By Nikhil Swaminathan Scientists have found that a lessened supply of new nerve cells in the adult brain apparently triggers short-term memory loss typically associated with aging, setting the stage for one day developing therapies designed to maintain a steady supply of fresh neurons to keep the mind sharp. "Neurogenesis (nerve-cell production) goes down with age … it's known that with old age there's a decrease in short- term memory," says Ronald Evans, a genetics professor at the Salk Institute for Biological Studies in La Jolla, Calif. "We know that if we can increase the process, we know what the consequence could be in the brain, which would be to increase short-term learning and memory." "New experiences, new memories [and] new learning [are] greatly facilitated by neurogenesis," he adds. "Neurogenesis is in fact a fundamental feature of learning and memory. … Neurogenesis goes down with age; and, it's known that with old age there's a decrease in short-term memory." Evans is co-author of a study published in Nature that shows impaired short-term memory and learning in adult mice, in which scientists blocked the process of neurogenesis. They did this by engineering mice that lacked one copy of the gene responsible for the production of Tlx, a protein that the team had previously determined was crucial to maintaining and renewing the arsenal of neural stem cells. © 1996-2007 Scientific American Inc.

Keyword: Learning & Memory; Neurogenesis
Link ID: 11264 - Posted: 06.24.2010

Heidi Ledford US soldiers who became concussed during deployment in Iraq are more likely to report poor general health than are veterans with other injuries, a study has found. But questions remain about what causes those lingering health problems: the physical blow to the head, or the emotional trauma associated with violent experiences. A study released today, in the New England Journal of Medicine, notes that the link between concussion and poor health might have resulted from higher rates of post-traumatic stress disorder in those with head injuries1. "The possibility that symptoms could be accounted for by emotional disorders such as post-traumatic stress disorder is very important for us to know," says Roger Pitman, a professor of psychiatry at Harvard Medical School in Boston, Massachusetts. "We have to be very careful about who we call 'brain-damaged', because of the possible adverse effects of labelling people in this way." Traumatic brain injuries are the most common physical injury seen in troops deployed to Iraq and Afghanistan — largely thanks to improvised explosive devices. They have been designated a 'signature' of the two conflicts. © 2008 Nature Publishing Group

Keyword: Brain Injury/Concussion; Stress
Link ID: 11263 - Posted: 06.24.2010

Jennifer Viegas -- Feline defensive rage, the aggressive cat behavior that recently led to the death of a California zoo visitor by a tiger that felt threatened, is comparable to human rage, both in the way that it emerges and unleashes in the brain, suggests a new study. Because scientists are gaining a better understanding of the mammalian brain's recipe for rage, violent behavior in humans and other mammals may one day be quelled with improved drug therapies. For cats, such a drug could prevent the hissing, back arching, ear retraction, claw extensions and fur standing-on-end that are typical indicators of feline defensive rage. In humans, related anger reveals itself with road rage, an impulsive form of anger that involves little or no thought. "In road rage, the person never thinks about what he is doing but just acts in the way he does because he feels that he has been threatened by someone else and the impulsive behavior represents a way by which he can protect himself from such a threat," co-author Allan Siegel told Discovery News. "In reality, his actions are usually much more dangerous to him than to the person whom he perceived cut him off on the road," added Siegel, a professor in the Department of Neurology & Neurosciences at New Jersey Medical School in Newark. © 2008 Discovery Communications, LLC

