by Katia Moskvitch In the days before GPS, we needed both a compass and a map to navigate. Migrating birds are no different. Studies have suggested that the animals rely on an internal map and compass to traverse large distances, though just where these senses reside is unclear. Now, scientists say they have the strongest evidence yet that map sense is associated with the beak. Researchers have long suspected that migrating birds navigate by sensing Earth's magnetic field. The idea was that their beaks, which contain a lot of iron, worked like real magnets, with the metal aligning itself relative to the field. Supposedly, the so-called trigeminal nerve transmitted this information to the brain. But in 2009, a team led by Henrik Mouritsen of the University of Oldenburg in Germany cut the trigeminal nerve in several European robins and found that the animals still oriented perfectly. In lab-based experiments, the birds were able to locate the natural and artificial magnetic north. It seemed that the beak played no role in the compass sense. The finding gave support to another hypothesis, one that suggested that the inner compass was instead a magnetism-sensing chemical reaction in the birds' eyes. But Mouritsen's team was still convinced that the beak had to be involved in the magnetosense in some way, and it decided to do another test. In 2010 and 2011, the scientists captured 57 Eurasian reed warblers near Kaliningrad, Russia. Every spring, these birds migrate northeast to their breeding grounds in southern Scandinavia, up to 1000 kilometers away. Once again, the scientists snapped the trigeminal nerve, in half of the birds. But then they also moved all 57 birds 1000 kilometers to the east, where the magnetic field differs from their home site, and released them. © 2010 American Association for the Advancement of Science

Keyword: Animal Migration
Link ID: 18327 - Posted: 06.29.2013

by Douglas Heaven Toss a stone into a pool and it leaves ripples long after it sinks. Ideas and experiences have a similar affect on our brains: short bouts of intense neural activity leave ripples in the brain's background activity that can still be detected 24 hours later. The finding effectively opens a window into a person's recent past. Previous studies have shown that it is possible to use brain activity to detect simple thoughts or words, and even what image someone is looking at. But this is the first time activity from the past has been observed. Even when you are doing nothing, the brain is busy. Cut off from external stimuli and left to "idle", the brain enters a resting state. "You would expect it to quieten down," says Rafael Malach at the Weizmann Institute of Science in Rehovot, Israel. But instead, the brain just switches gear, producing patterns of activity that are slower but no less noisy. "The activity is very organised, very rich and very consistent," says Malach. But what it means is largely a mystery. Malach and his colleagues wondered whether the activity might in fact be a kind of echo. Could it tell us something about what the brain had been up to previously? "It might be a window into the previous day's activity," says Malach. To test the idea, the team compared fMRI scans of 20 people taken before, during and after a period of intense cognitive activity. They focused on a region of the brain called the dorsal anterior cingulate cortex, which is linked to decision-making and volition. © Copyright Reed Business Information Ltd.

Keyword: Brain imaging
Link ID: 18326 - Posted: 06.29.2013

Till Roenneberg Sleep is essential for health, performance and wellbeing. Yet in many countries, people are getting one to two hours less of it each night than their ancestors did 50–100 years ago. Even when people have the opportunity to sleep, many cannot. Sleep pathologies are approaching epidemic levels, affecting an estimated 70 million people in the United States alone (see go.nature.com/6dgqhg). And in some countries, direct and indirect costs of sleep-related problems are thought to approach 1% of gross domestic product1. Despite these alarming numbers, sleep research ranks only 91st in the 235 categories on this year's funding list of the US National Institutes of Health — below, for instance, studies of tobacco (see go.nature.com/ces1rf). Researchers have made great advances in understanding which neurotransmitters and brain regions are involved in sleep2, and how the timings of sleep and wakefulness are controlled by an internal (circadian) clock3, among other things. Yet we still do not have answers to the most basic questions. It is not really understood, for instance, what sleep is for, how much is optimal, how sleep quality can be measured and predicted, or the role of genetic and environmental factors in determining ideal sleeping patterns. One reason for this lack of understanding is that most of what is known about sleep comes from laboratory studies. Subjects in these studies tend to be mice or hamsters that are kept in artificial light–dark cycles, or people who have been instructed to sleep at certain times in beds that are not their own, with electrodes fastened to their heads. Assessments of sleep are also often based on subjective responses to questions about how 'well' people feel after they have slept, or whether they think they experienced a good night's sleep. To learn about sleep in the real world, and to establish how to manage sleep to improve productivity, health and quality of life, we need a multidisciplinary 'human sleep project'. © 2013 Nature Publishing Group

