How our brains undergo five complete rewirings throughout our lives

Scientists have discovered that the human brain undergoes complete rewiring five times during a lifetime, revealing key changes in how we think and function at different ages. According to the study published in Nature Communications, major neural reorganization occurs around the ages of 9, 32, 66, and 83.

"These phases highlight when the brain excels in certain tasks or is particularly susceptible to challenges," explains Alexa Mousley from the University of Cambridge. "They also help explain why learning difficulties or age-related cognitive decline may appear at specific stages of life."

The researchers analyzed roughly 3,800 brain scans from healthy individuals up to 90 years old. Using MRI diffusion imaging, which traces the movement of water molecules in neural tissue to map connections, the team identified four major points where brain networks undergo significant restructuring.

Early Childhood: Building the Foundation

From birth to about nine years old, the brain overproduces synapses, then prunes unused connections, keeping only those frequently activated. The first major turning point at age nine coincides with a surge in cognitive development, but also brings heightened vulnerability to mental health challenges.

Adolescence to Early Adulthood: Efficiency Peaks

Between ages nine and 32, the brain becomes highly efficient. Communication networks are refined, and cognitive abilities improve significantly. This period is unique as it is the only stage in life where neural efficiency increases substantially.

Adulthood: Stability and Plateau

By the early 30s, the brain reaches its peak performance. At around age 32, the most significant rewiring occurs across the lifespan. While timing varies with cultural and social factors, this stage marks a prolonged period of structural stability lasting roughly three decades, with intelligence and personality generally plateauing.

Mid-Sixties: Gradual Restructuring

The next turning point occurs around age 66. While structural changes are less dramatic, brain networks gradually reorganize. Health factors like high blood pressure can pose increased risks for cognitive decline during this period.

Late Ageing: Final Changes

The final stage begins around 83, when brain network efficiency continues to decline. Since participants over 90 were not included, the studys findings end at this age. Future research aims to explore larger populations and potential differences between sexes.

"Recognizing that brain development occurs in distinct phases rather than steadily will help identify periods when neural wiring is most vulnerable," says lead author Duncan Astle of the University of Cambridge.

Author: Sophia Brooks