Keyword: Emotions; Aggression
Link ID: 11262 - Posted: 06.24.2010

By Constance Holden Like a skyscraper skeleton that goes up overnight--but doesn't get windows for another decade--languages evolve in fits and starts, according to a new study. The idea that languages evolve in bursts, rather than gradually, isn't new. When applied to species, it's called punctuated evolution. But the idea is controversial in both fields--and proof has been hard to come by. Now, scientists in the United Kingdom say they've mustered the power of mathematics to demonstrate the phenomenon in the evolution of languages. The researchers, headed by evolutionary biologist Quentin Atkinson and mathematician Mark Pagel of the University of Reading, looked at related versions, or homologs, of common words in three of the world's major language families: Indo-European, Bantu, and Austronesian. Like species, changes in languages can be tracked through the fate of certain words, just as mutations in key genes can tell a species' history. The words the researchers tracked are from the so-called Swadesh lists: compilations of heavily used words denoting things such as numbers or body parts that change little over time and are rarely borrowed, making them good clues about how one language relates to another. An example from the Indo-European language family is the words for "water" in English, German ("Wasser"), Hittite ("watar"), and Russian ("voda"). Despite many borrowings, English is much further from Latin languages such as French, according to the Swadesh lists. Consider, for example, the French for water--"eau." © 2008 American Association for the Advancement of Science

Keyword: Language; Evolution
Link ID: 11261 - Posted: 06.24.2010

Dan Jones “It is scientifically incorrect to say that we have inherited a tendency to make war from our animal ancestors … that war or any other violent behaviour is genetically programmed into our human nature … [and] that humans have a 'violent brain'.” These are the ringing words of the 'Seville Statement on Violence', fashioned by 20 leading natural and social scientists in 1986 as part of the United Nations International Year of Peace, and later adopted by the United Nations Educational, Scientific and Cultural Organization (UNESCO). It was written to counter the pessimistic view that violence and war are inevitable features of human life. The decades since have not been kind to these cherished beliefs. A growing number of psychologists, neuroscientists and anthropologists have accumulated evidence that understanding many aspects of antisocial behaviour, including violence and murder, requires the study of brains, genes and evolution, as well as the societies those factors have wrought. At the same time, though, historians, archaeologists and criminologists have started to argue that in most places life was more violent — and more likely to end in murder — in the past than it is today. The time span of this apparent decline in violence has been too short for appeals to natural selection to be convincing. If humans have evolved to kill, then it seems that they have also evolved to live without killing, given the right circumstances. © 2008 Nature Publishing Group

Keyword: Aggression; Evolution
Link ID: 11260 - Posted: 06.24.2010

By Linda Carroll When her 5-year-old son showed up at the door with a black eye and a bloody cut on his head, Brooke Fike knew it was time to take on the bullies. For weeks, several boys at school had been swinging their backpacks into her son's head. One day they dumped a carton of milk over him during lunch. As Fike tried to remedy the problem, she realized that the bullies seemed to be the kids in class who couldn’t sit still and listen. They didn’t do their homework. They were almost constantly in motion. Turns out, those behaviors could have been the first clue to parents and school officials that these boys might be the ones who were going to turn into bullies. A new study shows that children with attention deficit hyperactivity disorder are almost four times as likely as others to be bullies. And, in an intriguing corollary, the children with ADHD symptoms were almost 10 times as likely as others to have been regular targets of bullies prior to the onset of those symptoms, according to the report in the February issue of the journal Developmental Medicine & Child Neurology. © 2008 MSNBC Interactive

Keyword: ADHD
Link ID: 11259 - Posted: 06.24.2010

Jennifer Viegas -- Sperm whales literally drift to sleep, but it's a snooze like no other, according to a recent study that found whales perform slow, rhythmic dives as they slumber. Because these drift dives keep the whales in constant motion as they rest, scientists now think the seafaring mammals sleep with one side of their brain at a time. The two sides alternate until both are rested. Sperm whales might even break a world record for least amount of sleep needed by a mammal. "If the only sleep sperm whales get is during these drift dives, it would be less than any mammal studied so far," lead author Patrick Miller told Discovery News. Miller, a senior research fellow at the University of St. Andrews Gatty Marine Research Institute, and his colleagues affixed suction cups with data-logging tags onto 59 sperm whales at various open-water locations worldwide. The tags allowed the scientists to monitor the whales' movements 24/7. The researchers, whose study was recently published in Current Biology, noticed the whales performed the mesmerizing drift dives 7.1 percent of the time, usually between 6 p.m. and midnight. The scientists observed two types of drift dives. The first, head-up drift dives, happen when a whale's rear end slowly sinks into the water from a horizontal posture. © 2008 Discovery Communications, LLC

