By James Gallagher Health and science reporter, BBC News A tiny "genetic patch" can be used to prevent a form of deafness which runs in families, according to animal tests. Patients with Usher syndrome have defective sections of their genetic code which cause problems with hearing, sight and balance. A study, published in the journal Nature Medicine, showed the same defects could be corrected in mice to restore some hearing. Experts said it was an "encouraging" start. There are many types of Usher syndrome tied to different errors in a patient's DNA - the blueprint for building every component of the body. One of those mutations runs in families descended from French settlers in North America. When they try to build a protein called hormonin, which is needed to form the tiny hairs in the ear that detect sound, they do not finish the job. It results in hearing loss at birth and has a similar effect in the eye where it causes a gradual loss of vision. Scientists at the Rosalind Franklin University of Medicine and Science, in Chicago in the US, designed a small strip of genetic material which attaches to the mutation and keeps the body's factories building the protein. There has been something of a flurry of developments in restoring hearing in the past year. BBC © 2013

Keyword: Hearing; Genes & Behavior
Link ID: 17759 - Posted: 02.05.2013

By Erin Wayman The story of the Neandertals may need a new ending, a controversial study suggests. Using improved radiocarbon methods, scientists redated two of the youngest known Neandertal cave sites and concluded that they are at least 10,000 years older than previous studies have found. The findings cast doubt on the reliability of radiocarbon dates from other recent Neandertal sites, the researchers suggest online February 4 in the Proceedings of the National Academy of Sciences. This means the last Neandertals might have died out much earlier than previously thought, which could cause anthropologists to rethink how and why these hominids vanished. Researchers have long debated whether the harsh Ice Age climate, the appearance of modern humans migrating out of Africa, or some other factor drove Neandertals to extinction. “The paper is simply excellent,” says archaeologist Olaf Jöris of the Romano-Germanic Central Museum in Mainz, Germany. The new research supports Jöris’ own review of Neandertal dates, in which he concluded that the most-recent Neandertals probably lived around 42,000 years ago. The standard view suggests that the last of these hominids occupied Europe as recently as about 28,000 years ago. But other archaeologists are not convinced by the new work. “We shouldn’t get too carried away over results that amount to a few radiocarbon dates from two sites,” says Paul Pettitt, an archaeologist at Durham University in England. © Society for Science & the Public 2000 - 2013

Keyword: Evolution
Link ID: 17758 - Posted: 02.05.2013

By Melissa Dahl, NBC News Scarlet fever plays the villain in some of the best children's books: It got "Little Women's" Beth March. It got the child in "The Velveteen Rabbit" (although the kid survives, so, really, the fever got the stuffed rabbit). And it robbed Mary Ingalls, sweet sister of "Little House" series author Laura Ingalls Wilder, of her sight. Or so we were told. But today, the journal Pediatrics asserts that it wasn't scarlet fever that caused Mary's blindness -- it was viral meningoencephalitis, an inflammatory disease that attacks the brain. This is the sort of thing that is extremely interesting if you are interested in this sort of thing. And we'd wager many people are: The "Little House" books have remained in print ever since the initial publication of "Little House in the Big Woods" in 1932, and they're still popular today, with three titles landing on the School Library Journal's 2012 list of best children's chapter books. Even if you never read the books, you probably remember the TV series, which aired from 1974 to 1983. Dr. Beth Tarini, assistant professor of pediatrics at the University of Michigan, and her co-authors make their claim after scouring epidemiological data on blindness and infectious disease around the time of Mary's illness, plus analyzing local newspapers and Laura's unpublished memoir, "Pioneer Girl." For Tarini, it's the culmination of a project she began in medical school 10 years ago, after a confusing conversation with a professor. © 2013 NBCNews.com

