The ‘Fertile’ Brain: How Neurogenesis May Hold the Key to Healthy Aging and Preventing Alzheimer’s
Gianna Pratesi, a 105-year-old who recently graced the stage at the Sanremo Festival, embodies a question many of us ponder: what’s the secret to a long, healthy life? New research published in Nature sheds light on this exceptionally question, focusing on the brain’s remarkable ability to generate new neurons, a process called adult neurogenesis.
Cognitive Resilience and the ‘Super-Agers’
The study reveals that the brains of “super-agers”—individuals over 80 with exceptional cognitive abilities—are more “fertile” in terms of neurogenesis than those of their peers. Conversely, the brains of individuals with Alzheimer’s disease exhibit minimal growth of new neurons.
Adult Neurogenesis: A Lifelong Process
For decades, scientists believed that neurogenesis only occurred during development. However, in the latter half of the 20th century, it was discovered that new neurons can be generated throughout life in the hippocampus, a brain region crucial for learning and memory [1]. Initial observations in rodents sparked skepticism about whether this phenomenon occurred in other mammals, but subsequent primate studies linked neurogenesis to healthier brain aging and improved memory function.
The Study: Examining Brain Samples Across Cognitive States
Researchers from the University of Illinois at Chicago (UIC), Northwestern University, and the University of Washington examined brain samples from five groups: healthy young adults, healthy elderly individuals, super-agers, individuals with mild cognitive decline, and Alzheimer’s patients. Brains from super-agers, aged 80 and older with exceptional memories, were sourced from Northwestern University, while other samples came from the University of Washington.
The team analyzed three stages of neuron development in the hippocampus: stem cells (potential neurons), neuroblasts (developing stem cells), and immature neurons. Researchers likened these stages to an infant, toddler, and adolescent, respectively.
Superior Memory and the Resilience Signature
The results demonstrated that the hippocampus of healthy adults undergoes neurogenesis. Notably, super-agers exhibited significantly higher rates of new neuron production compared to other healthy elderly individuals—a “resilience signature.” According to Orly Lazarov, professor at UIC and director of the Training Program on Alzheimer’s disease and related dementias, “The super elderly have double the neurogenesis compared to other healthy elderly people. Something in their brain allows them to maintain superior memory. I believe that hippocampal neurogenesis is the secret ingredient and the data confirms it.”
Brain samples from individuals with preclinical cognitive decline showed minimal neurogenesis, while those with Alzheimer’s disease showed virtually no new neuron generation.
Epigenetic Characteristics and the Future of Cognitive Health
The study also revealed that new neurons display different epigenetic characteristics—patterns influenced by environmental factors—depending on an individual’s cognitive health. Jalees Rehman, head of the Department of Biochemistry and Molecular Genetics at UIC and co-author of the study, emphasized the importance of extending not just lifespan, but also “high quality, including cognitive health,” in an era of increasing longevity.
Targeted Therapies and Lifestyle Factors
Understanding the molecular details of neurogenesis and its epigenetic signature could pave the way for targeted therapies to preserve memory and cognitive function in aging populations. The research team plans to investigate how environmental and lifestyle factors—such as diet, exercise, and inflammation—interact with neurogenesis to influence the aging process.
A Hopeful Outlook on Brain Aging
“It’s exciting to discover that the aging brain is not necessarily destined to decline,” says Ahmed Disouky, first author of the study. “Understanding how some people naturally maintain neurogenesis paves the way for strategies that could aid more adults preserve their memory and cognitive health as we age.”