By Rob Stein Is there such a thing as a "gay brain"? And, if so, are some people born with brains that make them more likely to be homosexual? Or do the brains of gay people develop differently in response to experiences? Those are some of the thorny questions that have been raised by a provocative new study that found striking differences between the brains of homosexuals and heterosexuals in both men and women. Some scientists say the new findings are part of an increasingly convincing body of evidence that suggests sexual orientation results from fundamental developmental differences that are probably caused by hormonal exposures in the womb. "This research is pointing to basic differences in the brain between homosexual and heterosexual people that are likely there right from the beginning," said Sandra F. Witelson, a professor of psychiatry and behavioral neurosciences at McMaster University in Ontario. "These could be reflecting some genetic or hormonal factors that predetermine your sexual orientation." Others, however, argue that such research is far from conclusive. "I remain skeptical," said William Byne, a professor of psychiatry at Mount Sinai School of Medicine in New York. "There's been a history of jumping to conclusions and overinterpreting findings in this field." © 2008 The Washington Post Company

Keyword: Sexual Behavior
Link ID: 11739 - Posted: 06.24.2010

Scientists have long questioned whether the abundant amounts of amyloid plaques found in the brains of patients with Alzheimer's actually caused the neurological disease or were a by-product of its progress. Now, using new research techniques, scientists have shown that a two-molecule aggregate (or dimer) of beta-amyloid protein fragments may play a role in initiating the disease. The study, supported by the National Institutes of Health, suggests a possible new target for developing drug therapies to combat the irreversible and progressive disorder. Ganesh M. Shankar, Ph.D., and Dennis J. Selkoe, M.D., of Brigham and Women's Hospital and Harvard Medical School, conducted the study in collaboration with other researchers at Harvard and in Ireland at University College Dublin, Beaumont Hospital and Royal College of Surgeons Ireland, and Trinity College Dublin. The National Institute on Aging (NIA), part of NIH, funded the study which appears online in the June 22, 2008, Nature Medicine. Alzheimer's disease is marked by the build-up of plaques consisting of beta-amyloid protein fragments, as well as abnormal tangles of tau protein found inside brain cells. Early in the disease, Alzheimer's pathology is first observed in the hippocampus, the part of the brain important to memory, and gradually spreads to the cerebral cortex, the outer layer of the brain. In this study, researchers tested cerebral cortex extracts from brains donated for autopsy by people aged 65 and older with Alzheimer's and other dementias, as well as those without dementia. The extracts contained soluble one-molecule (monomer), two-molecule (dimer), three-molecule (trimer) or larger aggregates of beta-amyloid, as well as insoluble plaque cores. The researchers then injected the extracts into normal rats or added the extracts to slices of normal mouse hippocampus.

Keyword: Alzheimers
Link ID: 11738 - Posted: 06.24.2008

Jennifer Viegas -- Neanderthals were hardly a weak group just before their extinction around 30,000 years ago, suggests new research. On the contrary, Britain's last Neanderthals had sophisticated weapons and lived in strategic spots, demonstrating impressive command of their territory. Archaeologists analyzing 180 flint tools and weapons, which survived an original collection of 2,300 artifacts found in 1900 at a site called Beedings near Pulborough, England, have traced them to the Neanderthals, according to an announcement made today by the University College London Institute of Archeology. The discoveries were also recently reported in British Archeology magazine. "The tools we've found at the site are technologically advanced and potentially older than tools in Britain belonging to our own species," said UCL's Matthew Pope. "It's exciting to think that there's a real possibility these were left by some of the last Neanderthal hunting groups to occupy northern Europe," he added. "The impression they give is of a population in complete command of both landscape and natural raw materials with a flourishing technology -- not a people on the edge of extinction." Pope is leading the recent excavations after Roger Jacobi of the Ancient Human Occupation of Britain Project first linked the tools to others discovered in northern Europe, which dated to between 35,000 and 42,000 years ago. The Beedings collection, however, is more diverse and extensive than any others from the region. © 2008 Discovery Communications, LLC

