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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Yanis Varoufakis: The left never recovered from the fall of the Soviet Union — yet there is hope

A radical internationalism is needed to democratise the EU and breathe new life into the left.

The left has been in disarray since 1991 – it never fully recovered from the collapse of the Soviet Union, despite widespread opposition to Stalinism and ­authoritarianism. In the past two decades, we have witnessed a major spasm of global capitalism that has triggered a long deflationary period across the United States and Europe. Just as the Great Depression did in the 1930s, this has created a breeding ground for xenophobia, racism and scapegoating.

The rise of centrism is also partly to blame. For a period in the late 1990s, it seemed that this had become the new doctrine of the left. In Britain, New Labour under Tony Blair was never part of the left. Margaret Thatcher was delighted by the manner in which his governments copied her policies and adopted her neoliberal mantra, though she did ask the question: if you want to vote for a Conservative, why not vote for a real one instead?

Parties such as New Labour, the Socialists in France and the Social Democrats in Germany might have called themselves the radical centre, but that was just labelling. What was happening under the surface was that the progressive parties of the left were being lured into financialisation. In the 1960s and 1970s the centre left was aware of its duty to act as a mediator between industrial capital and labour. Harold Wilson’s Labour Party, Willy Brandt’s Social Democrats in Germany and others understood that their duty was to strike a grand bargain whereby industrial capital ceded to workers’ demands for higher wages and better conditions, while they agreed to help fund the welfare state.

From the mid-1980s onwards, the left-wing leadership abandoned this duty. Industrial capital was in decline and it was much easier to look towards the super-profits of the City of London and the global banks. A Faustian pact was made with the financial sector – European governments turned a blind eye to what the bankers were doing and offered them further deregulation in exchange for a few crumbs from their table to fund welfare. This is what Tony Blair and Gordon Brown did in Britain, Gerhard Schröder did in Germany and the Socialists did in France. Then the financial crisis struck. At that point, social democrats throughout Europe lacked the moral strength and analytical power to tell bankers that although they would salvage the banks, their reign was over.

The best hope for the left is to come together to defeat the worst enemy of European democracy: “Euro-tina”, the reactionary dogma that “there is no alternative” to the continent’s current policies. Hence the EU’s true democratisation is the only alternative. This is what my collaborators and I hope to achieve with our new Democracy in Europe Movement 2025 (DiEM25). We are compiling a new economic agenda for Europe, which will answer the question I am asked on the streets everywhere I go, from Sweden to the UK: what can we do better within the EU? If the answer is “nothing”, the Brexiteers have a point – we might as well blow the whole thing up and start afresh. The alternative to the “Year Zero” approach is to recalibrate European institutions in the context of a practical and comprehensive agenda comprised of policies that will stabilise Europe’s social economy.

The EU institutions are anti-Europeanist and contemptuous of democracy. People might wonder: if that is the case, why am I arguing to stay in, but against the Union? In response, I ask those who support the left-wing argument in favour of Brexit: since when has the British state been a friend of the working class? Never. And yet their argument is: do not dismantle it. The nation state was created to promote a fictitious notion of a national interest to co-opt labour and those on the fringes of society – the “lumpenproletariat”, as we once called them. The left understands that it is not our job to destroy institutions. Instead, we struggle to take them over and use them for good. I cut my political teeth protesting against the Greek state but I do not believe that it should be dismantled and the same argument applies to the EU.

Good people who are motivated to change society often fall out with each other. I am reminded of a scene in Monty Python’s Life of Brian – when the Judaean People’s Front confronts the People’s Front of Judaea and the Popular Front of Judaea. DiEM25’s task is to try to convince our fellow left-wingers that the solution is a pan-European unity movement. A concrete example of the power that this can have is the election of Barcelona’s new mayor, Ada Colau. A DiEM25 supporter, she won the race against the odds,
having started her career running a protest movement that championed the rights of citizens threatened with eviction because they were unable to pay their mortgages.

The Syriza government, in which I served as finance minister from January to July 2015, failed to achieve change because we ended up disunited and the prime minister capitulated to the EU at the moment when he had a mandate from the Greek people to do the opposite. My hope was that if Syriza had carried on with the struggle, we would have been a catalyst for movements across Europe (such as the one that has fuelled the rise of Jeremy Corbyn) to join us.

The capitulation of Alexis Tsipras was a hefty blow to the concept of radical inter­nationalism, but I still believe that internationalism offers the solution to the problems facing Europe in this deflationary era. The number of good-quality jobs has decreased, investment is depressed and optimism about the future is being destroyed. It is the left’s duty to do all we can to end this. If we can explain to the masses what the sources of their discontent are, we have a chance to breathe new life into the left. There are no guarantees – just a chance.

This is the latest article in our “New Times” special series

This article first appeared in the 29 September 2016 issue of the New Statesman, May’s new Tories