Jennifer Viegas -- For years, fishermen in Alaska wondered why their catches were mysteriously disappearing, and now remarkable new footage shows a sperm whale adroitly "stealing" fish on lines without leaving behind any tell-tale evidence, save for its candid camera appearance. The video presents the first known footage of a male sperm whale eating in the wild. Since it includes ear-splitting sounds made by the feeding whale, the video is also helping scientists better understand how the marine giants vocalize, allowing researchers to estimate population sizes based on whale chatter. "We definitely did a high-five when we saw the video," project leader Aaron Thode of Scripps Institution of Oceanography told Discovery News. "It was a fist-pumping moment." With the help of black cod longline fisherman Kendall Folkert, Thode and colleague Delphine Mathias deployed video cameras and acoustic recorders like flying kites on Folkert's fishing lines off Sitka, Alaska, at a depth of 328 feet. Longline operations consist of a main fishing line draped across the ocean and fastened with shorter lines bearing baited hooks. Marine mammals often avoid anything that looks foreign in their environment, so the researchers camouflaged their setup with "fake tangled rope" and other disguises. One male sperm whale fell for the camera trap. © 2009 Discovery Communications, LLC.

Keyword: Intelligence; Evolution
Link ID: 12888 - Posted: 06.24.2010

by Holly Hight OREGON, U.S.: The high-pitched, maniacal 'laugh' of the hyena is not used by all individuals equally, but mostly by subordinates as a sign of frustration. "The hyena's laugh is a multi-informative signal," said Nicholas Mathevon, a biologist at the University of Jean Monnet, in Saint-Etienne, France, who studied captive hyenas, recording their laughs and subjecting them to sophisticated acoustical studies. The hyena has up to 20 vocalisation types, but only two had previously been studied. One is a 'whoop', used as a long-distance call, while the other is a groan, used for communication over short ranges. Mathevon found that the laugh tends to occur when subordinate animals are attacked or chased away by dominant hyenas during feeding times and "is mainly emitted when [the animal] is frustrated," said Mathevon, who presented his results this week at the Acoustics Society of America's annual conference in Portland, Oregon. The spotted hyena (Crocuta crocuta), which is found widely across Africa, has a complex social structure – as complex as the social systems of primates such as baboons and macaques. It is a savage hierarchy; subordinates are frequently attacked and denied access to food and mates. ©2007 Luna Media Pty Ltd,

Keyword: Animal Communication; Language
Link ID: 12887 - Posted: 06.24.2010

by Ewen Callaway Do you think you're smarter than most? Chances are, your children will feel the same way about themselves. A new study of thousands of twins suggests that intellectual confidence is genetically inherited, and independent from actual intelligence. Moreover, these genetic differences predict grades in school, says Tomas Chamorro-Premuzic, a psychologist at Goldsmiths University in London, whose team found that 7- to 10-year-old children who achieved the best marks in school tended to rate their own abilities highly, even after accounting for differences due to intelligence and environment. Psychologists have long known that intelligence isn't the only predictor of scholastic achievement and that intellectual confidence does a good a job of predicting grades as well. "There has been a very, very big lobby within educational psychology against the notion of IQ," says Chamorro-Premuzic. "And part of this lobby has been based on the idea that self-perceptions matter more than actual ability." Most of these researchers assumed that environmental factors – the influence of parents, teachers and friends – explained why some students think more of their abilities than others. © Copyright Reed Business Information Ltd

Keyword: Emotions; Intelligence
Link ID: 12886 - Posted: 06.24.2010

By Rebecca Morelle Rooks have a remarkable aptitude for using tools, scientists have found. Tests on captive birds revealed that they could craft and employ tools to solve a number of different problems. The findings, published in the Proceedings of the National Academy of Sciences, came as a surprise as rooks do not use tools in the wild. Despite this, the UK team said the birds' skills rivalled those of well-known tool users such as chimpanzees and New Caledonian crows. Dr Nathan Emery, from Queen Mary, University of London, an author of the paper, said: "The study shows the creativity and insight that rooks have when they solve problems." The scientists focused on four captive rooks: Cook, Fry, Connelly and Monroe, and discovered that the birds were able to use tools in a number of ways to solve a variety of problems. For example, the birds were presented with a vertical tube, running down to a trap-door with an out-of-reach worm perched upon it, as well as a number of different-sized stones placed nearby. The scientists discovered that the rooks would select the largest stone, which was heavy enough to push open the trap-door when dropped and release the snack. And when given a selection of different-shaped stones, some of which could fit into the tube some of which could not, the rooks opted for a tool that would give them access to the treat. Lead author Christopher Bird, from Cambridge University, said: "We have found that they can select the appropriate tools out of a choice of tools and they show flexibility in the types of tools they use." (C)BBC

