By Gisela Telis The next time you miss the forest for the trees, blame your jittery eyeballs. The small, involuntary movements our eyes make when they focus help the brain discern the finer details of an image, according to new research. Although the findings leave several questions unanswered, they mark an important step toward settling a 50-year-old controversy. Most animals with sharp central vision, such as humans, monkeys, and cats, make microscopic eye adjustments when they fix their gaze. These jitters wiggle the image on the retina, and scientists know surprisingly little about why this happens. In the 1950s, vision researchers used cumbersome techniques involving rotating mirrors to negate the jitter when volunteers stared at an image. The volunteers began to see a featureless gray field rather than the image at hand, so scientists concluded that jittering kept the image from fading. But it wasn't clear how, or if, the jitters served other functions. Boston University neuroscientist Michele Rucci and colleagues revisited these questions using a less awkward approach: They used a computer to track the eye's movements. The researchers showed six subjects one of two images on a monitor: a gray background with either thick or thin slanted lines at its center. For each trial, the computer either held the image steady or moved it in tandem with the subject's miniature jitters. The subject then had to tell the researchers which way the lines on the image slanted. © 2007 American Association for the Advancement of Science

Keyword: Vision
Link ID: 10408 - Posted: 06.24.2010

Heidi Ledford Whether the pain comes from holding an ice cube for too long or staying out on a frigid winter day, the source is clear: it's the cold that hurts. Now researchers have found a protein responsible for provoking pain in response to extreme cold in mice. The protein, called Nav1.8, was already known to play a role in detecting tissue damage, and was previously associated with inflammation and pain in response to damaged nerves. Now it looks like the same protein gets involved when the temperature plummets. Physiologist Katharina Zimmermann at the University of Erlangen-Nuremberg, Germany, and her colleagues found that mice lacking the protein became impervious to pain from cold. Normal mice placed on a plate chilled to 0°C will hop about and lift their feet, but mice engineered to lack Nav1.8 do not, they found. The results are published this week in Nature.1 The protein works by helping sodium ions to pass through the cell membrane of neurons, a process that is crucial to transmitting signals — including pain signals — along nerve fibres. It works unusually well in the cold; unlike other similar proteins, its activity doesn't decline as the temperature drops. "That goes against what cells are supposed to do in the cold," says Ardem Patapoutian, a cell biologist at Scripps Research Institute in La Jolla, California, who was not affiliated with the study. ©2007 Nature Publishing Group

Keyword: Pain & Touch
Link ID: 10407 - Posted: 06.24.2010

Conrad McCallum High-profile paternity suits point to a trendy obsession for the ultimate proof of biological fatherhood. But to evolutionary psychologists, they're just a recent and hi-tech twist on age-old anxieties. Since hunter-gatherer times, men have relied not on DNA swabs but on a little-understood calculus of physical resemblance to decide whether to invest in little Emma or Ethan. In the infant's upper face and eyes, the skeptical pater familias looks for clues. Comedian Chris Rock probably went through a similar mental process after a Georgia woman claimed he fathered of a child she had 13 years ago. Ditto Larry Birkhead and Howard K. Stern when they first saw Anna Nicole Smith's baby daughter, Dannielynn, born last September. Birkhead, after DNA testing, was determined the biological dad and won custody of his little look-alike following Smith's death last February. The latest study, done early this year by Brock University psychology professor Anthony Volk, show cues of genetic relatedness are more important to men than women. He showed photos of infants' faces to male and female subjects, and asked them to make hypothetical adoption choices. In the journal Evolutionary Psychology, Volk reported that men reacted more positively to children with facial traits resembling them, while women's decisions were influenced more by healthy looks. © Copyright Toronto Star 1996-2007

