Associated Press A sophisticated, real-world study confirms that dialing, texting or reaching for a cell phone while driving raises the risk of a crash or near-miss, especially for younger drivers. But the research also produced a surprise: Simply talking on the phone did not prove dangerous, as it has in other studies. This one did not distinguish between handheld and hands-free devices - a major weakness. And even though talking doesn't require drivers to take their eyes off the road, it's hard to talk on a phone without first reaching for it or dialing a number - things that raise the risk of a crash, researchers note. Earlier work with simulators, test tracks and cell phone records suggests that risky driving increases when people are on cell phones, especially teens. The 15- to 20-year-old age group accounts for 6 percent of all drivers but 10 percent of traffic deaths and 14 percent of police-reported crashes with injuries. For the new study, researchers at the Virginia Tech Transportation Institute installed video cameras, global positioning systems, lane trackers, gadgets to measure speed and acceleration, and other sensors in the cars of 42 newly licensed drivers 16 or 17 years old, and 109 adults with an average of 20 years behind the wheel. © 2014 Hearst Communications, Inc.

Keyword: Attention
Link ID: 19091 - Posted: 01.04.2014

People with severe mental illness such as schizophrenia or bipolar disorder have a higher risk for substance use, especially cigarette smoking, and protective factors usually associated with lower rates of substance use do not exist in severe mental illness, according to a new study funded by the National Institute on Drug Abuse (NIDA), part of the National Institutes of Health. Estimates based on past studies suggest that people diagnosed with mood or anxiety disorders are about twice as likely as the general population to also suffer from a substance use disorder. Statistics from the 2012 National Survey on Drug Use and Health indicate close to 8.4 million External Web Site Policy adults in the United States have both a mental and substance use disorder. However, only 7.9 percent of people receive treatment for both conditions, and 53.7 percent receive no treatment at all, the statistics External Web Site Policy indicate. “Drug use impacts many of the same brain circuits that are disrupted in severe mental disorders such as schizophrenia,” said NIDA Director Dr. Nora D. Volkow. “While we cannot always prove a connection or causality, we do know that certain mental disorders are risk factors for subsequent substance use disorders, and vice versa.” In the current study, 9,142 people diagnosed with schizophrenia, schizoaffective disorder, or bipolar disorder with psychotic features, and 10,195 controls matched to participants according to geographic region, were selected using the Genomic Psychiatry Cohort program. Mental disorder diagnoses were confirmed using the Diagnostic Interview for Psychosis and Affective Disorder (DI-PAD), and controls were screened to verify the absence of schizophrenia or bipolar disorder in themselves or close family members. The DI-PAD was also used for all participants to determine substance use rates.

Keyword: Schizophrenia; Drug Abuse
Link ID: 19090 - Posted: 01.04.2014

By GRETCHEN REYNOLDS African tribesmen walk through their landscape in a pattern that eerily echoes the movements of scavenging birds, flocking insects, gliding sharks and visitors to Disneyland, a new study finds, suggesting that aspects of how we choose to move around in our world are deeply hard-wired. For the new study, which appeared online recently in Proceedings of the National Academy of Sciences, researchers at the University of Arizona at Tucson, Yale University, the New York Consortium in Evolutionary Primatology and other institutions traveled to northern Tanzania to study the Hadza, who are among the last human hunter-gatherers on earth. The Hadza generally spend their days following game and foraging for side dishes and condiments such as desert tubers and honey, frequently walking and jogging for miles in the process. The ways in which creatures, including people, navigate their world is a topic of considerable scientific interest, but one that, until the advent of global positioning systems and similar tracking technology, was difficult to quantify. In the past decade, however, scientists have begun strapping GPS units to many varieties of animals and insects, from bumblebees to birds, and measuring how they move. What they have found is that when moving with a purpose such as foraging for food, many creatures follow a particular and shared pattern. They walk (or wing or lope) for a short time in one direction, scouring the ground for edibles, then turn and start moving in another direction for a short while, before turning and strolling or flying in another direction yet again. This is a useful strategy for finding tubers and such, but if maintained indefinitely brings creatures back to the same starting point over and over; they essentially move in circles. Copyright 2014 The New York Times Company

