By Meghan Rosen Alcohol may give heavy drinkers more than just a buzz. It can also fuel their brains, a new study suggests. Long-term booze use boosts brain levels of acetate, an energy-rich by-product of alcohol metabolism, researchers report online March 8 in the Journal of Clinical Investigation. In the study, people who downed at least eight drinks per week also sucked more energy from acetate than their light-drinking counterparts. The extra energy may give heavy drinkers more incentive to imbibe, says study coauthor Graeme Mason of Yale University. And the caloric perk might help explain why alcohol withdrawal is so hard. “I think it's a very good hypothesis,” says biochemical geneticist Ting-Kai Li of Duke University. Scientists had suspected that heavy drinkers absorb and burn more acetate, but, he adds, “Graeme Mason showed that this is actually happening.” Acetate is best known as a chemical in vinegar. But when people drink a glass of wine or drain a can of beer, their liver breaks down the alcohol and pumps out acetate as leftovers. The bloodstream then delivers acetate throughout the body, including to the brain. Human brains typically run on sugar. But with enough acetate in the blood, Mason thought, brains might crank up their ability to burn it too. To find out if his suspicion was correct, Mason and his colleagues peered into the brains of seven heavy drinkers and seven light drinkers, who quaffed fewer than two drinks per week. © Society for Science & the Public 2000 - 2013

Keyword: Drug Abuse
Link ID: 17887 - Posted: 03.11.2013

SAN FRANCISCO (AP) — The future is unclear for a heart device aimed at preventing strokes in people at high risk of them because of an irregular heartbeat. Early results from a key study of the device, Boston Scientific’s Watchman, suggested it is safer than previous testing found, but may not be better than a drug that is used to prevent strokes, heart-related deaths and blood clots in people with atrial fibrillation in the long term. Atrial fibrillation, a common heart arrhythmia that affects millions of Americans, causes blood to pool in a small pouch. Clots can form and travel to the brain, causing a stroke. The usual treatment is blood thinners like warfarin, sold as Coumadin and other brands. But they have their own problems and some are very expensive. The Watchman is intended to be a permanent solution that would not require people to take medication for the rest of their lives. It is a tiny expandable umbrella that plugs the pouch of blood, and is inserted without surgery, via a tube pushed into a vein. A study four years ago indicated the device was at least as good at preventing strokes as warfarin, but the procedure to implant it led to strokes in some patients. The Food and Drug Administration required another test of its safety and effectiveness. The new study was led by Dr. David Holmes Jr. of the Mayo Clinic in Rochester, Minn. He and the clinic have a financial stake in the device. © 2013 The New York Times Company

Keyword: Stroke
Link ID: 17886 - Posted: 03.11.2013

By Neuroskeptic “Layered Voice Analysis” (LVA) is a controversial technology promoted as a tool for helping detect stress and other emotions by analysis of the human voice. According to the company behind the method, Nemesysco: LVA technology enables better understanding of your suspect’s mental state and emotional makeup at a given moment by detecting the emotional cues in his or her speech. The technology identifies various types of stress levels, cognitive processes, and emotional reactions that are reflected in different properties of the voice… it provides the professional user easy access to truth verification in real time or from recorded data, during face to face and over the phone, during a free or structured investigation session. Long-term Neuroskeptic readers will remember LVA and Nemesysco from way back in 2009. That was when I blogged about the company’s legal moves against two Swedish academics who had published a paper critical of LVA. That contentious article is still available online. Now, a newly published study evaluated whether LVA is an effective truth verifying tool: The Accuracy of Auditors’ and Layered Voice Analysis (LVA) Operators’ Judgments of Truth and Deception During Police Questioning. The authors, led by Michigan Professor Frank Horvath, studied 74 suspects who were interviewed by the Michigan State Police. Audio recordings of the interviews were made. Which of the suspects were being deceptive? Two investigators used LVA (after receiving the manufacturer’s recommended 40 hours of training) to try to judge deception from the records. Three other investigators just listened to the recordings, and formed an opinion based on their own intuition and experience.