Keyword: Evolution
Link ID: 11737 - Posted: 06.24.2010

By Jennifer Couzin A stroke drug known as tPA, or tissue plasminogen activator, has been a lightning rod since it was first approved in the United States in 1996. Although studies have found that the drug can reduce the brain damage wrought by strokes, it can also cause potentially fatal bouts of cerebral bleeding. Now a team of researchers has identified one reason for tPA's ill effect. And it turns out that in mice, the problem can be eased by administering a cancer drug. TPA works by dissolving blood clots. That helps to restore blood flow to the brain after a stroke, potentially preventing additional brain cells from dying. tPA is only recommended if it can be given within 3 hours of a stroke; otherwise, doctors deem that the drug will do more harm than good, causing hemorrhages in the brain. One clue to why tPA can cause bleeding came several years ago. Vascular biologist Daniel Lawrence of the University of Michigan, Ann Arbor, found that in mice the drug appeared to damage the blood-brain barrier, a membrane that protects brain cells from toxins in the rest of the body. Soon after, in an entirely separate study, molecular biologist Ulf Eriksson and colleagues at the Karolinska University Hospital in Stockholm, Sweden, found a new target of tPA: a molecule called platelet-derived growth factor-CC (PDGF-CC), which helps drive blood vessel formation. Why this might matter wasn't clear at the time, however, and it did not seem connected to tPA's clot-busting power. But drugs often have more than one molecular target, including targets not relevant to the diseases they're designed to treat. © 2008 American Association for the Advancement of Science.

Keyword: Stroke
Link ID: 11736 - Posted: 06.24.2010

Kerri Smith General anaesthetics can worsen postoperative pain, suggests a new study in mice. The discovery could help surgeons avoid picking the most painful drugs or lead to alternative ways of relieving post-surgery pain. Pain is a by-product of many surgical procedures, but it was always assumed that the cause was the surgery itself. “It was never considered that the anaesthetic could contribute to the pain,” says Gerard Ahern of Georgetown University in Washington DC, who led the study. “The paradoxical finding is that the anaesthetic can worsen the severity of the damage done by the surgeon.” General anaesthetics were already known to cause some problems. Taken in the form of either an injection or gas, anaesthetics can cause irritation either at the site of the jab or in the airways, and surgeons often give patients a local anaesthetic first to reduce this side-effect. But it was a surprise that general anaesthetics can also worsen pain after surgery. Now, Ahern and his colleagues show that that these drugs can activate pain-sensing nerves throughout the body. When a patient is ‘put under’, the general anaesthetic activates a protein in the central nervous system called a GABA receptor. Switching these receptors off shuts down parts of the central nervous system, and the patient slips into unconsciousness. © 2008 Nature Publishing Group

Keyword: Pain & Touch
Link ID: 11735 - Posted: 06.24.2010

A passionate advocate for taking science to the masses, the Oxford professor has been showered with honours in Britain and Australia for her ability to make science relevant to broader society, and she generally does it with a beaming smile and a thousand words and ideas a minute. All of which makes it striking that Greenfield, one of Britain's leading brain scientists, is now expressing profound fears about the way new technology is changing our thought patterns and behaviour. "I don't want to sound like a techno-Luddite but we have to realise that something profound seems to be happening to the human brain," Greenfield explains in the central London office from where she runs the Royal Institution, a 209-year-old seat of scientific education and research. "And what really worries me is that we could be sleepwalking into a new world of technology without even considering what it is doing to our brains." The 57-year-old scientist may not want to sound alarmist or gloomy but her warning is about as serious as it gets. In a new book, ID: The Quest for Identity in the 21st Century, published by Sceptre, she says the challenge to our inner mental world is as big a crisis as the threat climate change poses to our outer world. Copyright 2008 News Limited.