Keyword: Learning & Memory; Evolution
Link ID: 19089 - Posted: 01.02.2014

by Paul Heltzel Have you ever looked at your dorsal fin — I mean, really looked at it? Dolphins, nature’s playful jokers, apparently have a little habit they’ve been keeping a secret: They get high. A BBC film crew recently captured some unusual footage of dolphins passing a puffer fish between them. The fish then secretes a toxin — a defense mechanism — which the dolphins appear to enjoy — a lot. As the dolphins nudged the puffer fish back and forth, they fell into a trancelike state, reports the Guardian. “At one point the dolphins are seen floating just underneath the water’s surface, apparently mesmerized by their own reflections,” according to the Guardian. Filmmaker John Downer cleverly disguised underwater cameras as squid, tuna and other dolphins to record the footage. Downer told the BBC the dolphins handled the puffer carefully, so they wouldn’t hurt or kill it. “The dolphins were specifically going for the puffers,” Downer said, “and deliberately handling them with care.” © 2014 Discovery Communications, LLC.

Keyword: Drug Abuse
Link ID: 19088 - Posted: 01.02.2014

By Christof Koch I grew up in a devout and practicing Roman Catholic family with Purzel, a fearless and high-energy dachshund. He, as with all the other, much larger dogs that subsequently accompanied me through life, showed plenty of affection, curiosity, playfulness, aggression, anger, shame and fear. Yet my church teaches that whereas animals, as God's creatures, ought to be treated well, they do not possess an immortal soul. Only humans do. Even as a child, to me this belief felt intuitively wrong. These gorgeous creatures had feelings, just like I did. Why deny them? Why would God resurrect people but not dogs? This core Christian belief in human exceptionalism did not make any sense to me. Whatever consciousness and mind are and no matter how they relate to the brain and the rest of the body, I felt that the same principle must hold for people and dogs and, by extension, for other animals as well. It was only later, at university, that I became acquainted with Buddhism and its emphasis on the universal nature of mind. Indeed, when I spent a week with His Holiness the Dalai Lama earlier in 2013 [see “The Brain of Buddha,” Consciousness Redux; Scientific American Mind, July/August 2013], I noted how often he talked about the need to reduce the suffering of “all living beings” and not just “all people.” My readings in philosophy brought me to panpsychism, the view that mind (psyche) is found everywhere (pan). Panpsychism is one of the oldest of all philosophical doctrines extant and was put forth by the ancient Greeks, in particular Thales of Miletus and Plato. Philosopher Baruch Spinoza and mathematician and universal genius Gottfried Wilhelm Leibniz, who laid down the intellectual foundations for the Age of Enlightenment, argued for panpsychism, as did philosopher Arthur Schopenhauer, father of American psychology William James, and Jesuit paleontologist Teilhard de Chardin. It declined in popularity with the rise of positivism in the 20th century. © 2014 Scientific American,

Keyword: Consciousness
Link ID: 19087 - Posted: 01.02.2014

By PAM BELLUCK Does vitamin E help people with Alzheimer’s disease? For years, scientists have been trying to find out, guessing that the vitamin’s antioxidant properties might be beneficial. But the results from clinical trials have been mixed and — following a report that high doses of vitamin E may increase the risk of death — cautionary. Now a study suggests that vitamin E supplements may be good for some Alzheimer’s patients after all. The benefit was not huge, but for a devastating disease that has proved almost impervious to treatment, it was notable. The study, published in Wednesday’s issue of JAMA, The Journal of the American Medical Association, found that over a little more than two years, high-dose vitamin E slowed the decline of people with mild to moderate Alzheimer’s by about six months on average. Vitamin E did not delay cognitive or memory deterioration, however. Instead, it seemed to temporarily protect something many patients consider especially valuable: their ability to perform daily activities like putting on clothes and feeding themselves. Compared with other study participants, people who took vitamin E also required about two fewer hours of help from caregivers per day, the researchers said. “Is it really going to dramatically alter the lives of Alzheimer’s patients? That’s unclear,” said Dr. Scott Small, director of Columbia University’s Alzheimer’s Disease Research Center, who was not involved in the study. “But it might improve patients’ ability to bathe themselves and dress themselves.” © 2014 The New York Times Company