Keyword: Stress
Link ID: 17885 - Posted: 03.11.2013

By Marilynn Marchione, Associated Press Stress does bad things to the heart. New studies have found higher rates of cardiac problems in veterans with PTSD, New Orleans residents six years after Hurricane Katrina and Greeks struggling through that country's financial turmoil. Disasters and prolonged stress can raise "fight or flight" hormones that affect blood pressure, blood sugar and other things in ways that make heart trouble more likely, doctors say. They also provoke anger and helplessness and spur heart-harming behaviors like eating or drinking too much. "We're starting to connect emotions with cardiovascular risk markers" and the new research adds evidence of a link, said Dr. Nieca Goldberg, a cardiologist at NYU Langone Medical Center and an American Heart Association spokeswoman. She had no role in the studies, which were discussed Sunday at an American College of Cardiology conference in San Francisco. The largest, involving 207,954 veterans in California and Nevada ages 46 to 74, compared those with PTSD, or post-traumatic stress disorder, to those without it. They were free of major heart disease and diabetes when researchers checked their Veterans Administration medical records from 2009 and 2010. Checked again about two years later, 35 percent of those with PTSD but only 19 percent of those without it had developed insulin resistance, which can lead to diabetes and hardening of the arteries. © 2013 NBCNews.com

Keyword: Stress
Link ID: 17884 - Posted: 03.11.2013

by Moheb Costandi Mice transplanted with a once-discounted class of human brain cells have better memories and learning abilities than normal counterparts, according to a new study. Far from a way to engineer smarter rodents, the work suggests that human brain evolution involved a major upgrade to cells called astrocytes. Astrocytes are one of several types of glia, the other cells found alongside neurons in the nervous system. Although long thought to merely provide support and nourishment for neurons, it's now clear that astrocytes are vital for proper brain function. They are produced during development from stem cells called glial progenitors. In 2009, Steven Goldman of the University of Rochester Medical Center in New York and his colleagues reported that human astrocytes are bigger, and have about 10 times as many fingerlike projections that contact other brain cells and blood vessels, than those of mice. To further investigate these differences, they have more recently grafted fluorescently labeled human glial progenitors into the brains of newborn mice and examined the animals when they reached adulthood. Most of the grafted cells remained as progenitors, but some matured into typical human-looking astrocytes. They connected to their mouse counterparts to form astrocyte networks that transmitted electrical signals. Furthermore, they propagated internal signals about three times faster than the mouse astrocytes and improved the strengthening of connections between neurons in the hippocampus, a process thought to be critical for learning and memory. © 2010 American Association for the Advancement of Science.

Keyword: Glia; Learning & Memory
Link ID: 17883 - Posted: 03.09.2013

By JAN HOFFMAN Physically active children generally report happier moods and fewer symptoms of depression than children who are less active. Now researchers may have found a reason: by one measure, exercise seems to help children cope with stress. Finnish researchers had 258 children wear accelerometers on their wrists for at least four days that registered the quality and quantity of their physical activity. Their parents used cotton swabs to take saliva samples at various times throughout a single day, which the researchers used to assess levels of cortisol, a hormone typically induced by physical or mental stress. There was no difference in the cortisol levels at home between children who were active and those who were less active. But when the researchers gave the children a standard psychosocial stress test at a clinic involving arithmetic and storytelling challenges, they found that those who had not engaged in physical activity had raised cortisol levels. The children who had moderate or vigorous physical activity showed relatively no rise in cortisol levels. Those results indicate a more positive physiological response to stress by children who were more active, the researchers said in a study that was published this week in The Journal of Clinical Endocrinology and Metabolism. The children who were least active had the highest levels. “This study shows that children who are more active throughout their day have a better hormonal response to an acute stressful situation,” said Disa Hatfield, an assistant professor of kinesiology at the University of Rhode Island, who was not involved in the study. Copyright 2013 The New York Times Company

