By Benjamin Lester For young men from the Maasai tribe of Kenya, spearing an elephant is part of the transition to manhood. The farmers of the Kamba tribe pose no threat to elephants, however. New research shows that wary pachyderms in Kenya's Amboseli National Park have learned to distinguish between the two groups based on odors and colors. The findings demonstrate the animals' ability to accurately classify threats from indirect cues. The Maasai are a cattle-herding Kenyan tribe who habitually wear red or other deep, rich colors. Although the practice is now illegal, young Maasai continue to spear elephants as a rite of passage. Other ethnic groups in the area do not harass elephants, and researchers working in the park noticed that the local herds reacted differently to Maasai than to these groups. To determine how the elephants discern a Maasai from a Kamba, evolutionary psychologists Lucy Bates and Richard Byrne, both of the University of St. Andrews in Fife, U.K., and colleagues recruited male volunteers from both tribes and gave them red clothes to wear for 5 days. The team then placed the fragrant garments upwind and out of sight of 18 different elephant family groups. Both types of clothing elicited more of a response--tensing, sniffing the air, and moving away--than did unworn duds of the same color, but the reaction to Maasai smells was much stronger. In a paper published online 18 October in Current Biology, the team reports that the animals moved away 27% faster and 65% farther from the Maasai scents than from Kamba odors. "If they got a whiff of the Maasai, they would just be running away," says Byrne. © 2007 American Association for the Advancement of Science.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 10862 - Posted: 06.24.2010

Kerri Smith Researchers delving into the DNA of Neanderthal remains have found the human form of a gene crucial for the development of language. The result indicates that this modern form of the gene could have appeared much earlier than previously thought — in the ancestors of humans and Neanderthals. However, the presence of this gene alone does not guarantee that Neanderthals actually spoke to each other using anything that we would classify as a language. Studies of their anatomy haven’t answered this question either: a bone in the Neanderthal throat called the hyoid resembles the human form, but the inner ear appears different. It is extremely difficult to extract nuclear DNA from such ancient samples, so the study is an impressive technical achievement. But the group cannot rule out entirely the possibility that their results are due to contamination of the samples with modern human DNA. One of the first studies of Neanderthal DNA1, published in Nature in 2006, was reanalysed this year and it was claimed that a large chunk could have been modern human DNA, not Neanderthal2. In the new study, Johannes Krause of the Max-Planck Institute for Evolutionary Anthropology in Leipzig, Germany and an international team of colleagues took DNA from two Neanderthal males whose bones were found in a cave in Northern Spain. © 2007 Nature Publishing Group

Keyword: Language; Genes & Behavior
Link ID: 10861 - Posted: 06.24.2010

By Steve Mitchell A new study has identified brain cells that play a key role in ensuring that we rise and shine when the alarm clock buzzes. The findings could lead to a better understanding of sleep disorders. People with narcolepsy--a condition marked by falling asleep at inappropriate times--have fewer neurons that produce a small protein called hypocretin, also known as orexin (ScienceNOW, 29 January). So scientists had a hunch that these neurons, which are located in the hypothalamus region of the brain, play a role in transitioning from sleep to wake states, but their exact function had been difficult to pin down. Now, a team led by neuroscientist Luis de Lecea of Stanford University in Palo Alto, California, has literally shed some light on the problem. The researchers used a virus to insert the gene that encodes a light-sensing protein into hypocretin-producing neurons in the brains of mice. This enabled them to activate the neurons by shining a laser deep into the brain via fiber optics. When the cells were activated, sleeping mice woke faster than animals that did not have their neurons stimulated, the researchers report online today in Nature. Further experiments indicated that hypocretin is key in stimulating the transition from asleep to awake. Mice given a compound that blocks the action of hypocretin, for example, woke up more slowly upon activation of the neurons than did mice given a placebo. Knockout mice that lacked the gene for hypocretin also had a delay in waking up, although they still awoke faster than normal mice that did not have their neurons stimulated, suggesting that additional chemicals are involved in the process. "The hypocretin-producing neurons are very important in switching from sleep to wakefulness," de Lecea says, noting that the findings help explain the sleep disorders in narcoleptics who are deficient in these types of cells. © 2007 American Association for the Advancement of Science.

