Your brain has 5 secret ages and one of them lasts almost your entire life. “Adult mode” only at age 32: that’s when we enter the cognitive golden phase.
This age thing has a lot to say about it. A new study from the University of Cambridge, in the United Kingdom, drew a “life map” of the human brain and concluded that its architecture does not change linearly over the years.
Instead, the structure of our neural networks traverses five major phasesseparated by four remarkable turning points.
These four turning points occur, according to research, at 9, 32, 66 and 83 years old.
The work today in the journal Nature Communications analyzed brain images of 3,802 people between birth and 90 years of age. The researchers used diffusion magnetic resonance imaging, a technique that allows them to follow the movement of water molecules in brain tissue and thus infer how different regions are connected. From this data, they were able to identify patterns of connectivity that are repeated throughout life and that define major “eras” of brain organization.
According to the team, these periods correspond to different modes of cognitive functioning and also to windows of greater vulnerability to neurodevelopmental problems, mental health or cognitive decline.
From childhood to pre-adolescence (0 to 9 years old)
The first major phase runs from birth to around 9 years of age. In the first years of life, the brain produces a huge excess of connections between neurons, called synapses. Then, enter a intense “pruning” process, as categorized: the most used connections are reinforced and maintained, the least active are eliminated. It is this fine-tuning that shapes the initial architecture of brain networks.
During this period, both the gray matter (where the neuron bodies are concentrated) and the white matter (the bundles of fibers that connect different areas of the brain) grow quickly in volume.
The researchers found that, on average, the pattern of reorganization of connections is very consistent between birth and age 9, suggesting a relatively common sequence of structural development.
This moment coincides with a leap in cognitive capacity – language, attention, reasoning – but also with an increased risk of some mental health problems.
Subtle changes in the way this “childhood architecture” is organized may help explain learning difficulties or neurodevelopmental disorders.
The turning point of 32 years
The second major turning point occurs around age 32. This is where the brain really comes into play. “adult way”, according to the study. White matter continues to enlarge and become more efficient, and refines the communication networks between brain regions.
Based on the changes observed in the images, the authors describe this phase as the point of greatest directional change in a lifetime: is the moment when the trajectory of brain organization deviates most in relation to the previous and following phases. From a structural point of view, This is where typical teenage patterns endeven if socially or psychologically this border is less clear.
Scientists relate this stage to a peak cognitive performance: processing speed, mental flexibility, ability to plan and make complex decisions.
After this turning point, the architecture of the brain stabilizes very well. Around three decades followed, between the 30s and 60s, in which no new major structural shifts were observed. This long “adulthood” seems to correspond, on average, to a plateau of intelligence and personality traits.
66 years: the beginning of brain aging
The third turning point appears around the age of 66 and marks the beginning of a phase of “premature aging” of brain architecture. This is not a sudden rupture, but the culmination of a gradual reorganization of the networks over the previous years.
From here onwards, signs of decreased connectivityparticularly as the white substance degrades. This phase coincides with the age at which the risk of various medical conditions that affect the brain increases, such as high blood pressure or cardiovascular problems, which can contribute to subtle but significant changes in neuronal networks.
Late aging: the last phase of life
The last major turning point identified by researchers is around the 83 years. From this age onwards, the brain’s global connectivity decreases further and networks become less comprehensive. Instead of broad communication between many regions, the brain becomes more dependent on local circuits and some key areas, while others lose influence.
Data from this age group are more limited because there are fewer very old participants in brain imaging databases, but the trend is clear: as we move into very old ages, neural networks become more fragmented.
For the study authors, recognizing that the brain goes through large structural “ages” helps to better contextualize what each age group is, on average, better at – and also more vulnerable to. Many neurodevelopmental problems, mental health disorders or neurodegenerative diseases are associated with the way the brain is “wired” throughout life.
Knowing that the organization of networks does not evolve uniformly, but rather with marked turning points, can guide future investigations: for example, understanding why certain difficulties arise in certain periods (such as childhood or prolonged adolescence until the age of 30), or why some forms of dementia and cognitive decline become more frequent at specific ages.