Keyword: Stress
Link ID: 17882 - Posted: 03.09.2013

By Deborah Kotz, Globe Staff No doubt, the biggest appeal of exercise is to build biceps, heart muscle, and perhaps some definition in those abdominal muscles, but how about using exercise to build your brain? It’s been known for some time that exercise can lift your mood, ward off depression, and help the brain age more gracefully -- free of memory loss and dementia. But now researchers have found that even just one bout of exercise can -- even better than a cup of coffee -- improve your mental focus and cognitive performance for any challenging task you face that day. A new analysis of 19 studies involving 586 kids, teens, and young adults that was published Wednesday in the British Medical Journal found that short 10 to 40 minutes bursts of exercise led to an immediate boost in concentration and mental focus, likely by improving blood flow to the brain. “These results provide further evidence that doing about 20 minutes of exercise just before taking a test or giving a speech can improve performance,” said Harvard psychiatrist Dr. John Ratey, who wrote the best-selling book Spark: The Revolutionary New Science of Exercise and the Brain. Another piece of proof can be seen in the brain scan above -- from a 2009 University of Illinois study also included in the new analysis -- which compares the brain activity of 9-year-olds who took a brisk walk and those who didn’t take a walk. The walkers had far more activity in brain regions involved with focused attention and filtering out noisy distractions while they were taking a challenging test compared to the non-walkers. © 2013 NY Times Co.

Keyword: Learning & Memory
Link ID: 17881 - Posted: 03.09.2013

Jennifer Raymond I have a bias against women in science. Please don't hold this against me. I am a woman scientist, mentor and advocate for women in science, and an associate dean in my school's Office of Diversity, with a budding field biologist as a daughter. Yet my performance on the Implicit Association Test (https://implicit.harvard.edu/implicit/demo), which measures unconscious associations between concepts, revealed that I have a tendency to associate men with science and career, and women with liberal arts and family. I didn't even need to wait for my score; I could feel that my responses were slower and that I made more mistakes when I had to group science words such as 'astronomy' with female words such as 'wife' rather than male words such as 'uncle'. The results from hundreds of thousands of people indicate that I am not an outlier — 70% of men and women across 34 countries view science as more male than female1. Gender bias is not just a problem in science. A host of studies shows that people tend to rate women as less competent than men across many domains, from musical abilities to leadership2, and that many individuals hold biases about competency on the basis of other irrelevant attributes, such as skin colour, body weight, religion, sexual orientation and parental status. Such biases have important consequences in the workplace. One study showed that mothers are 79% less likely to be hired and are offered US$11,000 less salary than women with no children3. By contrast, the same study shows that parenthood confers an advantage to men in the workplace. © 2013 Nature Publishing Group,

Keyword: Attention; Sexual Behavior
Link ID: 17880 - Posted: 03.09.2013

By Partha Mitra The Sherlock Holmes novel The Hound of the Baskervilles features the great Grimpen Mire, a treacherous marsh in Dartmoor, England. Holmes’ protagonist, the naturalist Stapleton, knows where the few secure footholds are, allowing him to cross the mire and reach the hills with rare plants and butterflies, but he warns Dr. Watson that a false step can be fatal, the bog inexorably consuming the unsuspecting traveller. Trying to unravel the complexities of the brain is a bit like crossing the great Grimpen Mire: one needs to know where the secure stepping-stones are, and a false step can mean sinking into a morass. As we enter the era of Big Brain Science projects, it is important to know where the next firm foothold is. As a goal worthy of a multi-billion dollar brain project, we have now been offered a motto that is nearly as rousing as “climb every mountain”: “record every action potential from every neuron.” According to recent reporting in the New York Times, this goal, proclaimed in a paper published in 2012, will be the basis of a decade-long “Brain Activity Map” project. Not content with a goal as lofty as this in worms, flies and mice, the press reports imply (and the authors also speculate) that these technologies will be used for comprehensive spike recordings in the human brain, generating a “Brain Activity Map” that will provide the answers to Alzheimers and Schizophrenia and lead us out of the “impenetrable jungles of the brain” that hapless neuroscientists have wandered over the past century. Neuroscience is most certainly in need of integration, and brain research will without doubt benefit from the communal excitement and scaled up funding associated with a Big Brain Initiative. However, success will depend on setting the right goals and guarding against irrational exuberance. Successful big science projects are engineering projects with clear, technically feasible goals: setting a human on the moon, sequencing the Human Genome, finding the Higgs Boson. The technologies proposed in the paper under discussion may or may not be feasible in a given species (they will not be feasible in the normal human brain, since the methods involved are invasive and require that the skull be surgically opened). However, technology development is notoriously difficult to predict, and may carry unforeseen benefits. What we really need to understand is whether the overall goal is meaningful. © 2013 Scientific American,

