Chapter 11. Emotions, Aggression, and Stress
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Ian Sample Science editor Dozens of British children who developed narcolepsy as a result of a swine flu vaccine could be compensated after the high court rejected a government appeal to withhold payments. Six million people in Britain, and more across Europe, were given the Pandemrix vaccine made by GlaxoSmithKline during the 2009-10 swine flu pandemic, but the jab was withdrawn after doctors noticed a sharp rise in narcolepsy among those who received it. The sleep disorder is permanent and can cause people to fall asleep dozens of times a day. Some narcoleptics have night terrors and a muscular condition called cataplexy that can lead them to collapse on the spot. In 2015, a 12-year-old boy, known as John for the proceedings, was awarded £120,000 by a court that ruled he had been left severely disabled by narcolepsy caused by the vaccine. He was seven when he had the jab and developed symptoms within months. Because of his tiredness, John became disruptive at school and found it almost impossible to make friends. He takes several naps a day, cannot shower or take a bus on his own, and may never be allowed to drive a car. Despite paying out, the Department for Work and Pensions argued John’s disability was not serious enough to warrant compensation and said the court was wrong to take into account how the illness would affect him in the future. But the high court on Thursday rejected the government’s appeal that only the boy’s disability at the time should have been considered. The ruling paves the way for more than 60 other people to claim compensation. © 2017 Guardian News and Media Limited
Bruce Bower A small, poorly understood segment of the population stays mentally healthy from age 11 to 38, a new study of New Zealanders finds. Everyone else encounters either temporary or long-lasting mental disorders. Only 171 of 988 participants, or 17 percent, experienced no anxiety disorders, depression or other mental ailments from late childhood to middle age, researchers report in the February Journal of Abnormal Psychology. Of the rest, half experienced a transient mental disorder, typically just a single bout of depression, anxiety or substance abuse by middle age. “For many, an episode of mental disorder is like influenza, bronchitis, kidney stones, a broken bone or other highly prevalent conditions,” says study coauthor Jonathan Schaefer, a psychologist at Duke University. “Sufferers experience impaired functioning, many seek medical care, but most recover.” The remaining 408 individuals (41 percent) experienced one or more mental disorders that lasted several years or more. Their diagnoses included more severe conditions such as bipolar and psychotic disorders. Researchers analyzed data for individuals born between April 1972 and March 1973 in Dunedin, New Zealand. Each participant’s general health and behavior were assessed 13 times from birth to age 38. Eight mental health assessments occurred from age 11 to 38. |© Society for Science & the Public 2000 - 2016.
Link ID: 23200 - Posted: 02.08.2017
Aylin Woodward Fearful, flighty chickens raised for eating can hurt themselves while trying to avoid human handlers. But there may be a simple way to hatch calmer chicks: Shine light on the eggs for at least 12 hours a day. Researchers at the University of California, Davis bathed eggs daily in light for different time periods during their three-week incubation. When the chickens reached 3 to 6 weeks old, the scientists tested the birds’ fear responses. In one test, 120 chickens were randomly selected from the 1,006-bird sample and placed one by one in a box with a human “predator” sitting visibly nearby. The chickens incubated in light the longest — 12 hours — made an average of 179 distress calls in three minutes, compared with 211 from birds incubated in complete darkness, animal scientists Gregory Archer and Joy Mench report in January in Applied Animal Behaviour Science. Chickens exposed to lots of light as eggs “would sit in the closest part of the box to me and just chill out,” Archer says. The others spent their time trying to get away. How light has its effect is unclear. On commercial chicken farms, eggs typically sit in warm, dark incubation rooms. The researchers are now testing light's effects in large, commercial incubators. Using light exposure to raise less-fearful chickens could reduce broken bones during handling at processing plants, Archer says. It might also decrease harmful anxious behaviors, such as feather pecking of nearby chickens. G. S. Archer and J. A. Mench. Exposing avian embryos to light affects post-hatch anti-predator fear responses. Applied Animal Behaviour Science. Vol. 186, January 2017, p. 80. doi: 10.1016/j.applanim.2016.10.014. © Society for Science & the Public 2000 - 2016
By Emma Hiolski Imagine cells that can move through your brain, hunting down cancer and destroying it before they themselves disappear without a trace. Scientists have just achieved that in mice, creating personalized tumor-homing cells from adult skin cells that can shrink brain tumors to 2% to 5% of their original size. Although the strategy has yet to be fully tested in people, the new method could one day give doctors a quick way to develop a custom treatment for aggressive cancers like glioblastoma, which kills most human patients in 12–15 months. It only took 4 days to create the tumor-homing cells for the mice. Glioblastomas are nasty: They spread roots and tendrils of cancerous cells through the brain, making them impossible to remove surgically. They, and other cancers, also exude a chemical signal that attracts stem cells—specialized cells that can produce multiple cell types in the body. Scientists think stem cells might detect tumors as a wound that needs healing and migrate to help fix the damage. But that gives scientists a secret weapon—if they can harness stem cells’ natural ability to “home” toward tumor cells, the stem cells could be manipulated to deliver cancer-killing drugs precisely where they are needed. Other research has already exploited this method using neural stem cells—which give rise to neurons and other brain cells—to hunt down brain cancer in mice and deliver tumor-eradicating drugs. But few have tried this in people, in part because getting those neural stem cells is hard, says Shawn Hingtgen, a stem cell biologist at the University of North Carolina in Chapel Hill. © 2017 American Association for the Advancement of Science.