Keyword: Sleep; Biological Rhythms
Link ID: 10860 - Posted: 06.24.2010

Matt Kaplan Men have it tough: they age faster and die younger than women. Now research suggests that this trait could be linked to humankind’s ancestral breeding habits. Several explanations have been proposed for the lifespan difference between men and women. It could be a result of the ageing effects of testosterone. Or it could be thanks to evolutionary forces: having the men die early might ease pressure on valuable resources, for example, helping the overall success of the species. Or perhaps it has something to do with mating behaviour. Casual observations had previously suggested that polygyny is a common characteristic among species in which males die younger than females, including red deer, lions and elephant seals. In more monogamous species, including Bewick’s swans and meerkats, a gender-related lifespan difference is not seen. So Tim Clutton-Brock and Kavita Isvaran of Cambridge University pulled together data sets in which measures of survival and descriptions of breeding were available for both sexes, to see whether this observation holds true. In monogamous species, they found no consistent sex differences in breeding lifespans, annual rates of mortality or rates of ageing. But the more polygynous a species was, the more short-lived the male was likely to be, and the shorter their duration of effective breeding, the team reports in Proceedings of the Royal Society of London B 1. © 2007 Nature Publishing Group –

Keyword: Sexual Behavior; Evolution
Link ID: 10859 - Posted: 06.24.2010

Emma Marris Zebrafish won't be caught napping after a sleepless night.Zebrafish don't nap more during daylight hours when sleep deprived, a new study shows. The work suggests that fish are better able to use light cues to stay awake during the day than mammals, hinting that evolution has produced different systems for regulating sleep in different groups of animals. Every animal sleeps, but many do so in ways that humans would hardly recognize. Cows stand stock still on their four legs; dolphins take a separate nap in each hemisphere of their brains so they can keep swimming. Even fruitflies catch forty winks now and again in their short lives. The way you can tell a zebrafish is asleep, says Emmanuel Mignot at Stanford University in Palo Alto, California, is that its tail droops, it hangs immobile at the bottom of the tank, and it requires more of a prod — a mild electric current will do — to get it swimming than when it is awake. Mignot and his colleagues are keen to keep zebrafish awake to study how sleep — or the lack of it — affects this often-studied fish. No one really understands why people sleep; how sleep evolved is equally mysterious, says Mignot. "Sleep is one of the basic mysteries remaining, in terms of why it has been selected for." To understand that, he is studying sleep in animals from dogs to zebrafish. "It is better to understand how we sleep across evolution, and then we will understand the reason for sleep," he says. © 2007 Nature Publishing Group

Keyword: Sleep; Evolution
Link ID: 10858 - Posted: 06.24.2010

Mark D'Esposito How does the brain organize its work? And how does it heed what it needs to heed? Theories of brain organization focus on two distinct but complementary principles of brain organization: modularity, the existence of brain regions with specialized functions, and network connectivity, the integration of information from various brain regions that results in organized behavior. In the study under review here, the modular and network models appear to play specialized roles in directing the attention of monkeys seeking certain visual targets through either "top-down" or "bottom-up" attentional strategies. In the modules-versus-network debate, modularity is probably the simpler brain model to understand. Clinical observation of individuals with brain damage, as well as brain-imaging studies (functional MRIs, or fMRIs) of healthy individuals, demonstrate that certain brain regions control specific cognitive processes, such as the ability to produce speech. For instance, in patients with nonfluent aphasia, which creates a selective inability to speak, comprehension of spoken language remains intact. In 1861 Paul Broca observed that damage to the left frontal lobe in an autopsied brain had produced nonfluent aphasia. Modern brain-imaging studies of patients with strokes to this area (now known as "Broca's area") confirmed Broca's theory. Moreover, fMRIs of healthy individuals reveal that the left frontal lobe is activated when subjects generate speech. © 1996-2007 Scientific American, Inc.