Keyword: Brain imaging
Link ID: 17879 - Posted: 03.09.2013

By JAMES GORMAN Nothing kicks the brain into gear like a jolt of caffeine. For bees, that is. And they don’t need to stand in line for a triple soy latte. A new study shows that the naturally caffeine-laced nectar of some plants enhances the learning process for bees, so that they are more likely to return to those flowers. “The plant is using this as a drug to change a pollinator’s behavior for its own benefit,” said Geraldine Wright, a honeybee brain specialist at Newcastle University in England, who, with her colleagues, reported those findings in Science on Thursday. The research, other scientists said, not only casts a new light on the ancient evolutionary interaction between plants and pollinators, but is an intriguing confirmation of deep similarities in brain chemistry across the animal kingdom. Plants are known to go to great lengths to attract pollinators. They produce all sorts of chemicals that affect animal behavior: sugar in nectar, memorable fragrances, even substances in fruit that can act like laxatives in the service of quick seed dispersal. Lars Chittka, who studies bee behavior at Queen Mary, University of London, and wrote a commentary on the research in the same issue of Science, said that in the marketplace of plants seeking pollinators, the plants “want their customers to remain faithful,” thus the sugary nectar and distinctive scents. © 2013 The New York Times Company

Keyword: Drug Abuse; Evolution
Link ID: 17878 - Posted: 03.09.2013

by Andy Coghlan Stimulating the brain with electrical signals can sharpen some of your faculties, but now it seems it can dim others at the same time. Transcranial electrical stimulation (TES), delivered by electrodes on the surface of the head, has been shown to double people's speed of learning. Now the first evidence has emerged that improvements in one aspect of learning might come at the expense of other abilities. Roi Cohen Kadosh of the University of Oxford, showed volunteers pairs of unfamiliar symbols. Each symbol had a secret numerical value, and the volunteers' task was to state – as quickly as possible while avoiding mistakes – which symbol in a pair had the bigger value. The correct answer was then displayed. Over six sessions in one week, it was possible to measure how quickly and efficiently the volunteers learned the value of each symbol. Second task In a second task, participants had to register which of each pair of symbols was physically larger, a measure of automatic thinking. "Automaticity is the skill of doing things without thinking about them, such as reading, driving or mounting stairs," says Cohen Kadosh, who conducted the experiment with Teresa Iucalano of the Stanford Cognitive and Systems Neuroscience Laboratory in Palo Alto, California. During the experiments, volunteers received TES to their posterior parietal cortex – vital for numerical learning – or their dorsolateral prefrontal cortex – vital for automaticity. Some unknowingly received a sham treatment. © Copyright Reed Business Information Ltd.