Keyword: Sexual Behavior; Evolution
Link ID: 10406 - Posted: 06.24.2010

It may make the stomach turn, but scientists in Norway suggest that taking a spoonful of cod liver oil each day could stave off depression. In a study of almost 22,000 people aged over 40, those who regularly took the oil were less likely to suffer depression than those who did not. The study in the Journal of Affective Disorders also suggested the longer one took it, the less depressed one became. The oil is rich in Omega-3 fatty acids which are linked to various benefits. Children's brains are said to be boosted by Omega-3s, which have also been claimed to reduce the risk of stroke, heart attack and cancer, although some studies have cast doubt on this. In this latest claim, scientists said a spoonful of cod liver oil could reduce the risk of depression by as much as 30%. Depressive symptoms among cod liver oil users was 2.5%, compared to 3.8% in the rest of the population. (C)BBC

Keyword: Depression
Link ID: 10405 - Posted: 06.13.2007

By Tan Ee Lyn HONG KONG (Reuters) - Cockroaches have a memory and can be taught to salivate in response to neutral stimuli in the way that Pavlov's dogs would do when the famed Russian doctor rang his bell, Japanese researchers found. Such "conditioning" can only take place when there is memory and learning, and this salivating response had only previously been proven in humans and dogs. Now, cockroaches appear to have that aptitude too. Writing in the latest edition of the online journal Public Library of Science, the researchers said they hoped to learn more about the human brain by exploring what goes on in the simpler brain of the cockroach. (Article is freely available on http://www.plosone.org/doi/pone.0000529) "Understanding the brain mechanism of learning in insects can help us to understand the functionings in the human brain. There are many, many common characteristics," said Makoto Mizunami, of Tohoku University's Graduate School of Life Sciences, in a telephone interview. In the experiment, the scientists exposed a group of cockroaches to an odor whenever they fed them a sugar solution. They found that when they later exposed the cockroaches to the odor alone, they still drooled. © 1996-2007 Scientific American, Inc.

Keyword: Learning & Memory
Link ID: 10404 - Posted: 06.24.2010

Patients taking an obesity pill in clinical trials were more likely to report suicidal thoughts or actions, US drug reviewers have said. A Food and Drug Administration advisory panel will consider on Wednesday whether regulators should approve US sales. The FDA said the 20-milligram dose of the drug, Zimulti, produced clinically significant weight loss over one year. With a low-calorie diet, the drug "was shown to reduce body weight by approximately 5% relative to diet alone during trials of more than 6000 moderately overweight and obese subjects", the FDA reviewers said. Known generically as rimonabant, the drug is already sold in 18 countries under the name Acomplia. The agency has delayed a final decision on rimonabant several times amid concerns about depression and a high drop-out rate in clinical trials. "We remain concerned about rimonabant's adverse event profile, specifically adverse psychiatric reactions," an FDA staff summary said. Psychiatric problems "represent the most common and worrisome rimonabant-induced adverse events", the reviewers said. Depression was roughly twice as high for rimonabant patients compared with others who received a placebo, they said. © Copyright Reed Business Information Ltd.

Keyword: Obesity; Depression
Link ID: 10403 - Posted: 06.24.2010

Roxanne Khamsi Mouse mothers show a much stronger brain response to the distress calls of infant mice than their virgin counterparts do, new research shows. The finding suggests that hormonal or behavioural changes linked to motherhood can alter animals' receptiveness to calls. Previous research has demonstrated that when young mouse pups are separated from their mothers, they start making high-pitched noises at around 65 kilohertz – far above the hearing range of a human, which typically peaks around 15 kHz. Listen to the pup calls, slowed down to be audible to humans. "Some scientists have named these noises 'distress calls', but that's been controversial because some people say it's more a physiological response than an emotional response," explains Robert Liu at Emory University in Atlanta, Georgia, US. In the wild, a mother mouse will leave her nest and follow the sound of these high-pitched squeals to find her crying pup. (Watch a lab video of a mother leaving the nest to retrieve a crying pup that has been placed into the cage – .avi format.) Behavioural studies have found that mother mice show twice as much interest in these distress calls than in a simple 20 kHz tone when these sounds are played through different speakers. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior; Hearing
Link ID: 10402 - Posted: 06.24.2010