Keyword: Sleep; Evolution
Link ID: 11258 - Posted: 06.24.2010

Alison Abbott Electrodes implanted into the brain of a patient undergoing an experimental treatment for obesity have surprisingly improved his memory skills. The startling and unexpected effects — reported in Annals of Neurology 1 — have prompted the Canadian team of neurologists to launch a new deep-brain stimulation (DBS) trial in patients with early Alzheimer’s disease. Three patients have already had electrodes implanted, says neurosurgeon Andres Lozano from the University of Toronto's Toronto Western Research Institute. “The surgery seems safe and the results are promising,” he says. During DBS, a hair-thin electrode with four contact points is placed in a very precise area of the brain. Each contact can be stimulated individually with different frequencies of electric current — or switched off — by remote control. The tiny currents are intended to activate specific neural circuits in the brain that under-perform in particular disorders. The procedure is most often used to treat Parkinson’s disease but, in the past few years, neurosurgeons have been experimenting with treating psychiatric disorders including depression and obsessive-compulsive disorder. © 2008 Nature Publishing Group

Keyword: Learning & Memory
Link ID: 11257 - Posted: 06.24.2010

Andrew W. McCollough & Edward K. Vogel Anyone who has tried to find an urgent email amid masses of advertisements for dubious stock opportunities and sexual enhancement drugs understands the critical importance of being able to filter out distracting information. That important email may be in there but it is lost among irrelevant clutter. And while the capacity of our email inbox is limited only by disc space, our mental 'inbox' of working memory is much more constrained. In fact, several decades of research have indicated that our capacity to hold information “in mind” for immediate use is limited to a mere three or four items. Moreover, just as people vary in height and eye color, we also vary in the capacity of this memory inbox. Interestingly, these differences in working memory capacity are strongly predictive of a person’s ability to perform abstract reasoning, mathematics, and other forms of complex problem solving. This relationship between memory capacity and fluid intelligence has motivated many scientists to try to understand why and how people differ in this important cognitive ability. There are at least two primary explanations for this severe limitation in working memory capacity. First, it could be that working memory capacity is essentially determined by storage space, and that some people have larger "hard drives" than others do. The alternative explanation is that capacity depends not on the amount of storage space but on how efficiently that space is used. Thus high-capacity individuals might simply be better at keeping irrelevant information out of mind, whereas low capacity individuals may allow more irrelevant information to clutter up the mental inbox. High-capacity individuals may just have better spam filters. © 1995-2007 Scientific American Inc

Keyword: Learning & Memory; Attention
Link ID: 11256 - Posted: 06.24.2010

United States researchers suggest long-ago lead exposure can make an aging person's brain work as if it's five years older than it really is. "We're trying to offer a caution that a portion of what has been called normal aging might in fact be due to ubiquitous environmental exposures like lead," says Dr. Brian Schwartz of Johns Hopkins University, a leader in the study of lead's delayed effects. The notion of long-delayed effects is familiar; tobacco and asbestos, for example, can lead to cancer. But in recent years, scientists are coming to appreciate that exposure to other pollutants in early life also may promote disease much later on. "It's an emerging area" for research, said Dr. Philip Landrigan of the Mount Sinai School of Medicine in New York. It certainly makes sense that if a substance destroys brain cells in early life, the brain may cope by drawing on its reserve capacity until it loses still more cells with aging, he said. Only then would symptoms like forgetfulness or tremors appear. Studying delayed effects in people is difficult because they generally must be followed for a long time. Research with lead is easier because scientists can measure the amount that has accumulated in the shinbone over decades and get a read on how much lead a person has been exposed to in the past. © CBC 2008