By Chelsea Whyte It was a gruesome scene. The body had severe wounds and was still bleeding despite having been lying for a few hours in the hot Senegalese savanna. The murder victim, a West African chimpanzee called Foudouko, had been beaten with rocks and sticks, stomped on and then cannibalised by his own community. This is one of just nine known cases where a group of chimpanzees has killed one of their own adult males, as opposed to killing a member of a neighbouring tribe. These intragroup killings are rare, but Michael Wilson at the University of Minnesota says they are a valuable insight into chimp behaviour such as male coalition building. “Why do these coalitions sometimes succeed, but not very often? It’s at the heart of this tension between conflict and cooperation, which is central to the lives of chimpanzees and even to our own,” he says. Chimps usually live in groups with more adult females than males, but in the group with the murder it was the other way round. “When you reverse that and have almost two males per every female — that really intensifies the competition for reproduction. That seems to be a key factor here,” says Wilson. Jill Pruetz at Iowa State University, who has been studying this group of chimpanzees in south-eastern Senegal since 2001, agrees. She suggests that human influence may have caused this skewed gender ratio that is likely to have been behind this attack. In Senegal, female chimpanzees are poached to provide infants for the pet trade. Fall from power Thirteen years ago, Foudouko reigned over one of the chimp clans at the Fongoli study site, part of the Fongoli Savanna Chimpanzee Project. As alpha male, he was “somewhat of a tyrant”, Pruetz says. © Copyright Reed Business Information Ltd.
By Simon Oxenham Ever felt hungry and angry at the same time? There’s evidence that “hanger” is a real phenomenon, one that can affect your work and relationships. The main reason we become more irritable when hungry is because our blood glucose level drops. This can make it difficult for us to concentrate, and more likely to snap at those around us. Low blood sugar also triggers the release of stress-related hormones like cortisol and adrenaline, as well as a chemical called neuropeptide Y, which has been found to make people behave more aggressively towards those around them. This can all have an alarming effect on how you feel about other people – even those you love. A classic study of married couples asked them to stick pins into “voodoo dolls” that represented their loved ones, to reflect how angry they felt towards them. The volunteers then competed against their spouse in a game, in which the winner could blast loud noise through the loser’s headphones. The researchers tracked the participants’ blood glucose levels throughout. They found that when people had lower sugar levels, the longer the blasts of unpleasant noise they subjected their spouse to, and the more pins they stuck into their dolls. But while being hungry really does change your behaviour, the effects of hanger have sometimes been overstated. One study that attracted attention a few years ago found that judges are less likely to set lenient sentences the closer it gets to lunch. © Copyright Reed Business Information Ltd.
