A new large-scale study by neurobiologists at the University of Cambridge, published on November 24, 2025, outlines "five ages" of the human brain. The team analyzed 3,800 brain scans of individuals aged 0 to 90 and found four pivotal milestones—at ages 9, 32, 66, and 83—that divide our lives into five distinct epochs.
Childhood (0–9): The first stage is marked by "network consolidation"—a massive surplus of synapses is pruned to the most active ones. The cortex reaches peak thickness and the brain maps out general connections, but operates less efficiently—information travels more slowly between regions.
Adolescence/Young adulthood (9–32): The brain becomes more efficient at information transfer; connectivity is fastest, and cognitive and social capacities soar.
Mature adulthood (32–66): Brain structure stabilizes, neural connections gradually adapt to skills and experience; this is a period of mental equilibrium but also the beginning of a gradual cognitive plateau.
Early aging (66–83): Information transfer slows, connectivity wanes, and vulnerability to dementia increases.
Late aging (83+): Organizational networks break down further, with significant losses in memory and abilities.
"These epochs are essential for understanding when the brain is most vulnerable or has the greatest potential," says Dr Alexa Mousley. The research helps explain why the risks of learning challenges or dementia are tightly linked to age.
Neuroscientists emphasize: changes are not linear, and each stage presents unique vulnerabilities—childhood networks are fragile to learning disorders, while after 66, risks of neurodegeneration rise.
Unveiling these ages and their major milestones can help both diagnostics (from speech difficulties to early detection of Alzheimer’s) and targeted prevention strategies throughout life.