Keyword: Neurotoxins; Alzheimers
Link ID: 11255 - Posted: 06.24.2010

Life may begin at 40, but research suggests that 44 is the age at which we are most vulnerable to depression. Data analysis on two million people from 80 countries found a remarkably consistent pattern around the world. The risk of depression was lowest in younger and older people, with the middle-aged years associated with the highest risk for both men and women. The study, by the University of Warwick and Dartmouth College in the US, will feature in Social Science & Medicine. The only country which recorded a significant gender difference was the US, where unhappiness reached a peak around the age of 40 for women, and 50 for men. Previous research has suggested that the risk of unhappiness and depression stays relatively constant throughout life. However, the latest finding - of a peak risk in middle age - was consistent around the globe, and in all types of people. Researcher Professor Andrew Oswald, an economist at the University of Warwick, said: "It happens to men and women, to single and married people, to rich and poor, and to those with and without children." He said the reason why middle age was a universally vulnerable time was unclear. However, he said: "One possibility is that individuals learn to adapt to their strengths and weaknesses, and in mid-life quell their infeasible aspirations. Another possibility is that a kind of comparison process is at work in which people have seen similar-aged peers die and value more their own remaining years. Perhaps people somehow learn to count their blessings." (C)BBC

Keyword: Depression
Link ID: 11253 - Posted: 01.29.2008

By JANE E. BRODY When a woman complains of genital pain so severe that it makes sexual intercourse all but impossible, her partner may jump to the conclusion that she has a phobia about sex. But what if that same woman also experiences excruciating pain when trying to insert a tampon, undergo a pelvic exam, wear a pair of jeans, ride a bicycle or go jogging? Can phobia explain all those problems? Not very likely. In fact, studies have shown that sexual phobias are rarely the explanation for a condition known as vulvodynia, a chronic discomfort of the vulva that can result in searing or shooting pain when any amount of pressure is placed on the sensitized tissues. Some women compare the feeling to acid being poured on an open wound. The problem can last months, years or a lifetime. Worse, doctors often misdiagnose it or treat it inappropriately, if at all. For decades, women suffering from vulvodynia have been told that nothing seems to be wrong with them — nothing, that is, that the examining physician can discern — or that the condition may be real but that nothing can be done. Christin Veasley of Providence, R.I., said that vulvodynia, which was diagnosed at age 18 during her freshman year at college, made it impossible for her to sit long enough to finish a midterm exam. Her doctor said there was no help for her condition. Copyright 2008 The New York Times Company

Keyword: Pain & Touch; Sexual Behavior
Link ID: 11252 - Posted: 06.24.2010

By HENRY FOUNTAIN Researchers who study the brain know that it’s far from an immutable object. “It’s much more plastic than most people think,” said Giulio Tononi, a psychiatrist at the University of Wisconsin. “It’s changing all the time.” One area of change is the synapses, the connections between neurons, which are altered as the brain receives stimuli. “What happens when you’re awake is you produce an overall strengthening of synapses,” Dr. Tononi said. “That’s good, because that’s how you learn.” But that is unsustainable in the long run, because stronger synapses require more energy and material, and there’s a limit to how much of both is available. “It’s as if in the morning you start with a V-6 engine,” he said, “and in the evening you find yourself idling, but you’re running a V-8.” Stronger synapses are also bigger, but the brain cannot grow bigger or denser. “If you strengthen synapses because you learn, soon you’d reach a point where you can’t learn further,” he added. So Dr. Tononi and a colleague, Chiara Cirelli, have hypothesized that during sleep, the synapses weaken. The downscaling is across the board, so that the synapses’ relative strength is maintained. Those that have been used (those involved in learning) stay stronger than those that haven’t. Copyright 2008 The New York Times Company