Keyword: Learning & Memory
Link ID: 17877 - Posted: 03.09.2013

by Trevor Quirk Many smartphones claim to filter out background noise, but they've got nothing on the human brain. We can tune in to just one speaker at a noisy cocktail party with little difficulty—an ability that has been a scientific mystery since the early 1950s. Now, researchers argue that the competing noise of other partygoers is filtered out in the brain before it reaches regions involved in higher cognitive functions, such as language and attention control. Their experiments were the first to demonstrate this process. The scientists didn't do anything as social as attend a noisy party. Instead, Charles Schroeder, a psychiatrist at the Columbia University College of Physicians and Surgeons in New York City, and colleagues recorded the brain activity of six people with intractable epilepsy who required brain surgery. In order to identify the part of their brains responsible for seizures, the patients underwent 1 to 4 weeks of observation through electrocorticography (ECoG), a technique that provides precise neural recordings via electrodes placed directly on the surface of the brain. Schroeder and his team, using the ECoG data, conducted their experiments during this time. The researchers showed the patients two videos simultaneously, each of a person telling a 9- to 12-second story; they were asked to concentrate on just one speaker. To determine which neural recordings corresponded to the "ignored" and "attended" speech, the team reconstructed speech patterns from the brain's electrical activity using a mathematical model. The scientists then matched the reconstructed patterns with the original patterns coming from the ignored and attended speakers. © 2010 American Association for the Advancement of Science.

Keyword: Attention; Hearing
Link ID: 17876 - Posted: 03.07.2013

Meredith Wadman Ron Kalil, a neuroscientist at the University of Wisconsin–Madison, didn’t expect to see his son among the 28,500 attendees at the meeting of the Society for Neuroscience in New Orleans last October. And he wondered why Tom Kalil, deputy director for policy at the White House’s Office of Science and Technology Policy (OSTP), was accompanied by Miyoung Chun, vice-president of science programmes at the Kavli Foundation in Oxnard, California. Tom Kalil told his father that the Kavli Foundation had wanted his help in bringing nanoscientists together behind an ambitious idea. Ron Kalil says he thought: “Why are you talking about it at a neuroscience meeting?” He understands now. These two people, neither of them a working scientist, had been quietly pushing into existence the Brain Activity Map (BAM), the largest and most ambitious effort in fundamental biology since the Human Genome Project — and one that would need advances in both nanoscience and neuroscience to achieve its goals. This is the kind of science — big and bold — that politicians like. President Barack Obama praised brain mapping in his State of the Union address on 12 February. Soon after, Francis Collins, director of the US National Institutes of Health (NIH) in Bethesda, Maryland, which will be the lead agency on the project, talked up the idea in a television appearance. The Obama administration is expected to provide more details about the initiative this month, possibly in conjunction with the release of the federal 2014 budget request. But already, some scientists are wondering whether the project, a concept less than two years old and still evolving, can win new funding from Congress, or whether it would crowd out projects pitched by individual scientists. “Creative science is bottom-up, not top-down,” says Cori Bargmann, a neurobiologist at the Rockefeller University in New York. “Are we talking about central planning inside the Beltway?” © 2013 Nature Publishing Group

Keyword: Brain imaging
Link ID: 17875 - Posted: 03.07.2013

By Scicurious I heard the rumblings on Twitter, and then on the blogs. It was telepathy. No, it wasn’t telepathy, but it was close. It was like the Borg. No it wasn’t. It was a mind meld! Ok, maybe. So what was it? It was one rat learning to do something, while electrodes recorded his every move. In the meantime, on another continent, another rat received the signals into his own brain…and changed his behavior. Telepathy? No. A good solid proof of concept? I’m not sure. An interesting idea? Absolutely. So I wanted to look at this paper in depth. We know already that some other experts weren’t really thrilled with the results. But I’m going to look at WHY, and what a more convincing experiment might look like. So what actually happened here? Each experiment involved two sets of rats. First, you have your “encoder rats”. These rats were water-deprived (not terribly, just thirsty), and trained to press a lever for a water reward (water deprivation is one training technique for lever pressing, and is one of the fastest. But you can also food-deprive and train for food or just train the animal to something tasty, like Crisco or sweetened milk). The rats were trained until they were 95% accurate at the task. They were then implanted with electrodes in the motor cortex, that recorded the firing of the neurons as the rats pressed the left or right lever. © 2013 Scientific American,

