(12 min read)
First, are adult brains plastic?
Can you teach an old dog new tricks? It used to be widely believed that we were born with all the brain cells we would ever have, that brain plasticity only occurred in children, and that if we didn’t therefore cram in all the learning we needed to during childhood, then success in adulthood was doomed. Which presents a bit of a problem now that we’ve realised that life-long learning is going to be key to a successful and fulfilling future. (I suppose that back in the day when young adults left education fully-trained for their profession as an accountant, solicitor or banker, this assumption was fine. No one expected the way we operate to change that much. The theory fitted).
However, one of the most seminal studies into adults and learning was the famous London Taxi Driver discovery. In 2000, Dr Eleanor Maguire lead a team of researchers at UCL to examine the volume of hippocampi (an area linked to long-term memory) of London taxi drivers. In those hazy days before sat nav and Über, black cab drivers would have to pass a test called ‘The Knowledge’: the ability to recall from memory the route from any place to another in London, including every road and turning and one-way street.
The longer the drivers spent in the job, the larger a part of the hippocampus grew. The brain structure changed to accommodate their navigating experience. It proved without a doubt that adult brains were plastic. “It makes you wonder what happened to the rest of my brain” commented David Cohen, one of the study participants. Good question.
In another experiment, young adults were taught to juggle. The training went on until they all could keep at least three balls in the air at once. MRI images of the subjects’ brains before and after the experiment showed that learning to juggle generated increased density in a small part of the brain associated with vision, especially in the area that responds to movement. When they stopped practicing, these areas shrank back again. Gosh.
Rather alarmingly, after the age of about 40, we start losing neurons at an estimated rate of up to a thousand a day. It may well be part of the brain’s way of increasing efficiency – to focus resources on the parts of the brain that contribute to life and sod the rest. What we do know is that it is really important to use it or lose it.
Monkey brains.
Professor Michael Merzenich has spent his entire career showing that plasticity perseveres into adulthood. In 1968, he mapped the parts of a macaque monkey’s brain that responded to their hand being stimulated. He would tap the monkey’s hand and using a piece of equipment that could measure the activity of a single neuron, plotted which parts of the brain responded.
Merzenich then worked with two young neurosurgeons to see what happened in the brain of adult monkey with a bad hand injury. At the time, it was thought that at around age one, an adult macaque brain would have become fixed and thus, with the lack of input, the part of the brain relating to the injury would be inactive.
But this wasn’t the case: not only did neighbouring areas in the brain move into the inactive territory, but the original area later reclaimed much of its original space as the injured nerves in the hand regenerated. The adult brain was most definitely plastic.
Their findings were so at odds with conventional opinions, that their scientific report was deleted by their senior professor. It was too conjectural, apparently.
Despite repeatedly demonstrating that adult brains could be plastic, Merzenich suffered insults and sarcastic commentary from neuro flat-earthers. He says he wasn’t bothered about not being listened to (he knew the scientific truth would come out) but cared deeply that people didn’t take him seriously when he argued that his discoveries about adult brain plasticity could be used therapeutically, to treat injuries and disorders.
It took two decades, but he succeeded in transforming the field of neurology.
Treating adult plasticity as a ‘revelation’ has always struck me as rather nonsensical. If we weren’t able to learn new things in adulthood, what would be the point in newspapers or watching tv shows? How would we meet new friends in our 20s? Cope with moving house in our 30s? Learn to use a new computer in our 40s? Get to know grandchildren in our 60s? In any event, whatever the degree of plasticity your brain has, it is possible to enhance it.
10 steps to maintaining brain plasticity in adulthood.
We can help protect against the loss of brain plasticity. ‘Exercising’ the brain daily is, of course, what we do simply by being alive. But if we use our brains in unfamiliar ways, we may encourage new connections to form. Here are some ideas:
- Get lost. Quite literally. Try going on your usual journeys a different way – see if you can get lost and find yourself.
- Read new things: Join a club or book group or read about a topic you’re unfamiliar with.
- Cook a different recipe. Challenge yourself to a new recipe every week.
- Use your non-dominant hand to brush your teeth, open doors or brush your hair.
- Lean to use a piece of technology (I’m still working on this with my father. We bullied him into renouncing his push-button Nokia for a smartphone, which he now refuses to use, in stubborn rebellion. All my lovely dreams of him facetiming the grandchildren and sending loving voice messages have turned to ash. On the upside, his battery life is, like, a week).
- Exercise. Start a new class or join a gym. Physical activity boosts the amount of cerebrospinal fluid – the liquid our brains are bathed in, full of nourishing growth factors that keep neurons healthy. These ‘neurotrophins’ are to the neurons as fertiliser is to plants. As we age, the abundance of neurotrophins tails off. A combination of aerobic exercise and resistance training has been shown to boost cerebrospinal fluid’s potency.
- Take up art lessons. Research shows a positive effect on IQ, attention and fluid intelligence (how well you can problem solve and reason abstractly)i.
- Make music. At all stages in life, creating music is proven to enhance memory, attention and learningii.
- Dance. As we know, exercise is great for the brain. But when it involves coordinated movement, it has an even greater effect. Dancing also triggers the release of neurotrophins, as evidenced in over 400 neuroscience studiesiii. If you think about it, dancers possess an impressive skill set: coordination of limbs, posture, balance, gesture, perception and sequenced action – all with the correct facial expression. Those that dance, have bigger brains.
- Study a foreign language. As you learn new vocabulary, the brain accordingly makes new connections. Eventually, the hippocampus (linked to memory) and the area of the brain related to language enlargeiv. The benefit of language learning is transferred: brains scans show that students learning languages have better connectivity between disparate brain regions.
Knowing that brains are plastic is one of the best ways to motivate your children to learn: you can and will get ‘cleverer’ at something the more you persist. Here’s a guide to teaching children.
If you’re still with me, your brain has changed. If you can remember anything I’ve said, its evidence that new connections have formed.
Ta daa!
i Brain Scientists Identify Links between Arts, Learning
2009 by Dana Foundation
ii Wan, C.Y. and Schlaug, G., 2010. Music making as a tool for promoting brain plasticity across the life span. The Neuroscientist, 16(5), pp.566-577.
iii Hannah, J. 2016. What Educators and Parents Should Know About Neuroplasticity, Learning and Dance
iv Mårtensson, J., et al. 2012. Growth of language-related brain areas after foreign language learning, NeuroImage, 63(1), pp 240-244.