Music and the Mind: “can’t get it” and “can’t get it out of my head”

MusicWhen I was at the Science Museum Lates event this week, I attended a talk on the perception of music by researchers from the Music, Mind and the Brain group at Goldsmiths, University of London.

The first half of the talk was by Lauren Stewart, a cognitive neuroscientist, who outlined how the brain understands music.

Music is entirely a construct of the mind, she pointed out, because sound waves are simply vibrating air molecules, nothing more.  What is remarkable is not just that the brain understands how to interpret these sequences of molecules, but that we can also understand composites of several different strings of molecules interwoven together; i.e. the different musical elements – for example, guitarist, bass, drums, singer – that make up a song.

Activity of the brain when music is heardBut how did the brain evolve this ability?  One possibility is that music is a super stimulus for pleasure, said Dr Stewart.  The brain, she said, is adapted to recognise patterns. The process of hearing a song and predicting what comes next sets off the neurotransmitter dopamine in areas of the brain associated with other pleasure stimuli, like sex and drugs – suddenly the old adage “sex, drugs and rock’n’roll” makes more sense!  The “musical chills” that you experience when you hear a song you really like is a good example of this process in action.

Dr Stewart studies the disorder amusia, which is a lifelong failure to recognise familiar tunes or tell one tune from another. Sufferers frequently complain that music sounds like a “din” and often avoid social situations in which music plays a crucial role. Such individuals are unable to understand the up and down pitch of music, but have no problems with the pitch changes in speech, like rhythm, stress, and intonation.

Some people develop this problem after significant brain trauma, like a car accident, whereas others are born with it. Dr Stewart describes the genetic component of amusia, “congential amusia,” by highlighting a family of eight siblings from Northern Ireland, four of whom have amusia and four of whom hear music fine. In fact, a study of nine families with some amusic members and ten normal families found that 39% of first-degree relatives of amusic people have the same cognitive disorder, whereas only 3% have it in the control families.

By studying a “broken system,” Dr Stewart hopes to find out more about the “correct” cognitive architecture of music, and its relation to other cognitive skills such as language and spatial awareness. Her present research aims to elucidate exactly which perceptual and cognitive mechanisms are at fault in amusia, whether disordered musical processing has implications for language, and the extent to which such difficulties can impact upon sociocultural functioning.

The second half of the talk was by Daniel Müllensiefen, a computational scientist, who studies involuntary musical imagery, or “earworms.”

Prevalence of earmwormsAn earworm, a direct translation of the German word “ohrwurm,” is a portion of a song or other music that repeats compulsively within one’s mind – “I’ve got a song stuck in my head.” Earworms are related to voluntary musical imagery – earworm activate the same areas of the brain as when you’re listening to music.

Apparently, as many as 90% of people experience an earworm at least once a week, whereas about 50% have one everyday.  The average length an earworm is on repear is 27 minutes, and between 15% and 33% of people find these “cognitively infectious musical agents” unpleasant or disturbing.

Dr Müllensiefen is using computational analysis of music to determine what it is about a song that makes it stick in our heads and become an earworm. He and his team have broken down the melodies over 14,000 pop songs from the 1950s to the present day into sequences of 0s and 1s that computers can deal with.

They have then analysed the statistical distributions and regularities in the data from commercially successful songs to determine what elements make a song a hit. Apparently, what you need is a chorus melody that has a large range and uses only few pitches much more frequently than the majority of its pitches.  Which looks like this:Hit song equation

This talk was a great introduction to how the brain deals with music – both in instances where people can’t get a grip on music and in cases where they can’t get it to go away.

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After hours in the Science Museum

Science Museum DJThis evening my friends and I went to the Science of Music event at the Science Museum in South Kensington. The evening was part of Science Museum Lates, a monthly adults only event where the museum is open until 10pm and special talks and displays are laid on.

The place was pretty packed out with a surprisingly young and trendy crowd. Four of the museum’s seven floors were open, and each handily had several bars and DJs, surely a prerequisite for an event about music. There was even a silent disco, somewhat incongruously located among the satellites and rockets in the Exploring Space gallery.

First off we went to to the Launchpad area, an interactive hands on gallery that is usually packed with kids on a daytime visit to the museum. Instead we had the gallery to ourselves and got to have a proper play with things like electromagnets, generators, and circuit boards.