By NICHOLAS BAKALAR Men who had poor relationships with siblings during childhood are at significantly greater risk for depression in adulthood than those who got along better, a new study has found. Childhood Sibling Relationships as a Predictor of Major Depression in Adulthood: A 30-Year Prospective Study (American Journal of Psychiatry)The researchers emphasize that their findings do not mean that a poor childhood relationship with a sibling causes depression, but they say the two are strongly associated. Moreover, whether the men’s parents did a good or a poor job of raising them seemed to have little effect on their risk of depression. “Poor parenting may be reflected in poor sibling relationships,” said Dr. Robert J. Waldinger, the lead author of the study and an associate professor of psychiatry at Harvard. “But once you’ve taken account of the quality of sibling relationships, knowing about the quality of parenting doesn’t add much information.” The findings, published in the June issue of The American Journal of Psychiatry, are based on an analysis of data from 229 men who were followed for more than 30 years beginning at age 18 or 19. They were first assessed in the period 1939-42 by internists, psychiatrists, psychologists and anthropologists, and then they completed questionnaires every other year. Researchers also interviewed their parents. Copyright 2007 The New York Times Company

Keyword: Depression
Link ID: 10401 - Posted: 06.24.2010

By Howard Schneider The People Who Know What's Good For Us have made life progressively difficult, moving from general recommendations such as "maintain ideal weight" to detailed orders for 60 to 90 minutes of exercise every day. You can now add weightlifting to the creeping set of obligations. It's not explicit in the government's overall guidelines, but the more detailed suggestions from agencies such as the Centers for Disease Control and Prevention recommend a couple of rounds of resistance training each week. (And, yes, Vicky, that includes you cardio junkies out there because aaaallllll thaaaaatttt time on the treadmill won't guarantee that you can sit up straight when 27 becomes 77.) This won't make a lot of us happy. The basic exercise recommendations are pretty easy to cope with: Take a walk. Ride a bike. Lather, rinse, repeat. Weightlifting, on the other hand, conjures the threat of being stuck next to some grunting mesomorph who will one day be governor. The chance of injury is greater. The advice gets confusing and may include a lecture about how, if you don't disrupt the Z lines between your sarcomeres, it's a waste of time. It's manageable, however, if you understand some basics. The reason there is so much varying advice -- over what exercises to do, how frequently and how intensely -- is that this is an enterprise that should be tailored to your goals and your body. Cardio focuses on training just one muscle, the heart. There are more than 600 others that need attention. © 2007 The Washington Post Company

Keyword: Muscles
Link ID: 10400 - Posted: 06.24.2010

By ELIZABETH SVOBODA When 71-year-old Marilyn Josselyn finished a weeklong cruise on the Volga River in Russia with her husband, Roger, in 1998, she expected to feel like a bobbing buoy for a little while after returning to land. “I felt a rocking sensation, but I thought it was just the usual kind of thing,” she said. But when the feeling persisted for weeks, then months, she began to realize something in her brain was truly off kilter. A smorgasbord of doctor-recommended treatments followed, including medication and vestibular therapy for patients with dizziness. “They’d have me stand in front of a chair, turn around as fast as I could, and then sit down,” she said. “But it made me feel worse instead of better.” Nine years of pitching and rolling have forced Mrs. Josselyn to quit her job as a court reporter and forgo the exotic trips she used to enjoy, and she wants nothing more than to get off the boat. “Landsickness” or “reverse seasickness” is familiar to many people who have taken long cruises — once the body has become accustomed to constant motion, the vestibular system, which controls balance, usually takes a few hours or days to acclimate to being on land again. But in patients like Mrs. Josselyn, who suffer from what is known as mal de débarquement, or debarkation sickness, the brain never seems to readapt. Copyright 2007 The New York Times Company