Keyword: Robotics
Link ID: 17874 - Posted: 03.07.2013

Surgically implanting pacemaker-like devices into the brains of people with severe anorexia might help improve their symptoms, a small Canadian study suggests. Anorexia affects an estimated 15,000 to 20,000 people in Canada, mainly young women who face a high risk of premature death. The mortality rate is between six to 11 per cent. About 60 to 70 per cent of people with anorexia recover fully with traditional treatments, said Dr. Blake Woodside, medical director of the eating disorders program at Toronto General Hospital. But in Wednesday's online issue of the medical journal The Lancet, Woodside and his co-authors describe using deep brain stimulation to treat six women with severe anorexia that did not respond to treatment. The treatment involves surgery to implant the electrical stimulators. It's considered minimally invasive and the stimulation can be turned off. In the pilot study, the average age of the women at diagnosis was 20 and they ranged in age from 24 to 57 when the surgery was performed. Five had a history of repeated hospital admissions for eating disorders. While the study was meant to test the safety of the procedure, not its effectiveness, Woodside's team found three of the six patients achieved and maintained a body mass index greater than their historical level. © CBC 2013

Keyword: Anorexia & Bulimia
Link ID: 17873 - Posted: 03.07.2013

By Meghan Rosen Zombies aren’t the only things that feast on brains. Immune cells called microglia gorge on neural stem cells in developing rat and monkey brains, researchers report in the March 6 Journal of Neuroscience. Chewing up neuron-spawning stem cells could help control brain size by pruning away excess growth. Scientists have previously linked abnormal human brain size to autism and schizophrenia. “It shows microglia are very important in the developing brain,” says neuroscientist Joseph Mathew Antony of the University of Toronto, who was not involved in the research. Scientists have long known that in adult brains, microglia hunt for injured cells as well as pathogens. “They mop up all the dead and dying cells,” Antony says. And when the scavengers find a dangerous intruder, they pounce. “These guys are relentless,” says study coauthor Stephen Noctor, of the University of California, Davis MIND Institute in Sacramento. “They seek and destroy bacteria — it’s really quite amazing.” Microglia also lurk in embryonic brains, but the immune cells’ role there is less well understood. Previous studies had found microglia near neural stem cells — tiny factories that pump out new neurons. When Noctor’s team examined slices of embryonic human, monkey and rodent brains, he was struck by just how many microglia crowded around the stem cells and how closely the two cell types touched. © Society for Science & the Public 2000 - 2013

Keyword: Glia; Neuroimmunology
Link ID: 17872 - Posted: 03.07.2013

By Helen Shen When does a monkey turn down a free treat? When it is offered by a selfish person, apparently. Given the choice between accepting goodies from helpful, neutral or unhelpful people, capuchin monkeys (Cebus apella) tend to avoid individuals who refuse aid to others, according to a study published today in Nature Communications. “Humans can build up an impression about somebody just based on what we see,” says author James Anderson, a comparative psychologist at the University of Stirling, UK. The capuchin results suggest that this skill “probably extends to other species”, he says. Anderson chose to study capuchins because of their highly social and cooperative instincts. Monkeys in the study watched as a person either agreed or refused to help another person to open a jar containing a toy. Afterwards, both people offered a food pellet to the animal. The monkey was allowed to accept food from only one. When help was given, the capuchins showed little preference between the person requesting help and the one providing aid. But when help was denied, the seven monkeys tended to accept food less often from the unhelpful person than from the requester. To try to understand the monkeys’ motivations, Anderson and his team tested different scenarios. The animals showed no bias against people who failed to help because they were busy opening their own jar. But they tended to avoid people who were available to help but did not do so. © 2013 Scientific American

