Unraveling the Secrets of the Super-Ager Brain: A Journey into Cognitive Resilience
In a groundbreaking discovery, researchers have unveiled a fascinating genetic advantage possessed by a select group of older adults known as super-agers. These individuals, despite their advanced age, maintain an exceptional level of cognitive sharpness, leaving their peers in awe. The study, conducted by scientists at the University of Illinois College of Medicine Chicago, sheds light on a remarkable phenomenon: super-agers produce twice as many new neurons in the hippocampus, a crucial region for learning and memory, compared to typical older adults.
Published in the prestigious journal Nature, the research reveals a molecular capability that sets super-agers apart. Dr. Orly Lazarov, the study's co-author and director of UIC's Alzheimer's Disease and Related Dementia Training Program, explains, "Neurogenesis, or the birth of new neurons, is a profound form of brain plasticity. Super-agers' brains are more accommodating, allowing them to perform cognitively at a higher level."
So, who are these super-agers? According to Dr. M. Marsel Mesulam, founder of the Mesulam Institute for Cognitive Neurology and Alzheimer's Disease at Northwestern University Feinberg School of Medicine, a super-ager is an individual aged 80 or older with a memory capacity akin to someone two to three decades younger. This determination is made through delayed word recall testing.
In their study, Lazarov and colleagues examined brain tissue samples from five distinct groups: healthy adults under 40, healthy older adults, individuals with early-stage cognitive decline, those diagnosed with Alzheimer's disease, and the elusive super-agers. The brains of six super-agers, donated by Northwestern's SuperAging Program, were a key focus.
The researchers' findings were astonishing. Super-agers had twice as many new, or immature, neurons as healthy older adults, and a staggering two and a half times more compared to individuals with Alzheimer's. This discovery challenges the long-held belief that mammals are born with a fixed number of brain neurons, a notion that was prevalent until the mid-20th century.
Lazarov's research suggests that adult human brains not only have the capacity to generate new neurons but that this process is influenced by age and cognitive status. Super-agers' brains exhibit a "resilience signature," as Lazarov puts it, allowing them to cope with aging and excel cognitively.
Furthermore, the study revealed that changes in two specific cell types, astrocytes, and CA1 neurons, play a crucial role in regulating memory and cognition in the aging hippocampus. However, the authors acknowledge limitations, citing a small sample size and the typical variability among human brain samples.
The Northwestern SuperAging Program emphasizes that this research marks the first identification of a genetic difference between super-agers and typical older adults. Tamar Gefen, co-director of the program and a co-author of the study, highlights the uniqueness of super-agers' hippocampi, stating, "Their brains are completely different from other human beings, period."
The program's research has unveiled intriguing insights into these exceptionally healthy older brains. Super-agers often describe themselves as extroverts and possess more von Economo neurons, nerve cells linked to social behavior. Gefen emphasizes the importance of socialization for healthy aging and the detrimental effects of isolation.
Super-agers also tend to embrace a go-with-the-flow attitude, remaining open to new experiences and exhibiting low levels of neuroticism. Additionally, their brains shrink more slowly with age compared to their peers, a finding published in the Journal of the American Medical Association in 2017.
In 2021, Gefen and her team published research in the journal Cerebral Cortex, demonstrating that super-agers are resistant to neurofibrillary tangles, abnormal protein buildups associated with Alzheimer's. When it comes to immunity, super-agers present a fascinating paradox, with fewer activated microglia, immune cells in the brain, compared to individuals with dementia, and similar levels to those 30 to 40 years younger.
While super-agers may have won the genetic lottery, Dr. Jennifer Pauldurai, medical director of the Inova Brain Health and Memory Disorders Program in northern Virginia, emphasizes that anyone can take steps to support brain health throughout adulthood. She advocates for prioritizing cognitive well-being long before natural decline or dementia sets in.
"The concept of super-aging gives us control. We're living longer, but with increasing rates of dementia and Alzheimer's. If we can slow down the breakdown, we should discuss it," Pauldurai says.
This latest research highlights the brain's remarkable malleability. Pauldurai compares the brain to a lump of clay, suggesting that while some may be born with higher-quality clay, it can be molded and nurtured throughout life to build neural pathways. However, a neglected lump of clay hardens, becoming difficult to work with, much like an inactive brain.
Maintaining overall health is crucial for a pliant brain, as factors like poorly managed chronic illness or untreated mental trauma can impact neuron growth. Pauldurai emphasizes the importance of cognitive fitness, engagement, and physical activity throughout life.
Sel Yackley, an 86-year-old participant in Northwestern's SuperAging Program, jokes about keeping up with her "super-ager duties." She attributes her cognitive resilience to her career as a journalist, saying, "I had a curious mind, and I followed up on a lot of stories."
Yackley's advice to non-super-agers is simple: stay engaged, both mentally and physically. "Don't worry about the years; just stay active."
This research not only provides insights into the fascinating world of super-agers but also offers a glimmer of hope for those seeking to maintain cognitive health as they age.
