Image source, Monte Racusen/Getty
Scientists say the brain goes through five distinct stages in life, with major turning points at ages 9, 32, 66 and 83.
These results are part of a study that included about 4,000 people up to the age of 90, who underwent scans that showed the connections between their neurons.
Researchers at the University of Cambridge in England have shown that the brain remains in adolescence until our early 30s, when we reach our fullest potential.
They say the findings could help us understand why the risk of developing mental health disorders and dementia varies across the lifespan.
The brain is constantly changing in response to new knowledge and experiences, but research shows that this is not a uniform pattern from birth to death.
Alexa Mosley, from the University of Cambridge, told the BBC: “The brain rewires itself throughout life. It is always strengthening and weakening connections, and it does not follow a stable pattern. There are fluctuations and stages in rewiring the brain.”
Some people will reach these milestones earlier or later than others, but the researchers said it’s surprising how clear these ages are in the data.
These are the five stages of the brain:
- Childhood: from birth to 9 years
- Adolescence: from 9 to 32 years
- Adulthood: from 32 to 66 years
- Premature aging: from 66 to 83 years
- Late aging: aged 83 years and above.
These patterns have only been revealed now thanks to the number of brain scans available in the study published in the journal Nature Communications.
The five stages of the brain
childhood: This first period is when the brain grows rapidly in size, but the overabundance of connections between nerve cells, called synapses, created early in life, also weakens.
During this stage, the brain becomes less efficient. It acts like a child wandering through a park, going where it wants, instead of going directly from point A to point B.
Image source, Getty Images
adolescence: This phase changes suddenly from the age of nine, when brain connections go through a period of extreme efficiency. “It’s a huge change,” Mosley said, describing the most profound shift between brain stages.
This is also the time of highest risk for mental health disorders to develop.
As you might expect, adolescence begins with the onset of puberty, but this is the latest evidence to suggest that it ends much later than previously assumed. It was thought to be limited to adolescence, before neuroscience suggested it continues into the twenties and now the early thirties.
This stage is the only period in the brain when its neural network becomes more efficient. This supports several measures of brain function that suggest a peak in the early 30s, Moseley said, but added that it is “very interesting” that the brain stays at the same stage between ages 9 and 32.
Image source, Getty Images
Puberty: After that comes a period of stability for the brain, which enters its longest stage, lasting for three decades.
Change is slower during this stage than during the previous mutation, but here we see the improvement in brain efficiency reflected.
This is “in keeping with the level of intelligence and personality” that many of us have witnessed or experienced, Mosley explained.
Premature aging: This starts at age 66, but it’s not a sharp, sudden decline. Changes occur in communication patterns in the brain.
Instead of coordinating as a whole, the organ becomes increasingly separated into areas that work closely with each other, like band members starting their solo projects.
Although the study looked at healthy brains, this is also the age at which dementia and high blood pressure, which affect brain health, begin to appear.
Image source, Getty Images
Late aging: At 83 years old, we are entering the final stage. There is less data than for other groups, because finding healthy brains to scan has been more difficult. The brain changes are similar to those that occur in premature aging, but are more pronounced.
Mosley said what really surprised him was the good agreement between the different ages and many important milestones, such as puberty, later health problems, and even the big social changes of the early 30s, such as fatherhood.
Interesting study
The study did not look at men and women separately, but questions such as the impact of menopause will be asked.
Duncan Astle, professor of neuroinformatics at the University of Cambridge, said: “Many neurological, mental health and neurodevelopmental conditions are linked to brain composition. Indeed, differences in brain composition predict difficulties with attention, language, memory and a wide range of behaviours.”
Professor Tara Spiers-Jones, Director of the Brain Science Discovery Center at the University of Edinburgh, said: “This is a very interesting study that highlights how much our brain changes throughout life.”
He added that the findings fit well with our understanding of brain aging, but cautioned that not everyone will experience these brain network changes at exactly the same age.
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