By Alan S. Brown Eight years ago, when Erik Ramsey was 16, a car accident triggered a brain stem stroke that left him paralyzed. Though fully conscious, Ramsey was completely paralyzed, essentially “locked in,” unable to move or talk. He could communicate only by moving his eyes up or down, thereby answering questions with a yes or a no. Ramsey’s doctors recommended sending him to a nursing facility. Instead his parents brought him home. In 2004 they met neurologist Philip R. Kennedy, chief scientist at Neural Signals in Duluth, Ga. He offered Ramsey the chance to take part in an unusual experiment. Surgeons would implant a high-tech device called a neural prosthesis into Ramsey’s brain, enabling him to communicate his thoughts to a computer that would translate them into spoken words. Today Ramsey sports a small metal electrode in his brain. Its thin wires penetrate a fraction of an inch into his motor cortex, the part of the brain that controls movement, including the motion of his vocal muscles. When Ramsey thinks of saying a sound, the implant captures the electrical firing of nearby neurons and transmits their impulses to a computer, which decodes them and produces the sounds. So far Ramsey can only say a few simple vowels, but Kennedy believes that he will recover his full range of speech by 2010. © 1996-2008 Scientific American Inc.

Keyword: Miscellaneous
Link ID: 12152 - Posted: 06.24.2010

Ewen Callaway A mole that can no longer open its eyelids, thanks to its adaptation to an underground lifestyle, retains the basics of vision, research suggests. "What we think we're seeing in the mole is the very start of a breakdown in the eye," says Martin Collinson, a developmental biologist at the University of Aberdeen, UK. "I think the moles would have no problem seeing light and dark." The same genetic changes might also underlie congenital eye diseases in humans, he says. Collinson and colleague David Carmona studied eye development in Iberian moles, a species so adapted to subterranean life that its eyelids are glued shut. "They might occasionally need some visual ability, but they're also swimming through soil that would damage their eyes and cause infection," Collinson says. Few researchers had studied the cellular and molecular details of mole eye development, and Collinson's team expected to see eyes ravaged by the millions of years of evolution in a dark world. In cavefish, for example, the loss of lens cells creates a chain reaction that prevents the formation of other eye structures, such as the retina and light-sensing cells. Disrupted development However, "things that were going wrong with the moles' eyes were the opposite of things that were going wrong with the cavefish", Collinson says. © Copyright Reed Business Information Ltd.

Keyword: Evolution; Vision
Link ID: 12151 - Posted: 06.24.2010

Top mountaineers may be suffering subtle brain damage each time they reach the upper slopes of the world's highest peaks, say scientists. Italian researchers scanned "world-class" climbers before and after expeditions, publishing their results in the European Journal of Neurology. They found changes in brain tissue even though, outwardly, the climbers had no obvious new neurological problems. The most likely cause was a lack of oxygen at high altitudes, they said. At the summit of Everest, the world's highest mountain, the concentration of oxygen in the air is reckoned to be only a third of that found at sea level, more than 8,000m lower. All of the nine male climbers involved in the study, at the IRCCS Fondazione Santa Lucia in Rome, had reached their summit without the use of a supply of extra oxygen, a frequent practice among leading mountaineers. Before the trip, they underwent MRI scans, and were checked for any neurological illnesses, then matched against "control subjects" of the same age and sex, who had never climbed above 3,000m. Three of the climbers reached the top of at least one 8,000m peak, while the remainder reached altitudes of at least 7,500m, spending in excess of 15 days above 6,500m. When they were scanned eight weeks after returning, compared with the "controls", there was a fall in the density and volume of brain tissue in two parts of the brain, the "left pyramidal tract" and the "angular gyrus". However, Dr Margherita Di Paola, who led the study, said that this reduction did not appear to have a direct impact on their neurological performance. "The climbers in our study did not suffer any significant neuropsychological changes after the expedition," she said. However, some abnormal results on both the "before" and "after" tests, she said, might be the result of small, progressive brain damage caused by repeated trips to high-altitude. (C)BBC