We then tried to catch the break dance demonstrations in the flight gallery. Alas we only made it for the tail end, but we did find out how angular momentum affects how fast a break dancer can spin on their head: arms out, they slow down; arms flat against their body, they speed up.

Materials man close upMaterials in the bodyWe were unexpectedly quite fascinated by the Plasticity exhibition, which showcases 100 years of plastics. I was particularly interested in the US Olympic ski suit, which had foam pads on areas like the shoulders and forearms that are soft when racing but instantly turn hard impact to absorb shock energy.

While we’re on the subject of materials, another of my favourite exhibits in the that I saw this evening was this “materials man,” who shows the anatomical location and real size of a selection the medical materials and devices that are currently in use.

In the close up, you can see a silicone artificial larynx, a carbon fibre bone plate, a titanium and silicone cardiac pacemaker, and a polytetrafluoroethene methanical aortic valve.  Dentures and a glass eye are in there as well.

All in all, the event was a great chance to have a look around the museum in a laid back atmosphere without hundreds of kids tearing around the place. Oh, and with a beer in my hand, always a bonus!

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Obese children are at high risk of death before middle age

childhood obesityA study published in the New England Journal of Medicine has found that children who were obese were almost twice as likely to die before 55 years of age than those who were not obese. Moreover, children whose weight was in the top 25% out of nearly 5,000 kids were 2.3 times more likely to die from diseases before middle age than those whose weight fell in the bottom 25%.

The authors of this big, long study looked at body mass index (BMI; a measure of weight that takes into account a person’s height) and risk factors for cardiovascular disease in 4,857 children aged 5-19 years who lived on an American Indian reserve in Arizona.

BMI and markers of cardiovascular disease were measured in all children when the study started in 1966 or after. The participants were then followed up until their death, their 55th birthday, or the end of 2003, whichever came first.

A total of 559 (11.5%) participants died before the age of 55, 166 (3.4%) of whom died from a disease or from self inflicted injury such as alcohol or drug abuse – so-called “endogenous causes.”

Children whose BMI fell within the top 25% of all those in the study were 2.3 times more likely to die from endogenous causes before the age of 55 than those whose BMI was in the lowest 25%. In fact, each one unit increase in BMI increased the risk of early death from endogenous causes by 40%.  This relationship persisted but at a slightly lower level once factors like cholesterol level and blood pressure were taken into account.

The authors then looked specifically at the 1394 (28.7%) children who were obese – those whose BMI fell in the top 5% on growth charts from governmental public health body the Centers for Disease Control and Prevention. Compared with non-obese children, these kids were 31% more likely to die before they reached 55.

Children with high blood glucose levels – a sign that diabetes might be on the horizon – were at 73% higher risk of dying early, whereas those with hypertension were at 57% higher risk. This link prompted the authors to say that the link between obesity and premature death “may be partially mediated by the development of glucose intolerance and hypertension in childhood.”

Childhood cholesterol level and blood pressure, however, had no effect on the risk of premature death from endogenous causes.

Speaking to the New York Times, senior author Helen Looker said, “This suggests that obesity in children, even prepubescent children, may have very serious long-term health effects through midlife — that there is something serious being set in motion by obesity at early ages. We all expect to get beyond 55 these days.”

American Indians were studied because childhood obesity has been common for decades in this ethnic group. The prevalence of obesity in young Arizona Pima Indians in the 1960s, when this study was initiated, was similar to that seen in Hispanic and African American children today, so hopefully the results from this long study should be generalisable to kids today.

In a linked editorial, Edward W Gregg of the Centres for Disease Control and Prevention pointed out: “Since the trends with respect to obesity and diabetes among the Pima Indians have been a reliable harbinger for trends in the rest of the U.S. population during recent decades, the present study should intensify the debate about whether interventions that are initiated during childhood and young adulthood can affect our broader diabetes epidemic.”

Furthermore, in a previous study the same authors found that BMI correlated closely with total body fat – adiposity – and that adiposity in turn correlated with cardiovascular risk factors. By extension, the link between BMI and early death in this study suggests that actual body fat is linked with early death.

This is important because BMI is an imperfect measure of weight – for example, some very muscular people might be heavy for their height and thus have a high BMI – thus despite the study results weight might not genuinely be associated with early death. On the other hand, high adiposity – “fatness” – is a more indicative of an unhealthy weight.