Keyword: Intelligence; Evolution
Link ID: 12885 - Posted: 05.26.2009

By JANE E. BRODY Edward Ferguson, a civil engineer living in Vancouver, Wash., retired at age 65 from a job handling multimillion-dollar contracts. Five years later he could not balance a checkbook, walk without falling, drive a car, control his bladder or recognize his granddaughter. Instead of the active retirement he had anticipated, Mr. Ferguson, now 74, thought he would spend the rest of his life in a wheelchair, incontinent and struggling with dementia. Ten doctors were unable to tell him what was wrong, but an Internet search by his daughter found a condition that seemed to match his symptoms: normal pressure hydrocephalus, or N.P.H. The disorder involves a build-up of spinal fluid in the ventricles of the brain, causing pressure on nerves that control the legs, balance, bladder and cognitive function. “It’s as if the brain has reverted to babyhood,” Dr. Michael Kaplitt, a neurosurgeon at NewYork-Presbyterian Hospital/Weill Cornell Medical Center, said in an interview. “Like babies, people with N.P.H. walk slowly with feet wide apart, they are incontinent and have no memory.” Dr. Kaplitt calls it “a classic triad of symptoms” that should alert doctors to the possibility of N.P.H. Yet the condition is frequently misdiagnosed as dementia, Alzheimer’s disease, Parkinson’s disease or a spinal problem. Or it is attributed to age — nearly all who are affected are over 55. Copyright 2009 The New York Times Company

Keyword: Alzheimers; Movement Disorders
Link ID: 12884 - Posted: 06.24.2010

By ANAHAD O’CONNOR For almost a century, eye exercises have been promoted as a way to strengthen vision and ease nearsightedness and astigmatism, much like exercise for the body trims fat and improves health. Some of the most popular techniques include eye-hand coordination drills, eye movement routines and focusing on blinking lights. The techniques are widely promoted online and advocated by various companies, some even claiming that they can reduce the need for glasses and ease learning disabilities. But several studies have concluded that many of these do-it-yourself techniques are baseless. One of the latest studies, published in 2009, found little evidence in support of vision exercises that supposedly slow or reduce myopia, ease dyslexia and correct conditions caused by physiological problems, like blurred vision. A similar conclusion had been reached in a 2005 report that reviewed 43 previous studies, finding “no clear scientific evidence” for most of the methods reviewed. But there are some areas of vision therapy that have been scientifically validated, including one called orthoptics. In this therapy, eye doctors prescribe exercises that can relieve double vision, focus problems and conditions like strabismus, also known as crossed eyes. Orthoptics can treat convergence insufficiency, in which the eyes have trouble working together. It affects as many as 1 in 5 people, but with the right exercises it can be all but cured, studies show. Copyright 2009 The New York Times Company

Keyword: Vision
Link ID: 12883 - Posted: 06.24.2010

Scientists believe they have made a breakthrough in the treatment of a severe muscle disease that causes floppy baby syndrome. Most babies born with the rare disorder are severely paralysed and the majority die before the age of one. The Australian team was able to cure affected mice by replacing a missing muscle protein. A UK expert said the findings, in the Journal of Cell Biology, could lead to improved movement for affected babies. The team focussed on proteins called actins. A gene called ACTA1 controls the production of actin in skeletal muscles. It is key to allowing muscles to contract, but children with this disease have flawed versions of the gene and so the protein is not produced. However, the scientists had seen that some children with floppy baby syndrome were not totally paralysed at birth. When these children were studied, it was found that heart actin - another form of the protein - was "switched on" in their skeletal muscles, when that would not normally be the case. Heart actin is found in skeletal muscles while the baby is developing in the womb, but has almost completely disappeared by birth. The researchers found it was possible to cure mice genetically engineered to have the recessive form of the muscle disorder by replacing the missing skeletal muscle actin with heart actin. Dr Kristen Nowak, of the Western Australian Institute for Medical Research, who led the study, said: "The mice with floppy baby syndrome were only expected to live for about nine days, but we managed to cure them so they were born with normal muscle function, allowing them to live naturally and very actively into old age. This is an important step towards one day hopefully being able to better the lives of human patients - mice who were cured of the disease lived more than two years, which is very old age for a mouse." (C)BBC