Keyword: Sleep; Genes & Behavior
Link ID: 18325 - Posted: 06.29.2013

By Cristy Gelling Lemur species that live in large groups can tell when to steal food from a competitor in a lab experiment, researchers report June 26 in PLOS ONE. The finding supports the idea that brainpower in primates evolved to fit their complex social lives. Because the sneakier lemurs don't have bigger brains than less sneaky ones living in smaller groups, researchers suggest that social smarts don’t always depend on brain size. Much of the evidence for sociality’s role in the evolution of intelligence comes from indirect measures such as brain size, says study coauthor Evan MacLean of Duke University. But brain size does not always correspond to brainpower, so MacLean uses behavioral tests. He and his colleagues tested the social intelligence of six species of lemur, primates from Madagascar distantly related to monkeys and apes. Each of the species lives in social groups ranging from families of just three, mongoose lemurs’ preferred posse, to gangs of about 16, a typical size for a group of ring-tailed lemurs. The researchers trained lemurs to view humans as competitors for food, then presented the animals with a choice between pilfering treats from one of two people: one facing the animals or another with his or her back turned. Species that live in small groups reached for the food under a competitor’s nose as often as they did behind people’s backs. But the ring-tailed lemurs were much more likely to choose the unguarded food. © Society for Science & the Public 2000 - 2013

Keyword: Evolution; Emotions
Link ID: 18324 - Posted: 06.29.2013

Sid Perkins Sporting feats such as baseball's 100-mile-per-hour fastball are made possible by a suite of anatomical features that appeared in our hominin ancestors about 2 million years ago, a video study of college athletes suggests. And this ability to throw projectiles may have been crucial for human hunting, which in turn may have had a vital role in our evolution. “Throwing projectiles probably enabled our ancestors to effectively and safely kill big game,” says Neil Roach, a biological anthropologist at George Washington University in Washington DC, who led the work. Eating more calorie-rich meat and fat would have helped early hominins' brains and bodies to grow, enabling our ancestors to expand into new regions of the world, he suggests. The study is published today in Nature1. Although some primates occasionally throw objects, and with a fair degree of accuracy, only humans can routinely hurl projectiles with both speed and accuracy, says Roach. Adult male chimpanzees can throw objects at speeds of around 30 kilometres per hour, but even a 12-year-old human can pitch a baseball three times faster than that, he notes. In fact, the quickest motion that the human body produces — rotation of the humerus, the long bone in the upper arm, at a rate that is briefly equivalent to 25 full rotations in a single second — occurs while a person is throwing a projectile. © 2013 Nature Publishing Group,

Keyword: Evolution; Muscles
Link ID: 18323 - Posted: 06.29.2013

By Dwayne Godwin and Jorge Cham A new initiative aims to invent new technologies for understanding the brain

Keyword: Brain imaging
Link ID: 18322 - Posted: 06.29.2013

By Susan Milius After 17 years underground, throngs of ruby-eyed cicadas clawed up through the soil this year to partake in a once-in-a-lifetime, synchronized mating frenzy. Except it wasn’t one big insect orgy: It was three. The insects that unearthed themselves to breed in 2013 belong to three distinct species. You need only flip them over to see some differences, written in the varieties of their orange markings. You can hear the differences too, says Chris Simon of the University of Connecticut in Storrs. The tymbals on either side of a male’s abdomen vibrate to make the racket for which cicadas are famous. A chorus of courting Magicicada cassini males sounds like an electric carving knife revving up. M. septendecula coughs out a series of rasps. And M. septendecim serenades with the whistling drone of a B-movie spaceship. The various thrums and buzzings may mingle in the same neighborhood, but the last time ancestors of these species mated with each other was almost 4 million years ago, Simon says. That’s the conclusion of the most detailed genetic studies yet of periodical cicada evolutionary history, which Simon and colleagues published in April in the Proceedings of the National Academy of Sciences. With DNA plus episodic field observations, the scientists are getting an idea about the odd family tree of periodical cicadas, how the insects synchronize their life cycles and why they breed side-by-side with others unsuitable for mating. © Society for Science & the Public 2000 - 2013