Keyword: Miscellaneous
Link ID: 10399 - Posted: 06.24.2010

When cats smell catnip they exhibit several behaviors common to queens in season (females in heat): They may rub their heads and body on the herb or jump, roll around, vocalize and salivate. This response lasts for about 10 minutes, after which the cat becomes temporarily immune to catnip's effects for roughly 30 minutes. Response to catnip is hereditary; about 70 to 80 percent of cats exhibit this behavior in the plant's presence. In addition, catnip does not affect kittens until they are about six months old and begin to reach sexual maturity. Catnip plants (Nepeta cataria and other Nepeta species) are members of the mint family and contain volatile oils, sterols, acids and tannins. Native to Europe, Asia and Africa, the plant was brought to North America by settlers; nowadays, the plant is popular in herb gardens and grows widely as a weed. Catnip is considered to be nonaddictive and completely harmless to cats. So, how does catnip work? Nepetalactone, one of catnip's volatile oils, enters the cat's nasal tissue, where it is believed to bind to protein receptors that stimulate sensory neurons. These cells, in turn, provoke a response in neurons in the olfactory bulb, which project to several brain regions including the amygdala (two neuronal clusters* in the midbrain that mediate emotional responses to stimuli) and the hypothalamus, the brain's "master gland" that plays a role in regulating everything from hunger to emotions. The amygdala integrates the information flow from the olfactory bulb cells and projects to areas governing behavior responses. The hypothalamus regulates neuroendocrine responses through the pituitary gland, creating a "sexual response." That is, the cat essentially reacts to an artificial cat pheromone. © 1996-2007 Scientific American, Inc.

Keyword: Drug Abuse; Sexual Behavior
Link ID: 10398 - Posted: 06.24.2010

Alzheimer’s disease researchers may be able to reduce the time and expense associated with clinical trials, according to early results from the Alzheimer’s Disease Neuroimaging Initiative (ADNI), a public-private research partnership organized by the National Institutes of Health. Preliminary results from ADNI show how it might yield improved methods and uniform standards for imaging and biomarker analysis, so these techniques can be employed in the fight against Alzheimer’s disease. These first findings will be presented at the Alzheimer’s Association International Conference on the Prevention of Dementia being held in Washington, D.C., June 9-12. The ADNI study observes and tracks changes in normal individuals, in people with mild cognitive impairment — a condition which often precedes Alzheimer’s — and in people with Alzheimer’s. Researchers will use PET (positron emission tomography) and MRI (magnetic resonance imaging) scans to track changes in the brain, laboratory analyses of cerebrospinal fluid and blood to study biomarkers, and clinical interviews to track cognitive performance over time. ADNI is expected to improve neuroimaging and biomarker measures and consequently allow faster and more efficient evaluation of potential therapies for Alzheimer’s. The $60 million, five-year study began recruiting in early 2006, and today about 800 older people at 58 sites in the United States and Canada participate in the effort.

Keyword: Alzheimers; Brain imaging
Link ID: 10397 - Posted: 06.24.2010

Researcher James Bibb and his team were on a mission to learn more about the role of the gene Cdk5 in brain function. When they turned off this gene in mice, they expected deficiencies to appear. Instead, the mice showed increased flexibility in learning. Can you explain more about what you mean by flexibility with the water maze experiments? The animals that no longer had the CDK5 gene were able to find this platform faster, but even more interestingly was how flexible they were. We did an experiment called "reversal," in which we moved the platform to a different position underneath the water. So that meant they had to reestablish where it was with regard to the spatial cues, and then they would swim to the new position. What was amazing, is the knockouts were very, very quickly, after the first trial, able to understand that the platform had been moved and began to adjust so they always went to the new position. Whereas the normal animals continued to kind of look for the platform and were not sure if it moved or was at the old location on subsequent trials. So that was a really clear indication that these animals were much more flexible and adaptable in the way they were able to perceive and learn and remember things. © ScienCentral, 2000-2007.

