What happens to our brains as we get older?
Our bodies change as we get older – do our brains? If so, is there anything we can do to compensate? Can you teach an old dog new tricks?
As we get older our brains can shrink. Some cognitive functions (like memory and speed of processing) can deteriorate. And, as we live longer, the number of cases of dementia is rising. This helps explain why we tend to have a negative perception of our mental ability as we age.
In fact research published in 2012 suggests the memory of a person declines at a faster rate in the last two-and-a-half years of life than at any other time after memory problems first begin.
Can our brains adapt?
Fortunately there’s increasing evidence emerging that our brains can adapt. Mental decline isn’t inevitable - there is much we can do to keep mentally fit as we get older. You can teach an old dog new tricks, as a New Scientist article explained in 2013. And history is full of examples. Leo Tolstoy learned to ride a bicycle when he was 67 and Queen Victoria started to learn Hindustani at 68. In the modern world Adult Education classes attract older students keen to learn new skills each year.
Neurocognitive scaffolding – our brain’s Plan B?
MRI scans of the human brain have suggested one possible explanation. Even when the brain is shrinking, these scans have shown reliable increases in prefrontal activation. This is important because the prefrontal cortex is believed to act as the brain’s executive or conductor – helping us plan complex behaviour, express our personality and make decisions.
These observed increases in prefrontal activation have given rise to the theory of neurocognitive scaffolding as a means by which the brain adapts as we age. We know that human bodies have the ability to self regulate, for instance to maintain a reasonably constant temperature. By self regulating the body maintains equilibrium and enables us to keep functioning in a reasonably stable way. The same principle may apply to our brains. If so then, as they begin to shrink and functions deteriorate, our brain will seek a way to self regulate, adapt or compensate, in order to keep functioning. Neurocognitive scaffolding assumes the brain adapts by engaging in ongoing reorganization and repair. This might be through strengthening existing connections, forming new connections or stopping using weak or faulty connections.
This leads to the hypothesis: ‘Scaffolding is protective of cognitive function in the aging brain, and available evidence suggests that the ability to use this mechanism is strengthened by cognitive engagement, exercise, and low levels of default network engagement.’
Cognitive Reserve - can we do things to protect our brains?
The scaffolding hypothesis was revisited in a 2014 article - which suggested that what happens to us in the course of our lives can influence that scaffolding. As the article indicated this fits with the idea that we can develop a cognitive reserve, through education, work and interests that are intellectually challenging and possibly even a healthy diet. This reserve is then believed to protect our brains for longer, for example by delaying the onset of symptoms of Alzheimer's.
There's more information about foods that may help protect our brains here. You will neeed to register to access it but registration is free.
The idea of a Cognitive Reserve may help explain why dementia rates seem to be falling in the developed world (something that isn't always evident because we have an ageing population, so a smaller proportion of a larger number is still a lot of people). One suggested explanation is that people are receiving education for longer than in previous generations and that this is helping build a Cognitive Reserve.
A systematic review of research published in 2015 also suggests that some commercially available brain training products can help promote healthy brain ageing.
Mental fitness – a spectrum?
Mental fitness as we get older seems to span a spectrum. Sadly, people suffering from early onset Alzheimer’s will start to see their mental fitness erode from their fifties or early sixties. At the other end of the spectrum many people remain mentally very fit well into their eighties and nineties. For example Verdi was still composing operas in his 80’s and George Bernard Shaw still writing plays in his 90’s.
So what can we do to increase our chances of keeping mentally fit as we get older?
As we report here, our brain can shrink as we get older. However, we can help protect it through education and by finding work and interests that challenge us intellectually. As we report elsewhere on Age Watch:
- What is good for our bodies (physical exercise and a healthy diet) is usually good for our brains.
- Keeping socially active, mentally active and learning new skills also help keep our brains working well.
- Dance seems particularly helpful, as it combines physical exercise, social activity and (if the dance moves are complicated enough) mental activity.
- However passive activity, like watching TV, is associated with an increased risk of cognitive impairment.
Reviewed and updated by Christiane Hahne January 2017, Next review date January 2021