Keyword: Alzheimers
Link ID: 19086 - Posted: 01.02.2014

One night of sleep deprivation can increase the levels of molecules that are biomarkers for brain damage, according to a new study out of Sweden. The study, conducted by researchers from Uppsala University's Department of Neuroscience and published in the journal Sleep, looked at levels of two types of brain molecules. These molecules typically rise in the blood under conditions resulting in brain damage or distress. An increase in levels of the molecules can be measured after everything from sports injuries to the head and carbon monoxide poisoning, to sleep apnea and fetal distress after childbirth. Researchers measured the levels of NSE and S-100B in the blood of 15 healthy young men who were sleep-deprived for one night, and found morning serum levels of the molecules increased by about 20 per cent compared with values obtained after a night of sleep. "The blood concentration of both biomarkers was elevated after sleep loss. This makes it unlikely that our results were caused by chance," lead researcher Christian Benedict said. He said the results indicate a lack of sleep may promote "neurodegenerative processes. "In conclusion, the findings of our trial indicate that a good night's sleep may be critical for maintaining brain health," he said. © CBC 2014

Keyword: Sleep
Link ID: 19085 - Posted: 01.02.2014

By KELLEY McMILLAN BEAVER CREEK, Colo. — The fact that Michael Schumacher was wearing a helmet when he sustained a life-threatening head injury while skiing in France on Sunday probably did not come as a surprise to experts who have charted the increasing presence of helmets on slopes and halfpipes in recent years. The fact that the helmet did not prevent Schumacher’s injury probably did not surprise them, either. Schumacher, the most successful Formula One driver in history, sustained a traumatic brain injury when he fell and hit his head on a rock while navigating an off-piste, or ungroomed, area at a resort in Méribel, France. Although he was wearing a helmet, he sustained injuries that have left him fighting for his life in a hospital in Grenoble, France. Schumacher’s injury also focused attention on an unsettling trend. Although skiers and snowboarders in the United States are wearing helmets more than ever — 70 percent of all participants, nearly triple the number from 2003 — there has been no reduction in the number of snow-sports-related fatalities or brain injuries in the country, according to the National Ski Areas Association. Experts ascribe that seemingly implausible correlation to the inability of helmets to prevent serious head injuries like Schumacher’s and to the fact that more skiers and snowboarders are engaging in risky behaviors: skiing faster, jumping higher and going out of bounds. © 2013 The New York Times Company

Keyword: Brain Injury/Concussion
Link ID: 19084 - Posted: 01.02.2014

By MICHAEL M. PHILLIPS Roman Tritz’s memories of the past six decades are blurred by age and delusion. But one thing he remembers clearly is the fight he put up the day the orderlies came for him. “They got the notion they were going to come to give me a lobotomy,” says Mr. Tritz, a World War II bomber pilot. “To hell with them.” The orderlies at the veterans hospital pinned Mr. Tritz to the floor, he recalls. He fought so hard that eventually they gave up. But the orderlies came for him again on Wednesday, July 1, 1953, a few weeks before his 30th birthday. This time, the doctors got their way. The U.S. government lobotomized roughly 2,000 mentally ill veterans—and likely hundreds more—during and after World War II, according to a cache of forgotten memos, letters and government reports unearthed by The Wall Street Journal. Besieged by psychologically damaged troops returning from the battlefields of North Africa, Europe and the Pacific, the Veterans Administration performed the brain-altering operation on former servicemen it diagnosed as depressives, psychotics and schizophrenics, and occasionally on people identified as homosexuals. The VA doctors considered themselves conservative in using lobotomy. Nevertheless, desperate for effective psychiatric treatments, they carried out the surgery at VA hospitals spanning the country, from Oregon to Massachusetts, Alabama to South Dakota. The VA’s practice, described in depth here for the first time, sometimes brought veterans relief from their inner demons. Often, however, the surgery left them little more than overgrown children, unable to care for themselves. Many suffered seizures, amnesia and loss of motor skills. Some died from the operation itself. Mr. Tritz, 90 years old, is one of the few still alive to describe the experience. “It isn’t so good up here,” he says, rubbing the two shallow divots on the sides of his forehead, bracketing wisps of white hair.