Keyword: Vision
Link ID: 17757 - Posted: 02.05.2013

By Tia Ghose The identity of a mysterious patient who helped scientists pinpoint the brain region responsible for language has been discovered, researchers report. The finding, detailed in the January issue of the Journal of the History of the Neurosciences, identifies the patient as Louis Leborgne, a French craftsman who battled epilepsy his entire life. In 1840, a wordless patient was admitted to the Bicetre Hospital outside Paris for aphasia, or an inability to speak. He was essentially just kept there, slowly deteriorating. It wasn’t until 1861 that the man, who was known only as “Monsieur Leborgne” and who was nicknamed “Tan” for the only word he could say, came to physician Paul Broca’s ward at the hospital. Leborgne died shortly after the meeting, and Broca performed his autopsy, during which Broca found a lesion in a region of the brain tucked back and up behind the eyes. After doing a detailed examination, Broca concluded that Tan’s aphasia was caused by damage to this region and that the particular brain region controlled speech. That part of the brain was later renamed Broca’s area. At the time, scientists were debating whether different areas of the brain performed separate functions or whether it was an undifferentiated lump that did one task, like the liver, said Marjorie Lorch, a neurolinguist in London who was not involved in the study. © 1996-2013 The Washington Post

Keyword: Language; Stroke
Link ID: 17756 - Posted: 02.05.2013

by Elizabeth Pennisi Though often associated with dirty environments, cockroaches are actually quite fastidious, especially when it comes to their antennae. They clean them often by grabbing one in with a front leg and drawing it through their mouth. Researchers have long observed that many insects groom themselves, and now they know why. When scientists restrained American cockroaches or prevented grooming by gluing mouthparts for 24 hours, they noticed a shiny, waxy buildup on the antennae that clogs the tiny pores that lead to odor-sensing cells. Measurements of the electrical activity in those cells in response to sex-attractant and food odors showed that the gunk interfered with the roach's sense of smell, they report online today in the Proceedings of the National Academy of Sciences. The insects appear to produce wax continuously, likely to keep from drying out, and grooming helps remove the excess as well as dust and other foreign chemicals that land on the antennae and get trapped in the gunk. Carpenter ants, houseflies, and German cockroaches also suffered from gunk overload when prohibited from grooming, suggesting that fastidiousness is widespread. © 2010 American Association for the Advancement of Science

Keyword: Chemical Senses (Smell & Taste)
Link ID: 17755 - Posted: 02.05.2013

A telltale boost of activity at the back of the brain while processing emotional information predicted whether depressed patients would respond to an experimental rapid-acting antidepressant, a National Institutes of Health study has found. “We have discovered a potential neuroimaging biomarker that may eventually help to personalize treatment selection by revealing brain-based differences between patients,” explained Maura Furey, Ph.D., of NIH’s National Institute of Mental Health (NIMH). Furey, NIMH’s Carlos Zarate, M.D., and colleagues, reported on their functional magnetic resonance imaging (fMRI) study of a pre-treatment biomarker for the antidepressant response to scopolamine, Jan. 30, 2013, online in JAMA Psychiatry. Scopolamine, better known as a treatment for motion sickness, has been under study since Furey and colleagues discovered its fast-acting antidepressant properties in 2006. Unlike ketamine, scopolamine works through the brain’s acetylcholine chemical messenger system. The NIMH team’s research has demonstrated that by blocking receptors for acetylcholine on neurons, scopolamine can lift depression in many patients within a few days; conventional antidepressants typically take weeks to work. But not all patients respond, spurring interest in a predictive biomarker. The acetylcholine system plays a pivotal role in working memory, holding information in mind temporarily, but appears to act by influencing the processing of information rather than through memory. Imaging studies suggest that visual working memory performance can be enhanced by modulating acetylcholine-induced activity in the brain’s visual processing area, called the visual cortex, when processing information that is important to the task.