Keyword: Learning & Memory
Link ID: 10396 - Posted: 06.24.2010

Human trials of isradipine (or DynaCirc) – which is prescribed for hypertension and stroke – are now planned. Over time, Parkinson's patients lose a set of brain cells that produce the crucial signalling chemical dopamine – and these cells do not regenerate. Without enough dopamine, people cannot control their body movements and ultimately develop severe neurological problems, including dementia. Scientists have struggled to understand why the dopamine-producing brain cells start dying, but ageing plays a strong role. James Surmeier at Northwestern University in Illinois, US, and colleagues found that in young mice these cells use sodium channels to send signals, but in older mice they rely more on a certain kind of calcium channel. This can prove deadly for a neuron because calcium accumulates inside the cell, eventually triggering a complete breakdown. Surmeier wondered whether he could reverse the switch to calcium channels: "The cells had put their old childhood tools in the closet. The question was, if we stopped them from behaving like adults, would they go into the closet and get them out again?" © Copyright Reed Business Information Ltd

Keyword: Parkinsons
Link ID: 10395 - Posted: 06.24.2010

Helen Pilcher Human stem cell transplants have eased the symptoms of Parkinson's disease in a monkey model of the brain disorder. The study, which brings the prospect of human trials one step closer, hints that stem cells do more than just replace cells — they may help persuade the brain to heal itself. Parkinson's disease, which affects around 1 in 500 people, destroys nerve cells that produce the chemical dopamine, leading to movement and balance problems. Most treatments attempt to boost dopamine levels through drugs, but the results can be patchy and short-lived. So the hope is that stem cells — primitive cells that can produce many other cell types — may offer a more permanent solution. In the current study, published in Proceedings of the National Academy of Sciences1, researchers isolated stem cells from the brains of aborted fetuses and grew them into large numbers in the laboratory. The cells were then injected into the brains of monkeys with a severe form of chemically induced Parkinson's disease. Before the treatment, the animals couldn't walk unaided, struggled to use their hands and were sometimes unable to move at all. But two months afterwards, they could walk, feed themselves and move more normally. "They're not as good as normal monkeys, but the improvement is still dramatic," says team-member and neuroscientist Richard Sidman from the Harvard Institutes of Medicine, Boston, Massachusetts. ©2007 Nature Publishing Group

Keyword: Parkinsons; Stem Cells
Link ID: 10394 - Posted: 06.24.2010

Urgent safety studies are needed for newer anti-epilepsy drugs that are being increasingly prescribed for children, say UK researchers. The British Journal of Clinical Pharmacology report says prescriptions have risen five-fold in 13 years. Yet the drugs' long-term safety has not been established, say the researchers. Many medicines are not fully tested on children before licensing, meaning consultants have no official guidance on doses to refer to when prescribing. Instead they often have to estimate a safe and effective dose based on the age and the size of the child. Lead author Professor Ian Wong, from the Centre for Paediatric Pharmacy Research in London, studied antiepileptic drugs given to nearly 8,000 children over a 13-year period. The centre is a collaborative project run by the School of Pharmacy at the University of London, the UCL Institute of Child Health and Great Ormond Street Hospital. Professor Wong and his colleagues found three drugs in particular - lamotrigine, topiramate and levetiracetam - had seen a "massive" rise in prescribing. Professor Wong said this was concerning. "The uptake of these drugs has been rapid, yet their long-term safety has not been established and further research must now be seen as a priority." (C)BBC

Keyword: Epilepsy
Link ID: 10393 - Posted: 06.11.2007

US scientists have unveiled what they say could be the next generation of implants designed to offer hearing to the profoundly deaf. The new device described by the University of Michigan team fits directly to the auditory nerve. The researchers claim it works better than cochlear implants, currently the leading technology. But the device has been tested only in animals, the Journal of the Association for Research in Otolaryngology reports. A UK researcher hailed the project as "potentially a brilliant idea". Cochlear implants have been in use since the mid-1980s, and are placed near to the nerve that carries sound impulses to the brain. However, they are still separated from the nerve by a bony wall and fluid, and users often find it hard to hear low-pitched sounds, which can make conversation difficult, especially in noisy environments. The Michigan team have managed to place their tiny device inside the nerve itself in cats. Lead researcher Professor John Middlebrooks said testing showed the new device performed better over a wider range of frequencies, suggesting that users might be able to enjoy a far wider range of hearing. They measured the cats' brain responses to sounds, and compared the results with those in cats given cochlear implants. Professor Middlebrooks said: "The intimate contact of the array with the nerve fibres achieves more precise activation of fibres signalling specific frequencies, reduced electrical current requirements and dramatically reduced interference among electrodes when they are stimulated simultaneously." (C)BBC

