Ballet dancers’ brains adapt to stop them going dizzy

Years of training in “spotting”, the technique of quickly and repeatedly bringing your gaze to two specific points in front and behind you, certainly helps, but new research suggests that the brain’s ability to adapt plays a powerful role.

If you’ve ever tried spinning in circles while looking up to the sky, you’ll know the accompanying dizziness that can follow. But what stops ballet dancers, who pirouette endlessly for a living, from falling into each other like a set of dominoes?

Years of training in “spotting”, the technique of quickly and repeatedly bringing your gaze to two specific points in front and behind you, certainly helps, but new research suggests that the brain’s ability to adapt plays a powerful role. And it could help better treat and diagnose people who suffer from chronic dizziness.

Neuroscientists at Imperial College London recruited 29 female ballet dancers and spun them around in a chair in a dark room. When the chair was stopped, the dancers were asked to turn a lever to indicate how quickly they still felt they were spinning. This measured their perception response to dizziness. Eye reflexes – the quick flicking of the eyes from moving around rapidly – were also measured. In normal people, these two responses correlate well, but in the dancers there appeared to be an uncoupling: while their eye reflexes kept going, their perception response fell.

A group of 20 female rowers, who were similar in age and fitness, were also recruited as a control group. Brain scans were then taken to analyse the brain structures of all the individuals.

Powerful resistance

In cases of chronic dizziness, tests are usually taken of the vestibular organs in the inner ear. These fluid-filled organs use tiny hairs to sense the movement of the fluid, which in turn send signals to the brain. The continued movement of fluid explains one of the reasons you can continue to feel dizzy after you’ve stopped moving. But this doesn’t go far enough to explain dizziness in chronic suffers, said Barry Seemungal, co-author of the study, published in Cerebral Cortex.

“We measured sensation perception and eye reflexes and found dancers were much more resistant to non-dancers,” he said. “In the rowers, sensation correlated very well to reflexes, but in dancers the two were not correlated – they had de-coupled. In a person with chronic dizziness, the duration of their perceptual response is much longer; there’s a disproportionately higher reaction compared to a dancer who shows powerful resistance.”

An MRI scan then looked at the amount of grey matter (the bit that calculates) and the white matter (the part of the brain that makes connections) in the cerebellum. This also threw up differences between dancers and non-dancers.

“A statistical comparison between brain structures showed that in dancers an area of the cerebellum was smaller than in the rowers. This part of the brain also known to be involved in processing signals from the ear. And the more experienced the dancer, the smaller it is. The cerebellum can process signals that are then sent to areas of the brain linked to perception. In dancers it reduces the flow of signals – it acts like a gate.”

The researchers then looked at the cerebral cortex, which is associated in perception, and found stronger white matter in the control group. “More white matter means you’re more likely to be dizzy – in dancers we didn’t see it,” Seemungal said.

Seeing is believing

So how can these findings help people with chronic dizziness? For a start, we now have recognition that the brain is the organ that controls balance and, crucially, that it’s able to adapt.

“Traditional testing considers the ear as the organ of balance,” Seemungal said. “I’m a neurologist so I consider it as the brain.”

“The brain takes in lots of different information to make an assessment and compensates if it needs to. The ear is one source, vision is another. If you hear a noise to the right and move your head to look at it, your brain combines the estimates and places greater weight on the more reliable, in this case the eye.”

“But vision can be ambiguous – for example when you’re sat on a train and another one moves and you think you’re the one moving. As a general principle the brain prioritises visual motion over vestibular organs [the ear]. Another example is the ventriloquist’s doll, it combines the auditory and visual inputs but relies more on the visual so you think it’s the doll that’s talking.”

“If your vestibular organs aren’t working well, your brain won’t trust them and even trivial visual stimuli can trigger a dizzy sensation. But traditional testing relies on testing the vestibular organs, which might indicate nothing is wrong.”

People with chronic dizziness can be treated for underlying causes but also longer-term physio treatment. Depending on the form of the condition, this can include exposing them to self-motion (the swaying we all do but don’t notice if we don’t suffer from dizziness) and visual motion to get the brain more habituated.

One lucky find (for the researchers anyway) was that one of the dancers involved in the study later went on to develop chronic dizziness. This enabled the team to test her against their original findings. They found that although her reflex functions had remained the same, her perception response had become stronger.

Professor Nicky Clayton, a Professor of Comparative Cognition at Cambridge and Scientist in Residence at Rambert, the contemporary dance company, said: “As a dancer you learn tricks that allow your body to move in very flamboyant ways but without losing control. One of the tricks I learned was that when you get that sense of spinning, you use your core muscles to pull up; and that you’re disengaging with that feeling of fluidity and creating a stabilising energy.

She added: “Dancers think in very abstract ways … The way in which the brain talks to the cognitive system, whether through its plasticity or psychologically, is more than just spotting. Spotting helps you to focus but it’s not the only thing.”