Keyword: Depression; Brain imaging
Link ID: 17754 - Posted: 02.05.2013

By Laura Sanders Not all fear is the same. A woman who laughs at horror movies, grabs dangerous snakes and calmly deals with knife-wielding men nonetheless surrenders to terror at a single puff of suffocating carbon dioxide. This woman, known as SM, has a disease that damaged her amygdala, a brain structure implicated in fear. But the new results involving her and two others with the same disease, published online February 3 in Nature Neuroscience, show that a certain kind of danger signal can bypass the amygdala, hitting the panic button in other parts of the brain. The need to breathe is one of the most fundamental requirements for survival. Clinical neuropsychologist Justin Feinstein of the University of Iowa in Iowa City believes that the instinct to get air might tap into a brain system that’s more primal than the amygdala. Feinstein and colleagues work with SM and other patients who suffer from a rare genetic disorder called Urbach-Wiethe disease. In late childhood, this disease destroys the amygdala, a pair of almond-shaped structures deep in the brain. SM shows no fear when confronted with haunted houses, ominous spiders and scary movies (SN: 1/15/11, p/ 14). Now, the scientists have found something that does scare her. A breath of gas that is 35 percent carbon dioxide can immediately provoke a strong, panicky fear. (By contrast, normal air is less than one percent carbon dioxide.) When the gas hits the body, specialized proteins sense that something is amiss and send an urgent “must have air, now” message to the brain. © Society for Science & the Public 2000 - 2013

Keyword: Emotions
Link ID: 17753 - Posted: 02.04.2013

By ALAN SCHWARZ VIRGINIA BEACH — Every morning on her way to work, Kathy Fee holds her breath as she drives past the squat brick building that houses Dominion Psychiatric Associates. It was there that her son, Richard, visited a doctor and received prescriptions for Adderall, an amphetamine-based medication for attention deficit hyperactivity disorder. It was in the parking lot that she insisted to Richard that he did not have A.D.H.D., not as a child and not now as a 24-year-old college graduate, and that he was getting dangerously addicted to the medication. It was inside the building that her husband, Rick, implored Richard’s doctor to stop prescribing him Adderall, warning, “You’re going to kill him.” It was where, after becoming violently delusional and spending a week in a psychiatric hospital in 2011, Richard met with his doctor and received prescriptions for 90 more days of Adderall. He hanged himself in his bedroom closet two weeks after they expired. The story of Richard Fee, an athletic, personable college class president and aspiring medical student, highlights widespread failings in the system through which five million Americans take medication for A.D.H.D., doctors and other experts said. Medications like Adderall can markedly improve the lives of children and others with the disorder. But the tunnel-like focus the medicines provide has led growing numbers of teenagers and young adults to fake symptoms to obtain steady prescriptions for highly addictive medications that carry serious psychological dangers. These efforts are facilitated by a segment of doctors who skip established diagnostic procedures, renew prescriptions reflexively and spend too little time with patients to accurately monitor side effects. © 2013 The New York Times Company

Keyword: ADHD; Drug Abuse
Link ID: 17752 - Posted: 02.04.2013

The number of children being diagnosed with epilepsy has dropped dramatically in the UK over the past decade, figures show. A study of GP-recorded diagnoses show the incidence has fallen by as much as half. Researchers said fewer children were being misdiagnosed, but there had also been a real decrease in some causes of the condition. Other European countries and the US had reported similar declines, they added. Epilepsy is caused when the brain's normal electrical activity result in seizures. Data from more than 344,000 children showed that the annual incidence of epilepsy has fallen by 4-9% year on year between 1994 and 2008. Overall the number of children born between 2003-2005 with epilepsy was 33% lower then those born in 1994-96. When researchers looked in more detail and included a wider range of possible indicators of an epilepsy diagnosis the incidence dropped by 47%. Correct diagnosis Better use of specialist services and increased caution over diagnosing the condition explains some, but not all, of the decline in the condition, the researchers reported in Archives of Diseases in Childhood. Introduction of vaccines against meningitis and a drop in the number of children with traumatic brain injuries, both of which can cause epilepsy, has probably also contributed to falling cases, they added. BBC © 2013

