Researchers have long known that dopamine, a brain chemical that plays important roles in the control of normal movement, and in pleasure, reward and motivation, also plays a central role in substance abuse and addiction. In a new study conducted in animals, scientists found that a specific dopamine receptor, called D2, on dopamine-containing neurons controls an organism's activity level and contributes to motivation for reward-seeking as well as the rewarding effects of cocaine. "Research in humans and other species has shown that increased vulnerability to drug addiction correlates with reduced availability of D2 dopamine receptors in a brain region called the striatum," explains study coauthor David M. Lovinger, Ph.D., chief of NIAAA's Laboratory for Integrative Neuroscience. "Furthermore, healthy non-drug-abusing humans that have low levels of the D2 dopamine receptor report more pleasant experiences when taking drugs of abuse." Efforts to investigate dopamine's role in addiction and normal biological processes have been complicated by the fact that the nervous system contains multiple kinds of receptor molecules for dopamine as well as different types of nerve cells that use dopamine. In the current study, scientists in Dr. Lovinger's lab worked with Argentinean researchers led by senior author Marcelo Rubinstein, Ph.D., to develop genetically engineered mice in which expression of D2 receptors was selectively prevented in nerve cells that use dopamine as their neurotransmitter. These nerve cells are present in the midbrain region and connect to other neurons in the striatum. The receptors normally present on these cells are known as D2 autoreceptors.

Keyword: Drug Abuse
Link ID: 15544 - Posted: 07.12.2011

By Tina Hesman Saey A study of twins in California downgrades the role genes play in autism, but the work doesn’t hold water with some autism researchers. Previous studies indicated that autism spectrum disorders are due mainly to genes. But the new study suggests that environment — including conditions in the womb, age of parents and other factors — may account for a greater fraction of the risk of developing autism spectrum disorders. Other studies estimated genetic heritability of autism to be as high as 90 percent, meaning that genetic factors account for the vast majority of variables contributing to the development of autism. But the new study suggests that genetic heritability accounts for just 37 percent of variation in risk of classical autism and 38 percent of other autism spectrum disorders, such as Asperger syndrome. Shared environmental factors are responsible for 55 percent of autism and 58 percent of autism spectrum disorders, researchers report online July 4 in the Archives of General Psychiatry. “People are, more and more, recognizing that autism is a complex disorder that would be hard to explain with genes alone,” says study coauthor Joachim Hallmayer, a psychiatric geneticist at Stanford University. But some researchers question whether the new estimates accurately reflect the contributions of genes and environment to autism. “When somebody gets a totally different answer from what anyone else has seen, you need to see it a few more times before you believe it,” says Susan Folstein, a child psychiatrist at the University of Miami whose 1977 twin study found that autism has a large genetic component. Before that study, autism was often blamed on bad parenting and cold, withdrawn “refrigerator mothers.” Folstein fears that the new study will cause a resurgence in that attitude. “We just lost the battle again. It’s all the mother’s fault,” she says. © Society for Science & the Public 2000 - 2011

Keyword: Autism; Genes & Behavior
Link ID: 15543 - Posted: 07.09.2011

By Bruce Bower Panzee doesn’t talk, but she knows a word when she hears one — even if it’s emitted by a computer with a synthetic speech impediment. That’s not too shabby for a chimpanzee. Raised to recognize 128 spoken words by pointing to corresponding symbols, Panzee perceives acoustically distorted words about as well as people do, say psychology graduate student Lisa Heimbauer of Georgia State University in Atlanta and her colleagues. Panzee thus challenges the argument that only people can recognize highly distorted words, thanks to brains tuned to speech sounds and steeped in chatter, the scientists contend in a paper published online June 30 in Current Biology. “Auditory processing abilities that already existed in a common ancestor of chimpanzees and humans may have been sufficient to perceive speech,” Heimbauer says. Panzee’s immersion in talk began in infancy and fueled her word-detection skills, much as occurs in people, Heimbauer suggests. Originally, the researchers thought that Panzee would need training to grasp the word task, since she had never heard artificially distorted words. But after hearing only one such word, the chimp identified the next four synthetically distorted words before making a mistake. “What were supposed to be training sessions became test sessions,” Heimbauer says. © Society for Science & the Public 2000 - 2011