Keyword: Miscellaneous
Link ID: 12150 - Posted: 10.20.2008

A University of B.C. epidemiologist says there is now evidence to support a heroin-assisted addictions therapy clinic in Vancouver. The North American Opiate Medication Initiative, or NAOMI, study was a Vancouver and Montreal-based clinical trial assessing how patients respond to heroin, methadone and other opiate treatment. The three-year study treated 251 of the most chronically addicted in both Vancouver and Montreal who have not responded well to other treatment options. "These people are out in the alleys, injecting heroin of unknown quality and quantity," said Dr. Martin Schechter, the study's principal investigator. "They're committing crimes, they're involved in sex work to pay for that, and they're certainly, in that situation, not going to get better." The study was funded by an $8.1-million research grant from the Canadian Institutes of Health Research and was approved by Health Canada. The study's participants received methadone, injected heroin or an opiate known as hydromorphone. © CBC 2008

Keyword: Drug Abuse
Link ID: 12149 - Posted: 06.24.2010

Controlling the level of a fatty acid in the brain could help treat Alzheimer's disease, an American study has suggested. Tests on mice showed that reducing excess levels of the acid lessened animals' memory problems and behavioural changes. Writing in Nature Neuroscience, the team said fatty acid levels could be controlled through diet or drugs. A UK Alzheimer's expert called the work "robust and exciting". There are currently 700,000 people living with dementia in the UK, but that number is forecast to double within a generation. Scientists from Gladstone Institute of Neurological Disease and the University of California looked at fatty acids in the brains of normal mice and compared them with those in mice genetically engineered to have an Alzheimer's-like condition. They identified raised levels of a fatty acid called arachidonic acid in the brains of the Alzheimer's mice. The scientists again used genetic engineering to lower PLA2 levels in the animals, and found that even a partial reduction halted memory deterioration and other impairments. Dr Rene Sanchez-Mejia, who worked on the study, said: "The most striking change we discovered in the Alzheimer's mice was an increase in arachidonic acid and related metabolites [products] in the hippocampus, a memory centre that is affected early and severely by Alzheimer's disease." He suggested too much arachidonic acid might over-stimulate brain cells, and that lowering levels allowed them to function normally. (C)BBC

Keyword: Alzheimers
Link ID: 12148 - Posted: 10.20.2008

David Robson The moment when Dorothy passes out in monochrome Kansas and awakes in Technicolor Oz may have been more significant than you'd ever imagined. A new study reveals that children exposed to black-and-white film and TV are more likely to dream in greyscale throughout their life. Opinions have been divided on the colour of dreams for almost a century. Studies from 1915 through to the 1950s suggested that the vast majority of dreams are in black and white. But the tides turned in the 60s, and later results suggested that up to 83% of dreams contain some colour. Since this period also marked the transition between black-and-white film and TV and widespread Technicolor, an obvious explanation was that the media had been priming the subjects' dreams, but differences between the studies prevented the researchers from drawing any firm conclusions. Whereas the later studies asked subjects to complete dream diaries as soon as they awoke, the earlier research used questionnaires completed in the middle of the day, so the subjects may have simply forgotten colour elements to their dreams and assumed they were greyscale. To lay the debate to rest, Eva Murzyn from the University of Dundee, UK, has incorporated both methods into one study. © Copyright Reed Business Information Ltd.

Keyword: Sleep
Link ID: 12147 - Posted: 06.24.2010

The brain's response to food is linked to future weight gain in women, US researchers report in Science. Brain imaging showed those who had the weakest response to drinking a chocolate milkshake were most likely to have put on weight a year later. Poor responses to food were also associated with a gene controlling the brain's response to dopamine - a chemical controlling pleasure. It backs previous work showing obese people may get less pleasure from food. Two separate studies, one in 43 female students aged 18 to 22 and another in 33 teenage girls aged 14 to 18, measured activation in a certain part of the brain (the dorsal striatum) when drinking chocolate milkshake or a tasteless drink. The researchers also tested for a particular genetic variant - TaqA1 - which is linked to fewer dopamine receptors in the brain. A year later, those with the "blunt" responses to the milkshake and the genetic variant were most likely to gain weight. Dr Eric Stice, from the Oregon Research Institute, said although recent studies had suggested that obese people may experience less pleasure when eating and eat more to compensate, this is the first study to link that with future weight gain. "The evidence that this relation is even stronger for individuals at genetic risk for compromised signalling in these brain regions points to an important biological factor that appears to increase risk for obesity onset." (C)BBC