Keyword: Attention
Link ID: 10857 - Posted: 06.24.2010

The next time you pause to mull over menu selections even after you have decided to order your favorite entrée, it may comfort you to know that you may be behaving that way because your brain is hard-wired to ponder decisions, leaving room for a possible change of mind. New studies have identified a specific neural circuit in the brains of monkeys that is activated when they postpone acting on a decision. The circuit is thought to keep potential choices brewing in memory even after a decision has already been made. The brain may continue to consider the options even after a decision is made because that extra consideration may sometimes result in a change of mind - and a possible reward, such as a tastier meal. The researchers said that their findings could offer important insight into the function of neural circuits that drive the brain's memory and decision-making machinery. The researchers, led by Howard Hughes Medical Institute international research scholar Ranulfo Romo, reported their findings in the October 16, 2007, issue of the Proceedings of the National Academy of Sciences. Romo and his colleagues are at the National Autonomous University of Mexico. In their experiments, the researchers trained monkeys to judge whether, when a pair of vibrations were delivered to their fingertip, the second vibration was at a higher or lower frequency than the first. The animals indicated their choice by pressing a button. During this process, the researchers recorded electrical activity in relevant areas of the monkeys' brains. © 2007 Howard Hughes Medical Institute.

Keyword: Miscellaneous
Link ID: 10856 - Posted: 06.24.2010

Chimpanzees under attack exaggerate their screams to get help from higher ranking group members, researchers from Fife have discovered. The study found primates produce high-pitched and prolonged screams when they were the victims of severe aggression such as beating. Their cries were exaggerated if there was another higher-ranking chimp in the area who could challenge the aggressor. St Andrews University experts spent nine months in Budongo Forest, Uganda. They recorded the apes' screams during attacks by chimps and carried out a computerised analysis of the acoustics. Dr Katie Slocombe from the university's School of Psychology, who led the study, said: "We conclude victims use screams flexibly to recruit help from others and have a complex understanding of third party relations. "They know exactly who can challenge who, and this knowledge of social relationships influences their vocal production. If no-one is there to help them then the screams are normal but if someone is about then they make it sound even worse than it is. This shows there is more flexibility in their vocal communication than previously thought." Dr Slocombe said they were still researching the underlying reasons for the exaggerated screams. "It could be that they are wanting to falsely deceive the higher ranking chimpanzee into thinking it is really bad," she said. (C)BBC

Keyword: Language; Emotions
Link ID: 10855 - Posted: 10.16.2007

CHICAGO - Julio and Mauricio Cabrera are gay brothers who are convinced their sexual orientation is as deeply rooted as their Mexican ancestry. They are among 1,000 pairs of gay brothers taking part in the largest study to date seeking genes that may influence whether people are gay. The Cabreras hope the findings will help silence critics who say homosexuality is an immoral choice. If fresh evidence is found suggesting genes are involved, perhaps homosexuality will be viewed as no different than other genetic traits like height and hair color, said Julio, a student at DePaul University in Chicago. Adds his brother, “I think it would help a lot of folks understand us better.” The federally funded study, led by Chicago area researchers, will rely on blood or saliva samples to help scientists search for genetic clues to the origins of homosexuality. Parents and straight brothers also are being recruited. While initial results aren’t expected until next year — and won’t provide a final answer — skeptics are already attacking the methods and disputing the presumed results. Previous studies have shown that sexual orientation tends to cluster in families, though that doesn’t prove genetics is involved. Extended families may share similar child-rearing practices, religion and other beliefs that could also influence sexual orientation. © 2007 The Associated Press.