Keyword: Biological Rhythms; Evolution
Link ID: 18321 - Posted: 06.29.2013

by Andrew Porterfield Honey bees may have only a fraction of our neurons—just under a million versus our tens of billions—but our brains aren't so different. Take sidedness. The human brain is divided into right and left sides—our right brain controls the left side of our body and vice versa. New research reveals that something similar happens in bees. When scientists removed the right or left antenna of honey bees, those insects with intact right antennae more quickly recognized bees from the same hive, stuck out their tongues (showing willingness to feed), and fended off invaders. Bees with just their left antennae took longer to recognize bees, didn't want to feed, and mistook familiar bees for foreign ones. This suggests, the team concludes today in Scientific Reports, that bee brains have a sidedness just like ours do. The researchers also think that right antennae might control other bee behavior, like their sophisticated, mysterious "waggle dance" to indicate food. But there's no buzz for the left-antennaed. © 2010 American Association for the Advancement of Science

Keyword: Laterality; Evolution
Link ID: 18320 - Posted: 06.29.2013

David Derbyshire Every year Robert Hodgson selects the finest wines from his small California winery and puts them into competitions around the state. And in most years, the results are surprisingly inconsistent: some whites rated as gold medallists in one contest do badly in another. Reds adored by some panels are dismissed by others. Over the decades Hodgson, a softly spoken retired oceanographer, became curious. Judging wines is by its nature subjective, but the awards appeared to be handed out at random. So drawing on his background in statistics, Hodgson approached the organisers of the California State Fair wine competition, the oldest contest of its kind in North America, and proposed an experiment for their annual June tasting sessions. Each panel of four judges would be presented with their usual "flight" of samples to sniff, sip and slurp. But some wines would be presented to the panel three times, poured from the same bottle each time. The results would be compiled and analysed to see whether wine testing really is scientific. The first experiment took place in 2005. The last was in Sacramento earlier this month. Hodgson's findings have stunned the wine industry. Over the years he has shown again and again that even trained, professional palates are terrible at judging wine. "The results are disturbing," says Hodgson from the Fieldbrook Winery in Humboldt County, described by its owner as a rural paradise. "Only about 10% of judges are consistent and those judges who were consistent one year were ordinary the next year. © 2013 Guardian News and Media Limited

Keyword: Chemical Senses (Smell & Taste); Attention
Link ID: 18319 - Posted: 06.29.2013

By Carrie Arnold We all experience the occasional life-changing event—a new baby, a cross-country move, a serious injury. In rare cases, such events can precipitate a mental disorder. The problem is compounded because people often assume their suffering is par for the course after such upheaval. In reality, relief is probably a short treatment away, via therapy or medication. For a new mother, dealing with a newborn is fraught with anxieties. Did I fasten the car seat properly? Is the baby still breathing? In more than one in 10 new mothers, these normal worries can escalate into more serious obsessions that can interfere with her ability to care for herself and her baby. Most of the research on postpartum psychiatric problems has focused on depression and psychosis. Obstetricians such as Emily Miller of Northwestern University, however, were also noticing a range of anxiety-related disorders, including intrusive thoughts and repetitive behaviors. “It's good to check that your baby is strapped into the car seat,” Miller notes. “But these women aren't just doing it once. They're doing it over and over, and it's interfering with their lives.” With her colleagues, Miller followed 461 women after they gave birth. Eleven percent said they had obsessions and compulsions two weeks after delivery that the researchers found to be the equivalent of mild to moderate obsessive-compulsive disorder (OCD)—a sharp increase over the 2 to 3 percent rate of OCD in the general population. Half of these women's symptoms continued six months' postpartum, and an additional 5.4 percent developed new OCD symptoms in that time. The afflicted women indicated that their symptoms were distressing, taking up a significant amount of time and otherwise interfering with their daily life. © 2013 Scientific American

Keyword: OCD - Obsessive Compulsive Disorder; Hormones & Behavior
Link ID: 18318 - Posted: 06.26.2013

Male twin Vietnam veterans with post-traumatic stress disorder (PTSD) were more than twice as likely as those without PTSD to develop heart disease during a 13-year period, according to a study supported by the National Institutes of Health. This is the first long-term study to measure the association between PTSD and heart disease using objective clinical diagnoses combined with cardiac imaging techniques. “This study provides further evidence that PTSD may affect physical health,” said Gary H. Gibbons, M.D., director of the NIH's National Heart, Lung, and Blood Institute (NHLBI), which partially funded the study. “Future research to clarify the mechanisms underlying the link between PTSD and heart disease in Vietnam veterans and other groups will help to guide the development of effective prevention and treatment strategies for people with these serious conditions.” The findings appear online today in the Journal of the American College of Cardiology and in the September 10 print issue. Researchers from the Emory University Rollins School of Public Health in Atlanta, along with colleagues from other institutions, assessed the presence of heart disease in 562 middle-aged twins (340 identical and 222 fraternal) from the Vietnam Era Twin Registry. The incidence of heart disease was 22.6 percent in twins with PTSD (177 individuals) and 8.9 percent in those without PTSD (425 individuals). Heart disease was defined as having a heart attack, having an overnight hospitalization for heart-related symptoms, or having undergone a heart procedure. Nuclear scans, used to photograph blood flow to the heart, showed that individuals with PTSD had almost twice as many areas of reduced blood flow to the heart as individuals without PTSD.

