According to new research, throughout an average human lifespan, the goes through five distinct stages of development.
To uncover this, neuroscientists from the University of Cambridge (UK) scanned the brains of around 4,000 individuals ranging from birth to 90 years old. Ultimately, the researchers identified key milestones that signify fundamental changes in the neural connections that enable our brain to function.
One of the most astonishing discoveries is that the period scientists refer to as adolescence begins around age 9 and lasts until about 30.
The study, the results of which were published in the journal Nature Communications, confirmed that our brains are constantly learning and adapting as we absorb new information. However, this process is not smooth or continuous; it is characterized by bursts of activity, especially in the first half of life.
Five Key “Epochs” of Brain Development
Childhood – from birth to 9 years.
Adolescence – from 9 to 32 years.
Adulthood – from 32 to 66 years.
Early Aging – from 66 to 83 years.
Late Aging – from 83 years onward.
These distinct “epochs” were identified using datasets obtained from diffusion MRI scans, which allowed researchers to map neural connections by tracking the movement of water molecules through brain tissue.
Dr. Alexa Mousley, who led the research, noted, “We knew that the structure of the brain is crucial for our development, but we lacked a comprehensive picture of how it changes throughout our lives and why.”
Thus, understanding these “epochs” provides important context for recognizing when our brains may be most effective or vulnerable at different life stages. It helps explain why individuals’ brains can develop differently at critical moments in life.
Childhood
The team discovered that during the first “epoch” (from birth to 9 years), the brain undergoes “network consolidation.” In this process, the number of synapses (connections between neurons) that the child’s brain produces in excess is reduced, with only the most active connections surviving.
By the end of this first stage, the brain experiences significant changes in cognitive abilities. This is accompanied by an increase in vulnerability. Following this stage, the risk of mental disorders also rises, as reported by Independent.
Adolescence
During adolescence, the brain’s communication networks become increasingly sophisticated. This “epoch” is characterized by the formation of faster and smoother communication both within specific areas of the brain and across the entire brain. Such transformation leads to a significant improvement in cognitive skills.
The team stated that this process typically concludes only after the age of 30.
Adulthood
Starting around age 32, the longest “epoch” begins—adulthood. The architecture of the brain stabilizes compared to previous phases. During the next thirty years, there are few significant turning points.
Despite this, neuroscientists noted that during this period, areas of the brain gradually become more disconnected.
Early Aging
The reorganization of the brain’s neural networks peaks between the ages of 60 and 70. According to Dr. Mousley, this is likely “related to aging, during which the number of neural connections increasingly declines as white matter begins to degenerate.”
This is a period when individuals face an elevated risk of various serious diseases that can affect the brain, such as .
Late Aging
The final stage of brain structure formation occurs around age 83. Scientists believe that a defining feature of this “epoch” is a significant weakening of “regional” connections in the brain. Individuals increasingly rely on well-known neural pathways and areas.
Duncan Astle, a professor of neuroinformatics at Cambridge, noted that the research helps understand the degree of vulnerability of the brain at different stages of development, as well as identify ways to treat specific conditions.
“Looking back, many of us feel that our lives have consisted of different stages. It turns out that the brain goes through them as well,” he said.
Photo: Unsplash
