How our brains change at 66 and 83 – and what it means for us
Experts have discovered the two key ages at which our brain changes in later life - we examine the science and how to best look after our grey matter as we get older.
Experts have discovered the two key ages at which our brain changes in later life - we examine the science and how to best look after our grey matter as we get older.
Much like our bodies, our brains operate differently as we get older. We notice changes in how we think and function, which could be a decline in lightning-fast decision making or our ability to multitask with aplomb.
But the changes are not quite as gradual as we think, with neuroscientists at the University of Cambridge identifying five “major epochs” of brain structure over the course of human life. They found that our brains re-configure to support different ways of thinking as we mature and move through life’s chapters.
But when and how do these shifts occur? The neuroscience study Topological turning points across the human lifespan identified ages 66 and 83 as key times of change in later life (ages nine and 32 were identified as being pivotal in early life).
Although some people will reach these milestones earlier or later than others, the researchers reported that it was striking to see just how clearly these ages stood out in the data.
The study compared the brains of 3,800 people aged between zero and 90 years old, using MRI scans to track neural connections. “This study is the first to identify major phases of brain wiring across a human lifespan,” says Dr Alexa Mousley, lead author of the research.
“These eras provide important context for what our brains might be best at, or more vulnerable to, at different stages of our lives,” she adds
While the young brain is growing and developing quickly, it fine-tunes itself by whittling down the billions of neurons (connections) it’s born with. The brain holds on to the connections it uses the most, and gets rid of the rest in order to operate more efficiently.
This re-wiring follows a similar pattern up until age nine, when it settles into its final shape, with stronger thinking skills and a higher level of ability and organisation. However, this is when mental-health vulnerabilities can start to appear.
Efficiency and organisation increase in adolescence, a period the study suggests is much longer than we’ve previously thought in terms of brain development.
The organ communicates faster and more smoothly throughout this time, maturing through the teens and 20s, and peaking in the early 30s.
“Around the age of 32, we see the most directional changes in wiring and the largest overall shift in trajectory, compared to all the other turning points,” explains Dr Mousley.
“Based purely on neural architecture, we found that adolescent-like changes in brain structure end around the early 30s.”
Up next is a period of stability as the brain enters its longest era – more than three decades. The rate of change is slower here and “aligns with a plateau of intelligence and personality,” according to Dr Mousley, which will resonate with many of us.
The processing speed of the brain very slowly declines as 'grey matter' (where thinking and processing happen) thins slightly, affecting memory and attention, and 'white matter' (which helps these areas talk to each other) becomes a little less robust, which can slow down our reactions.
While the brain has formerly acted as a whole, now it becomes increasingly separated with specialised areas acting more independently. It’s a bit like a busy kitchen where each chef has their own station, with one chopping, another preparing sauces and so on. They function very closely when required but largely operate separately to make the whole meal work.
This epoch signals further steady shifts in the patterns of connections in the brain. The 'turning point' at age 66 isn’t defined by any major structural shifts, but researchers did find meaningful changes to the wiring of the brain at this age.
“The data suggests that a gradual reorganisation of brain networks culminates in the mid-60s,” says Dr Mousley. “This is probably related to ageing, with further reduced connectivity as white matter starts to degenerate.”
Researchers looked at healthy brains during the study, but, as Dr Mousley explains: “This is an age when people face increased risk for a variety of health conditions that can affect the brain, such as hypertension.”
The study’s authors say that, while the data for this era is limited, a defining feature was identified at around age 83, with a further shift from whole-brain communication towards a heavier reliance on specialised regions. This includes the temporal lobe for hearing and memory, and the prefrontal cortex for planning and decision making.
Senior author of the study Professor Duncan Astle says: “Looking back, many of us feel that our lives have been characterised by different phases. It turns out that brains also go through these eras.
“Many neurodevelopmental, mental health and neurological conditions are linked to the way the brain is wired. Indeed, differences in brain wiring predict difficulties with attention, language, memory and a whole host of different behaviours.”
Neuroscientist Dr Rachel Taylor says that she sees many positives in the study’s findings from the 'late ageing brain' era, and that she isn’t surprised by some of the results.
“The data clearly illustrated two things that we see consistently in later life,” Dr Taylor explains. “At age 66, you see the nervous system shifting into a phase of consolidation – people become more selective, more efficient and more anchored in what truly matters.
“That's a predictable outcome of how the prefrontal cortex (the ‘control centre’ that helps you think, plan and control your behaviour) and the limbic system (the brain’s ‘feel and react’ system) rebalance with age.”
Dr Taylor adds: “By age 83, what stands out is not decline but refinement. The brain becomes extraordinarily good at conserving energy, prioritising emotional meaning, and drawing on accumulated pattern recognition. It's a stage defined less by loss and more by distilled wisdom.
“So, while the findings were not new to me, they were a beautiful confirmation of something I have seen repeatedly in research and in practice – the brain doesn’t simply age; it adapts, economises and, in many ways, becomes more itself.”
The study revealed that in the latter stages of the 'adult' phase of brain development, there is a significant shift away from the brain acting as a whole. But why does this happen and what does it mean for our everyday functioning?
“As we age, large-scale networks become slightly less globally synchronised, and instead, you see tighter, more efficient local clustering,” explains Dr Taylor.
“The brain stops trying to run every process through every network, and instead relies on specialised circuits that have been refined over a lifetime. It is a predictable, adaptive change.
"I would describe it as the orchestra becoming more disciplined; fewer unnecessary flourishes, more precision, and a greater reliance on well-practised sections working together. It is a normal part of neurodevelopment across the lifespan.”
To truly nurture our brains is to acknowledge the importance of daily habits, simple pleasures, and the intricate relationship between healthy bodies and minds, advises Dr Taylor: “The brain is a metabolic organ, and its function depends on the quality of the body’s internal environment – cardiovascular health, inflammation, sleep, movement, nutrition and social connection.
“When the body is supported, the brain has the conditions it needs to adapt, repair and stay coherent across the lifespan.”
In later life, the most protective acts of self-care for our brains are “beautifully ordinary”, says Dr Taylor. “Good sleep, movement, nutrition, emotional safety and meaningful social connection.
“But equally important is novelty. The brain is an adaptive organ – it needs newness, complexity and purpose to stay flexible. Learning new skills, engaging with unfamiliar environments and staying curious all help to maintain neural plasticity.”
She adds that there is no quick fix to a healthy, nurtured mind in later life. We simply have to look after ourselves with consistent lifestyle routines. “Self-responsibility is key. There is no magic pill, no single supplement or ‘brain hack’ that replaces the cumulative effect of daily habits.”
Keeping active and finding calm and joy in our daily lives can also work wonders, Dr Taylor says: “Brain health is built through the rhythms of a life well lived: stable routines, supportive relationships and a willingness to keep growing. So, my recommendation is simple but profound: treat your brain as part of your whole system, not as an isolated organ.
“Give it nourishment, movement, rest, novelty and connection. Those are the conditions that support brain health at every age – and they matter even more as we grow older.”
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