Keyword: Epilepsy; Development of the Brain
Link ID: 17751 - Posted: 02.04.2013

By JUDY BATTISTA NEW ORLEANS — The N.F.L., faced with increasing concern about the toll of concussions and confronted with litigation involving thousands of former players, is planning to form a partnership with General Electric to jump-start development of imaging technology that would detect concussions and encourage the creation of materials to better protect the brain. The four-year initiative, which is expected to begin in March with at least $50 million from the league and G.E., is the result of a late October conversation between Commissioner Roger Goodell and G.E.’s chief executive, Jeffrey Immelt, a former offensive tackle at Dartmouth. When Goodell explained his idea of getting leading companies in innovation to join the N.F.L. to accelerate research, Immelt said he wanted to help. After years of insisting there was no link between head injuries sustained on the field and long-term cognitive impairment, the N.F.L. has altered rules, fined and suspended players who hit opponents in the head and contributed millions of dollars for the study of head injuries. “Is this their way of defending themselves with this cloud over the sport? I’d be lying if I told you it had nothing to do with it,” Kevin Guskiewicz, the founding director of the Matthew Gfeller Sport-Related Traumatic Brain Injury Research Center at the University of North Carolina, said of the initiative. Guskiewicz is a member of the league’s Head, Neck and Spine Committee and the chairman of a subcommittee focused on safety equipment and playing rules. He will work with the N.F.L. and G.E. to identify areas of focus. © 2013 The New York Times Company

Keyword: Brain imaging; Brain Injury/Concussion
Link ID: 17750 - Posted: 02.04.2013

IF TWO animals have identical brain cells, how different can they really be? Extremely. Two worm species have exactly the same set of neurons, but extensive rewiring allows them to lead completely different lives. Ralf Sommer of the Max Planck Institute for Developmental Biology in Tübingen, Germany, and colleagues compared Caenorhabditis elegans, which eats bacteria, with Pristionchus pacificus, which hunts other worms. Both have a cluster of 20 neurons to control their foregut. Sommer found that the clusters were identical. "These species are separated by 200 to 300 million years, but have the same cells," he says. P. pacificus, however, has denser connections than C. elegans, with neural signals passing through many more cells before reaching the muscles (Cell, doi.org/kbh). This suggests that P. pacificus is performing more complex motor functions, says Detlev Arendt of the European Molecular Biology Laboratory in Heidelberg, Germany. Arendt thinks predators were the first animals to evolve complex brains, to find and catch moving prey. He suggests their brains had flexible wiring, enabling them to swap from plant-eating to hunting. © Copyright Reed Business Information Ltd.

Keyword: Genes & Behavior; Evolution
Link ID: 17749 - Posted: 02.04.2013

By Morgen Peck Co-sleeping, the practice of sharing a bed with your baby, has a controversial place in modern society. Proponents argue that it increases the parent-child bond, whereas detractors worry about safety. Now an anthropological study adds a new finding to the debate: fathers who sleep next to their babies tend to have significantly lower levels of testosterone than those who sleep in a different room. Lee Gettler, an anthropologist at the University of Notre Dame, compared Filipino men's testosterone levels before having a child and again four years later. Men who reported sleeping on the same surface as their child experienced a steep decline in nighttime testosterone levels not seen in men who slept in another room, according to the paper published in September 2012 in PLOS One. Studies on women have shown that mothers who sleep with their children pass in and out of sleep. The same disruptions in men could possibly decrease testosterone production, Gettler and his co-authors write. Previous work in the same population showed that fathers who fully throw themselves into caring for their children are more likely to have low testosterone, suggesting that hormonal fluctuations may support men in being good fathers. “Lower testosterone might orient men more toward the needs of the partner and children and away from risky behavior and competition with other males—which could conflict with investments in parenting,” Gettler says. © 2013 Scientific American

