Great Britain Childhood to old age - brain structure goes through five phases
According to a study, the brain extensively rewires itself five times over the course of a lifetime. At an average age of around 9, 32, 66 and 83 years, there are turning points in neuronal networking, reports a research team in the journal "Nature Communications".
28.11.2025, 04:54
SDA
The rewiring goes hand in hand with different ways of thinking in the course of growth, maturation and ageing. "The phases provide important clues as to what our brain is best suited to at different stages of life or when it is most vulnerable," explained Alexa Mousley from the University of Cambridge. "They help us to understand why some brains develop differently at important points in life, for example in the form of learning difficulties in children or dementia in old age."
For the study, the team analyzed around 3,800 data sets from people up to 90 years old with no known neurological diseases. They used MRI diffusion scans, which map neuronal connections by tracking the movement of water molecules through brain tissue.
"From this, we identified four important topological turning points in the course of life - at around 9, 32, 66 and 83 years of age," explains the research group in the study. Each of these age groups marks the beginning of a new epoch in development, which is accompanied by characteristic age-related changes in the structure of the brain. The longest phase is the adult mode, which lasts for more than three decades.
From infant to child: the permanent construction site
In the first phase, from birth to around the age of nine, the number of synapses overproduced in a baby's brain is reduced, as the researchers explain. The more actively used connections between the neurons are retained. According to the study, the first turning point at around nine years of age is associated with a sudden change in cognitive abilities, but also an increased risk of mental disorders.
Adolescence and early adulthood: efficiency at its peak
Between the ages of around 9 and 32, the brain is in its second phase - and on a real high. The organization of the brain's communication networks becomes increasingly refined, the team explains. This is characterized by rapid communication throughout the brain, combined with improved cognitive performance. Adolescence is the only phase in life in which neuronal efficiency increases, said Mousley.
The adult brain - three decades of stability
On average, the research team believes that the brain reaches its maximum efficiency in the early 30s, the strongest turning point of the entire lifespan. "At around the age of 32, we observe the biggest changes in wiring and the biggest overall shift in development compared to all other turning points," says Mousley.
The exact timing is quite variable and depends on cultural, historical and social factors, among other things. The brain architecture stabilizes compared to earlier phases - and does so for around three decades. There is a plateau in terms of intelligence and personality, the researchers explain.
Mid-sixties: the early phase of ageing begins
The least pronounced turning point without major structural changes then occurs at around 66 years of age: In the mid-sixties, a gradual restructuring of brain networks reaches its peak. "At this age, people are at increased risk for a variety of health problems that can affect the brain, such as high blood pressure," said Mousley.
Late aging - the final stage of development
According to the analysis, the final turning point occurs at around 83 years of age: The human brain enters the phase of late ageing. Networking continues to decline. As there were no study participants over the age of 90, the study period only extended up to this age. Future studies should consider larger samples and investigate gender-specific differences, the team hopes.
"Understanding that the structural development of the brain is not a question of steady progress, but rather a question of a few important turning points, will help us to recognize when and how its wiring is susceptible to disruption," lead author Duncan Astle from the University of Cambridge is convinced.