Keyword: Language; Evolution
Link ID: 15542 - Posted: 07.09.2011

By Rachel Ehrenberg Eating fatty foods may give you the munchies. A new study shows that when rats taste fat, it stimulates the same cellular buttons triggered by the active ingredient in marijuana, telling the body to keep on eating. Uncovering the events that lead to this molecular “eat, eat” missive will make it easier to develop drugs that curb binge eating and other weight related-problems, says pharmacologist Daniele Piomelli, who led the new work. Piomelli and his colleagues were interested in compounds known as endocannabinoids — the body’s version of the active ingredient in marijuana — and the role they play in overeating. Several kinds of endocannabinoids are released in the brain and body, but researchers are still discovering the nitty-gritty of where and when these compounds regulate mood and behavior. So the researchers fed rats one of four liquid diets: fat (in the form of corn oil), protein, sugar or a nutrition shake combination of fat, protein and sugar. To ensure that the body’s digestive signals wouldn’t interfere with the experiments, a surgically implanted valve in the rats’ upper stomach drained the food once eaten. Then the team measured endocannabinoid activity in the brain and other tissues. Compared with rats eating sugar or protein alone, rats on the fat diet had a surge of endocannabinoid activity in their gut, the team reported online July 5 in the Proceedings of the National Academy of Sciences. And these rats wouldn’t stop slurping their corn oil. When given a compound that blocked the cellular buttons that the endocannabinoids typically hit, the fat-eating rats immediately stopped eating. © Society for Science & the Public 2000 - 2011

Keyword: Obesity; Drug Abuse
Link ID: 15541 - Posted: 07.09.2011

By Hal Arkowitz and Scott O. Lilienfeld Earlier this year a 22-year-old college dropout, Jared Lee Loughner, shot Arizona congresswoman Gabrielle Giffords through the head near a Tucson supermarket, causing significant damage to Giffords’s brain. In the same shooting spree, Loughner killed or wounded 18 others, including a federal judge and a nine-year-old girl. Information from Loughner’s postings on YouTube and elsewhere online suggests that he is severely mentally ill. Individuals with serious mental illnesses have perpetrated other recent shoot-ings, including the massacre in 2007 at ­Virginia Tech in which a college senior, ­Seung-Hui Cho, killed 32 people and wounded 17. These events and the accompanying media coverage have probably fed the public’s perception that most profoundly mentally ill people are violent. Surveys show that 60 to 80 percent of the public believes that those diagnosed with schizophrenia, in particular, are likely to commit violent acts. Although studies have pointed to a slight increase in the risk of violent behaviors among those afflicted with major psychiatric ailments, a closer examination of the research suggests that these disorders are not strong predictors of aggressive behavior. In reality, severely mentally ill people account for only 3 to 5 percent of violent crimes in the general population. The data indicate that other behaviors are likely to be better harbingers of physical aggression—an insight that may help us prevent outbursts of rage in the future. Not all psychological and emotional disorders portend violence, even in society’s eyes. In this column, we refer only to severe mental illness—meaning schizophrenia, bipolar disorder or psychotic depression. Symptoms of schizophrenia include marked disturbances in thoughts, emotions and behaviors; delusions (fixed false beliefs); hallucinations (perceiving things that are not physically present); disorganization; and withdrawal from social activities. Bipolar disorder is usually characterized by swings between depression and mania, which involves euphoria and grandiosity, a boost in energy and less need for sleep. Psychotic depression includes acute depressive symptoms, along with delusions or hallucinations, or both. © 2011 Scientific American,