Keyword: Emotions; Intelligence
Link ID: 11734 - Posted: 06.21.2008

By Nikhil Swaminathan Nearly a century after the discovery of strange star-shaped cells in the brain, scientists say they have finally begun to unravel their function. Researchers from the Massachusetts Institute of Technology report in Science that it appears astrocytes—named for their stellar form—provide nerve cells (neurons) with the energy they need to function and communicate with one another, by signaling blood to deliver the cell fuels glucose and oxygen to them. When astrocytes were first discovered, it was believed that they were bit players in the brain. But the new research indicates they may actually be major operators that, when out of whack, may help trigger mental disorders such as autism and schizophrenia. Study coauthor Mriganka Sur, a neuroscientist and head of MIT's Department of Brain and Cognitive Science, says his team saw astrocytes in action while examining brain activity in ferrets. Using technology called two-photon microscopy, Sur and his colleagues observed that astrocytes in the visual cortex (part of the brain responsible for vision) activated and blood flow increased to nerve cells just seconds after the neurons had fired or sent out signals. © 1996-2008 Scientific American Inc.

Keyword: Glia; Brain imaging
Link ID: 11733 - Posted: 06.24.2010

By Ann Gibbons Girls who eat more omega-3 fatty acids outsmart those who eat higher amounts of omega-6 fatty acids, according to new research. As a result of this and other studies, government dietary recommendations--especially those aimed at pregnant women--should emphasize fish over soy and corn oils, which are respectively high in these fatty acids, says Joseph Hibbeln, a psychiatrist and lipid biochemist at the National Institute on Alcohol Abuse and Alcoholism in Bethesda, Maryland. "We don't want the brain to be deficient in its critical nutrients during development." The omega-3 advantage was first hinted at in studies of distribution of body fat. Earlier this year, William Lassek, an epidemiologist at the University of Pittsburgh in Pennsylvania, and anthropologist Steven Gaulin of the University of California, Santa Barbara, reported that women who accumulated more fat on their hips than on their waists--and who, therefore, had low waist-hip ratios like many movie stars--had higher cognitive test scores, as did their children. They proposed that because the fat on the hips and thighs contains more omega-3s than belly fat does, these women were storing omega-3s critical for fetal and infant brain development--and boosting their own brainpower as they grew up. They also predicted that women who ate more omega-3s would perform better on cognitive tests than those who ate more omega-6s. To test this hypothesis, Lassek and Gaulin analyzed data on about 4000 girls and boys between the ages of 6 and 16. The children had participated in the Third National Health and Nutrition Examination Study, part of a U.S. project to assess the health and nutritional status of kids and adults. After the researchers controlled for the parents' income and education and for the children's age, race, number of siblings, and blood lead levels, they found that girls who ate more omega-3 scored significantly better on four cognitive tests, including an IQ test. © 2008 American Association for the Advancement of Science

Keyword: Intelligence; Obesity
Link ID: 11732 - Posted: 06.24.2010

Jennifer Viegas -- What goes on in an ape's mind might be more similar to our own way of thinking than previously realized, suggests a new study that found chimpanzees and orangutans plan for their futures. Since this skill also entails forethought involving self-control and mental time travel, the findings point to a complex "inner mental world" possessed by apes, including gorillas, which were studied in trials before the official research began. "When humans shut their eyes, a new vivid world takes hold," co-author Mathias Osvath told Discovery News. "This mental world with its first-person perspective has been suggested to be unique to humans," added Osvath of Lunds University Cognitive Science in Sweden. "It is arguably impossible to plan like the apes do without having an inner world of some sort. (Our results) strongly imply a consciousness that many think is restricted to the human domain." For the study, published in Animal Cognition, he and colleague Helena Osvath first showed two female chimps, Linda and Maria Magdalena, along with a male orangutan named Naong, how to sip a yummy fruit soup using a straw-like hose. The researchers next presented their furry test subjects with a favorite fruit -- a grape -- and the hose, which the animals could save and use to sip soup later. The apes exercised self-control by foregoing the immediate grape reward. They instead chose the hose and patiently waited for the bigger food payoff. © 2008 Discovery Communications, LLC.