Keyword: Obesity
Link ID: 12146 - Posted: 10.18.2008

By MELISSA FAY GREENE On a typical Monday morning at an atypical high school, teenage boys yanked open the glass doors to the First Baptist Church of Decatur, Ga. Half-awake, iPod wires curling from their ears, their backpacks unbuckled and their jeans baggy, the guys headed for the elevator. Arriving at Morning Meeting in the third-floor conference room, Stephen, his face hidden under long black bangs, dropped into a chair, sprawled across the table and went back to sleep. The Community School, or T.C.S., is a small private school for teenage boys with autism or related disorders. Sleep disturbances are common in this student body of 10, so a boy’s staggering need for sleep is respected. Nick Boswell, a tall fellow with thick sideburns, arrived and began his usual pacing along the windows that overlook the church parking lot and baseball diamond. Edwick, with spiky brown hair and a few black whiskers, tumbled backward with a splat into a beanbag chair on the floor. “O.K., guys, let’s talk about your spring schedules,” said Dave Nelson, the 45-year-old founding director. He wore a green polo shirt, cargo shorts and sneakers and had a buzz haircut and an open, suntanned face. After his son Graham, 19, was given a diagnosis of autism spectrum disorder (A.S.D.) as a young child, Nelson left the business world and went into teaching and clinical and counseling work. On that Monday, he was instantly interrupted. “I had a very bad night!” Edwick yelled from the floor. “Nightmares all night!” “What was disturbing you, Edwick?” Nelson asked. “What do you think?” Edwick cried in exasperation. “It’s St. Patrick’s Day!” “What’s upsetting about that?” Nelson asked. Edwick dropped his shoulders to relay how tiring it was to have to explain every little thing. “Leprechauns,” he yelled. Copyright 2008 The New York Times Company

Keyword: Autism
Link ID: 12145 - Posted: 06.24.2010

Reyhan Harmanci -- Brain scans presented as evidence in courts have had mixed results on legal proceedings. Some juries and judges have been swayed by the images; others less so. Below is a short list of prominent cases in which neuroscience played a part. United States vs. John W. Hinckley Jr. (1982) - One of the very first appearances of brain scans in court occurred during one of the most famous trials of the last century. Lawyers defending John Hinckley, who in 1981 attempted to assassinate President Ronald Reagan, presented a CT scan to buttress evidence of Hinckley's insanity. While the scan's role in the verdict isn't precisely known, Hinckley was found not guilty by reason of insanity. People of New York vs. Weinstein (1992) - Lawyers for Herbert Weinstein, a 64-year-old Manhattan advertising executive who admitted to strangling his wife and throwing her off a high-rise, successfully argued that a positron emission tomographic (PET) scan showing an arachnoid cyst should be admitted as evidence to explain that Weinstein could not be held criminally responsible for his actions. The prosecutors were reported to have been worried about a jury seeing the visual evidence and settled on a lesser charge, manslaughter, on the final day of jury selection. © 2008 Hearst Communications Inc.

Keyword: Brain imaging
Link ID: 12144 - Posted: 06.24.2010

Reyhan Harmanci, Chronicle Staff Writer -- Science and the American legal system historically have had a complicated relationship. While good science has driven solid law, junk science like eugenics and phrenology have influenced due process with often terrible consequences. Over the past decade, researchers have made huge advances in neuroscience, developing brain-imaging techniques that show not just the structure of the brain but its inner workings. According to experts in a new field called neurolaw, the effect of these breakthroughs on the legal system could be revolutionary. "The law is mainly about brains or, at least, the mind," said Stanford law Professor Hank Greely, one of the directors of the year-old MacArthur Foundation-funded Law and Neuroscience Project. "If my fist hits your chin, what, if anything, I was thinking is crucial. If I was in an epileptic fit, if I was thrown from a car when I hit you, you don't convict me of a crime. ... If I'm mad at you, we do." The degree to which brain scans will be admissible in court remains unclear, but experts already are pointing to precedent-setting cases and warning that neuroscience could alter the law, creating new methods and new visual evidence to determine criminal intent and criminal responsibility. © 2008 Hearst Communications Inc.