Keyword: Stress; Genes & Behavior
Link ID: 18317 - Posted: 06.26.2013

By Meghan Rosen Paralyzed rats can now decide for themselves when it’s time to take a leak. Animals in a new study regained bladder control thanks to a new treatment that coaxes severed nerves to grow. Instead of dribbling out urine, the rodents squeezed out shots of pee almost as well as healthy rats do, researchers report June 25 in the Journal of Neuroscience. The study is the first to regenerate nerves that restore bladder function in animals with severely injured spinal cords. “This is a very big deal,” says neurologist John McDonald of the Kennedy Krieger Institute in Baltimore, Md. If the treatment works in people with spinal cord injuries, he says, “it would change their lives.” Unlike paralyzed rats, severely paralyzed humans can’t leak urine to relieve a full bladder. Unless injured people are fitted with a catheter, urine backs up into the kidneys. “These people get kidney failure all the time,” says study leader Jerry Silver, a neuroscientist at Case Western Reserve University in Cleveland. “It’s a terrible problem. If they didn’t have the catheter, they would die.” Some of the worst spinal cord injuries sever the bundle of nerve cells that reach from a mammal’s brain down through the vertebrae. The neurons can’t just grow back. Instead, the cells’ stumps get stuck in a gummy thicket of scar tissue that forms around the wound. © Society for Science & the Public 2000 - 2013

Keyword: Regeneration; Movement Disorders
Link ID: 18316 - Posted: 06.26.2013

By Helen Briggs BBC News Our perception of how food tastes is influenced by cutlery, research suggests. Size, weight, shape and colour all have an effect on flavour, says a University of Oxford team. Cheese tastes saltier when eaten from a knife rather than a fork; while white spoons make yoghurt taste better, experiments show. The study in the journal Flavour suggests the brain makes judgements on food even before it goes in the mouth. More than 100 students took part in three experiments looking at the influence of weight, colour and shape of cutlery on taste. The researchers found that when the weight of the cutlery confirms to expectations, this had an impact on how the food tastes. For example, food tasted sweeter on the small spoons that are traditionally used to serve desserts. Colour contrast was also an important factor - white yoghurt eaten from a white spoon was rated sweeter than white yoghurt tasted on a black spoon. Similarly, when testers were offered cheese on a knife, spoon, fork or toothpick, they found that the cheese from a knife tasted saltiest. "How we experience food is a multisensory experience involving taste, feel of the food in our mouths, aroma, and the feasting of our eyes," said Prof Charles Spence and Dr Vanessa Harrar. BBC © 2013

Keyword: Chemical Senses (Smell & Taste)
Link ID: 18315 - Posted: 06.26.2013

The prevalence of traumatic brain injuries such as concussions among students points to a silent epidemic that demands a wake-up call from parents, coaches and other adults, Canadian neurosurgeons and psychologists say. One in five students in grades 7 to 12 said they’d had a traumatic brain injury that left them unconscious for at least five minutes or required a hospital stay overnight after symptoms, researchers said in Wednesday’s issue of the Journal of the American Medical Association. The researchers from St. Michael's Hospital and the Centre for Addiction and Mental Health in Toronto surveyed 8,915 students across Ontario in 2011 as part of one of the longest ongoing school surveys in the world. "It needs to be a wake-up call to say, look, young people are sustaining brain injuries at a very high rate,” said the study’s lead author, Dr. Michael Cusimano, a neurosurgeon at St. Michael’s Hospital. "If we want to protect future generations, because our brain really defines how we are … not just as an individual, we need to do something collectively as a society to address this problem." Of the 464 students reporting a traumatic brain injury in the past 12 months, sports injuries accounted for more than half of the cases, 56 per cent, particularly for boys. Concussions that didn't lead to loss of consciousness or a hospital stay weren't included. © CBC 2013

Keyword: Brain Injury/Concussion; Development of the Brain
Link ID: 18314 - Posted: 06.26.2013