Simon Lloyd, an ENT specialist, said: “The tests could potentially be useful because at the moment we have no effective way of testing how well parts of the balance system within the brain are working. Testing this would also allow us to measure how people are responding to treatment.”

The Conversation

This article was originally published at The Conversation. Read the original article.

Dancers of Cuba national ballet perform during a rehearsal for Swan Lake in Madrid in 2009. Photo: AFP/Getty Images

Jo Adetunji is the commissioning editor for health and medicine at The Conversation UK.

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Politics doesn't just connect us to the past and the future – it's what makes us human

To those people who tell me that they’re not interested in politics, I often say: “But politics is interested in you!”

I have long been haunted by a scene in George Orwell’s great novel Nineteen Eighty-Four. Winston Smith, the hero, is forced to watch propaganda films depicting acts of war and destruction. He is moved by something he sees: a woman trying to protect a child by wrapping her arm around him as they are attacked. It’s a futile gesture. She cannot shield the boy or stop the bullets but she embraces him all the same – before, as Orwell writes, “The helicopter blew them both to pieces.”

For Winston, what Orwell calls the “enveloping, protecting gesture” of the woman’s arm comes to symbolise something profoundly human – an expression of selflessness and of unconditional love in an unforgiving world. Scenes such as this we now witness daily in footage from the besieged eastern Aleppo and other Syrian towns, people in extreme situations showing extraordinary dignity and kindness.

I read Nineteen Eighty-Four for the first time in late adolescence. I’d dropped out of sixth-form college without completing my A-levels and was commuting on a coach from my parents’ house in Hertfordshire to London, where I worked as a junior clerk for the Electricity Council. During this long daily journey – sometimes two hours each way – I started to read seriously for the first time in my life.

I was just getting interested in politics – this was the high tide of the Thatcher years – and Orwell’s portrayal of a dystopian future in which Britain (renamed “Airstrip One”) had become a Soviet-style totalitarian state was bleakly fascinating. Fundamentally the book seemed to me to be about the deep ­human yearning for political change – about the never-ending dream of conserving or creating a better society.

Nineteen Eighty-Four was published in 1949 (Orwell died in January 1950, aged 46), at a time of rationing and austerity in Britain – but also of renewal. Under the leadership of Clement Attlee, Winston Churchill’s deputy in the wartime coalition, the Labour government was laying the foundations of what became the postwar settlement.

The National Health Service and the welfare state were created. Essential industries such as the railways were nationalised. The Town and Country Planning Act was passed, opening the way for the redevelopment of tracts of land. Britain’s independent nuclear deterrent was commissioned. New towns were established – such as Harlow in Essex, where I was born and brought up.

To grow up in Harlow, I now understand, was to be part of a grand experiment. Many of the families I knew there had escaped the bomb-ruined streets of the East End of London. Our lives were socially engineered. Everything we needed was provided by the state – housing, education, health care, libraries, recreational facilities. (One friend described it to me as being like East Ger­many without the Stasi.)

This hadn’t happened by accident. As my father used to say, we owed the quality of our lives to the struggles of those who came before us. The conservative philosopher Edmund Burke described society as a partnership between “those who are living, those who are dead, and those who are to be born” – and I find this idea of an intergenerational social contract persuasive.

Progress, however, isn’t inevitable. There is no guarantee that things will keep getting better. History isn’t linear, but contingent and discontinuous. And these are dark and turbulent new times in which we are living.

A civil war has been raging in Syria for more than five years, transforming much of the Middle East into a theatre of great-power rivalry. Europe has been destabilised by economic and refugee crises and by the emergence of insurgent parties, from the radical left and the radical right. The liberal world order is crumbling. Many millions feel locked out or left behind by globalisation and rapid change.

But we shouldn’t despair. To those people who tell me that they’re not interested in politics, I often say: “But politics is interested in you!”

And part of what it means to be human is to believe in politics and the change that politics can bring, for better and worse.

What, after all, led so many Americans to vote for an anti-establishment populist such as Donald Trump? He has promised to “make America great again” – and enough people believed him or, at least, wanted to believe him to carry him all the way to the White House. They want to believe in something different, something better, in anything better – which, of course, Trump may never deliver.

So politics matters.

The decisions we take collectively as ­humans have consequences. We are social creatures and rational agents, yet we can be dangerously irrational. This is why long-established institutions, as well as the accumulated wisdom of past generations, are so valuable, as Burke understood.

Politics makes us human. It changes our world and ultimately affects who we are and how we live, not just in the here and now, but long into the future.

An edited version of this essay was broadcast as part of the “What Makes Us Human?” series on BBC Radio 2’s “Jeremy Vine” show

Jason Cowley is editor of the New Statesman. He has been the editor of Granta, a senior editor at the Observer and a staff writer at the Times.

This article first appeared in the 01 December 2016 issue of the New Statesman, Age of outrage