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 10854 - Posted: 06.24.2010

Sabin Russell, Chronicle Medical Writer PDT Stanford - -- Researchers at Stanford University have developed a potentially pathbreaking blood test that, according to preliminary studies, is able to identify patients with Alzheimer's disease - an ailment that has been notoriously difficult to diagnose. The test has also shown promise in predicting which patients with mild memory loss are at high risk of developing the dreaded syndrome, which kills 66,000 Americans each year and inflicts incalculable heartache on the families of its victims. Scientists have been working for years without success to develop a simple way to diagnose Alzheimer's disease, a degenerative brain disease that saps memory, sows confusion and will eventually kill patients who may have lost the ability to speak, walk or swallow. In a paper published Sunday in the online edition of the British journal Nature Medicine, a team of scientists led by Stanford neurology Professor Tony Wyss-Coray describe a unique method that can spot Alzheimer's patients by screening for a set of 18 chemical signals that consistently turn up in the blood of people suffering from the disease. The 18 different molecules are drawn from a phrase book of chemical chatter that occurs among cells in the body. Together, they present a pattern that with surprising consistency appears in the blood of Alzheimer's patients. © 2007 Hearst Communications Inc

Keyword: Alzheimers
Link ID: 10853 - Posted: 06.24.2010

By AMANDA SCHAFFER An explosion of new research is vastly changing scientists’ understanding of diabetes and giving new clues about how to attack it. The fifth leading killer of Americans, with 73,000 deaths a year, diabetes is a disease in which the body’s failure to regulate glucose, or blood sugar, can lead to serious and even fatal complications. Until very recently, the regulation of glucose — how much sugar is present in a person’s blood, how much is taken up by cells for fuel, and how much is released from energy stores — was regarded as a conversation between a few key players: the pancreas, the liver, muscle and fat. Now, however, the party is proving to be much louder and more complex than anyone had shown before. New research suggests that a hormone from the skeleton, of all places, may influence how the body handles sugar. Mounting evidence also demonstrates that signals from the immune system, the brain and the gut play critical roles in controlling glucose and lipid metabolism. (The findings are mainly relevant to Type 2 diabetes, the more common kind, which comes on in adulthood.) Focusing on the cross-talk between more different organs, cells and molecules represents a “very important change in our paradigm” for understanding how the body handles glucose, said Dr. C. Ronald Kahn, a diabetes researcher and professor at Harvard Medical School. Copyright 2007 The New York Times Company

Keyword: Obesity; Hormones & Behavior
Link ID: 10852 - Posted: 06.24.2010

By ERIC NAGOURNEY A machine that can quickly assess the state of nerve fibers in the retina may offer a better way to measure the progression of multiple sclerosis than the M.R.I. examinations now used, researchers said yesterday. Writing in Neurology, the researchers said the machine used a method known as optical coherence tomography to measure the thickness of the nerve fibers, which shrink as multiple sclerosis progresses. The lead author of the study, Dr. Peter Calabresi of Johns Hopkins, said the problem with M.R.I. scans for multiple sclerosis patients was that they measured brain shrinkage, a symptom that tends to occur in the later stages of the disease. A test that shows changes in the retinal nerve fibers would allow doctors to begin treatment earlier, although the changes can signal other problems besides multiple sclerosis. It may also allow researchers developing new drugs against the disease to see how well they work. Copyright 2007 The New York Times Company

Keyword: Multiple Sclerosis; Brain imaging
Link ID: 10851 - Posted: 10.16.2007

Lauran Neergaard, Associated Press — When aging hampers memory, some people's brains compensate to stay sharp. Now scientists want to know how those brains make do — in hopes of developing treatments to help everyone else keep up. This is not Alzheimer's disease, but the wear-and-tear of so-called normal aging. New research is making clear that memory and other brain functions decline to varying degrees even in otherwise healthy people as they age, as anyone who habitually loses car keys probably suspected. The question is how to gird our brains against time's ravages, a question becoming critical as the population grays. If you're 65 today, odds are you'll live to 83. But improving health care means people in their 50s today may live another 40 years. "I don't think we've recognized, as scientists or a society, (that) this is the front-and-center public health issue we face as a nation," Dr. Denise Park, director of the University of Illinois' Center for Healthy Minds, told fellow brain specialists assembled by the government last week. "We need to understand how to defer normal cognitive aging ... the way we've invested in fighting heart disease and cancer." There are intriguing clues, gleaned from discoveries that some seniors' brains literally work around aging's damage, forging new pathways when old ones disintegrate. © 2007 Discovery Communications