Keyword: Schizophrenia; Depression
Link ID: 19083 - Posted: 12.31.2013

Stephen S. Hall Hochelaga was the original Iroquoian name for the village that ultimately became Montreal, but it is also the name of a rough-hewn French–Canadian neighbourhood located east of — and a world away from — the cosmopolitan city centre. The district's tidy two- and three-storey brick duplexes, adorned with Montreal's characteristic wrought-iron staircases, predominantly house families that have, because of poverty and lack of education, never quite attained thriving middle-class status. During the 1980s, public-school officials identified Hochelaga and many other impoverished neighbourhoods in the eastern part of Montreal as places where kindergarten children disproportionately displayed severe behavioural problems, such as physical aggression. The school system asked a young University of Montreal psychologist named Richard Tremblay for help. “Their parents didn't have a high-school diploma, and many of the mothers had their first child before the age of 20,” Tremblay says of the families he began to study, as he walks along Rue Ontario in Hochelaga on a sunny afternoon in September. Those were the women, he adds, “most at risk of having children who have problems”. Over the past three decades, Hochelaga and similar neighbourhoods have served as living laboratories in the study of the roots of aggression. Since 1984, Tremblay and his collaborators have followed more than 1,000 children from 53 schools in the city from childhood into adulthood. And in 1985, he initiated a ground-breaking experiment in which some families of at-risk children were given support and counselling to help curb bad behaviour. His research overturned ideas about when aggressive behaviour first emerges, and showed that early intervention can deflect children away from adult criminality. © 2013 Nature Publishing Group

Keyword: Epigenetics; Aggression
Link ID: 19082 - Posted: 12.31.2013

By JOHN MARKOFF PALO ALTO, Calif. — Computers have entered the age when they are able to learn from their own mistakes, a development that is about to turn the digital world on its head. The first commercial version of the new kind of computer chip is scheduled to be released in 2014. Not only can it automate tasks that now require painstaking programming — for example, moving a robot’s arm smoothly and efficiently — but it can also sidestep and even tolerate errors, potentially making the term “computer crash” obsolete. The new computing approach, already in use by some large technology companies, is based on the biological nervous system, specifically on how neurons react to stimuli and connect with other neurons to interpret information. It allows computers to absorb new information while carrying out a task, and adjust what they do based on the changing signals. In coming years, the approach will make possible a new generation of artificial intelligence systems that will perform some functions that humans do with ease: see, speak, listen, navigate, manipulate and control. That can hold enormous consequences for tasks like facial and speech recognition, navigation and planning, which are still in elementary stages and rely heavily on human programming. Designers say the computing style can clear the way for robots that can safely walk and drive in the physical world, though a thinking or conscious computer, a staple of science fiction, is still far off on the digital horizon. “We’re moving from engineering computing systems to something that has many of the characteristics of biological computing,” said Larry Smarr, an astrophysicist who directs the California Institute for Telecommunications and Information Technology, one of many research centers devoted to developing these new kinds of computer circuits. © 2013 The New York Times Company

Keyword: Learning & Memory; Robotics
Link ID: 19081 - Posted: 12.31.2013

Tomas Jivanda Being pulled into the world of a gripping novel can trigger actual, measurable changes in the brain that linger for at least five days after reading, scientists have said. The new research, carried out at Emory University in the US, found that reading a good book may cause heightened connectivity in the brain and neurological changes that persist in a similar way to muscle memory. The changes were registered in the left temporal cortex, an area of the brain associated with receptivity for language, as well as the the primary sensory motor region of the brain. Neurons of this region have been associated with tricking the mind into thinking it is doing something it is not, a phenomenon known as grounded cognition - for example, just thinking about running, can activate the neurons associated with the physical act of running. “The neural changes that we found associated with physical sensation and movement systems suggest that reading a novel can transport you into the body of the protagonist,” said neuroscientist Professor Gregory Berns, lead author of the study. “We already knew that good stories can put you in someone else’s shoes in a figurative sense. Now we’re seeing that something may also be happening biologically.” 21 students took part in the study, with all participants reading the same book - Pompeii, a 2003 thriller by Robert Harris, which was chosen for its page turning plot. “The story follows a protagonist, who is outside the city of Pompeii and notices steam and strange things happening around the volcano,” said Prof Berns. “It depicts true events in a fictional and dramatic way. It was important to us that the book had a strong narrative line.” © independent.co.uk