Traci Watson When it comes to friendship it may be quantity, not quality, that matters — at least for Barbary macaques in a crisis. Scientists have long known that sociable humans live longer than their solitary peers, but is the same true for animals? A harsh natural experiment may offer some answers. It also raises intriguing questions about the type of social ties that matter. Endangered Barbary macaques (Macaca sylvanus) in the mountains of Morocco are accustomed to cold, but the 2008–09 winter was devastatingly hard for them. Snow covered the ground for almost four months instead of the usual one, and the monkeys, which eat seeds and grasses on the ground, began to starve. Richard McFarland, a behavioural ecologist at the University of the Witwatersrand in Johannesburg, South Africa, and his colleagues were studying the animals as part of a wider project on the monkeys' social lives launched in January 2008. When they went looking for the macaques in January 2009, they found corpses, says McFarland. Of the 47 adults in two troops that the team studied, only 17 survived, making for a 64% mortality rate, McFarland and his colleague Bonaventura Majolo of the University of Lincoln, UK, report today in Biology Letters1. Analysis showed that the more friends a monkey had, the more likely it was to have survived. Individuals with whom a monkey had exchanged grooming or had had bodily contact with at least once during observation sessions were deemed as social contacts. Perhaps the animals with more buddies had more partners with whom to huddle against the cold, the researchers suggest. Monkeys with large social networks may also have been able to look for food with fewer interruptions from hostile group members. © 2013 Nature Publishing Group

Keyword: Emotions; Evolution
Link ID: 18313 - Posted: 06.26.2013

By Melissa Hogenboom Science reporter, BBC News The social brain theory - that animals in large social groups have bigger brains - has now been supported by a computer model. For animals in smaller social groups, the cost of having a large brain outweighs the benefits. Scientists used a simulation modelling technique to confirm that large social groups are only possible through sophisticated communication. The study is published in Proceedings of the Royal Society B. The human brain is a very costly organ which consumes a lot of energy. Animals that live in small social groups could therefore be at a disadvantage if they had large brains taking up processing power that could better be used elsewhere. A team at Oxford University has now looked at the cognitive demands of making social decisions using a method called agent-based modelling, which models simplified representations of reality. As expected, they found that more complex social decisions take up more 'brain' power. The cognitive complexity of language evolved as social groups became larger and more complex, said lead author of the study Tamas David-Barrett from the University of Oxford. He explained that a group of five is an ideal number to coordinate an event such as a hunt, but as the group size increases, the coordination involved would become increasingly complex. BBC © 2013

Keyword: Evolution; Emotions
Link ID: 18312 - Posted: 06.26.2013

by Mara Hvistendahl and Martin Enserink A mysterious group of viruses known for their circular genome has been detected in patients with severe disease on two continents. In papers published independently this week, researchers report the discovery of agents called cycloviruses in Vietnam and in Malawi. The studies suggest that the viruses—one of which also widely circulates in animals in Vietnam—could be involved in brain inflammation and paraplegia, but further studies are needed to confirm a causative link. The discovery in Vietnam grew out of a frustrating lack of information about the causes of some central nervous system (CNS) infections such as encephalitis and meningitis, which can be fatal or leave lasting damage. "There are a lot of severe cases in the hospitals here, and very often we can't come to a diagnosis," says H. Rogier van Doorn, a clinical virologist with the Oxford University Clinical Research Unit in the Hospital for Tropical Diseases, Ho Chi Minh City. Extensive diagnostic tests turn up pathogens in only about half of patients with such infections, he says. Van Doorn and colleagues in Vietnam and at the University of Amsterdam's Academic Medical Center hoped that they might uncover new pathogens using a powerful new technique called next-generation sequencing. The group sequenced all the genetic material in cerebrospinal fluid (CSF) samples taken from more than 100 patients with undiagnosed CNS infections. One sample batch returned a promising lead: a viral sequence belonging to the Circoviridae family. © 2010 American Association for the Advancement of Science