Keyword: Aggression; Schizophrenia
Link ID: 15540 - Posted: 07.09.2011

by Rebecca Kessler While exploring Australia's Great Barrier Reef, professional diver Scott Gardner heard an odd cracking sound and swam over to investigate. What he found was a footlong blackspot tuskfish (Choerodon schoenleinii) holding a clam in its mouth and whacking it against a rock. Soon the shell gave way, and the fish gobbled up the bivalve, spat out the shell fragments, and swam off. Fortunately, Gardner had a camera handy and snapped what seem to be the first photographs of a wild fish using a tool. Tool use, once thought to be the distinctive hallmark of human intelligence, has been identified in a wide variety of animals in recent decades. Although other creatures don't have anything quite like a circular saw or a juice machine, capuchin monkeys select "hammer" rocks of an appropriate material and weight to crack open seeds, fruits, or nuts on larger "anvil" rocks, and New Caledonian crows probe branches with grass, twigs, and leaf strips to extract insects. In addition to primates and birds, many animals, including dolphins, elephants, naked mole rats, and even octopuses, have shown forms of the behavior. Tool-using fish have been few and far between, however, particularly in the wild. Archerfish target jets of water at terrestrial prey, but whether this constitutes tool use has been contentious. There have also been a handful of reports of fish cracking open hard-shelled prey, such as bivalves and sea urchins, by banging them on rocks or coral, but there's no photo or video evidence to back it up, according to Culum Brown, a behavioral ecologist at Macquarie University in Sydney, Australia, and a co-author of the present paper, to be published in a forthcoming issue of Coral Reefs. © 2010 American Association for the Advancement of Science

Keyword: Evolution
Link ID: 15539 - Posted: 07.09.2011

by Daniel Strain A protein in the brain that has been linked to the development of human language may push developing neurons to reach out and touch someone—or, at least, other brain cells, according to a new study. Such early links could organize the cell-to-cell connections critical for learning complex tasks later in life, including reciting Dr. Seuss, researchers say. Researchers first identified the FOXP2 gene and its protein in 2001. The study involved a family that had difficulty pronouncing and understanding words, and since then scientists have suspected that the gene may have played a role in the evolution of human language. It even appears to be important to "speech" in other animals: zebra finches with low levels of the FOXP2 protein, for example, can't learn the songs that other birds sing. Most studies of FOXP2 have focused on its effects post-birth, says Simon Fisher, a neurogeneticist at the Max Planck Institute for Psycholinguistics in Nijmegen, Netherlands. So scientists have been unclear about its role in very early brain building. To tease this out, Fisher and colleagues turned to embryonic mice. The team screened thousands of known genes in whole mice brains, looking for those switched on or off by the FOXP2 protein. In brain tissue bathed in high concentrations of FOXP2, the protein kicked about 160 genes into gear. Another 180 genes in these cells slowed down protein production. All of this suggests that FOXP2 is a "hub in a network of genes which might be important," Fisher says. © 2010 American Association for the Advancement of Science.

Keyword: Language; Development of the Brain
Link ID: 15538 - Posted: 07.09.2011

by Kat McGowan The woman in the wheelchair wearing burgundy scrubs is lovely, with full eyebrows arching over her closed eyes. Joseph Giacino, director of rehabilitation neuro­psychology at Spaulding Rehabilitation Hospital in Boston, squats beside her, looking into her face. “Hi, Kellie, it’s Dr. Giacino. How are you? Can you open your eyes?” No response. Two and a half months ago, during what was supposed to be a simple nasal operation for sinusitis, Kellie’s left carotid artery was accidentally sliced open, starving half her brain of blood and oxygen. Since that day, she has not spoken or clearly responded in any way. She opens her eyes, and sometimes she groans or gropes toward people nearby. Most of the time she seems to be asleep. Is Kellie still in there? Giacino, 52, an expert in disorders of consciousness, will establish her condition more precisely with this exam. First, though, he needs Kellie to be more alert. He rubs her arm and her leg firmly, applying deep-muscle pressure, and her dark eyes pop open. She begins to breathe heavily and to shake. Giacino soothes her. “I’m just waking you up,” he says gently. “You had some bleeding in your brain, and we’re trying to help you get better.” The expression on her face is intense and hard to read. It mixes fear with annoyance, as if she has just woken from a nightmare. “Every kid has a dad and a…” he prompts. She moans, or is she trying to say “mom”? It is difficult to tell whether she is oblivious or struggling to respond. When she makes eye contact and holds it, she seems just as aware as anyone else in the room. By her fierce expression, she looks as if she is about to tell Giacino to buzz off. Yet she does not speak. That is why this exam, calibrated to distinguish between reflexes and real cognition, is so important. When Giacino hands her a toy ball, she grabs it, smoothly and naturally. It is a good sign. Copyright © 2011, Kalmbach Publishing Co.