Link ID: 23172 - Posted: 02.01.2017
By JAMES HAMBLIN In 1997, a few hundred people who responded to a job posting in a Pittsburgh newspaper agreed to let researchers spray their nostrils with a rhinovirus known to cause the common cold. The people would then be quarantined in hotel rooms for five days and monitored for symptoms. In return they’d get $800. “Hey, it’s a job,” some presumably said. Compensation may also have come from the knowledge that, as they sat alone piling up tissues, they were contributing to scientific understanding of our social-microbial ecosystem. The researchers wanted to investigate a seemingly basic question: Why do some people get more colds than others? To Gene Brody, a professor at the University of Georgia, the answer was “absolutely wild.” (Dr. Brody is a public-health researcher, so “wild” must be taken in that context.) He and colleagues recently analyzed the socio-economic backgrounds and personalities of the people in the Pittsburgh study and found that those who were “more diligent and tended to strive for success” were more likely than the others to get sick. To Dr. Brody, the implication was that something suffers in the immune systems of people who persevere in the face of adversity. Over the past two years, Dr. Brody and colleagues have amassed more evidence supporting this theory. In 2015, they found that white blood cells among strivers were prematurely aged relative to those of their peers. Ominous correlations have also been found in cardiovascular and metabolic health. In December, Dr. Brody and colleagues published a study in the journal Pediatrics that said that among black adolescents from disadvantaged backgrounds, “unrelenting determination to succeed” predicted an elevated risk of developing diabetes. The focus on black adolescents is significant. In much of this research, white Americans appeared somehow to be immune to the negative health effects that accompany relentless striving. As Dr. Brody put it when telling me about the Pittsburgh study, “We found this for black persons from disadvantaged backgrounds, but not white persons.” © 2017 The New York Times Company
By NICHOLAS BAKALAR Psychological distress may increase your chances of dying from cancer. Researchers interviewed 163,363 adults in England and Scotland using well-validated questionnaires on general and mental health. They followed the population in 16 studies conducted between 1994 and 2008. After controlling for age, smoking, physical activity and other factors, they found that compared with those with the lowest scores on depression and anxiety, those with the highest had higher rates of cancer death. The associations were particularly strong for colon and rectal, prostate, pancreatic and esophageal cancers, and for leukemia. In instances of colorectal and prostate cancer, they found a “dose-response” effect: the greater the distress, the greater the likelihood of death from those cancers. People might have had undiagnosed cancer at the start of the study, which would affect their mood, so the researchers accounted for this possibility by doing an analysis that excluded study members who died of cancer in the first five years. The results were largely the same. The study, in BMJ, is observational so cannot determine cause and effect, and it depended in part on self-reports. “The extent to which these associations could be causal,” the authors write, “requires further testing with alternative study designs.” © 2017 The New York Times Company
By Mitch Leslie When we have food poisoning, the last thing we want to do is eat. But in mice, a microbe that causes this ailment actually increases appetite, a new study reveals. Researchers say they might be able to use the same trick to increase eating in cancer patients and old folks, who often lose their desire for food. “I think it’s a fantastic paper,” says immunophysiologist Keith Kelley of the University of Illinois in Urbana, who wasn’t connected to the study. The researchers deserve praise for combining approaches from several disciplines such as microbiology, neurobiology, and immunology to draw a surprising conclusion, he says. “It’s the way disease responses should be investigated.” Some of the symptoms you endure when you are ill, such as lethargy and fever, are actually good for you. Lolling on the couch all day, for instance, saves energy for your immune cells. But the picture is more complex for another of these so-called sickness behaviors—reduced appetite. Animal studies have found that eating less seems to improve the odds of surviving some infections, perhaps because it robs the invading microbes of key nutrients, but in other cases the loss of appetite often proves fatal. © 2017 American Association for the Advancement of Science
By GRETCHEN REYNOLDS When people get up and move, even a little, they tend to be happier than when they are still, according to an interesting new study that used cellphone data to track activities and moods. In general, the researchers found, people who move are more content than people who sit. There already is considerable evidence that physical activity is linked to psychological health. Epidemiological studies have found, for example, that people who exercise or otherwise are active typically are less prone to depression and anxiety than sedentary people. But many of these studies focused only on negative moods. They often also relied on people recalling how they had felt and how much they had moved or sat in the previous week or month, with little objective data to support these recollections. For the new study, which was published this month in PLoS One, researchers at the University of Cambridge in England decided to try a different approach. They would look, they decided, at correlations between movement and happiness, that most positive of emotions. In addition, they would look at what people reported about their activity and compare it with objective measures of movement. To accomplish these goals, they first developed a special app for Android phones. Available free on the Google app store and ultimately downloaded by more than 10,000 men and women, it was advertised as helping people to understand how lifestyle choices, such as physical activity, might affect people’s moods. (The app, which is no longer available for download, opened with a permission form explaining to people that the data they entered would be used for academic research.) The app randomly sent requests to people throughout the day, asking them to enter an estimation of their current mood by answering questions and also using grids in which they would place a dot showing whether they felt more stressed or relaxed, depressed or excited, and so on. © 2017 The New York Times Company
What are you like? A look at your brain may tell you. A study has found a link between some elements of brain structure and certain personality traits. The study involved scanning the brains of 500 volunteers, and assessing their personalities in terms of five traits – neuroticism, openness, extraversion, agreeableness, and conscientiousness. The researchers focused on the structure of the cortex, the outer layer of the brain. They found that in people who are more neurotic and prone to mood changes, the cortex tends to be thicker and less wrinkly. People who appear more open – for example, curious and creative – show the opposite pattern. More mature The link between structure and personality may help explain how we mature as we get older. Folds and wrinkles are thought to increase the surface area of the brain, but make the cortex thinner. The cortex continues to stretch and fold throughout childhood and adolescence, and into adulthood. As we grow up, people generally become less neurotic, and more conscientious and agreeable. “Our work supports the notion that personality is, to some degree, associated with brain maturation,” says Roberta Riccelli, at Magna Graecia University in Catanzaro, Italy. Journal reference: Social Cognitive and Affective Neuroscience © Copyright Reed Business Information Ltd.
