional phenomena observed in super-agers, such as a relatively large hippocampus volume and increased connectivity between different brain regions. However, they emphasize that there are additional brain differences that cannot be explained solely by the creation of new nerve cells.
What happens in Alzheimer’s
The study also revealed an interesting finding regarding Alzheimer’s patients. In this group, more neural stem cells were actually found compared to healthy adults, but far fewer neuroblasts and immature nerve cells. One hypothesis is that during the disease process, neurogenesis is disrupted, the stem cells remain in a dormant state and do not progress to the next stages of development.
If this hypothesis is confirmed, it may open a new research direction in treating Alzheimer’s by reactivating dormant stem cells.
Despite the impressive findings, not all researchers are convinced. Critics in the field argue that this study also suffers from known methodological limitations in neurogenesis research, and that confirmation using additional techniques is needed.
While there is no dispute that babies and young children produce new nerve cells, and adult animals are capable of doing so, the question of whether adult humans also retain this ability remains open. Results from previous studies have presented a mixed picture, and conclusions have sometimes been influenced by the testing methods used.
Hope for preserving memory
Even if the current study does not resolve the debate, it provides important clues. If it is indeed possible to preserve or encourage the creation of new nerve cells at an older age, it may be possible in the future to develop treatments that help maintain memory and thinking over time.
At this stage, researchers are trying to understand how the unique young cells of super-agers contribute to their exceptional memory, and whether this process can be replicated through pharmacological means.
The message emerging from the study is that even at the age of eighty, the brain is not necessarily a frozen and declining organ. It may retain a certain degree of flexibility and the ability to regenerate, at least in some people.