Keyword: Evolution; Intelligence
Link ID: 11731 - Posted: 06.24.2010

Jo Marchant Why do donkeys snooze for just three hours a day, while hairy armadillos are knocked out for more than 20? Biologists have struggled to find any satisfactory explanation for the bewildering variation in how much different mammals sleep. However, new studies that take evolutionary relatedness into account promise to revolutionise the field. In particular, one large study suggests that REM (rapid eye movement) sleep – during which the brain is highly active – may play a key role in intelligence. Lab studies in humans already suggest that REM sleep is important for cognitive abilities such as consolidating memories – a good night's sleep – with plenty in the REM phase – can improve people's ability to remember what they have learned in the day by about 15%. In other species, the evidence is less clear cut. If REM sleep helps learning, then mammals with more developed brains should presumably need more of it, but in the past no such relationship has been found. One of the few biological functions that has been found to correlate with sleep patterns is metabolic rate. Animals with a relatively high metabolic rate for their body size seem to need more non-REM sleep, suggesting that catching extra Zs simply helps them conserve precious energy. © Copyright Reed Business Information Ltd

Keyword: Sleep; Intelligence
Link ID: 11730 - Posted: 06.24.2010

Ewen Callaway A handful of genes could mark the difference between high-strung Chihuahuas and unflappable basset hounds. A comparison of 148 dog breeds has uncovered genes for size, lifespan, and even complex behaviours such as pointing and herding. Geneticists have previously uncovered genes for dog traits such as coat colour and narcolepsy, but these searches tended to focus on a single breed, comparing pooches with variations in a single trait – for example, boxers with and without white spots. This strategy does not work for rooting out the genetic basis of behaviours because certain breeds either display these behaviours or they don't, says Gordon Lark at the University of Utah in Salt Lake City, US. So with the help of a dog show judge, Lark's team scored dogs from 148 breeds for traits including herding, pointing, boldness, excitability and trainability. Then they scoured their genomes for similarities and differences. Dogs were also scored for size, body proportions and longevity. The search implicated several genes in stereotypical dog behaviours. For example, herding behaviour typical of collies and shepherds may be linked to a gene that is similar to one associated with schizophrenia in humans. © Copyright Reed Business Information Ltd.

Keyword: Genes & Behavior; Evolution
Link ID: 11729 - Posted: 06.24.2010

By Tia Ghose In people with autoimmune diseases like multiple sclerosis and asthma, infection-fighting cells go haywire and wage war against the body’s own tissue, causing inflammation. Existing treatments can prevent the immune system from getting out of control, but can also compromise a person’s ability to fight some infections. But a new study suggests that a specific receptor on immune cells holds promise as a target for treating such disorders, perhaps without affecting immunity. The receptor, called DR3, lies on the surface of T cells, which help the body combat infection. When a molecule called TL1A binds to the receptor, it spurs the T cells into action. But this same interaction can also lead the T cells to attack healthy tissue. Turning off the gene for this receptor seems to quell this inflammation in mice, researchers report online June 19 in the journal Immunity. It wasn’t far-fetched to think DR3 may play a role in autoimmune disease. DR3 is part of a family of TNF receptors, which are involved in activating immune cells and have been implicated in autoimmune disease, says Michael Croft, an immunologist at the La Jolla Institute for Allergy and Immunology in California, who was not involved in the study. What’s more, DR3 looks very similar to another receptor implicated in inflammation, says Richard Siegel of the National Institute of Arthritis and Musculoskeletal and Skin Diseases in Bethesda, Md, who was involved in the study. © Society for Science & the Public 2000 - 2008

Keyword: Multiple Sclerosis; Neuroimmunology
Link ID: 11728 - Posted: 06.24.2010

A herbal extract used by an estimated 10% of people with dementia is not an effective treatment for it, an Imperial College London study suggests. Ginkgo biloba is commonly marketed as an aid to memory and some studies have reported benefits. But a six-month trial of 176 people with mild to moderate dementia found no difference between those taking ginkgo biloba and those taking placebo. The results are in the International Journal of Geriatric Psychiatry. The researchers tested 120 mg daily of ginkgo biloba in patients recruited from London general practices. They measured participants cognitive skills and quality of life at two, four and six months. Tests included exercises such as recalling words from memory or answering questions about time or places. There was no evidence that the standard dose of the herbal extract had any benefit on memory. And quality of life as reported by the patient or by their carer did not improve over the course of the research. A Cochrane review published in 2002 which had taken all relevant evidence into account found ginkgo may be a small beneficial effect on memory in dementia patients. But the researchers say that is being updated in view of this latest research and has found that it is unlikely to provide benefits. Study leader, Dr Rob McCarney who carried out the research at Imperial College London, said the lack of drug treatments in early dementia meant patients would try anything to slow down the progression of the disease. (C)BBC