Keyword: Attention
Link ID: 15537 - Posted: 07.07.2011

by Andy Coghlan People with Parkinson's disease might one day be treated with brain cells made from their own skin. Two teams of researchers have independently worked out how to turn skin cells into specialised neurons that make dopamine. This neurotransmitter, which is vital for mobility, is depleted in the brains of people with Parkinson's. The studies raise the possibility of improving mobility in people with Parkinson's by restoring dopamine production to normal. At present, most patients take a drug called L-dopa to readjust levels, but with varying levels of success. Both techniques avoid the initial step of converting skin cells into embryo-like pluripotent cells – a technique which poses a possible cancer risk. Vania Broccoli of the San Raffaele Scientific Institute in Milan, and colleagues, first reprogrammed mouse skin cells using three transcription factors – proteins previously linked with the development of the neurons. The same trio of factors transformed skin cells taken from human embryos, healthy adults and people with Parkinson's. The only drawback is that Broccoli's team first had to infect the skin cells with viruses carrying genes to make the transcription factors, although the viruses used are not ones that might disrupt DNA and cause cancer. © Copyright Reed Business Information Ltd.

Keyword: Parkinsons; Stem Cells
Link ID: 15536 - Posted: 07.07.2011

by Duncan Graham-Rowe The latest brain-computer interfaces meet smart home technology and virtual gaming TWO friends meet in a bar in the online environment Second Life to chat about their latest tweets and favourite TV shows. Nothing unusual in that - except that both of them have Lou Gehrig's disease, otherwise known as amyotrophic lateral sclerosis (ALS), and it has left them so severely paralysed that they can only move their eyes. These Second Lifers are just two of more than 50 severely disabled people who have been trying out a sophisticated new brain-computer interface (BCI). Second Life has been controlled using BCIs before, but only to a very rudimentary level. The new interface, developed by medical engineering company G.Tec of Schiedlberg, Austria, lets users freely explore Second Life's virtual world and control their avatar within it. It can be used to give people control over their real-world environment too: opening and closing doors, controlling the TV, lights, thermostat and intercom, answering the phone, or even publishing Twitter posts. The system was developed as part of a pan-European project called Smart Homes for All, and is the first time the latest BCI technology has been combined with smart-home technology and online gaming. It uses electroencephalograph (EEG) caps to pick up brain signals, which it translates into commands that are relayed to controllers in the building, or to navigate and communicate within Second Life and Twitter. © Copyright Reed Business Information Ltd.

Keyword: Robotics
Link ID: 15535 - Posted: 07.07.2011

By Linda Carroll What finally washed away Kari Adams’s denial was the flood of tears streaming down her dad’s face. Frightened by Kari’s plunging weight, her family had been begging the 41-year-old mother of two to seek help for months. But nobody could convince Kari that anything was wrong – until she saw her dad’s tears. “That’s when it hit me,” she said. “He never cried before in my whole life.” Kari’s story echoes that of many other middle-aged women in America. Major transitions and traumatic mid-life events — crumbling marriages, job losses or kids going off to college — can rekindle eating disorders that had begun years before. “It’s rare that an eating disorder shows up completely out of the blue in mid-life,” said Douglas Bunnell, vice president and director of out-patient clinical services at The Renfrew Center, where Kari eventually sought help. The more common scenario, Bunnell said, is the resurgence of a life-long problem. Eating disorder experts are seeing more and more patients like Kari these days. The Renfrew Center has seen a 42 percent increase in the number of women over the age of 35 seeking help. That’s prompted the center to come up with a special program geared to their older patients. Therapists focus on stressors that trigger eating disorders in adults and on the underlying issues inflaming the problem, such as anxiety. “For these people, there’s something soothing about not eating,” Bunnell said. “The eating disorder has become embedded in the way they manage anxiety.” © 2011 MSNBC Interactive