Joseph Palamar On Nov. 30 the FDA approved a Phase III clinical trial to confirm the effectiveness of treating post-traumatic stress disorder (PTSD) with MDMA, also known as Ecstasy. This news appeared in headlines throughout the world, as it represents an important – yet somewhat unorthodox – advance in PTSD treatment. However, the media have largely been referring to Ecstasy – the street name for this drug – as the treatment in this trial, rather than MDMA (3,4-methylenedioxymethamphetamine). This can lead to misunderstanding, as recreational Ecstasy use is a highly stigmatized behavior. Using this terminology may further misconceptions about the study drug and its uses. While Ecstasy is in fact a common street name for MDMA, what we call Ecstasy has changed dramatically since it became a prevalent recreational drug. Ecstasy now has a very different meaning – socially and pharmacologically. It is understandable why the media have referred to this drug as Ecstasy rather than MDMA. Not only has much of the public at least heard of Ecstasy (and would not recognize MDMA), but this also increases shock value and readership. But referring to a therapeutic drug by its street name (such as Ecstasy) is misleading – especially since MDMA is known to be among the most popular illicit drugs used at nightclubs and dance festivals. This leads some to assume that street drugs are being promoted and provided to patients, perhaps in a reckless manner. © 2010–2017, The Conversation US, Inc.
Jonathan Sadowsky Carrie Fisher’s ashes are in an urn designed to look like a Prozac pill. It’s fitting that in death she continues to be both brash and wryly funny about a treatment for depression. The public grief over Carrie Fisher’s death was not only for an actress who played one of the most iconic roles in film history. It was also for one who spoke with wit and courage about her struggle with mental illness. In a way, the fearless General Leia Organa on screen was not much of an act. Carrie Fisher at a screening of ‘Catastrophe’ at the Tribeca Film Festival in April 2016. PBG/AAD/STAR MAX/IPx via AP Fisher’s bravery, though, was not just in fighting the stigma of her illness, but also in declaring in her memoir “Shockaholic” her voluntary use of a stigmatized treatment: electroconvulsive therapy (ECT), often known as shock treatment. Many critics have portrayed ECT as a form of medical abuse, and depictions in film and television are usually scary. Yet many psychiatrists, and more importantly, patients, consider it to be a safe and effective treatment for severe depression and bipolar disorder. Few medical treatments have such disparate images. I am a historian of psychiatry, and I have published a book on the history of ECT. I had, like many people, been exposed only to the frightening images of ECT, and I grew interested in the history of the treatment after learning how many clinicians and patients consider it a valuable treatment. My book asks the question: Why has this treatment been so controversial? © 2010–2017, The Conversation US, Inc.