Keyword: Attention; Learning & Memory
Link ID: 19080 - Posted: 12.31.2013

By Christian Jarrett Christmas is over and the start of the movie awards season is only weeks away! This is my excuse for a post about cinema and the brain. Over the years I’ve been keeping note of actors who studied neuroscience and other similar factoids and now I have the chance to share them with you. So here, in no particular order, are 10 surprising links between the worlds of Hollywood and brain research: 1. Actress Mayim Bialik is a neuroscientist. Bialik currently plays the character of neuroscientist Amy Fowler in the Big Bang Theory, which is neat because Bialik herself has a PhD in neuroscience. Her PhD thesis, completed at UCLA in 2007, has the title: “Hypothalamic regulation in relation to maladaptive, obsessive-compulsive, affiliative, and satiety behaviors in Prader-Willi syndrome.” “I don’t try and rub my neuroscience brain in people’s face[s],” Bialik says, “but when we have lab scenes … I have had to say that’s not where the tectum would be, we need it down here … or I’ve actually carved the fourth ventricle into slices … ’cause you know, why not have me do it.” Among her other acting roles, Bialik also featured in the short film for Michael Jackson’s Liberian Girl and she played the child version of Bette Midler’s character in Beaches (1988). 2. Natalie Portman is a neuroscientist. Perform a Google Scholar search on her name and you won’t get very far. But under her original name of Natalie Hershlag, the Oscar-winning actress co-authored a paper in 2002 on the role of the frontal lobes in infants’ understanding of “object permanence” – recognizing that things still exist even when you can’t see them. According to the Mind Hacks blog, Ms. Portman contributed to this research while working as a research assistant at Harvard University. Her paper has now been cited in the literature over 100 times. © 2013 Condé Nast.

Keyword: Miscellaneous
Link ID: 19079 - Posted: 12.31.2013

For tobacco hornworms, bad breath might be the key to surviving the night. As their name suggests, these desert-dwelling caterpillars (larvae of the Manduca sexta moth) regularly chomp on nicotine-laced tobacco leaves. Scientists observed that caterpillars feeding on genetically modified, nicotine-free tobacco plants were more likely to disappear during the night than those chowing down on regular tobacco, leading them to suspect that the hornworms might be repurposing the toxic chemical to defend themselves against nocturnal predators like wolf spiders (Camptocosa parallela, pictured above feasting on a larva). The researchers investigated a gene called CYP6B46, which is active in the hornworm’s gut. Turning the gene off resulted in higher nicotine levels in the hornworms’ poop, suggesting that the gene helps the larvae avoid excreting the chemical by pumping it out of their guts and into their blood. The caterpillars had to be exuding the toxic nicotine somehow, so the scientists gave them an insect version of a breathalyzer test and discovered that they breathe it out with every exhale, the team reports online today in the Proceedings of the National Academy of Sciences. This “toxic halitosis” repelled wolf spiders, which actually flee from caterpillars with nicotine on their breath, as you can see in this video. Still, bad breath is no guarantee of a long life: It didn’t deter some of the hornworms’ other predators, including big-eyed bugs and antlion larvae. © 2013 American Association for the Advancement of Science