“Childhood obesity is becoming increasingly prevalent around the globe. Our observations, combined with those of other investigators, suggest that failure to reverse this trend may have wide-reaching consequences for the quality of life and longevity,” conclude the study authors.

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Franks P et al. (2010) Childhood Obesity, Other Cardiovascular Risk Factors, and Premature Death. New England Journal of Medicine 362 (6): 485-493. DOI: 10.1056/NEJMoa0904130

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Clinical research from the heart

Hot on the heels of Valentine’s day, the British Heart Foundation has announced the winners of their images competition “Reflections of Research,” in which UK scientists funded by the foundation were asked to submit the most striking still and video images of their research.

Winners of the video category are Dr Michael Markl of University of Freiburg, Germany, and Dr Philip Kilner of Imperial College London, and their video of blood flowing through the heart. Concentrate hard and you can see, in red/yellow, blood flowing through the left side of the heart, down the aorta, and into the body as the heart rotates. Blood flowing through the right side of the heart towards the lungs is shown in blue. According to the BBC, in the future doctors may be able to use this type of imaging to help simulate the blood flow in a patient’s heart.

looking-through-the-heartWinners of the picture category were Mathieu-Benoit Voisin and Doris Proebstl from London with their remarkable heart shaped cell stain.

The researchers are studying how white blood cells move from the blood into into damaged tissue to cause inflammation; for example, after a heart attack. They were using using fluorescent pigments to stain two key players in this inflammatory process – pericyte cells from the blood vessel wall (stained red and blue) and collagen (green) – when looking through the microscope they noticed that the cells had arranged themselves into a heart shape.

“Through better understanding of how white blood cells interact with the components of the vessel walls, we hope to identify new avenues to treat conditions that underlie heart and circulatory inflammatory diseases,” said Dr Voisin. “Our research is funded by the British Heart Foundation so we were really delighted to see this heart shaped arrangement of cells appear by chance through the microscope!”

I think my favourite image from the competition is this runner up picture of the muscle fibres in the left ventricle of the heart.

heart stringsThe image, from Dr Patrick Hales at University of Oxford, was generated using diffusion tensor imaging of the heart. This magnetic resonance imaging (MRI) technique tracks the movement of water molecules through the heart muscle, which reveals how the muscle cells are aligned.

“This technology allows us to model the structure of muscles in the heart in a non-invasive way, and how diseases can cause it to change,” said Dr Hales. “In the future, we hope that our research might be able to determine how the structure of the heart is damaged during a heart attack, and how the muscle fibres respond.

“We also hope that our computer models of individual hearts will one day be used as a tool for diagnosis, and could even provide patient-specific assessment of treatment options. Imagine your doctor trying out treatments on a ‘virtual’ version of you, before choosing the right prescription.”

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Half the top US academic medical centers have no policy on ghostwriting

Half of the top 50 academic medical centres in the United States have no policies on their staff ghostwriting research on the behalf of pharmaceutical companies – including UCLA and Mayo Medical School.

Medical ghostwriting is “the practice of pharmaceutical companies secretly authoring journal articles published under the byline of academic researchers.” By getting academics at top universities to put their names to papers, often for financial reward, pharmaceutical companies aim to improve the authority of their research or even sneak dodgy methodology or fabricated findings past journal editors and readers.

Only 10 (20%) of the top 50 US academic medical centres explicitly ban their staff from ghostwriting, according to the survey published in PLoS Medicine, although three of these institutions don’t specifically use the term “ghostwriting” in their policies.

A further three (6%) have authorship policies that prohibit medical ghostwriting in practice by insisting both that staff make a substantive contribution to the paper to qualify for authorship and that all who qualify for authorship be listed.

Although all the top 10 academic research centres in the US have authorship policies, only six ban ghostwriting and the remaining four – including Duke University and Yale – don’t have policies in place.

Ghostwritten articles can be used by pharmaceutical companies to influence the prescribing – and the sales – of their top products. The authors of the study explain this practise by describing how a pharmaceutical sales representative might use such an article to influence the prescribing of a practicing clinician. “When a pharmaceutical salesperson hands a clinician an article reprint, the name of the institution on the front page of the reprint serves as a stamp of approval,” they write. “The article is not viewed as an advertisement, but as scientific research; the reprint is an effective marketing tool because peer-reviewed journal articles generated in academia are perceived to be the result of unbiased scientific inquiry.”