Keyword: Anorexia & Bulimia
Link ID: 15534 - Posted: 07.07.2011

A chemical in the body that triggers pain from sunburn has been pinpointed by UK experts in a discovery that could lead to new painkillers. Scientists hope one day to be able to knock out the substance with drugs, helping people who suffer from chronic pain. Tests on volunteers showed CXCL5, as it is called, is produced when skin is burnt by UV rays from the sun. The research is published in the journal Science Translational Medicine. Exposure to ultraviolet light from sunlight causes premature skin ageing, cancer and other skin changes. UVB affects the outer layer of skin, and is the main agent responsible for sunburn. In the study, scientists at King's College London exposed small patches of the 10 volunteers' skin to UVB. Areas of sunburn were produced which became increasingly tender over a few days. The scientists took small samples of sunburnt skin and screened them for hundreds of known pain molecules. They discovered unusually high levels of CXCL5. BBC © 2011

Keyword: Pain & Touch
Link ID: 15533 - Posted: 07.07.2011

By Tia Ghose Blocking a death receptor causes damaged myelin, the protective coating surrounding nerve cells, to repair itself, according to a study published Sunday (July 3) in Nature Medicine. The finding suggests that drugs targeting the receptor could help treat multiple sclerosis by reversing the myelin damage characteristic of the disease. “Showing remyelination, as they do in vivo and in vitro, is a pretty cool result,” said Richard Ransohoff, a Cleveland Clinic neuroscientist who was not involved in the work. The new receptor is a novel first step in potentially repairing damaged nerves of multiple sclerosis patients, he said. Current multiple sclerosis drugs slow the disease’s progression by quieting the inflammatory response of the immune system, which attacks the myelin surrounding nerve cells and kills oligodendrocytes, brain cells that make and repair myelin. Without their myelin, nerve cells gradually lose their ability to send electrical signals. But because they suppress the immune response, these drugs make patients more susceptible to rare infections such as viral brain inflammation and diseases such as leukemia. They also cannot undo existing damage, leading scientists to seek out approaches that stimulate the growth of new myelin or the restoration of existing myelin. Though research has identified several candidate molecules that promote myelin survival, none have yet proven to do so successfully in patients. © 1986-2011 The Scientist

Keyword: Multiple Sclerosis; Apoptosis
Link ID: 15532 - Posted: 07.07.2011

By Nathan Seppa A nutritional supplement that is free of charge, offers a wide range of health benefits and poses little risk sounds like fodder for a late-night TV commercial. But proponents of vitamin D are increasingly convinced that the sunshine vitamin delivers the goods, no strings attached. It offers a safe route to better health, these advocates say, by promoting proper function of the bones, heart, brain, immune system, you name it. Yet, the proponents claim, most people don’t get enough. Whereas humans’ pre­historic ancestors lived outdoors and made oodles of vitamin D in their sun-exposed skin, people today have become shut-ins by comparison — and scant sun exposure means low vitamin D. Of course, not everyone sees such a grand reach for the vitamin. While scientists concur that it is essential for bone maintenance, some stop right there. The skeptics note that vitamin D’s other promising qualities have shown up largely in studies that fall short of the gold standard of medicine — the randomized controlled trial, in which groups of people get either a placebo or the real thing. While a handful of randomized trials have shown additional benefits, others have not, leaving a gap in the vitamin’s otherwise sterling reputation. This debate came to a head last November, when an Institute of Medicine panel of scientists announced new vitamin D recommendations. The old intake levels were barely high enough to prevent rickets, a bone condition associated with the Industrial Revolution. The IOM panel boosted the recommended daily intake of the vitamin from 200 to 600 international units per day for most of the population. The new dose is about 15 micrograms, in the range of vitamin D found in most multivitamins. © Society for Science & the Public 2000 - 2011