Keyword: Neurotoxins
Link ID: 19078 - Posted: 12.31.2013

By John Horgan New Year’s Day is approaching, a time when we—by which I mean I–brood over past failures and vow to improve ourselves: I will be less judgmental with my kids and more romantic with my girlfriend. I will stop binging on cookies and bad TV. (Why, oh why, do I keep watching Blacklist?) I will not assume that people who disagree with me are stupid or evil. Every time you choose one path over another, you are exercising your free will. Humanity has more freedom of choice now--and hence more free will--than in any previous era. At this time of year, I like to hearten my fellow Resolutionaries by defending the concept of free will, which has been attacked by various scientific pundits (who are just misguided, not stupid or evil). After all, how can you believe in resolutions unless you believe in free will? Below is an edited version of an essay that I originally wrote for The Chronicle of Higher Education. I never really thought about free will—or rather, I just took it for granted—until 1991, when I interviewed the late, great Francis Crick, who had switched from cracking the genetic code to solving the riddle of consciousness. With unnerving cheerfulness, Crick informed me that brain research is contradicting the notion of free will. Picking up a pen from his desk, he noted that even this simple act is underpinned and preceded by complex biochemical processes taking place below the level of consciousness. “What you’re aware of is a decision, but you’re not aware of what makes you do the decision,” Crick said. “It seems free to you, but it’s the result of things you’re not aware of.” I frowned, and Crick chuckled at my distress. © 2013 Scientific American,

Keyword: Consciousness
Link ID: 19077 - Posted: 12.28.2013

JoNel Aleccia NBC News Surgery to remove a brain tumor two years ago has left a 12-year-old Texas girl with a heartbreaking condition that makes her gain massive amounts of weight — even though her body thinks it’s starving. Doctors say a gastric bypass operation is the only thing that can help Alexis Shapiro, who is 4-foot-7 and weighs 198 pounds. But the U.S. military, which provides her family’s health insurance, says it won’t pay for the $50,000 weight-loss procedure because she’s too young. “Our reviewers have denied your request for Roux-En-Y Gastric Bypass,” reads the rejection notice sent this month. Alexis’ parents — and her doctor — are protesting the decision from insurer TRICARE, which they say sentences the child to a fate of dangerous health problems and social isolation caused by hypothalamic obesity, which is packing on at least 2 pounds every week. “It just keeps going up and up,” said her mother, Jenny Shapiro, 34, of Cibolo, Texas. “She desperately needs this. I feel like she will die if she does not get this surgery.” In just the past three months, Alexis was hospitalized for a kidney infection and developed Type 2 diabetes that requires nightly insulin injections, both related to her growing girth. Dr. Thomas H. Inge, a Cincinnati expert in pediatric obesity who is treating Alexis, acknowledged that there have been few cases like hers. But he said surgery may be the only way to stop weight gain that could top out at 400 pounds — and to cut the brain cravings that make Alexis want to eat an entire jar of peanut butter at one sitting.

Keyword: Obesity
Link ID: 19076 - Posted: 12.28.2013

Imagine this: Every day, you can feel people looking at you warily. They want to hurt you. Even the police are out to get you. You try to rid your mind of all the ill-intentioned people, but you can't ignore the other thing that is gnawing at you. Those bugs on your arm won't leave you alone, no matter how often you gouge at them. Such are the hallucinations and paranoia felt by those with a stimulant drug addiction. Sometimes the substance abuse is so severe it causes neurological damage and psychosis becomes a chronic condition. Combine untreated addiction with homelessness and physical health problems, and you get a health emergency. Vancouver police and the region's health authorities are desperately trying to figure out how to help the most vulnerable of mentally ill drug addicts. The province estimates that roughly 130,000 people in British Columbia suffer from a severe addiction and/or mental health illness. But police and emergency workers are increasingly dealing with a much smaller group of people whose brains have been damaged by their stimulant addiction and who appear to be responsible for random violent acts on Vancouver's streets. Dr. Nader Sharifi, addiction medicine lead with the Fraser Health Authority, said there are few good treatment options for those people. "It's a bit of a challenging question, because what we have available isn't necessarily structured for this patient sub-type. It's either structured for addiction, or structured for mental health illness, but not necessarily the two together." © CBC 2013

