- Human brain development occurs in five major phases from infancy to old age
- Childhood features network consolidation and peak cortical thickness by age nine
- Adolescence improves brain connectivity and cognitive ability until about age 32
Scientists have discovered that the human brain goes through five major phases of development from infancy to old age. In one of the largest studies of its kind, researchers analysed brain scans from nearly 4,000 people aged under one to 90. The study mapped how neural connections evolve over time and identified four key turning points when the brain shifts onto a new path, reported The Guardian.
Studies have revealed that brain development occurs in five main stages. The first stage, childhood, lasts from birth to about nine years of age. The brain then enters adolescence, which lasts until about 32 years of age.
Then comes early adulthood, which lasts for more than three decades. At about age 66, the brain reaches the stage of early aging, and the final stage, late aging, begins at about age 83.
According to the researchers, just as life is experienced at different stages, the brain also goes through different phases. They stated that brain development does not occur continuously, but in a series of major shifts, which can help scientists understand when the brain is most vulnerable.
During childhood, the brain undergoes "network consolidation." During this period, excess synapses are removed, and the most active connections are strengthened. The efficiency of brain wiring decreases slightly, while grey and white matter increase, cortical thickness reaches its peak, and brain folding stabilizes.
During adolescence, white matter continues to develop, and the brain's communication networks become more sophisticated. During this time, the efficiency of connections increases, which improves cognitive ability.
The researchers stated that these stages reflect patterns of brain change, not that a 30-year-old's brain functions like a teenager's. Understanding these patterns may help explain why mental health problems appear during adolescence.
The brain undergoes its greatest developmental changes around age 32. Life events, such as parenthood, may influence this change, although this was not directly examined in the study. After this stage, brain structure stabilizes, and intelligence and personality also remain stable. Brain regions become more compartmentalised.
The latter two major changes, manifested as a decrease in brain connectivity, occur around the ages of 66 and 83. These changes are associated with aging and the gradual deterioration of white matter.