Link ID: 23102 - Posted: 01.14.2017
By LISA SANDERS, M.D. “You don’t look well,” the man at the gas station told the older woman in the car. He’d known her for years, always thinking of her as a lively, robust woman. But that day she looked pale and tired. Her sharp blue eyes seemed dim. She gave a feeble smile. “I don’t feel well at all,” she told him. There’s an urgent-care clinic just up the street, he said. Could she make it there? She was nearly 45 minutes away from her home in Halifax, Nova Scotia. Stopping just up the street seemed a much better option. At the clinic, the doctor took one look at her, put a blood pressure cuff around her arm and told her assistant to call an ambulance. The rest of the day was a blur. The woman remembers being bundled onto a stretcher and one of the E.M.T.s saying her blood pressure was very low. It was an odd thing to hear, because her blood pressure was usually high enough to require three medications. She was taken to the emergency room at the Queen Elizabeth II Health Sciences Center in Halifax. She remembers being fussed over — having blood drawn, receiving intravenous fluids, feeling sticky snaps being placed on her chest that connected her to a continuous heart monitor. She had been a nurse for many years when she was younger, yet seeing herself at the center of these familiar activities was strange. A blood test indicated that there may have been damage to her heart. The doctor told her she was having a heart attack, she recalls. You’ve got the wrong patient, she thought to herself. Sure, she had a little high blood pressure, a little asthma, a little back pain. But problems with her heart? Never. The patient used a cane, but she had no difficulty getting up on the exam table — an important test of mobility. © 2017 The New York Times Company
Keyword: Hormones & Behavior
Link ID: 23101 - Posted: 01.14.2017
Jon Hamilton Mice that kill at the flip of a switch may reveal how hunting behavior evolved hundreds of millions of years ago. The mice became aggressive predators when two sets of neurons in the amygdala were activated with laser light, a team reported Thursday in the journal Cell. "The animals become very efficient in hunting," says Ivan de Araujo, an associate professor of psychiatry at Yale University and an associate fellow at The John B. Pierce Laboratory in New Haven. "They pursue the prey [a live cricket] faster and they are more capable of capturing and killing it." Activating the neurons even caused the mice to attack inanimate objects, including sticks, bottle caps and an insectlike toy. "The animals intensively bite the toy and use their forepaws in an attempt to kill it," De Araujo says. But the aggressive behavior is reserved for prey. Mice didn't attack each other, even when both sets of neurons were activated. The results hint at how the brain changed hundreds of millions of years ago when the first animals with jaws began to appear. This new ability to pursue and kill prey "must have influenced the way the brain is wired up in a major way," De Araujo says. Specifically, the brain needed to develop hunting circuits that would precisely coordinate the movements of a predator's jaw and neck. "This is a very complex and demanding task," De Araujo says. © 2017 npr
Link ID: 23099 - Posted: 01.13.2017
Being stressed out increases our risk of heart disease and stroke, and the key to how to counter it may lie in calming the brain, a new medical study suggests. Psychological stress has long been considered a source of sickness. But personal stress levels are difficult to measure and there isn't direct evidence of the link, even though population studies finger stress as a risk factor for cardiovascular disease just like smoking and hypertension. "I think that this relatively vague or insufficient link reduced our enthusiasm of taking stress seriously as an important risk factor," said Dr. Ahmed Tawakol, a cardiologist at Massachusetts General Hospital in Boston. Tawakol led a study published in Wednesday's online issue of The Lancet that sheds light on how the amygdala — a key part of the brain that is more active during emotional, stressful times — is linked to a greater risk of cardiovascular disease such as heart attacks and strokes. The researchers gave 293 patients aged 30 or older without cardiovascular disease PET/CT brain imaging scans, mainly for cancer screening and followed them over time. After an average of nearly four years, activity in the amygdala was significantly associated with cardiovascular events such as heart attacks, heart failure and strokes, after taking other factors into account. People with more amygdala activity also tended to suffer the events sooner, Tawakol said. ©2017 CBC/Radio-Canada.
Link ID: 23087 - Posted: 01.12.2017
By Virginia Morell We often say the same sweet, nonsensical things to our dogs that we say to our babies—and in almost the same slow, high-pitched voice. Now, scientists have shown that puppies find our pooch-directed speech exciting, whereas older dogs are somewhat indifferent. The findings show, for the first time, that young dogs respond to this way of talking, and that it may help them learn words—as such talk does with human babies. To find out how dogs reacted to human speech, Nicolas Mathevon, a bioacoustician at the University of Lyon in Saint Étienne, France, and his colleagues first recorded the voices of 30 women as they looked at a dog’s photograph and read from a script, “Hi! Hello cutie! Who’s a good boy? Come here! Good boy! Yes! Come here sweetie pie! What a good boy!” (The scientists were afraid the women would ad lib if they spoke to a real dog.) The women also repeated the passage to a person. When the scientists compared the human- and dog-directed speech, they found that, as expected, the women spoke in distinctive, high-pitched, sing-song tones to the pooches—but not the humans. “It didn’t matter if it was a puppy or an adult dog,” Mathevon says. But the women did speak at an even higher pitch when looking at puppy photos. Next, the researchers played these recordings in short trials with 10 puppies and 10 adult dogs at a New York City animal shelter and videotaped their responses. Nine of the puppies reacted strongly, barking and running toward the loudspeaker even when the recording had been made for an older dog, the team reports today in the Proceedings of the Royal Society B. Some even bent toward the loudspeaker in a play bow, a pose meant to initiate horseplay, suggesting they may regard dog-directed speech as “an invitation to play,” Mathevon says. © 2017 American Association for the Advancement of Science.