Keyword: Movement Disorders; Muscles
Link ID: 12882 - Posted: 05.26.2009

By Shankar Vedantam Soon after her sister committed suicide, Caroline Downing started doing poorly at school. During math tests she would freeze up, and she found her mind wandering constantly. Officials at St. Andrew's Episcopal School in Potomac gently suggested that the high school sophomore get a mental health screening. The idea of a psychiatric evaluation sent chills down the spine of Caroline's mother, Mathy Milling Downing, who believed that her younger daughter, Candace, had committed suicide because of an adverse reaction linked to a psychiatric drug -- the antidepressant Zoloft. Shortly after Candace's death, the Food and Drug Administration placed black-box warnings on several antidepressants to say they elevated suicidal thinking among some children. If Caroline were going to get the same kind of mental health care as Candace, Downing wanted no part of it. Downing's family offers a powerful case study into the pros and cons of new guidelines recommending widespread screening of adolescents for mental disorders: Last month, the U.S. Preventive Services Task Force, a federal group that makes public health recommendations, said that all adolescents between ages 12 and 18 should be screened for major depression. In March, the Institute of Medicine, which advises Congress on scientific matters, told policymakers that early screening was key to reducing the financial and medical burden of mental disorders in the United States. Downing said she agreed to have her older daughter screened because the child was obviously in distress, but she told school officials that if an evaluation led to a prescription for medications, she would refuse to go along. © 2009 The Washington Post Company

Keyword: Depression; Development of the Brain
Link ID: 12881 - Posted: 06.24.2010

By RONI CARYN RABIN A few years ago, shortly after she moved to New York City, one of her friends pointed out a young man standing on the other side of the room at a party. Ms. Jarett took one look and said, “Oh, I know who he is — I went to Hebrew school with him in fourth grade.” At the time, Ms. Jarett, who is now 38, had not seen the boy in nearly two decades, since they were both children. In a study published in April, Harvard scientists coined the term “super-recognizers” to describe people like Ms. Jarett who have an uncanny ability to recognize and remember faces. The brain’s ability to identify faces varies from person to person: while a small minority are unable to recognize others at all, the “super-recognizers” have an extraordinary talent for recollection, occupying the extreme end of the face-recognition spectrum, said Richard Russell, a postdoctoral researcher in psychology at Harvard University and lead author of the paper, published in Psychonomic Bulletin & Review. Dr. Russell assessed the recognition abilities of four subjects, including Ms. Jarett, who identified themselves as having a knack for remembering faces. In one exam, they were asked to identify celebrities through 56 photographs taken before they achieved fame or when they were children. Copyright 2009 The New York Times Compan

Keyword: Miscellaneous
Link ID: 12880 - Posted: 06.24.2010

Melissa Dahl Five-inch stilettos, too-heavy handbags, a wedding dress that seemingly weighed as much as a small child — Parmeeta Ghoman admits she’s no stranger to suffering for fashion. “I’m the kind of person who buys shoes two sizes too small just because they’re cute — and they’re on sale,” says Ghoman, who's 28 and lives outside of San Francisco. But when she wore a pair of super-tight skinny jeans to dinner with friends in December, she noticed an odd tingly sensation running up and down her thighs. And when she got up to walk around, things got weirder. She felt like she was almost "floating," because she couldn't feel her legs. “It felt really strange — it felt like my leg had gone to sleep,” Ghoman says. Ghoman’s skin-tight denim may have caused a temporary bout of a nerve condition called meralgia paresthetica, also known as “tingling thigh syndrome.” The condition can happen when constant pressure — in Ghoman's case, from the skin-tight denim — cuts off the lateral femoral cutaneous nerve, causing a numb, tingling or burning sensation along the thigh. Typically, sufferers of the nerve condition include construction workers or police officers with heavy, low-slung belts, pregnant women or obese people; it also can result from a pulled-tight seat belt in a car accident. But over the last several years, experts say they’ve been seeing more young women at a healthy weight complain of symptoms. The culprit: too-tight jeans. © 2009 msnbc.com