Keyword: Alzheimers
Link ID: 10850 - Posted: 06.24.2010

By Roger Highfield, Science Editor A "beauty spot", wonky nose or a lopsided grin are a turnoff, according to a study published today that shows that symmetry is sexy. Research to find whether symmetrical faces are more or less attractive in the UK and the Hadza of Tanzania, one of the last hunter gatherer cultures, has found that a symmetrical face is indeed a turn on, whatever your culture. advertisementThe find, resulting from presenting a series of faces for inspection by 80 Britons and 40 Hadza challenges feminist ideas, epitomised by the American writer Naomi Wolf, who argued that there is no such thing as a quality called beauty that "objectively and universally exists". Even the father of evolution, Charles Darwin was struck by cultural differences in attractiveness. He wrote: "It is certainly not true that there is in the mind of man any universal standards of beauty with respect to the human body." Today, in the Proceedings of the Royal Society, Biological Sciences, research by Dr Anthony Little of the University of Stirling, working with colleagues Coren Apicella at Harvard University and Frank Marlowe Florida State University, shows that symmetry transcends racial and national boundaries: a lopsided face is less attractive to both Hadza and Britons, so that the age-old idea that beauty is in the eye of the beholder is a romantic myth. © Copyright of Telegraph Media Group Limited 2007

Keyword: Sexual Behavior; Evolution
Link ID: 10849 - Posted: 06.24.2010

A look of horror will grab the attention of those around you faster than a smile, US research shows. Individuals react more quickly to a fearful expression than to faces showing other emotions such as joy, a study in the journal Emotion found. Researchers from Vanderbilt University found the same speedy reaction to fear when only the eyes were visible. The brain responds very quickly to all facial expressions - at a speed of less than 40 milliseconds. So to assess if certain emotions prompt a faster reaction, the researchers had to slow down the speed at which volunteers became aware of facial expressions. Volunteers looked through a viewer which flashed a black and white, quick-changing pattern to one eye and a static image of a face to the other eye. The flashing image had the effect of slowing down the speed at which the individual noticed the face. Participants became aware of a fearful expression far faster than a neutral or happy face. Reaction to happy faces was consistently slower than for the other expressions looked at. The fast reaction to fear was the same if the whole face was visible or just the eyes. (C)BBC

Keyword: Emotions
Link ID: 10848 - Posted: 10.15.2007

UK-based scientists say they have identified the brain circuits that control how much we eat. The Nature study, by University College London and King's College London, could aid development of new obesity drugs. Using brain scans, the teams showed the appetite-regulating hormone peptide YY (PYY) produces a more complex pattern of activity in the brain than thought. It targets not only the primitive areas controlling basic hunger urges, but also the pleasure and reward centres. PYY is released from the gut into the bloodstream after eating and signals to the brain that food has been eaten. A nasal spray containing the hormone is currently being trialled to see if it can be used to tackle obesity. Studies on animals suggest it regulates appetite by acting in primitive parts of the brain such as the hypothalamus and brainstem. The latest study showed that the same was true in humans. But the hormone was also found to act in the cortico-limbic regions that determine the pleasure sensations associated with eating food. The biggest effect of all was found in an area called the orbitofrontal cortex (OFC) - a region thought to make overall sense of the pleasure sensation. The researchers found that the greater the change in activity in that area, the less the volunteers ate. Eight normal-weight men took part in the study. After 14 hours without food, they were given a drip of either PYY or a placebo for 100 minutes while their brains were scanned using an MRI machine. Thirty minutes later they were offered an unlimited meal. Each volunteer was tested twice, a week apart, once with PYY and once with the placebo. (C)BBC