Keyword: Sleep; Learning & Memory
Link ID: 11251 - Posted: 06.24.2010

By Michael Balter Don't take that hammer for granted. Using tools may seem like second nature, but only a few animals can master the coordination and mental sophistication required. So how did primates learn to use tools in the first place? A new study in monkeys suggests that the brain's trick is to treat tools as just another body part. Primates, with their four flexible fingers and opposable thumbs, have a highly evolved ability to grasp and manipulate objects. Previous research has shown that many of these actions are controlled by an area of the brain called F5. As the hand opens and closes to grasp an object, neurons in area F5 fire in a predictable sequence. In the parlance of neuroscientists, the neurons are "coded" to control the hand movements. When a primate learns to use a tool, its brain must code neurons not only to move the hand but also to make the tool manipulate an object, a much more cognitively complex task. To investigate how the brain performs this sleight of hand, a team led by neuroscientist Giacomo Rizzolatti of the University of Parma in Italy recorded brain activity in two macaque monkeys. Each was trained for 6 to 8 months to grasp items of food with pliers. The team documented the activity of 113 neurons in F5 and in a brain area called F1, which has also been implicated in the manipulation of objects. The researchers first established the brain's firing sequence when the monkeys grasped only with their hands. The experiment was then repeated while the monkeys used normal pliers that required first opening the hand and then closing it to grasp the food. The same neurons fired in the same order. Remarkably, the same neurons also fired, in the same order, when the monkeys used "reverse pliers" that required them to close their fingers first and then open them to take the food, the team reports online today in the Proceedings of the National Academy of Sciences. © 2008 American Association for the Advancement of Science

Keyword: Miscellaneous
Link ID: 11250 - Posted: 06.24.2010

Jennifer Viegas -- Feline defensive rage, the aggressive cat behavior that recently led to the death of a California zoo visitor by a tiger that felt threatened, is comparable to human rage, both in the way that it emerges and unleashes in the brain, suggests a new study. Because scientists are gaining a better understanding of the mammalian brain's recipe for rage, violent behavior in humans and other mammals may one day be quelled with improved drug therapies. For cats, such a drug could prevent the hissing, back arching, ear retraction, claw extensions and fur standing-on-end that are typical indicators of feline defensive rage. In humans, related anger reveals itself with road rage, an impulsive form of anger that involves little or no thought. "In road rage, the person never thinks about what he is doing but just acts in the way he does because he feels that he has been threatened by someone else and the impulsive behavior represents a way by which he can protect himself from such a threat," co-author Allan Siegel told Discovery News. "In reality, his actions are usually much more dangerous to him than to the person whom he perceived cut him off on the road," added Siegel, a professor in the Department of Neurology & Neurosciences at New Jersey Medical School in Newark. © 2008 Discovery Communications,

Keyword: Emotions; Evolution
Link ID: 11249 - Posted: 06.24.2010

Debora MacKenzie Chameleons are famed for changing colour to blend in with their surroundings and hide from predators – but new research on chameleons in their native habitat shows some of their colour changes evolved for exactly the opposite purpose – attracting attention. African dwarf chameleons live in habitats in southern Africa ranging from grassland to rainforest. They engage in complex social signalling, with bright colour changes along their flanks used by females to signal interest or rejection to males, and by males to signal aggression or submission to other males, and interest towards females. Males even square off in rapid-fire, colourful signalling duels. "Chameleons use colour change for camouflage and communication, but we don't know why some species change colour much more than others", says Devi Stuart-Fox of the University of Melbourne in Australia. She and colleague Adnan Moussalli reasoned that if these differences evolved solely to enable the chameleon to match itself to its surroundings, chameleons living in backgrounds that vary a lot in colour should produce a wider palette, whereas chameleons in less colourful environments should not. © Copyright Reed Business Information Ltd.