For example, pharmaceutical companies have used ghostwritten articles to promote sertraline – the most prescribed antidepressant in the US in 2007 – methylphenidate – also known as ritalin, the widely used, and abused, ADHD drug – and rofecoxib – otherwise known as Vioxx, the arthritis drug withdrawn in 2004 because it caused heart attacks.

Given how ghostwritten articles can be used to influence drug approval or prescribing, the authors describe the practise as “a serious threat to public health.” To try to combat ghostwriting, they recommend that participating in medical ghostwriting is defined as academic misconduct akin to plagiarism or falsifying data.

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Lacasse J & Leo J (2010) Ghostwriting at Elite Academic Medical Centers in the United States. PLoS Medicine 7 (2) DOI: 10.1371/journal.pmed.1000230

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A diagnosis of prostate cancer ups the risk of fatal heart attack or suicide

Prostate cancerReceiving a diagnosis of prostate cancer is a very stressful and upsetting event, so much so that some men go on to have a fatal heart attack or kill themselves.

Two pieces of research by the same study group, one conducted in 340,000 men in the US and the other in 170,000 men from Sweden, have found that the risk of dying from a heart attack is raised by 2 to 11 times in men with a diagnosis of prostate cancer.

In addition, the risk of suicide in the first year after diagnosis in American men with prostate cancer was 40% higher than the national average and the risk in the first three months 90% higher. Astoundingly, Swedish guys were twice as likely to kill themselves in the first three months after diagnosis than men who were cancer free.

Interestingly, the US study found that the risk of suicide was only raised between 1979 and 1992, before the widespread use of screening to detect prostate cancer early.  There was no link between prostate cancer and suicide once screening, known as prostate-specific antigen (PSA) testing, was being used across the board.

So does this mean that screening for prostate cancer reduces the risk of suicide after a diagnosis? The authors think so, suggesting that early screening detects less aggressive tumors that are still treatable, thus less stress inducing.

On the other hand, the use of PSA testing has long been controversial. Many men will have small prostate tumours that never do them any harm and the test itself isn’t very reliable, so screening is associated with overdiagnosis and overtreatment.

By extension, some studies reckon that routine testing for prostate cancer causes undue stress and anxiety among patients who do not understand the implications of an abnormal result.  In fact, the Swedish study did not find any difference in suicide risk between the pre-screening era and after screening had been introduced.

This post was chosen as an Editor's Selection for ResearchBlogging.org

The authors aren’t sure about this difference between their two studies, admitting “The reason for this discrepancy is unclear.” However, it could potentially be caused by the large number of nonaggressive prostate cancers diagnosed during the later years in the US study or improved access to emotional support after diagnosis come the late 80s, which might have lessened despair among patients and reduced their suicide risk.

“These results add to the complex debate of pros and cons of extensive prostate-specific antigen testing and the many nonlethal prostate cancers thus detected,” say the authors.

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Fall K et al. (2009) Immediate Risk for Cardiovascular Events and Suicide Following a Prostate Cancer Diagnosis: Prospective Cohort Study PLoS Medicine 6 (12). DOI: 10.1371/journal.pmed.1000197

Fang F et al. (2010). Immediate Risk of Suicide and Cardiovascular Death After a Prostate Cancer Diagnosis: Cohort Study in the United States JNCI Journal of the National Cancer Institute DOI: 10.1093/jnci/djp537

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Reducing dietary salt by half a teaspoon could save 92,000 lives a year

SaltA Californian population based study has found that if everyone in the US reduced their daily salt intake by 3 grams – half a teaspoon – the annual number of deaths could be slashed by up to 92,000. In addition, the number of new people who get cardiovascular disease each year could drop by up to 120,000 – that’s equivalent to the population of Cambridge!

In fact, cutting dietary salt intake by as little as 1 gram a day could reduce the number of deaths from any cause by 15,000 to 32,000 and the number of new cases of cardiovascular disease by 20,000 to 40,000.

US regulations recommend that people consume less than 5.8 g of salt a day, yet the average American man gets through almost double that – 10.4 g of salt daily. This is bad news – high salt intake is associated with an increased risk of stroke and cardiovascular disease.