Keyword: Alzheimers; Learning & Memory
Link ID: 11727 - Posted: 06.19.2008

Australian researchers are using new imaging technology to provide an insight into the degenerative effect of Huntington's disease on the brain. Doctoral student India Bohanna, from the Howard Florey Institute in Melbourne, used diffusion magnetic resonance imaging technology to track the breakdown in structural connections within the brain. The research was presented at the Organization for Human Brain Mapping conference being held this week in Melbourne. Bohanna said she and her collaborators at Monash University found extensive white matter degeneration in patients recently diagnosed with Huntington's disease. The researchers used diffusion MRI, which maps the brain's white matter tracts by measuring the movement of water molecules in the tissues. White matter tracts are the connections between brain regions that allow one region to communicate with another. Bohanna said a breakdown in these structural connections disrupts the brain's communication. This could explain the motor and cognitive problems such as memory loss and clumsiness that appear as early symptoms of the onset of Huntington's disease. © Australian Broadcasting Corporation, 2008

Keyword: Huntingtons
Link ID: 11726 - Posted: 06.24.2010

Nicholas Wade, New York Times Intricate as the mating dance may be among people, for other primates like chimpanzees and baboons it is even more complicated. This is evident from the work of researchers who report that the distinctive calls made by female chimpanzees during sex are part of a sophisticated social calculation. Biologists have long been puzzled by these copulation calls, which can betray the caller's whereabouts to predators. To compensate for this hazard, the calls must confer a significant evolutionary advantage, but what? The leading explanation involves the way female primates protect their offspring. Male chimps and baboons are prone to kill any infant they believe could not be theirs, so females try to blur paternity by mating with as many individuals as possible before each conception. A side benefit is that by arranging to have sperm from many potential fathers compete for her egg, the female creates conditions for the healthiest male to father her child. The calls that female chimps make during sex seemed to be just part of this strategy. By advertising a liaison in progress, biologists assumed, females stood to recruit many more partners. But the study, by Simon Townsend, Tobias Deschner and Klaus Zuberbuhler, shows that in making calls or not, the females take the social situation into account. © 2008 Hearst Communications Inc.

Keyword: Sexual Behavior; Language
Link ID: 11725 - Posted: 06.24.2010

By Virginia Morell Like all immigrants, young male songbirds arriving in the United States have to make some quick decisions, beginning with finding the best place to build a nest. A new study reveals that youngsters make their choices after eavesdropping on the songs of their elders. The results add to a growing body of research indicating that birds' songs carry far more social information than scientists realize. Finding the right nesting habitat is key to a songbird's reproductive success, says Matthew Betts, a landscape ecologist at Oregon State University, Corvallis, and the lead author of the study. "Even 50% of experienced males will lose their chicks to predators," he says, so it makes sense for birds to look for places with the most cover. Other studies have shown, however, that songbirds are drawn to areas where they see and hear their fellows nesting. Betts and colleagues suspected that house-hunting young male black-throated blue warblers (Dendroica caerulescens), who arrive in the States from Jamaica, cue in on the songs of their elders. Successful warbler dads sing after their chicks have fledged, most likely to teach their songs to their offspring, says Betts. "But there could be another, unintentional message in their song: 'Hey, I've reproduced,' "--a clue that the older bird is sitting on prime nesting real estate. © 2008 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Language
Link ID: 11724 - Posted: 06.24.2010

By Michael Balter As gay couples race to the altar in California this week, scientists may have found an answer to the so-called gay paradox. Studies suggest that homosexuality is at least partly genetic. And although homosexuals have far fewer children than heterosexuals, so-called gay genes apparently survive in the population. A new study bolsters support for an intriguing idea: These same genes may increase fertility in women. Despite some tantalizing leads over the past 2 decades, researchers have yet to isolate any genes directly linked to homosexuality. Nevertheless, a number of studies have shown that male homosexuals have more gay male relatives on their maternal lines than on their paternal lines, leading some scientists to suggest that gay genes might be found on the X chromosome. And in 2004, a team led by evolutionary psychologist Andrea Camperio Ciani of the University of Padua in Italy reported that women related to gay men had more children than women related to heterosexual men. The differences were striking: The mothers of gay men, for example, had an average of 2.7 children, compared with 2.3 children for the mothers of heterosexual men. A similar trend held for maternal aunts. In new work, reported online this week in PLoS ONE, Camperio Ciani and his colleagues used mathematical modeling to see what kinds of genetic scenarios could explain these results. © 2008 American Association for the Advancement of Science