Keyword: Obesity
Link ID: 10847 - Posted: 10.15.2007

By LISA SANDERS, M.D. The indifferent voice crackled through the hospital intercom. “Please, I am so, so thirsty,” answered the young woman in the bed. “I feel awful, but I know I’d feel better if I could just have a drink of water.” Her mouth was so dry it hurt, and her head pounded painfully. She felt dizzy and sweaty. “I’ll let your nurse know,” replied the voice. It seemed to the woman that her life had always revolved around water. She was always thirsty, always drinking. When she went out, she carried two or three water bottles with her. When she went to sleep, she needed two glasses of water at her bedside. That morning she had come to the hospital for a C-section to deliver a baby too big to get out any other way. Now the beautiful baby was sleeping, and the mother was desperately thirsty. When the nurse appeared with a pitcher of water, the woman almost wept with relief. The next morning, Dr. Heidi Chen, the OB-GYN intern, woke the patient early. The young doctor was worried, and it showed on her face. The patient had drunk an enormous amount of water in the hours following her C-section — well over three gallons. Her urine output had been just as remarkable. The doctor needed to figure out what was going on. Copyright 2007 The New York Times Company

Keyword: Hormones & Behavior
Link ID: 10846 - Posted: 06.24.2010

CHICAGO -- What's so unusual about a baby fascinated with spinning a cup, or a toddler flapping his hands, or a preschooler walking on her toes? Parents and even doctors sometimes miss these red flags for autism, but a new online video "glossary" makes them startlingly clear. Dozens of video clips contrast the behavior of autistic kids with that of unaffected children. Some of the side-by-side differences can make you gasp. Others are more subtle. The free Web site, debuting today, also defines and depicts "stimming," echolalia and other confusing-sounding terms that describe autistic behavior. Stimming refers to repetitive, self-stimulating or soothing behavior, including hand-flapping and rocking, that autistic children sometimes do in reaction to light, sounds or excitement. Echolalia is echoing or repeating someone else's words or phrases, sometimes out of context. © 2007 The Washington Post Company

Keyword: Autism
Link ID: 10845 - Posted: 06.24.2010

— Japanese researchers say they have found a way to let people stroll through the virtual world of Second Life using their own imagination, in a development that could help paralysis patients. Previous studies have shown people can move computer cursors through brain waves, but the Japanese team says it is the first to apply the technology to an Internet virtual world. The technology "would enable people suffering paralysis to communicate with others or do business through chatting and shopping in a virtual world," said Junichi Ushiba, associate professor at Keio University's rehabilitation centre. Second Life is an increasingly popular virtual world in which people — and animals — are represented by animated avatars and can do everything from social activities to shopping. Ushiba said Second Life could motivate patients with severe paralysis, who are often too depressed to undergo rehabilitation. "If they can see with their own eyes their characters moving around, it could reinvigorate their brain activity and restore some functions," he said. Under the technology, a person wearing head gear embedded with electrodes, which analyse brain waves in the cerebral motor cortex, would be able to move a Second Life character forward by thinking he or she is walking. © 2007 Discovery Communications

Keyword: Robotics
Link ID: 10844 - Posted: 06.24.2010

Erika Check Hayden A survey of Alzheimer’s patients has identified some distinctive proteins in the blood that could be used to diagnose the disease more effectively. Earlier and more definitive diagnoses are wanted to help target treatments — both existing and experimental. More than 5 million North Americans currently have Alzheimer’s disease. It is estimated that about quarter of a million developing cases go undiagnosed every year. Doctors can diagnose Alzheimer’s only by eliminating other possible causes of mental decline. There is no definitive test for the disease until a person dies, when surgeons can examine his or her brain tissue to look for the protein plaques and tangles that are the hallmark of the disease. Researchers are trying to change that situation by finding biomarkers — definitive biological signatures of the disease. Today, a team led by neuroscientist Tony Wyss-Coray of Stanford University School of Medicine in California reports in Nature Medicine 1 the discovery of 18 proteins that together seem fairly diagnostic for the condition. If the biomarkers are confirmed by more rigorous testing, they could result in a simple blood test by which doctors could diagnose the disease. Sufferers could then take medications to delay the effects of Alzheimer’s, plan to change their finances or living situation, or enroll in clinical trials to test potential new drugs. © 2007 Nature Publishing Group

Keyword: Alzheimers
Link ID: 10843 - Posted: 06.24.2010