Keyword: Parkinsons; Hormones & Behavior
Link ID: 15531 - Posted: 07.05.2011

Rowan Hooper, news editor Poor old Carolyn. Six of her previous babies have been taken away from her, and, as this film opens, men are coming to take her seventh. Her son, a chimpanzee named Nim, is two weeks old and is about to be transplanted from his birthplace at a primate research centre in Oklahoma into - wait for it - a large brownstone on the upper west side of Manhattan. There he will live with a human family and be raised as a human child. Thus begins the stranger than fiction true story that's explored in James Marsh's new documentary, Project Nim. What on earth were they thinking of? Nim was put in diapers and dressed in clothes. He was breastfed by his human surrogate mother, Stephanie Lafarge. "It seemed natural," she says. Lafarge's daughter, Jenny Lee, has a better explanation: "It was the seventies". Jenny was 10-years-old when Nim came to live with her family. The film, assembled from archive footage shot at the time, recreated scenes and interviews with the main characters, tells the story of Nim's chaotic life. In the mid 1970s a scientific debate was raging over the origin of language. There were two camps: those who held that human language was part of a continuum, in which case we'd expect other primates to have the rudiments of language, and those who thought language was uniquely human and there would be no evolutionary trace of it in other apes. © Copyright Reed Business Information Ltd.

Keyword: Language; Evolution
Link ID: 15530 - Posted: 07.05.2011

By NATALIE ANGIER Among the Ache hunter-gatherers in eastern Paraguay, healthy adults with no dependent offspring are expected to donate as much as 70 to 90 percent of the food they forage to the needier members of the group. And as those strapping suppliers themselves fall ill, give birth or grow old, they know they can count on the tribe to provide. Among the !Kung bushmen of the Kalahari in Africa, a successful hunter who may be inclined to swagger is kept in check by his compatriots through a ritualized game called “insulting the meat.” You asked us out here to help you carry that pitiful carcass? What is it, some kind of rabbit? Among the Hadza foragers of northern Tanzania, people confronted by a stingy food sharer do not simply accept what’s offered. They hold out their hand, according to Frank Marlowe, an anthropologist at Durham University in England, “encouraging the giver to keep giving until the giver finally draws the line.” Among America’s top executives today, according to a study commissioned by The New York Times, the average annual salary is about $10 million and rising some 12 percent a year. At the same time, the rest of the tribe of the United States of America struggles with miserably high unemployment, stagnant wages and the worst economic crisis since the Great Depression. Now, maybe the wealth gap is a temporary problem, and shiny new quarters will soon rain down on us all. But if you’re feeling tetchy and surly about the lavished haves when you have not a job, if you’re tempted to go out and insult a piece of corporate meat, researchers who study the nature and evolution of human social organization say they are hardly surprised. © 2011 The New York Times Company

Keyword: Evolution
Link ID: 15529 - Posted: 07.05.2011

By PAM BELLUCK People in a large area of the American South have long been known to have more strokes and to be more likely to die from them than people living elsewhere in the country. Now, a large national study suggests the so-called stroke belt may have another troubling health distinction. Researchers have found that Southerners there also are more likely to experience a decline in cognitive ability over several years — specifically, problems with memory and orientation. The differences to date in the continuing study are not large: Of nearly 24,000 participants, 1,090 in eight stroke-belt states showed signs of cognitive decline after four years, compared with 847 people in 40 other states. But the geographic difference persisted even after the researchers adjusted for factors — like age, sex, race and education — that might influence the result. The most recent data from the study were published in Annals of Neurology. None of the people with cognitive decline in the study had had detectable strokes. But some experts believe their memory problems and other mental issues could be related to the same underlying risk factors, including lifestyle patterns that contribute to hypertension, high cholesterol, diabetes and obesity. Is it the fried food beloved by Southerners? Limited access to doctors? Too little exercise? Researchers are investigating those and other possible causes. Some experts also suggest that the participants could have had small, undetectable strokes that subtly affected brain function. © 2011 The New York Times Company