Keyword: Schizophrenia; Drug Abuse
Link ID: 19075 - Posted: 12.28.2013

By NICHOLAS BAKALAR Both acupuncture and sham acupuncture were effective in reducing menopausal symptoms in women being treated with aromatase inhibitors for breast cancer, a small randomized trial found. Joint and muscle pain, hot flashes and night sweats are common side effects of those estrogen-lowering drugs. The trial, published online in Cancer, randomized 47 breast cancer patients to eight weekly sessions of either real or sham acupuncture. Those assigned to real acupuncture received treatment with needles in recognized acupoints believed to be helpful in relieving menopausal symptoms. The controls got non-penetrating needles placed in sham acupuncture points. Patients and researchers did not know which patients had received which treatment. The patients kept daily diaries or filled out several questionnaires on the frequency and severity of hot flashes and other symptoms. Patient-reported symptoms, especially hot flashes, improved significantly after both sham and real treatment. There was no statistically significant difference between the two groups. The results may be attributable to a placebo effect, but the scientists suggest that the slight pricking of the skin could cause physiological changes. In any case, the lead author, Dr. Ting Bao, a medical oncologist at the University of Maryland, Baltimore, said there is no harm in trying acupuncture. “Acupuncture as a medical procedure has been practiced for thousands of years,” she said. “It has a minimal risk and potentially significant benefits.” Copyright 2013 The New York Times Company

Keyword: Pain & Touch
Link ID: 19074 - Posted: 12.28.2013

By Susana Martinez-Conde If you’re a bit lax with your post-holiday brushing, this little-known illusion may give you the incentive you need to keep those candy canes in check, or at least brush and floss afterwards. Vision scientist Robert O’Shea and his colleagues published a recent study in PLoS One showing that dentists can fall prey to a visual illusion of size and make larger holes in teeth than needed. The illusion fooling the dentists is a variant of a classical perceptual phenomenon known as the Delboeuf illusion, named after its creator, the Belgian natural philosopher, experimentalist, mathematician and hypnotist Joseph Remi Leopold Delboeuf. The scientists supplied 8 specialist dentists and endodontists, who served as experimental subjects, with a large pool of extracted teeth. The teeth contained holes, and the task of the dentists was to cut cavities in preparation for filling. Unknown to the dentists, each tooth presented a more or less powerful version of the Delboeuf illusion, making the holes appear smaller than their actual size. The results showed that the smaller the holes looked, the larger the cavities that the dentists made for later filling. The researchers recommend that dentists and other health practitioners receive training in “illusion awareness” (my words, not theirs), so that they may counteract these and related perceptual effects. © 2013 Scientific American,

Keyword: Vision
Link ID: 19073 - Posted: 12.28.2013

By CARL ZIMMER There are many things that make humans a unique species, but a couple stand out. One is our mind, the other our brain. The human mind can carry out cognitive tasks that other animals cannot, like using language, envisioning the distant future and inferring what other people are thinking. The human brain is exceptional, too. At three pounds, it is gigantic relative to our body size. Our closest living relatives, chimpanzees, have brains that are only a third as big. Scientists have long suspected that our big brain and powerful mind are intimately connected. Starting about three million years ago, fossils of our ancient relatives record a huge increase in brain size. Once that cranial growth was underway, our forerunners started leaving behind signs of increasingly sophisticated minds, like stone tools and cave paintings. But scientists have long struggled to understand how a simple increase in size could lead to the evolution of those faculties. Now, two Harvard neuroscientists, Randy L. Buckner and Fenna M. Krienen, have offered a powerful yet simple explanation. In our smaller-brained ancestors, the researchers argue, neurons were tightly tethered in a relatively simple pattern of connections. When our ancestors’ brains expanded, those tethers ripped apart, enabling our neurons to form new circuits. Dr. Buckner and Dr. Krienen call their idea the tether hypothesis, and present it in a paper in the December issue of the journal Trends in Cognitive Sciences. “I think it presents some pretty exciting ideas,” said Chet C. Sherwood, an expert on human brain evolution at George Washington University who was not involved in the research. Dr. Buckner and Dr. Krienen developed their hypothesis after making detailed maps of the connections in the human brain using f.M.R.I. scanners. When they compared their maps with those of other species’ brains, they saw some striking differences. © 2013 The New York Times Company

Keyword: Development of the Brain; Evolution
Link ID: 19072 - Posted: 12.27.2013