Keyword: Sexual Behavior; Sleep
Link ID: 17748 - Posted: 02.04.2013

By R. Douglas Fields Imagine if your biggest health problem could be solved with the flip of a switch. Deep-brain stimulation (DBS) offers such a dramatic recovery for a range of neurological illnesses, including Parkinson's disease, epilepsy and major depression. Yet the metal electrodes implanted in the brain are too bulky to tap into intricate neural circuitry with precision and corrode in contact with tissue, so their performance degrades over time. Now neurophysiologists have developed a method of DBS that avoids these problems by using microscopic magnets to stimulate neurons. In experiments published in June 2012 in Nature Communications, neurophysiologist John T. Gale of the Cleveland Clinic and his colleague Giorgio Bonmassar, a physicist at Harvard Medical School and an expert on brain imaging, tested whether micromagnets (which are half a millimeter in diameter) could induce neurons from rabbit retinas to fire. They found that when they electrically energized a micromagnet positioned next to a neuron, it fired. In contrast to the electric currents induced by DBS, which excite neurons in all directions, magnetic fields follow organized pathways from pole to pole, like the magnetic field that surrounds the earth. The researchers found that they could direct the stimulus precisely to individual neurons, and even to particular areas of a neuron, by orienting the magnetic coil appropriately. “That may help us avoid the side effects we see in DBS,” Gale says, referring to, for instance, the intense negative emotions that are sometimes accidentally triggered when DBS is used to relieve motor problems in Parkinson's. © 2013 Scientific American

Keyword: Brain imaging; Parkinsons
Link ID: 17747 - Posted: 02.02.2013

by Elizabeth Devitt Birds may not have big brains, but they know how to navigate. They wing around town and across continents with amazing accuracy, while we watch and wonder. Biologists believe that sight, smell, and an internal compass all contribute to avian orienteering. But none of these skills completely explains how birds fly long distances or return home from places they've never been. A new study proposes that the animals use infrasound—low-level background noise in our atmosphere—to fly by "images" they hear. These acoustical maps may also explain how other creatures steer. Scientists have long considered infrasound as a navigational cue for birds. But until U.S. Geological Survey geophysicist Jonathan Hagstrum in Menlo Park, California, became intrigued by the unexplained loss of almost 60,000 pigeons during a race from France to England in 1997, no one pinpointed how the process worked. The race went bust when the birds' flight route crossed that of a Concorde jet, and Hagstrum wanted to know why. "When I realized the birds in that race were on the same flight path as the Concorde, I knew it had to be infrasound," he says. The supersonic plane laid down a sonic boom when most of the animals were flying across the English Channel. Normally, infrasound is generated when deep ocean waves send pressure waves reverberating into the land and atmosphere. Infrasound can come from other natural causes, such as earthquakes, or humanmade events, such as the acceleration of the Concorde. The long, slow waves move across vast distances. Although humans can't hear them, birds and other animals are able to tune in. © 2010 American Association for the Advancement of Science

Keyword: Hearing; Animal Migration
Link ID: 17746 - Posted: 02.02.2013

Emotional behaviour in childhood may be linked with heart disease in middle age, especially in women, research suggests. A study found being prone to distress at the age of seven was associated with a significantly higher risk of cardiovascular disease in later life. Conversely children who were better at paying attention and staying focused had reduced heart risk when older. The US researchers said more work was needed to understand the link. Their study looked at 377 adults who had taken part in research as children. At seven they had undergone several tests to look at emotional behaviour. They compared the results from this with a commonly used risk score for cardiovascular disease of participants now in their early 40s. After controlling for other factors which might influence heart disease risk, they found that high levels of distress at age seven were associated with a 31% increased risk of cardiovascular disease in middle-aged women. For men with high levels of distress in childhood - which included being easily frustrated and quick to anger - the increased risk of cardiovascular disease was 17%. For 40-year-olds who had been prone to distress as a child, the chances of having a heart attack or stroke in the next 10 years increased from 3.2% to 4.2% for women and 7.3 to 8.5% for men. The researchers also looked at positive emotional factors such as having a good attention span and found this was linked with better cardiovascular health, although to a lesser degree. Other studies have linked adversity in childhood with cardiovascular disease in adults. BBC © 2013