Anouchka Grose Dannii Minogue has admitted to using Botox at difficult times in her life in a subconscious attempt to mask her feelings. Not only might she literally have been disabling her capacity to frown, she may also have been acting things out on her body in order to fend off her own emotions. Is America developing a ‘crack-like addiction’ to Botox beauty? Read more It’s about time someone said it. As a working therapist I have occasionally noticed my female patients’ faces change quite noticeably from week to week, but no one has ever spoken to me about what was making this happen. Cosmetic treatments, and the difficult thoughts and feelings that might make someone undergo them, are apparently one of the hardest things to talk about. On the one hand perhaps these treatments are so normalised that they do not seem worth discussing in therapy – a new study in the US shows that young women using Botox has risen by 41% since 2011 – but on the other you probably wouldn’t spend hundreds of pounds on something that carried serious health risks if you weren’t feeling pretty worried about your appearance. Doing stuff to your face is like the sunny side of self-harm; you might try it in order to short-circuit anxiety or sadness, but the end result is supposedly regeneration rather than damage. Still, nothing signals underlying unhappiness and self-loathing more than a pumped-up, frozen physiognomy. In that sense, it’s a socially acceptable form of wound. © 2017 Guardian News and Media Limited
Link ID: 23078 - Posted: 01.10.2017
By Andy Coghlan Is the fabled “cuddle hormone” really a “warmone”? Oxytocin levels surge in troops of chimpanzees preparing for conflict with rival groups to defend or expand their territory. The finding is at odds with the prevailing image of oxytocin as something that helps strengthen bonds between parent and infant, or foster friendships. But given its capacity to strengthen loyalty, oxytocin could also be a warmonger hormone that helps chimps galvanise and cooperate against a common enemy. Catherine Crockford of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and her colleagues monitored two rival groups of chimpanzees in the Taï National Park in Ivory Coast, each containing five males and five females, for prolonged periods between October 2013 and May 2015. Thanks to trust built up between the team and the chimps, the team could safely track and video the groups – even during conflict, observing at close quarters what was happening. Crucially, the team was also able to pipette up fresh samples from soil when chimps urinated. The samples revealed that oxytocin levels surge in the mammals whenever the chimps on either side prepared for confrontation, or when either group took the risk of venturing near or into rival-held territories. These surges dwarfed the oxytocin levels seen during activities such as grooming, collaborative hunting for monkey prey or food sharing. © Copyright Reed Business Information Ltd.
Hannah Devlin Science correspondent People living near a busy road have an increased risk of dementia, according to research that adds to concerns about the impact of air pollution on human health. Roughly one in 10 cases of Alzheimer’s in urban areas could be associated with living amid heavy traffic, the study estimated – although the research stopped short of showing that exposure to exhaust fumes causes neurodegeneration. Hong Chen, the scientist who led the work at Public Health Ontario, said: “Increasing population growth and urbanisation has placed many people close to heavy traffic, and with widespread exposure to traffic and growing rates of dementia, even a modest effect from near-road exposure could pose a large public health burden.” Previously, scientists have linked air pollution and traffic noise to reduced density of white matter (the brain’s connective tissue) and lower cognition. A recent study suggested that magnetic nano-particles from air pollution can make their way into brain tissue. The latest study, published in The Lancet, found that those who live closest to major traffic arteries were up to 12% more likely to be diagnosed with dementia – a small but significant increase in risk. The study, which tracked roughly 6.6 million people for more than a decade, could not determine whether pollution is directly harmful to the brain. The increased dementia risk could also be a knock-on effect of respiratory and cardiac problems caused by traffic fumes or due to other unhealthy life-style factors associated with living in built-up urban environments. © 2017 Guardian News and Media Limited