Keyword: Pain & Touch
Link ID: 12879 - Posted: 06.24.2010

By JOHN MARKOFF Mountain View, Calif. — It’s summertime and the Terminator is back. A sci-fi movie thrill ride, “Terminator Salvation” comes complete with a malevolent artificial intelligence dubbed Skynet, a military R.&D. project that gained self-awareness and concluded that humans were an irritant — perhaps a bit like athlete’s foot — to be dispatched forthwith. The notion that a self-aware computing system would emerge spontaneously from the interconnections of billions of computers and computer networks goes back in science fiction at least as far as Arthur C. Clarke’s “Dial F for Frankenstein.” A prescient short story that appeared in 1961, it foretold an ever-more-interconnected telephone network that spontaneously acts like a newborn baby and leads to global chaos as it takes over financial, transportation and military systems. Today, artificial intelligence, once the preserve of science fiction writers and eccentric computer prodigies, is back in fashion and getting serious attention from NASA and from Silicon Valley companies like Google as well as a new round of start-ups that are designing everything from next-generation search engines to machines that listen or that are capable of walking around in the world. A.I.’s new respectability is turning the spotlight back on the question of where the technology might be heading and, more ominously, perhaps, whether computer intelligence will surpass our own, and how quickly. Copyright 2009 The New York Times Company

Keyword: Intelligence; Robotics
Link ID: 12878 - Posted: 06.24.2010

Scientists have produced more evidence that vitamin D has an important role in keeping the brain in good working order in later life. A study of over 3,000 European men aged 40-79 found those with high vitamin D levels performed better on memory and information processing tests. The University of Manchester team believe vitamin D may protect cells or key signalling pathways in the brain. The study features in the Journal of Neurology Neurosurgery and Psychiatry. It follows research published in January which suggested that high levels of vitamin D can help stave off the mental decline that can affect people in old age. The latest study focused on men from eight cities across Europe. Their mental agility was assessed using a range of tests, and samples were taken to measure levels of vitamin D in their blood. Men with high vitamin D levels performed best, with those who had the lowest levels - 35 nmol/litre or under - registering poor scores. The researchers said the reason why vitamin D - found in fish and produced by sun exposure - seemed to aid mental performance was unclear. They suggested it might trigger an increase in protective hormonal activity in the brain. However, the only data to back this up so far comes from animal studies. There is also some evidence that vitamin D can dampen down an over-active immune system. Alternatively, it may boost levels of antioxidants that in effect detoxify the brain. The researchers stressed that many people, particularly in older age, were vitamin D deficient. (C)BBC

Keyword: Alzheimers; Hormones & Behavior
Link ID: 12877 - Posted: 05.25.2009

By Steve Connor, Science Editor People are more likely to become lovers if their genes share little in common, according to a study that demonstrates a possible biological mechanism controlling the sexual attraction between men and women. Heterosexual men and women with dissimilar genes are more likely to get married than people with a similar genetic heritage. The findings indicate that certain genes control some of the subconscious desires behind the choice of one partner over another, as a way of preventing inbreeding and boosting a child's immune defences. Researchers studied the genes of 90 married couples and found that their DNA in a key region of their chromosomes was significantly different compared with the same stretch of DNA in 152 couples chosen at random from the population and who were neither married nor having sexual relations with one another. The genes, called the major histocompatibility complex (MHC), are part of the immune system. This is the first rsearch of its kind showing that they may play a significant role in whether or not couples are likely to get married. If the MHC genes played no role in the choice of a mate, then the scientists would expect to find similar differences between both sets of couples – the married and the unmarried. However, the statistically significant difference suggests that the dissimilar MHC genes influenced whether men and women become attracted to one another. ©independent.co.uk

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 12876 - Posted: 06.24.2010

By Susan Milius “You’ve got to suffer if you want to sing the blues” may apply to mockingbirds too. In the Mimidae family, of mockingbirds and thrashers, the species with the more elaborate male courtship songs tend to be those living in the more challenging climates, says Carlos Botero of the National Evolutionary Synthesis Center in Durham, N.C. Virtuoso birdsong, Botero explains, means precision in repeated elements, abundant variety in tweets and trills plus dead-on mimicry of other sounds, whether from neighboring bird species or car alarms. Mockingbird species that excel in such performance tend to breed in zones of hard-to-predict and highly variable temperature and precipitation, Botero and his colleagues report online May 21 in Current Biology. Like other songbirds, mockingbirds and their relatives have to learn the vital singing skills for wooing and warring. If climate has something to do with brain evolution and learning, as some scientists have long hypothesized, then bird music may reveal the effects, the researchers propose. “Nobody has looked at climate and bird song before,” Botero says. This proposed link is important, says Daniel Sol of the Autonomous University of Barcelona in Spain, “because it suggests that sexual selection can also be affected by climatic variability.” That influence, he adds, “is key to understand the possible impact of climate change on biodiversity.” © Society for Science & the Public 2000 - 2009