Keyword: Stress; Development of the Brain
Link ID: 17745 - Posted: 02.02.2013

Wray Herbert The Invisible Gorilla is part of the popular culture nowadays, thanks largely to a widely-read 2010 book of that title. In that book, authors and cognitive psychologists Dan Simons and Christopher Chabris popularized a phenomenon of human perception—known in the jargon as “inattentional blindness”—which they had demonstrated in a study some years before. In the best known version of the experiment, volunteers were told to keep track of how many times some basketball players tossed a basketball. While they did this, someone in a gorilla suit walked across the basketball court, in plain view, yet many of the volunteers failed even to notice the beast. What the invisible gorilla study shows is that, if we are paying very close attention to one thing, we often fail to notice other things in our field of vision—even very obvious things. We all love these quirks of human perception. It’s entertaining to know that our senses can play tricks on us. And that’s no doubt the extent of most people’s familiarity with this psychological phenomenon. But what if this perceptual quirk has serious implications—even life-threatening implications? A new study raises that disturbing possibility. Three psychological scientists at Brigham and Women’s Hospital in Boston—Trafton Drew, Melissa Vo and Jeremy Wolfe—wondered if expert observers are also subject to this perceptual blindness. The subjects in the classic study were “naïve”—untrained in any particular domain of expertise and performing a task nobody does in real life. But what about highly trained professionals who make their living doing specialized kinds of observations? The scientists set out to explore this, and in an area of great importance to many people—cancer diagnosis. © Association for Psychological Science

Keyword: Attention
Link ID: 17744 - Posted: 02.02.2013

By Stephani Sutherland If you have trouble sleeping, laptop or tablet use at bedtime might be to blame, new research suggests. Mariana Figueiro of the Lighting Research Center at Rensselaer Polytechnic Institute and her team showed that two hours of iPad use at maximum brightness was enough to suppress people's normal nighttime release of melatonin, a key hormone in the body's clock, or circadian system. Melatonin tells your body that it is night, helping to make you sleepy. If you delay that signal, Figueiro says, you could delay sleep. Other research indicates that “if you do that chronically, for many years, it can lead to disruption of the circadian system,” sometimes with serious health consequences, she explains. The dose of light is important, Figueiro says; the brightness and exposure time, as well as the wavelength, determine whether it affects melatonin. Light in the blue-and-white range emitted by today's tablets can do the trick—as can laptops and desktop computers, which emit even more of the disrupting light but are usually positioned farther from the eyes, which ameliorates the light's effects. The team designed light-detector goggles and had subjects wear them during late-evening tablet use. The light dose measurements from the goggles correlated with hampered melatonin production. On the bright side, a morning shot of screen time could be used as light therapy for seasonal affective disorder and other light-based problems. Figueiro hopes manufacturers will “get creative” with tomorrow's tablets, making them more “circadian friendly,” perhaps even switching to white text on a black screen at night to minimize the light dose. Until then, do your sleep schedule a favor and turn down the brightness of your glowing screens before bed—or switch back to good old-fashioned books. © 2013 Scientific American