Keyword: Brain imaging
Link ID: 12143 - Posted: 06.24.2010

By Nicole Branan Losing a loved one is always painful, but for most people time eventually heals the wounds. For about 10 to 20 percent of the bereaved, however, accepting and getting over a loss remains extremely difficult, even years later. Now researchers have come a step closer to elucidating the neurobiological underpinnings of this condition called complicated grief (CG). An August 15 functional MRI study in NeuroImage shows that in CG patients reminders of the deceased activate a brain area associated with reward processing, pleasure and addiction. A team led by Mary-Frances O’Connor of the University of California, Los Angeles, studied 23 women—11 of whom suffered from CG—who had lost a mother or sister to breast cancer in the past five years. While in the scanner, the women saw pictures and words that reminded them of their loved one. Brain networks associated with social pain became activated in all women, but in the CG patients reminders of the deceased also excited the nucleus accumbens, a forebrain area most commonly associated with reward. O’Connor believes this continued neural reward activity probably interferes with adaptation to the new situation. “When we see a loved one or reminders of a loved one, we are cued to enjoy that experience,” she says. “But when a loved one dies, our brains have to adapt to the idea that these cues no longer predict this rewarding experience.” Scientists do not yet know why some people adapt better than others do. © 1996-2008 Scientific American Inc.

Keyword: Emotions
Link ID: 12142 - Posted: 06.24.2010

By Chad Boutin The Eighth Annual Sopchoppy Worm Gruntin' Festival in Sopchoppy, Florida, hardly seems like the place to make an important scientific discovery. But that's what happened this year, when two teams of researchers descended on the event, intent on figuring out why grunting noises bring burrowing earthworms to the surface. Dozens of Florida Panhandle residents earn their living by grunting. Rising before dawn, they head out to the pine forests, hammer a wooden stake about 30 cm into the ground, and rhythmically scrape its top with a long, smooth piece of steel called a rooping iron. The rasping noises, which sound like low-pitched grunts (see video), bring hundreds of earthworms above ground, and the grunters sell them as fish bait. Yet scientists have never successfully explained why the technique works. Hoping to get to the bottom of the mystery, a team led by biologist Jayne Yack of Carleton University in Ottawa, Canada, and another led by biologist Kenneth Catania of Vanderbilt University in Nashville, Tennessee, dragged geophones and other seismic equipment used to detect underground vibrations to the Sopchoppy festival last April. Yack and colleagues confirmed that worm grunting actually works. With help from experienced grunters, the researchers took up their own rooping irons and scraped their stakes about 25 times in 30 seconds, producing vibrations in the ground of about 100 hertz. As they report online 15 October in Biology Letters, in less than 2 minutes, their efforts brought up scores of native Diplocardia mississipiensis earthworms within a few meters of the grunting stake. © 2008 American Association for the Advancement of Science

Keyword: Hearing; Evolution
Link ID: 12141 - Posted: 06.24.2010

By Bruce Bower Long thought the province of the abstract, cognition may actually evolve as physical experiences and actions ignite mental life With gargantuan ears, gleaming brown eyes, a fuzzy white muzzle and a squat, furry body, Leonardo looks like a magical creature from a Harry Potter book. He’s actually a robot powered by an innovative set of silicon innards. Like a typical 6-year-old child, but unlike standard robots that come preprogrammed with inflexible rules for thinking, Leonardo adopts the perspectives of people he meets and then acts on that knowledge. Leonardo’s creators, scientists at the Massachusetts Institute of Technology’s Personal Robots Group and special effects aces at the Stan Winston Studio in Van Nuys, Calif., watch their inquisitive invention make social strides with a kind of parental pride. Consider this humanlike attainment. Leo, as he’s called for short, uses sensors to watch MIT researcher Matt Berlin stash cookies in one of two boxes with hinged, open covers. After Berlin leaves the room, another experimenter enters and creeps over to the boxes, a hood obscuring his face. The mysterious intruder moves the cookies from one box to the other and closes both containers before skulking out. Only Leo can unlock the boxes, by pressing buttons on a panel placed in front of him. Berlin soon returns and vainly tries to open the original cookie box. He asks Leo to unlock it for him. The robot shifts his gaze from one box to the other, his mental wheels seemingly turning. Then Leo unlocks the second box. The robot has correctly predicted that Berlin wants the cookies that were put in the first box, and that Berlin doesn’t realize that someone moved those cookies to the other box. © Society for Science & the Public 2000 - 2008

