Medical Bulletin 27/November/2025 - Video

Here are the top medical news for today:

Study finds Five Major Brain Development Phases, Adulthood Actually Begins 32

The human brain doesn’t just grow up overnight—it evolves in five distinct stages, each packed with its own unique changes and challenges. Researchers at the University of Cambridge analyzed brain scans from nearly 4,000 people aged from birth to 90, revealing that brain development and ageing follow a complex, non-linear journey. Their work, published in Nature Communications, identifies major milestones around ages 9, 32, 66, and 83 that mark shifts in how our brain’s wiring adapts throughout life.

Using advanced imaging to track how water moves through brain tissue, the team reconstructed the brain’s wiring diagram at different ages and measured how efficiently regions communicated with each other. This allowed them to spot four sharp “topological turning points” that mark transitions between five phases: childhood (0–9), adolescence (9–32), adulthood (32–66), early ageing (66–83) and late ageing (83+). The patterns held up across thousands of scans, even though the exact timing varied a little from person to person.

In the first stage—childhood, from birth to nine years—the brain rapidly expands and prunes connections. Dr. Alexa Mousley, lead author, describes this as a noisy, inefficient communication phase where the brain explores a wide range of connections before settling on the most efficient pathways.

Around nine years old, the brain hits a dramatic “rewiring” phase lasting into the early thirties—far beyond what was traditionally called adolescence. During this phase, neural pathways strengthen, becoming highly efficient and boosting peak cognitive performance typically seen in the early 30s. This period is also when many mental health conditions first emerge, possibly linked to the intense brain remodeling underway.

From 32 to 66 years, brain wiring changes slow significantly, marking a plateau in intelligence and personality development—what many recognize as stable adulthood. But then, around age 66, early ageing begins. The brain’s network starts to fragment into distinct clusters rather than a single integrated system. This shift coincides with increased prevalence of dementia and cardiovascular conditions affecting cognition.

Finally, after age 83, this modularity intensifies—certain brain regions become critical hubs, and overall connectivity changes further. These detailed brain “epochs” help explain why different cognitive and neurological conditions emerge at specific life stages and could guide personalized strategies to maintain brain health throughout our lives.

This groundbreaking study reshapes our understanding of brain lifelong development and ageing, highlighting the dynamic and ever-changing nature of our neural wiring.

REFERENCE: Mousley, A., Bethlehem, R.A.I., Yeh, FC. et al. Topological turning points across the human lifespan. Nat Commun 16, 10055 (2025). https://doi.org/10.1038/s41467-025-65974-8

Long-Term Calorie Restriction Slows Cellular Signs of Brain Aging: Study

Cutting calories may hold the key to preserving brain health and slowing cognitive decline as we age. A groundbreaking study from Boston University provides rare, long-term evidence that calorie restriction (CR) can slow brain aging and protect neural health.

Initiated in the 1980s in collaboration with the National Institute on Aging, the study followed two groups over decades: one consuming a normal diet, and the other eating roughly 30% fewer calories.

Subjects lived out their full lifespans, with researchers analyzing their brain cells postmortem using advanced single nuclei RNA sequencing to assess gene expression and metabolic pathways.

The methodology involved detailed molecular profiling of individual brain cells, comparing those from calorie-restricted versus normal diet groups. This allowed researchers to pinpoint differences in genes related to myelin—the insulating sheath around nerve fibers crucial for fast, accurate neural communication.

They found that calorie-restricted brains exhibited enhanced expression of myelin-associated genes and increased activity in glycolytic and fatty acid biosynthesis pathways, essential for myelin production and maintenance.

These brain cells were metabolically healthier and more functional, suggesting long-term calorie restriction supports cellular resilience and slows neurodegenerative processes.

Co-author Dr. Tara L. Moore emphasized that these molecular alterations could underlie better cognition and learning observed in calorie-restricted subjects. The study sheds new light on how sustained dietary habits influence the brain’s aging trajectory on a cellular level.

This research adds important validation to calorie restriction as a potential intervention to maintain brain health and delay cognitive decline in humans, building on previous short-lived animal studies.

While implementing long-term calorie reduction poses challenges, these findings deepen understanding of modifiable lifestyle factors in brain aging. Ongoing exploration of CR’s effects could guide development of strategies to promote healthy cognitive aging and reduce neurodegenerative disease risk, improving quality of life across aging populations.

REFERENCE: Vitantonio, A.T., et al. (2025). Calorie Restriction Attenuates Transcriptional Aging Signatures in White Matter Oligodendrocytes and Immune Cells of the Monkey Brain. Aging Cell. DOI: 10.1111/acel.70298. https://onlinelibrary.wiley.com/doi/10.1111/acel.70298

Study Reveals Mid-Life Exercise Cuts Dementia Risk Nearly Half

Want to protect your brain from dementia? Start Exercising. A compelling new study from Boston University reveals that staying physically active during mid-life and later years can dramatically cut the risk of developing dementia—by up to 45 percent.

Drawing on long-term data from over 4,300 adults in the renowned Framingham Heart Study, researchers tracked participants for up to 37 years, assessing how varying activity levels influenced dementia outcomes.

Published in The Journal of the American Medical Association (JAMA), the findings underscore the critical power of exercise in maintaining brain health as we age.

The study grouped participants into young adults, mid-life (45-64 years), and late-life (65 and older) categories, recording 567 cases of dementia by the study’s end. Physical activity was measured using a Physical Activity Index that counted hours spent in different intensities, from sedentary to vigorous.

Those with the highest activity levels in mid-life experienced a 41% lower risk of all-cause dementia, while late-life high activity was associated with a 45% reduced risk. Even moderate activity conferred significant protection, reducing dementia risk by 35-38%.

Crucially, the study also explored genetic risks related to the APOE e4 variant, a strong predictor of Alzheimer's. Non-carriers who exercised the most during mid-life achieved nearly 50-60% lower dementia risk, and late-life high activity led to a 46% risk drop. For APOE e4 carriers, late-life physical activity reduced dementia risk by an impressive 66% compared to inactive peers.

Researchers explained that exercise may slow amyloid protein accumulation—a hallmark of Alzheimer’s—while promoting growth and connectivity of neurons in the hippocampus, the memory center of the brain.

Given the rising global burden of dementia and limited pharmaceutical options, this study provides powerful evidence that regular physical activity during critical adult life stages is a practical, low-cost strategy to protect cognition and delay dementia onset.

REFERENCE: Marino FR, Lyu C, Li Y, Liu T, Au R, Hwang PH. Physical Activity Over the Adult Life Course and Risk of Dementia in the Framingham Heart Study. JAMA Netw Open. 2025;8(11):e2544439. doi:10.1001/jamanetworkopen.2025.44439