Keyword: Sexual Behavior; Evolution
Link ID: 12875 - Posted: 06.24.2010

The Alzheimer's research community is buzzing about a theory suggesting that a close relative of the beta-amyloid protein, and not necessarily beta-amyloid itself — the long-standing suspect — may be a major culprit in the disease. The theory holds that an amyloid-related mechanism that prunes neuronal connections in the brain in the fast-growth phase of early life may be triggered by ageing-related processes in later life to cause the neuronal withering of Alzheimer's disease (A. Nikolaev et al. Nature 457, 981–989; 2009). "We have yet to get a disease-modifying drug that works. So we're missing something, and maybe this is one of the missing pieces," says Donna Wilcock, a neurologist at Duke University in Durham, North Carolina. "I think people are bored of the amyloid hypothesis and would just love to have something else to follow up," adds John Hardy, a neurologist at University College London. Insoluble clumps of the beta-amyloid peptide appear in the brains of patients with Alzheimer's, and mutations in amyloid's precursor protein (APP) have been linked to rare, familial forms of the disease. But how amyloid contributes to the damage of Alzheimer's is not clear, and several anti-amyloid drugs have failed in phase III clinical trials (see Nature 456, 161–164; 2008). Some scientists are unsure that any form of beta-amyloid contributes to much of the neuronal destruction. © 2009 Nature Publishing Group,

Keyword: Alzheimers; Development of the Brain
Link ID: 12874 - Posted: 06.24.2010

by Ewen Callaway A newly identified gene called happyhour makes fruit flies sensitive to booze. Drugs that mimic the effects of the gene may offer a new treatment against alcohol abuse, researchers say. "People who are very sensitive to alcohol tend to drink less – that's the person who gets drunk on one glass of wine," says Robert Swift, a psychiatrist at Brown University in Providence, Rhode Island, who was not involved in the new study. "The person who can drink everybody under the table – that's that person who is more likely to become an alcoholic," he adds. When they drink, laboratory fruit flies aren't so different from pub-crawlers on a Friday night. "They go through a phase of hyperactivity and they gradually become uncoordinated; they stop moving and they fall over; and eventually they are unable to right themselves," says Ulrike Heberlein, a molecular biologist at the University of California, San Francisco, who led the new study. Bar flies Heberlein and colleague Ammon Corl hunted for mutant fruit flies able to keep the party going and not pass out. Two strains of flies fit this description, and both carried mutations in a gene that Heberlein's team dubbed happyhour. © Copyright Reed Business Information Ltd

Keyword: Drug Abuse; Genes & Behavior
Link ID: 12873 - Posted: 06.24.2010

By Andrew Holtz PORTLAND, OREGON -- It is easy to understand how explosions involving shrapnel – such as those caused by improvised explosive devices in Iraq – could cause brain damage. But what about such injuries that seem to be caused by blasts themselves, rather than from being thrown or hit by shrapnel? Researchers have a few ideas, but one scientist has used some of the world’s most powerful computers at the Lawrence Livermore National Laboratory in California to get a better answer. Willy Moss and colleague Michael King used available data on blast waves from explosions and the physical properties of the human skull, brain and cerebrospinal fluid to craft a three-dimensional simulation of a soldier standing less than 15 feet from an explosion of 5 lbs. of C4. (See image to the right.) “It sweeps over. There’s lots of oscillation. The skull is ringing. It’s not pleasant,” Moss told the audience at the meeting of the Acoustical Society of America here. Moss says their simulations suggest that the intense pressures of such blasts flex the skull and ripple the brain. Pressures as little as one atmosphere over normal atmospheric pressure can do that kind of damage. They repeated the simulation to include helmets, first using data from an older style that uses webbing to create space around a soldier’s head. (See video below.) “What you see is the blast sweeps under the helmet. It acts as a wind scoop; it focuses the blast. The blast pressure is bigger between your head and the helmet than if you weren’t wearing the helmet at all.” © 1996-2009 Scientific American Inc.