Keyword: Intelligence
Link ID: 12140 - Posted: 06.24.2010

By Stephen L. Macknik and Susana Martinez-Conde It is a fact of neuroscience that everything we experience is actually a figment of our imagination. Although our sensations feel accurate and truthful, they do not necessarily reproduce the physical reality of the outside world. Of course, many experiences in daily life reflect the physical stimuli that enter the brain. But the same neural machinery that interprets actual sensory inputs is also responsible for our dreams, delusions and failings of memory. In other words, the real and the imagined share a physical source in the brain. So take a lesson from Socrates: “All I know is that I know nothing.” One of the most important tools neuroscientists use to understand how the brain creates its sense of reality is the illusion. Historically, artists as well as illusionists have used illusions to develop deep insights into the inner workings of the visual system. Long before scientists were studying the properties of neurons, artists had devised a series of techniques to “trick” the brain into thinking that a flat canvas was three-dimensional or that a series of brushstrokes was actually a still life. Applied to architecture, their work continues to astound. Visual illusions are defined by the dissociation between physical reality and subjective perception of an object or event. When we experience such an illusion, we may see something that is not there, or fail to see something that is there, or even see something different from what is there. Because of this disconnect between perception and reality, these optical tricks demonstrate the ways in which the brain can fail to re-create the physical world. By studying these failings, we can learn about the computational methods the brain uses to construct visual experience. © 1996-2008 Scientific American Inc.

Keyword: Vision
Link ID: 12139 - Posted: 06.24.2010

Jim Horne ASK people whether they would like more sleep, and most will say yes. Does that mean they are not sleeping enough? The apparent desire for more shut-eye, together with oft-repeated assertions that our grandparents slept longer, all too easily leads to the conclusion that we in the west are chronically sleep-deprived. Adding to these concerns are recent claims that inadequate sleep causes obesity and related disorders, such as diabetes. Plus ça change. Claims of widespread sleep deprivation in western society are nothing new - in 1894, the British Medical Journal ran an editorial warning that the "hurry and excitement" of modern life was leading to an epidemic of insomnia. Even then it probably wasn't true. The fact is that most adults get enough sleep, and our collective sleep debt, if it exists at all, has not worsened in recent times. Moreover, claims that sleep deprivation is contributing to obesity and diabetes have been overblown. My assertion is that the vast majority of people sleep perfectly adequately. That's not to say that sleep deprivation doesn't exist. But in general we've never had it so good. Over the past 40 years, there have been several large studies of how much sleep people actually get, and the findings have consistently shown that healthy adults sleep 7 to 7½ hours a night. The well-known "fact" that people used to sleep around 9 hours a night is a myth. The figure originates from a 1913 study by researchers at Stanford University in California, which did find that average daily sleep was 9 hours - though this applied to children aged 8 to 17, not adults. Even today, children continue to average this amount. © Copyright Reed Business Information Ltd.

Keyword: Sleep
Link ID: 12138 - Posted: 06.24.2010

Linda Geddes JOSH VILLA was 26 and driving home after a drink with a friend on 28 August 2005 when his car mounted the kerb and flipped over. Villa was thrown through the windscreen, suffered massive head injuries and fell into a coma. Almost a year later, there was little sign of improvement. "He would open his eyes, but he was not responsive to any external stimuli in his environment," says Theresa Pape of the US Department of Veterans Affairs in Chicago, who helped treat him. Usually there is little more that can be done for people in this condition. Villa was to be sent home to Rockford, Illinois, where his mother, Laurie McAndrews, had volunteered to care for him. But Pape had a different suggestion. She enrolled him in a six-week study in which an electromagnetic coil was held over the front of his head to stimulate the underlying brain tissue. Such transcranial magnetic stimulation (TMS) has been investigated as a way of treating migraine, stroke, Parkinson's disease and depression, with some promising results, but this is the first time it has been used as a potential therapy for someone in a coma-like state. The rapidly changing magnetic fields that the coil creates can be used either to excite or inhibit brain cells - making it easier or harder for them to communicate with one another. In Villa's case, the coil was used to excite brain cells in the right prefrontal dorsolateral cortex. This area has strong connections to the brainstem, which sends out pulses to the rest of the brain that tell it to pay attention. "It's like an 'OK, I'm awake' pulse," says Pape. © Copyright Reed Business Information Ltd