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 11723 - Posted: 06.24.2010

John Whitfield Why does payday feel good? You can’t eat money, and it can’t have your babies — so how did that 'ker-ching!' feeling become so sweet? Working with rats, neuroscientists have gained an insight into how the brain comes to take pleasure in abstract rewards. Animals, they suggest, have a reward system that focuses on specific outcomes — what an action would achieve — which in turn plugs into a more general system that lets us know what feels good. Understanding how these two systems interact could help us understand what happens when they go wrong, such as in drug addiction or in general failures of willpower. The results are reported in Nature 1. It’s hard to explain why people work for things that are not intrinsically gratifying, says neuroscientist Geoffrey Schoenbaum of the University of Maryland in Baltimore. “People are not normally working for primary rewards, such as food or sex, but for proxies, such as money.” And, he says, they are able to plan their behaviour with distant goals in mind. “You work harder when you want a certain thing, like a new car.” © 2008 Nature Publishing Group

Keyword: Emotions; Drug Abuse
Link ID: 11722 - Posted: 06.24.2010

High levels of the "hunger hormone" ghrelin have an antidepressant effect, US researchers claim. Blocking the body's response to ghrelin has been suggested as a weight loss treatment but it may also produce unintended effects on mood, they said. The Nature Neuroscience study found mice with increased levels of the hormone showed fewer signs of depression and anxiety. Experts said the idea was interesting but further studies were needed. Ghrelin is released by the empty stomach into the bloodstream before moving to the brain, where it triggers feelings of hunger. Treatment with the hormone itself - or a drug designed to cancel its effects - might be able to help both people who are eating too little, such as cancer patients, or those who eat too much, researchers believe. In the latest study, Dr Jeffrey Zigman and colleagues restricted the food intake of laboratory mice for 10 days, causing their ghrelin levels to quadruple. Compared with mice who had free access to food, the calorie-restricted mice showed lower levels of depression and anxiety when subjected to mazes and other behaviour tests. The team also looked at mice genetically engineered to be unable to respond to ghrelin. When they were fed a restricted-calorie diet they did not experience the antidepressant or anti-anxiety effects. The researchers found the same thing when they induced higher ghrelin levels by subjecting the mice to stress. Those mice that could not respond to ghrelin had greater levels of depression-like symptoms than the normal mice. (C)BBC

Keyword: Depression; Obesity
Link ID: 11721 - Posted: 06.17.2008

By TARA PARKER-POPE About 2.5 million children in the United States take stimulant drugs for attention and hyperactivity problems. But concerns about side effects have prompted many parents to look elsewhere: as many as two-thirds of children with attention deficit hyperactivity disorder, or A.D.H.D., have used some form of alternative treatment. The most common strategy involves diet changes, like giving up processed foods, sugars and food additives. About 20 percent of children with the disorder have been given some form of herbal therapy; others have tried supplements like vitamins and fish oil or have used biofeedback, massage and yoga. While some studies of alternative treatments show promise, there is little solid research to guide parents. That is unfortunate, because for some children, prescription drugs aren’t an option. The drugs have been life-changing for many children. But nearly one-third experience worrisome side effects, and a 2001 report in The Canadian Medical Association Journal found that for more than 10 percent, the effects could be severe — including decreased appetite and weight loss, insomnia, abdominal pain and personality changes. Although the drugs are widely viewed as safe, many parents were alarmed when the Food and Drug Administration ordered in 2006 that stimulants like Adderall, Ritalin and Concerta carry warnings of risk for sudden death, heart attacks and hallucinations in some patients. Copyright 2008 The New York Times Company

Keyword: ADHD
Link ID: 11720 - Posted: 06.24.2010