Keyword: Stroke; Learning & Memory
Link ID: 15528 - Posted: 07.05.2011

By LAURA BEIL Just as the ear has two purposes — hearing and telling you which way is up — so does the eye. It receives the input necessary for vision, but the retina also houses a network of sensors that detect the rise and fall of daylight. With light, the body sets its internal clock to a 24-hour cycle regulating an estimated 10 percent of our genes. The workhorse of this system is the light-sensitive hormone melatonin, which is produced by the body every evening and during the night. Melatonin promotes sleep and alerts a variety of biological processes to the approximate hour of the day. Light hitting the retina suppresses the production of melatonin — and there lies the rub. In this modern world, our eyes are flooded with light well after dusk, contrary to our evolutionary programming. Scientists are just beginning to understand the potential health consequences. The disruption of circadian cycles may not just be shortchanging our sleep, they have found, but also contributing to a host of diseases. “Light works as if it’s a drug, except it’s not a drug at all,” said George Brainard, a neurologist at Thomas Jefferson University in Philadelphia and one of the first researchers to study light’s effects on the body’s hormones and circadian rhythms. Any sort of light can suppress melatonin, but recent experiments have raised novel questions about one type in particular: the blue wavelengths produced by many kinds of energy-efficient light bulbs and electronic gadgets. © 2011 The New York Times Company

Keyword: Biological Rhythms; Vision
Link ID: 15527 - Posted: 07.05.2011

By BENEDICT CAREY Researchers have long known that the brain links all kinds of new facts, related or not, when they are learned about the same time. Just as the taste of a cookie and tea can start a cascade of childhood memories, as in Proust, so a recalled bit of history homework can bring to mind a math problem — or a new dessert — from that same night. For the first time, scientists have recorded traces in the brain of that kind of contextual memory, the ever-shifting kaleidoscope of thoughts and emotions that surrounds every piece of newly learned information. The recordings, taken from the brains of people awaiting surgery for epilepsy, suggest that new memories of even abstract facts — an Italian verb, for example — are encoded in a brain-cell firing sequence that also contains information about what else was happening during and just before the memory was formed, whether a tropical daydream or frustration with the Mets. The new study suggests that memory is like a streaming video that is bookmarked, both consciously and subconsciously, by facts, scenes, characters and thoughts. Experts cautioned that the new report falls well short of revealing how contextual memory and different cues interact; some words might throw the mind into a vivid reverie, while others do not. But the report does provide a glimpse into how the brain places memories in space and time. “It’s a demonstration of this very cool idea that you have remnants of previous thoughts still rattling around in your head, and you bind the representation of what’s happening now to the fading embers of those old thoughts,” said Ken Norman, a neuroscientist at Princeton who did not participate in the study. “I think they have very good evidence that this process is crucial to time-stamping your memories.” © 2011 The New York Times Company

Keyword: Learning & Memory
Link ID: 15526 - Posted: 07.05.2011

By Stephanie Pappas It's hard to eat just one potato chip, and a new study may explain why. Fatty foods like chips and fries trigger the body to produce chemicals much like those found in marijuana, researchers report today (July 4) in the journal Proceedings of the National Academy of Sciences (PNAS). These chemicals, called "endocannabinoids," are part of a cycle that keeps you coming back for just one more bite of cheese fries, the study found. "This is the first demonstration that endocannabinoid signaling in the gut plays an important role in regulating fat intake," study researcher Daniele Piomelli, a professor of pharmacology at the University of California, Irvine, said in a statement. The study found that fat in the gut triggers the release of endocannabinoids in the brain, but the gray stuff between your ears isn't the only organ that makes natural marijuana-like chemicals. Human skin also makes the stuff. Skin cannabinoids may play the same role for us as they do for pot plants: Oily protection from the wind and sun. Endocannabinoids are also known to influence appetite and the sense of taste, according to a 2009 study in PNAS, which explains the munchies people get when they smoke marijuana. © 2011 LiveScience.com.

Keyword: Obesity; Drug Abuse
Link ID: 15525 - Posted: 07.05.2011