Health Check newsletter: The brain’s amazing adaptability

5 months ago 102
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By Clare Wilson

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Hello, and welcome to this week’s Health Check, the weekly newsletter that gives you the health and fitness news you can really trust. To receive this free, weekly newsletter in your inbox, sign up here.

I am learning to play the ukulele, and while progress is slow, it’s very satisfying when I memorise a sequence of finger movements and it becomes automatic. When that happens, I can’t help wondering what is going on in my brain.

Some light is shed on that question by one of the most interesting science books I read last year: Livewired: The inside story of the ever-changing brain by neuroscientist David Eagleman. It is about neuroplasticity, how the brain constantly remodels itself in response to changing demands.

Eagleman is developing devices that help people with disabilities make use of new kinds of sensory information. One such technology is a wristband for people who are deaf, called Buzz, which turns sounds into a pattern of vibrations on their wrists.

You might think this would feel strange, but Eagleman says people quickly get used to it and start to interpret the sensations as something akin to hearing. When I interviewed him in May last year, Eagleman said: “When we talk to participants about this, we say: ‘Do you feel a buzzing on your wrist and you think, ‘Oh, that must be a dog barking?’’ They say: ‘No, I’m just hearing the dog.’”

Now, a different group has developed a similar device to help people who are blind. Users wear goggles with a camera that turns information about their surroundings into a pattern of vibrations on a five-by-five grid worn on an armband.

The developers say participants were able to navigate around obstacles on their first attempt.

It’s funny, because a thought experiment in consciousness science is about how impossible it is for people to understand what it is like to be a bat, whose main sense for experiencing the world, echolocation, is so different to vision. The results for these new technologies suggest that, for all we know, “seeing” by echolocation may be a very similar experience to human sight. In fact, some people who are blind do learn to get around through echolocation, by clicking with their mouths.

It is early days for these ideas, but I hope they become useful aids for people who are deaf or blind. If they do, it’s likely that the longer someone uses one, the more their brain will adapt to the new sensations, thanks to neuroplasticity.

What mechanisms are involved? Two decades ago, there was great excitement over the idea that an important one could be the growth of new brain cells. There was hope that this could be harnessed in treatments for stroke or Alzheimer’s disease, for instance, or that we could stimulate the process with “brain-training” apps. Then the idea that new brain cells can develop after adolescence became more contentious, as New Scientist explored in this long read from 2012.

But there are plenty of other ways that brains can rewire themselves. Existing brain cells can form outgrowths and make new connections with each other, called synapses, and many other molecular changes can happen within brain cells that make an electrical impulse in one more (or less) likely to spark off another in its neighbour.

There may well be other weird and wonderful things going on in the brain that we don’t know about. Its adaptability continues to surprise doctors and researchers.

Take the case of a 6-year-old boy who needed half his brain removed as a last-ditch treatment for severe epilepsy, as Eagleman describes in Livewired. Straight after the surgery, the boy couldn’t walk or talk and was incontinent; after three months, he was almost back to normal, minus his seizures.

Post-mortem examinations of people’s brains show that you can even see the difference between the brain of a concert violinist and a non-musician with the naked eye, if you know where to look.

Professional violinists develop a small bulge on a ridge of their motor cortex, a part of the brain that controls movement – known as the omega sign – that is presumably made up of extra brain cells, outgrowths, synapses, and more.

I may have some way to go on the ukulele before I reach that level – but I’m doing my best to make my motor cortex bulge just a little.

Covid-19 news

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As the UK phases out covid-19 restrictions, people who are extremely vulnerable have a new weapon against the virus: antiviral drugs and antibodies. But they must be rushed to people at top speed. Meanwhile, in the US, an antibody treatment that gives six months protection against covid-19 is in short supply – and that means it goes to those who can fight for it hardest.

BA.2 variant

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Other health stories

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  • Vitamin D supplements cut the risk of auto-immune diseases, in one of the very few randomised trials of vitamins in healthy people to have shown a benefit.
  • For the first time, a robot has performed keyhole surgery with almost no human help – although it was being tested on pigs.

From the archive

It is an age-old question: are we shaped more by nature or nurture? Robert Plomin, a geneticist at King’s College London, has spent his career teasing apart the contributions of DNA and environmental factors to countless human traits, from bodyweight to personality and academic success. Environment is undoubtedly a key influence on almost every aspect of our lives. But Plomin argues that genetics plays a more important and measurable role, even to the extent that our parenting and schooling don’t matter that much.

That’s all for now. My plug this week is for our next online event: “Brain Power: Everything you need to know for a healthy, happy brain”. It is on Thursday 3 February at 6.00pm GMT.

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