Keyword: Miscellaneous
Link ID: 12137 - Posted: 06.24.2010

Kerri Smith A monkey's paralysed wrist can be moved and controlled by electrical signals artificially routed from its brain, according to scientists who say that their experiment is a step towards helping paralysed people to regain the use of their limbs. Previously, scientists have been able to train monkeys to move robotic arms using signals routed from electrodes in their brains1. This involved decoding the activity of tens of neurons at a time to replicate actions such as grasping, and required considerable computing power. Now, Chet Moritz and his colleagues at the University of Washington in Seattle have used similar signals to deliver direct electrical stimulation from just one neuron to a paralysed muscle. They first implanted a number of electrodes in the motor cortex of two macaque monkeys. Each electrode picked up signals from a single neuron, and those signals routed through an external circuit to a computer. The neuronal signals controlled a cursor on a screen, and the monkeys were trained to move the cursor using only their brain activity. The scientists then temporarily paralysed the monkeys' wrist muscles using a local anaesthetic. They re-routed the signals from the electrodes to deliver electrical stimulation to the wrist muscles, and found that the monkeys could control their previously paralysed limbs using the same brain activity. The monkeys learnt to do this in less than an hour, the team report in Nature2. © 2008 Nature Publishing Group

Keyword: Movement Disorders
Link ID: 12136 - Posted: 06.24.2010

Jessica Griggs Grief could be nature's way of keeping couples together, say neurobiologists. Using one of nature’s only monogamous mammals, the prairie vole, as a model for human attachment, Larry Young from the Emory University School of Medicine in Georgia and Oliver Bosch from the University of Regensburg, Germany, looked at the role stress plays in the grieving process. They paired 18 male voles with females and 20 males with males for five days, enough time for male and female to mate and form an enduring attachment to each other. Half of each group was then separated from its partner and their "mental state" assessed. Males that were separated from their female partner showed behaviour reminiscent of depression and anxiety in humans, say the researchers. They spent more time floating rather than swimming when dunked in water and struggled for less time when held upside down by the tail, compared with those voles that had been separated from another male. In vole terms, this means that they showed less will to fight against stressful situations. The bonded voles also had double the level of the stress hormone corticosterone in their blood, suggesting that CRF, the brain peptide that regulates the stress response, has a role to play in the grieving process. © Copyright Reed Business Information Ltd.

Keyword: Emotions; Sexual Behavior
Link ID: 12135 - Posted: 06.24.2010

By Ann Gibbons Bonobos have a reputation as the hippies of the primate world, with a make-love-not-war image. But scientists appear to have underestimated their bloodthirsty tendencies. In a new study, researchers report observing wild bonobos hunting and eating monkeys, which shows that the apes are not so different from their more aggressive cousins, the common chimpanzees. Ever since researchers recognized bonobos (Pan paniscus) as a different species from common chimpanzees (Pan troglodytes) 75 years ago, they have noticed fundamental differences between the two apes. Male common chimpanzees form gangs that hunt monkeys, dominate female chimpanzees, and even murder other males in territorial skirmishes. By contrast, bonobo males spend more time having sex, are pushed around by females, and have even been observed grooming monkeys. One explanation for the difference is that bonobo males are kept in check by females, which form tight alliances that prevent males from dominating them and forming macho hunting parties necessary to capture elusive monkeys. Researchers thought that bonobos hunted only prey such as forest antelopes and squirrels that were easy for an individual to capture. But far less is known about bonobos than about common chimpanzees, because there are so few bonobos left in the wild. Only between 5000 and 60,000 remain in the lowland forests of the Democratic Republic of the Congo, where regional conflicts have made it difficult for researchers to get an accurate picture of their behavior. © 2008 American Association for the Advancement of Science

Keyword: Aggression
Link ID: 12134 - Posted: 06.24.2010

By Anna Salleh for ABC Science Online Female lab mice can respond quite differently to male mice when it comes to anxiety, a new study has found, a discovery which could have important implications for scientific research. Neuroscientist Dr Tim Karl of the Garvan Institute of Medical Research and colleagues have reported their findings in the European Journal of Neuroscience. "In the end it has general implications for how to use animal models," he said. "At the moment male mice are used to apply findings to both male and female humans. That's definitely not the ideal situation." Dr Karl and colleagues studied the impact of a neurotransmitter known as neuropeptide Y (NPY), which helps lower anxiety levels as well as influences aggression and appetite. Previous studies have shown that when mice are given a drug that mimics NPY it reduces anxiety when they are put under stress. Studies have also shown that mice genetically-modified to lack the gene for NPY are more prone to anxiety than normal mice. But these previous studies used male mice, which are the standard laboratory animal. Dr Karl and colleagues studied the behaviour of both female and male mice that had their NPY gene knocked out. To their surprise, they found that while both sexes were more anxious than normal mice, lacking the NPY gene made the male mice more anxious than female mice. © 2008 ABC

Keyword: Sexual Behavior; Emotions
Link ID: 12133 - Posted: 06.24.2010