In this study, published in the New England Journal of Medicine, the authors used computer modelling to simulate heart disease and stroke in US adults aged 35-84 years.

They found that a population wide reduction in dietary salt of 3 g per day could potentially reduce the annual number of cases of cardiovascular disease by 60,000 to 120,000, stroke by 32,000 to 66,000, and heart attack by 54,000 to 99,000. The annual number of deaths from any cause could be cut by by 44,000 to 92,000.

Even a modest reduction of 1 g of salt per day could cut the yearly rates of cardiovascular disease, stroke, and heart attack by at least 20,000, 18,000, and 11,000, respectively. “It was a surprise to see the magnitude of the impact on the population, given the small reductions in salt that we were modeling,” Kirsten Bibbins-Domingo, lead author of the study, told Science Daily.

The effects seemed greater in black people – a population with high rates of hypertension and cardiovascular disease – and women would benefit in particular from a reduction in stroke incidence. The number of events related to cardiovascular disease – such as heart attack – would drop in older adults, whereas young people would benefit from lower overall mortality rates.

The public health benefits of a drop in salt intake of 3 g a day would be equivalent to half of all smokers quitting or a 5% reduction in body fat among obese adults, and would save $10 billion to $24 billion a year in healthcare costs.

“Reducing dietary salt is one of those rare interventions that has a huge health benefit and actually saves large amounts of money,” said senior author Lee Goldman. “At a time when so much public debate has focused on the costs of health care for the sick, here is a simple remedy, already proven to be feasible in other countries.”

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Bibbins-Domingo K et al. (2010) Projected Effect of Dietary Salt Reductions on Future Cardiovascular Disease. New England Journal of Medicine DOI: 10.1056/NEJMoa0907355

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Watching too much TV increases risk of death within the next six years

A study of nearly 9,000 Australian adults has reported that people who watched 4 hours of TV a day or more were 46% more likely to die within the next six and a half years than those who watched less than 2 hours a day.  Each one hour increase in daily television viewing increased the risk of death from any cause by 11% and death by cardiovascular disease by 18%.

Previous studies have suggested that sedentary behaviour is associated with a mortality risk.  Furthermore, surveys in the US and the UK indicate that, aside from sleeping, lounging around watching television takes up the most of our time at home – about 3 hours a day in the UK and up to 8 hours a day in the US, apparently.

This study, published in the journal Circulation, examined 8,800 adults aged 25 years or older who were in the Australian Diabetes, Obesity and Lifestyle Study (AusDiab). All participants were interviewed at the start of the study to find out their lifestyle habits, medical history, and the amount of time they had spent watching television or videos in the previous 7 days.

About six and a half years later, on average, mortality status and cause of death for each participant was established from the Australian National Death Index.

Each one hour increase in television viewing time was associated with an 11% increase in the risk of death from any cause and an 18% increase in the likelihood of death related to cardiovascular disease. However, these relationships were attenuated once other factors like medical history and smoking habits were taken into account, but the association between TV time and death from any cause did remain important. The link between television viewing time and cancer mortality was negligible though.

Strikingly, the risk of mortality was much higher in people who watched at least 4 hours of TV a day than in those who watched less than 2 hours – the risk of death from any cause was 46% higher and the risk of death from cardiovascular disease was a whopping 80% more.

Individuals who watched 4 hours of TV a day or more were more likely to be a current or ex-smoker, have a poor diet, be overweight, or have raised blood pressure than those who watched less than 2 hours daily – that is, they seemed generally less healthy and, in theory, would be more likely to just drop dead. However, none of these factors affected the associations between television viewing and mortality.

The public health implications of this study are pretty serious – get TV addicts to cut their viewing in half and they could considerably reduce their risk of death over the next 6 years or so. As the authors say, “our findings suggest that reducing time spent watching television (and possibly other prolonged sedentary behaviors) may also be of benefit in preventing CVD and premature death.” They recommend that as well as promoting exercise, public health bodies should also “focus on reducing sitting time, particularly prolonged television viewing.”

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Dunstan D et al. (2010) Television Viewing Time and Mortality: The Australian Diabetes, Obesity and Lifestyle Study (AusDiab). Circulation 121 (3): 384-391. DOI: 10.1161/CIRCULATIONAHA.109.894824

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