Keyword: Movement Disorders
Link ID: 18311 - Posted: 06.25.2013

A randomized clinical trial of estrogen therapy in younger postmenopausal women, aged 50–55, has found no long-term risk or benefit to cognitive function. The National Institutes of Health-supported study, reported in JAMA Internal Medicine on June 24, 2013, looked at women taking conjugated equine estrogens, the most common type of postmenopausal hormone therapy in the United States. The earlier Women’s Health Initiative Memory Study (WHIMS) linked the same type of hormone therapy to cognitive decline and dementia in older postmenopausal women. The new findings come from the Women’s Health Initiative Memory Study of Younger Women (WHIMSY) trial and were reported by Mark A. Espeland, Ph.D., Wake Forest School of Medicine, Winston-Salem, N.C., on behalf of the academic research centers involved in the study. The study was funded primarily by the National Institute on Aging (NIA), along with the National Heart, Lung, and Blood Institute (NHLBI), both components of the NIH. “The WHIMS study found that estrogen-based postmenopausal hormone therapy produced deficits in cognitive function and increased risk for dementia when prescribed to women 65 and older,” said NIA Director Richard J. Hodes, M.D. “Researchers leading the WHIMSY study wanted to expand on those results by exploring the possibility of a window of opportunity whereby hormone therapy might promote or preserve brain health when given to younger women.” “In contrast to findings in older postmenopausal women, this study tells women that taking these types of estrogen-based hormone therapies for a relatively short period of time in their early postmenopausal years may not put them at increased risk for cognitive decline over the long term,” said Susan Resnick, Ph.D., chief of the Laboratory of Behavioral Neuroscience, in NIA’s Intramural Research Program and a co-author of the study. “Further, it is important to note that we did not find any cognitive benefit after long-term follow-up.”

Keyword: Hormones & Behavior; Alzheimers
Link ID: 18310 - Posted: 06.25.2013

The risk posed by some popular antidepressants in early pregnancy is not worth taking for women with mild to moderate depression, an expert has warned. Professor Stephen Pilling says evidence suggests SSRIs can double the risk of a child being born with a heart defect. The drugs have been used by up to one in six women of child-bearing age. A manufacturer contacted by the BBC denies any link to major foetal malformations. Panorama has spoken to eight mothers who had babies born with serious heart defects after taking a commonly used SSRI (selective serotonin reuptake inhibitors) antidepressant while pregnant. Currently, prescription guidelines for doctors only warn specifically against taking the SSRI, paroxetine, in early pregnancy. But Prof Pilling, expert adviser to the National Institute for Health and Care Excellence (NICE), says that advice is about to be updated. "The available evidence suggests that there is a risk associated with the SSRIs. We make a quite a lot of effort really to discourage women from smoking or drinking even small amounts of alcohol in pregnancy, and yet we're perhaps not yet saying the same about antidepressant medication, which is going to be carrying similar - if not greater - risks," he said. When Anna Wilson, from Ayrshire, had her 20-week scan, doctors realised her son had a serious heart problem and would need immediate heart surgery when he was born. David Wilson David will need further surgery before he starts school Now eight months old, David was hooked up to machines for the first five weeks of his life. He will need more open-heart surgery before he starts school and doctors say he may not live beyond 40. BBC © 2013

Keyword: Drug Abuse; Depression
Link ID: 18309 - Posted: 06.25.2013

By DAVID DOBBS On average, about 700 Americans kill themselves each week — but in the fine-weather weeks of May and June, the toll rises closer to 800, sometimes higher. Every year, suicide peaks with the tulips and lilacs — increasing roughly 15 percent over the annual average to create one of psychiatry’s most consistent epidemiological patterns. It may seem perverse that the period of spring and early summer, as the psychologist Kay Redfield Jamison puts it in her splendid book “Night Falls Fast,” should contain “a capacity for self-murder that winter less often has.” Yet it does. This grim spring growth confounds conventional belief that suicides peak in winter. It also confounds researchers — and fascinates them. As they discover more angles into the biology of mood and behavior, they are finding new clues about why suicides rise with the sun’s arc. They hope solving this puzzle will help us better understand why people commit suicide at all — and perhaps reduce the numbers year-round. This effort takes an extra urgency from what Dr. Adam Kaplin, a psychiatrist at Johns Hopkins University, calls a “suicide epidemic” — a sharp increase in both absolute and per-capita rates since the recession that began in 2007, particularly among the middle-aged. More than 38,000 people committed suicide in the United States in 2010 — a 16.5 percent jump from the 32,600 suicides five years before, and a new high. The stakes involved in figuring out the dynamics of self-murder seem only to rise with time. The spring surge in suicides is actually the largest of a few oscillations throughout the year. After dropping to an annual low in February (October in the southern hemisphere), rates climb sharply through spring; fall slowly in summer; show a slight rise, according to some studies, in fall; and then begin a steep winter drop. The spring peak generally runs 10 to 25 percent above the yearly average and 20 to 50 percent above the February low. Copyright 2013 The New York Times Company

Keyword: Depression; Biological Rhythms
Link ID: 18308 - Posted: 06.25.2013