Keyword: Animal Communication
Link ID: 11248 - Posted: 06.24.2010

Andy Coghlan An internal clock hidden in human skin cells could reveal whether your body clock is out of sync with your lifestyle, say researchers. Steven Brown of the University of Zurich in Switzerland and his colleagues knew that the brain’s circadian clock causes a gene called Bmal1 to be more active in the body’s other cells during the daytime. To find out how closely matched this activity was, they used a virus to equip skin cells taken from 11 early-rising people dubbed "larks" and 17 late-rising "owls" with a firefly gene that would produce a visible glow whenever Bmal1 was active. “The result is light coming out of the cell in a 24-hour rhythm,” says Brown. By monitoring the times when the cells glowed, they demonstrated that skin cells showed the same sleep-wake patterns as those reported in questionnaires by at least half the donors. There were discrepancies too, however, most notably in three individuals with seasonal affective disorder. This suggested that skin biopsies might be useful for diagnosing sleep and circadian disorders. © Copyright Reed Business Information Ltd

Keyword: Biological Rhythms
Link ID: 11247 - Posted: 06.24.2010

Anna Petherick Researchers have added to the list of biological curiosities about mole-rats: the animals do not feel all types of pain. The discovery could eventually help humans who are battling chronic discomfort. African naked mole-rats (Heterocephalus glaber ) are unusual creatures — they are cold-blooded mammals, have a long lifespan, and live in co-operative societies of hundreds of individuals in a manner more typical of bees and wasps than moles or rats. The animals react normally to the mechanical pain caused by pinching and prodding, but are insensitive to a suite of other normally nasty stimuli, according to Thomas Park of the University of Illinois at Chicago, Gary Lewin at the Max-Delbrück Center for Molecular Medicine in Berlin, Germany, and their colleagues. Those stimuli include acid and capsaicin, the ingredient in chilli peppers that causes a burning sensation in many animals. These mole-rats are also odd in that their skin, when inflamed, does not become hypersensitive when exposed to unpleasantly hot objects, even though they react to excessive heat in the same way that other mammals do, the researchers report in PloS Biology 1. © 2008 Nature Publishing Group

Keyword: Pain & Touch; Evolution
Link ID: 11246 - Posted: 06.24.2010

If you need another reason to keep that New Year's resolution to quit smoking, here it is: a U.S. researcher says he has discovered smoking can disable a gene that protects against premature aging. The gene, SIRT1 is one of a group that regulates chronic inflammation, cancer and aging. When it is highly active, or over-expressed in mice, worms and fruit flies, their lifespans are greatly increased. Recent studies also show that SIRT1 helps ease the negative effects of stress, cell death and other processes involved in premature aging. According to University of Rochester associate professor of Environmental Medicine, Irfan Rahman, the toxins in cigarette smoke can decrease production of SIRT1 in the lungs. His research was published in two separate studies, in the American Journal of Respiratory Critical Care Medicine, appearing online Jan. 3, 2008, and in the American Journal of Physiology, appearing Dec. 27, 2007. Rahman has spent years studying how the 4,700 toxic chemical compounds in cigarettes assault lung tissue. © CBC 2008

Keyword: Drug Abuse
Link ID: 11245 - Posted: 06.24.2010

ST. PAUL, Minn. – Contrary to some reports, taking statins, which are cholesterol-lowering drugs, offers no protection against Alzheimer’s disease, according to research published in the January 16, 2008, online issue of Neurology®, the medical journal of the American Academy of Neurology. The study involved 929 Catholic clergy members who were an average of 75 years old, free of dementia at the beginning of the study and enrolled in the Religious Orders Study, an ongoing study of aging and Alzheimer’s disease. All of the participants agreed to a brain autopsy at the time of their death and underwent annual cognitive tests for up to 12 years. At the beginning of the study, 119 people were taking a statin. During the 12-year follow-up period, 191 people developed Alzheimer’s disease, of whom 16 used statins at the start of the study. “Some studies have suggested people taking cholesterol-lowering drugs are less likely to have Alzheimer’s disease, but our longitudinal findings found no relation between statin use and Alzheimer’s,” said study author Zoe Arvanitakis, MD, MS, Associate Professor of the Department of Neurological Sciences at Rush University Medical Center in Chicago and member of the American Academy of Neurology. “The study also found no association between taking statins and a slower cognitive decline among older people.”

Keyword: Alzheimers
Link ID: 11244 - Posted: 06.24.2010