Keyword: Brain Injury/Concussion
Link ID: 12872 - Posted: 06.24.2010

By BENEDICT CAREY LAGUNA WOODS, Calif. — The ladies in the card room are playing bridge, and at their age the game is no hobby. It is a way of life, a daily comfort and challenge, the last communal campfire before all goes dark. For all that scientists have studied it, the brain remains the most complex and mysterious human organ — and, now, the focus of billions of dollars’ worth of research to penetrate its secrets. This bridge game is not for the timid. Norma Koskoff, left, Ruth Cummins and Georgia Scott expect the best from every player. If someone’s skills start slipping, it is time to find a new table. “We play for blood,” says Ruth Cummins, 92, before taking a sip of Red Bull at a recent game. “It’s what keeps us going,” adds Georgia Scott, 99. “It’s where our closest friends are.” In recent years scientists have become intensely interested in what could be called a super memory club — the fewer than one in 200 of us who, like Ms. Scott and Ms. Cummins, have lived past 90 without a trace of dementia. It is a group that, for the first time, is large enough to provide a glimpse into the lucid brain at the furthest reach of human life, and to help researchers tease apart what, exactly, is essential in preserving mental sharpness to the end. Copyright 2009 The New York Times Company

Keyword: Learning & Memory; Alzheimers
Link ID: 12871 - Posted: 06.24.2010

Scientists say they have located the brain areas that may determine how sociable a person is. Warm, sentimental people tend to have more brain tissue in the outer strip of the brain just above the eyes and in a structure deep in the brain's centre. These are the same zones that allow us to enjoy chocolate and sex, the Cambridge University experts report in the European Journal of Neuroscience. The work suggests that some people may get a similar buzz from being sociable. It could also lead to new insights into psychiatric disorders where difficulties in social interaction are prominent, such as autism or schizophrenia. For some people, socializing is an intrinsic reward, just like chocolate or cannabis Professor Simon Baron Cohen, of the Autism Research Centre in Cambridge The brain scan study was carried out on 41 healthy male volunteers. The men who scored higher on questionnaire-based ratings of emotional warmth and sociability had more grey matter in two brain areas - the orbitofrontal cortex and ventral striatum. The researchers say it is not clear whether the men were born with these brain differences or whether the brain regions in question grew in response to personal experiences. Experts already know that the striatum becomes activated by receiving compliments and the orbitofrontal cortex is activated by attractive faces and smiling. Lead researcher Dr Graham Murray said: "Sociability and emotional warmth are very complex features of our personality. This research helps us understand at a biological level why people differ in the degrees to which we express those traits. It's interesting that the degree to which we find social interaction rewarding relates to the structure of our brains in regions that are important for very simple biological drives such as food, sweet liquids and sex." (C)BBC

Keyword: Emotions
Link ID: 12870 - Posted: 05.23.2009

Scientists have shown there may be biochemical reasons - quite apart from the mental trauma of diagnosis - why cancer patients can become depressed. A University of Chicago team found tumours produce chemicals which can produce negative mood swings. They say the findings shed new light on why depression is such a risk for many cancer patients. The study, carried out on rats, features in Proceedings of the National Academy of Sciences. It has long been known that cancer is associated with depression. Experts thought this was likely to be either a result of the trauma of diagnosis, or possibly a side effect of chemotherapy treatment. The Chicago study suggests a third possibility. The researchers found that substances associated with depression are produced in increased quantities by tumours, and then are transmitted to the brain where they impact on the hippocampus - the area which regulates emotion. In addition, chemical pathways which normally put a brake on the impact of these depression-causing substances appear to be disrupted when a tumour develops. The researchers carried out tests on about 100 rats, some of which had cancer, to determine their emotional state. They found animals with tumours were less motivated to try to escape when submitted to a swimming test - a condition similar to depression in humans. Rats with tumours were also less eager to drink sugar water, a substance that usually attracts the appetites of healthy rats. Further tests revealed that the rats with tumours had increased levels of cytokines in their blood and in the hippocampus when compared with healthy rats. Cytokines are produced by the immune system, and an increase in cytokines has been linked to depression. (C)BBC

Keyword: Depression
Link ID: 12869 - Posted: 05.19.2009