Keyword: Hearing; Robotics
Link ID: 10392 - Posted: 06.11.2007

The progression of Parkinson's disease could be slowed or even stopped by a drug commonly used to treat high blood pressure, a study in Nature suggests. Tests on mice at Northwestern University in Chicago showed isradipine can rejuvenate the brain neurons which are dying in Parkinson's patients. The disease, which mainly affects those aged over 40, leads to tremors and ultimately the inability to walk. Parkinson's charities welcomed the study but said they were early results. "It is too early to state with confidence that this drug will be appropriate for the treatment for Parkinson's disease," said Kieran Breen, director of research and development at the Parkinson's Disease Society. "A significant amount of further research will be required before any definite conclusions can be drawn." Isradipine is a calcium-blocker which is usually used to tackle high blood pressure, angina and stroke. But researchers at Northwestern University found mice, who had been engineered to develop a progressive Parkinson's-type disease, did not become ill when their condition was treated with the drug. Their dopamine neurons - cells which start to die in Parkinson's patients - appeared to revert back to their original, youthful form. Dopamine is a critical substance which affects the control of movement. When it is lacking, that movement becomes increasingly difficult and unco-ordinated. The team found that when people become older, calcium ions start to enter the dopamine neurons and change how they behave. It is thought that isradipine's ability to stop calcium entering the cells is key to the effectiveness of the treatment. (C)BBC

Keyword: Parkinsons
Link ID: 10391 - Posted: 06.11.2007

By STEPHANIE SAUL IN the book “Mrs. Frisby and the Rats of NIMH,” a group of lab rats acquire human intelligence through a genetic experiment. Every child recognizes the charming tale as pure fantasy, yet something similar is occurring at a major pharmaceuticals company, Wyeth, where rodents tested in its labs have, indeed, taken on some features of the human brain. Unlike the fictional rats that learned to read, write and operate machinery, Wyeth’s animals are slow-witted, confused and forgetful because they suffer from the crippling dementia of Alzheimer’s disease, which they acquired from a transplanted human gene. Something else extraordinary is going on at Wyeth. The company’s scientists not only can give rodents Alzheimer’s — they have also figured out how to take it away. Curing mice is a lot simpler than curing people, but the results are a tantalizing development that offers hope to humans suffering from the disease. The work also advances what Wyeth executives describe as their war on Alzheimer’s. Wyeth’s team faces a formidable foe. In an industry often criticized as making pricey “me too” drugs that involve minor tweaks to competitors’ products, as well as promoting medicines of marginal value, Wyeth has decided to go full bore against Alzheimer’s, a disease that has defied effective treatment since it was first identified a century ago. The company has dedicated more than 350 scientists exclusively to Alzheimer’s research, and they are working on 23 separate projects for medicines to possibly treat the disease. Copyright 2007 The New York Times Company

Keyword: Alzheimers
Link ID: 10390 - Posted: 06.24.2010

By Maggie Fox WASHINGTON (Reuters) - New tests involving blood and brain scans can detect symptoms of Alzheimer's disease, and brief appraisals of real-life functioning can predict who is likely to develop it, researchers saidSunday. The tests will be critical, experts told a meeting on Alzheimer's disease, because more than 26 million people now have the brain-wasting disease and this number will quadruple, to 106 million, by 2050. "By 2050, 1 in 85 persons worldwide will have Alzheimer's disease," said Ron Brookmeyer of Johns Hopkins University, who led the study on how many people have the disease. No drugs can significantly affect Alzheimer's disease, although four have a very modest impact if given early on. The disease is very difficult to detect until it has progressed from mild memory loss to clear impairment. Patients eventually lose all ability to care for themselves. Detecting the disease early can help patients and their families plan better for the future but can also help researchers develop drugs to treat and perhaps even prevent the disease. © 2007 Reuters

Keyword: Alzheimers
Link ID: 10389 - Posted: 06.24.2010