Keyword: Emotions; Aggression
Link ID: 17871 - Posted: 03.07.2013

by Elizabeth Norton The prospect of undergoing surgery while not fully "under" may sound like the stuff of horror movies. But one patient in a thousand remembers moments of awareness while under general anesthesia, physicians estimate. The memories are sometimes neutral images or sounds of the operating room, but occasionally patients report being fully aware of pain, terror, and immobility. Though surgeons scrupulously monitor vital signs such as pulse and blood pressure, anesthesiologists have no clear signal of whether the patient is conscious. But a new study finds that the brain may produce an early-warning signal that consciousness is returning—one that's detectable by electroencephalography (EEG), the recording of neural activity via electrodes on the skull. "We've known since the 1930s that brain activity changes dramatically with increasing doses of anesthetic," says the study's corresponding author, anesthesiologist Patrick Purdon of Massachusetts General Hospital in Boston. "But monitoring a patient's brain with EEG has never become routine practice." Beginning in the 1990s, some anesthesiologists began using an approach called the bispectral (BIS) index, in which readings from a single electrode are connected to a device that calculates, and displays, a single number indicating where the patient's brain activity falls on a scale of 100 (fully conscious) to zero (a "flatline" EEG). Anything between 40 and 60 is considered the target range for unconsciousness. But this index and other similar ones are only indirect measurements, Purdon explains. In 2011, a team led by anesthesiologist Michael Avidan at the Washington University School of Medicine in St. Louis, Missouri, found that monitoring with the BIS index was slightly less successful at preventing awareness during surgery than the nonbrain-based method of measuring exhaled anesthesia in the patient's breath. Of the 2861 patients monitored with the BIS index, seven had memories of the surgery, whereas only two of 2852 patients whose breath was analyzed remembered anything. © 2010 American Association for the Advancement of Science.

Keyword: Sleep; Consciousness
Link ID: 17870 - Posted: 03.05.2013

By David Brown, Hey, you, yawning in your cubicle at 2 in the afternoon. Your genes feel it, too. A new study, paid for by the U.S. Air Force but relevant for anyone with a small child, a large prostate or a lot on the mind, is helping illuminate what’s happening at the genetic level when we don’t get enough sleep. It turns out that chronic sleep deprivation — in this experiment, less than six hours a night for a week — changes the activity of about 700 genes, which is roughly 3 percent of all we carry. About one-third of the affected genes are ramped up when we go with insufficient sleep night after night. The other two-thirds are partially suppressed. Hundreds of “circadian genes” whose activity rises and falls each day abruptly lose their rhythm. Among the genes disturbed by sleep deprivation are ones involved in metabolism, immunity, inflammation, hormone response, the expression of other genes and the organization of material called chromatin on chromosomes. These changes may help explain how inadequate sleep alters attention and thinking and raises the risk for illnesses such as diabetes and coronary heart disease. “The findings will identify some of the pathways linking insufficient sleep and negative health outcomes,” said Derk-Jan Dijk, a physiologist at the University of Surrey in England, who led the study. “But how these things ultimately lead to obesity or diabetes is an unanswered question at this moment in time.” © 1996-2013 The Washington Post

Keyword: Sleep; Genes & Behavior
Link ID: 17869 - Posted: 03.05.2013

Steve Connor Physical exhaustion can occur when the brain – as well as the muscles – grows tired according to a study that sheds fresh light on the role played by the mind in determining endurance levels. Scientists have found that a key neurotransmitter in the brain, which controls signalling between nerve cells, can determine whether someone feels exhausted following physical exercise or after taking anti-depressant drugs such as Prozac. Although levels of serotonin rise during exercise, which provides a psychological boost and “feel-good” factor, it can also result in a widespread central fatigue that ultimately leads to someone feeling exhausted and unable to carry on, scientists found. Researchers led by Professor Jean-Francois Perrier of the University of Copenhagen found that while serotonin helps to keep people going during the early stage of vigorous exercise, a build-up of the neurotransmitter in the brain can have the opposite effect by causing “central fatigue” of the nervous system even when the muscles are still able to carry on. “We can now see it is actually a surplus of serotonin that triggers a braking mechanism in the brain. In other words, serotonin functions as an accelerator but also as a brake when the strain becomes excessive,” said Professor Perrier, whose study is published in the Proceedings of the National Academy of Sciences. © independent.co.uk

Keyword: Sleep
Link ID: 17868 - Posted: 03.05.2013