Keyword: Biological Rhythms; Sleep
Link ID: 17743 - Posted: 02.02.2013

by Carrie Arnold Studying the links between brain and behavior may have just gotten easier. For the first time, neuroscientists have found a way to watch neurons fire in an independently moving animal. Though the study was done in fish, it may hold clues to how the human brain works. "This technique will really help us understand how we make sense of the world and why we behave the way we do," says Martin Meyer, a neuroscientist at King's College London who was not involved in the work. The study was carried out in zebrafish, a popular animal model because they're small and easy to breed. More important, zebrafish larvae are transparent, which gives scientists an advantage in identifying the neural circuits that make them tick. Yet, under a typical optical microscope, neurons that are active and firing look much the same as their quieter counterparts. To see what neurons are active and when, neuroscientists have therefore developed a variety of indicators and dyes. For example, when a neuron fires, it is flooded with calcium ions, which can cause some of the dyes to light up. Still, the approach has limitations. Traditionally, Meyer explains, researchers would immobilize the head or entire body of a zebrafish larvae so that they could get a clearer picture of what was happening inside the brain. Even so, it was difficult to interpret neural activity for just a few neurons and over a short period of time. Researchers needed a better way to study the zebrafish brain in real time. © 2010 American Association for the Advancement of Science

Keyword: Brain imaging
Link ID: 17742 - Posted: 02.02.2013

By Laura Sanders Some nerve fibers seem to love a good rubdown. These tendrils, which spread across skin like upside-down tree roots, detect smooth, steady stroking and send a feel-good message to the brain, researchers report in the Jan. 31 Nature. Although the researchers found these neurons in mice, similar cells in people may trigger massage bliss. The results are the latest to emphasize the strong and often underappreciated connection between emotions and the sensation of touch, says study coauthor David Anderson, a Howard Hughes Medical Institute investigator at Caltech. “It may seem frivolous to be studying massage neurons in mice, but it raises a profound issue — why do certain stimuli feel a certain way?” he says. It’s no surprise that many people find a caress pleasant. Earlier studies in people suggested that a particular breed of nerve fibers detects a caress and carries that signal to the brain. But scientists hadn’t been able to directly link this type of neuron to good feelings, either in people or in animals. “The beauty of this paper is that it goes one step further and adds behavioral elements,” says cognitive neuroscientist Francis McGlone of Liverpool John Moores University in England. Directly linking these neurons with pleasure clarifies the importance of touch, McGlone says. “Skin is a social organ,” he says. A growing number of studies show that the sensation of touch, particularly early in life, profoundly sculpts the brain. Young animals deprived of touch grow up with severe behavioral abnormalities. Babies fare better when they are held and touched frequently. And touch sensation can be altered in certain disorders. People with autism, for instance, often dislike caresses. © Society for Science & the Public 2000 - 2013

Keyword: Pain & Touch; Emotions
Link ID: 17741 - Posted: 02.02.2013

By Tanya Lewis and LiveScience Drug cravings can be brought on by many factors, such as the sight of drugs, drug availability and lack of self-control. Now, researchers have uncovered some of the neural mechanisms involved in cigarette craving. Two brain areas, the orbitofrontal cortex and the prefrontal cortex, interact to turn cravings on or off depending on whether drugs are available, the study reports today (Jan. 28) in the journal the Proceedings of the National Academy of Sciences. The researchers scanned the brains of 10 moderate-to-heavy smokers using functional magnetic resonance imaging (fMRI), which measures brain activity by changes in blood flow. Researchers measured activity while the participants watched video clips of people smoking as well as neutral videos. Before viewing, some subjects were told cigarettes would be available immediately after the experiment, while others were told they would have to wait 4 hours before lighting up. When participants watched the smoking videos, their brains showed increased activity in the medial orbitofrontal cortex, a brain area that assigns value to a behavior. When the cigarettes were available immediately as opposed to hours later, smokers reported greater cravings and their brains showed more activity in the dorsolateral prefrontal cortex. The researchers hypothesize that this area modulates value. In other words, it can turns up or down the "value level" of cigarettes (or other rewards) in the first area, the medial orbitofrontal cortex. The results show that addiction involves a brain circuit important for self-control and decision-making. © 2013 Scientific American,

Keyword: Drug Abuse
Link ID: 17740 - Posted: 01.30.2013