From a teenager excelling with half a brain to the organ’s visual areas being co-opted in people who are blind, our brain’s ability to adapt continues to amaze Health | Leader 12 February 2020 Zephyr/Science Photo LibraryTHERE is something special about the human brain. Yes, it contains 86 billion neurons and billions of other cells,…
From a teenager excelling with half a brain to the organ’s visual areas being co-opted in people who are blind, our brain’s ability to adapt continues to amaze
12 February 2020
THERE is something special about the human brain. Yes, it contains 86 billion neurons and billions of other cells, and yes, it is arguably more complicated than anything else we have discovered in the universe. But more than that, our brains make us who we are. They keep us alive and functioning, while storing our thoughts and memories, shaping our behaviours, relationships and our lives.
Perhaps that is why it is so remarkable to hear that some people are living with only half a brain. This week, we cover the case of a teenager born without a left hemisphere (see “A woman with half a brain offers more proof of the organ’s superpowers”). Given that this is the half of the brain specialised for language, you might have expected her speaking and reading skills to suffer. Not so. In fact, she has above-average reading skills.
It appears the right side of her brain is compensating for the left side that isn’t there. The right hemisphere is unusually dense in white matter – the tissue that enables brain regions to communicate with each other – especially in areas involved in language.
“People who are blind appear to use the parts of their brain normally involved in vision for, say, language processing”
There are other stories of the brain’s astounding capacity to adapt. Perhaps the most famous is the finding that brain regions involved in navigation grow in London taxi drivers – and get larger as they spend more time on the job. Learning new skills, such as juggling, can literally grow your brain, too.
At the same time, the brain can repurpose regions that aren’t being used. People who are blind appear to use the parts of their brain normally involved in vision for language processing, or for maths, for example. People without hands can learn to use their feet for many of the same functions, including to paint. Such artists’ brains have dedicated “toe maps”: brain regions that represent each toe. Such maps simply don’t exist in people with hands.
There is plenty to learn about this complicated organ. We are only just discovering the brain’s potential to regenerate neurons later in life, and why sending a jolt of electricity into the brain might treat neurological conditions or improve cognition. But the more we do learn, the more this squidgy organ will continue to fascinate.
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