— Migrating birds may get their internal compass through a chemical reaction induced by the Earth's magnetic compass, rather than through magnetic material in their beaks as the conventional theory holds. University of California physicist Thorsten Ritz and colleague exposed European robins to weak but rapidly oscillating magnetic fields in a lab. When the artificial field was aligned with the Earth's own magnetic field, the birds faced in the right direction. But when the artificial field was shifted to a different direction, they were instantly confused. Copyright © 2004 Discovery Communications Inc.

Keyword: Animal Migration
Link ID: 5469 - Posted: 06.24.2010

WINSTON-SALEM, N.C. – Research in monkeys suggests that long-term use of estrogen therapy may reduce levels of androgens – hormones involved in maintaining bone density, muscle mass, sexual function, memory, and psychological wellbeing in postmenopausal women. "Our findings suggest that it might be important for women taking estrogen after menopause to also take androgen supplements – which can include testosterone," said Charles E. Wood, D.V.M., lead researcher, from Wake Forest University Baptist Medical Center. The research is reported in the current issue of The Journal of Clinical Endocrinology & Metabolism. The adrenal glands are the primary source of androgen hormones in women. While aging is associated with a marked decline in androgens, others factors involved in adrenal androgen production are not well-known. Regulation of androgen levels may be particularly important in postmenopausal women because observational studies have shown that older women who have higher levels tend to be healthier.

Keyword: ADHD
Link ID: 5468 - Posted: 06.24.2010

Human trial gives thumbs up to heart drug. HELEN R. PILCHER Cholesterol-lowering drugs called statins may help to treat multiple sclerosis, a human study suggests. A daily dose of the heart medicine helped to slow brain deterioration in patients with the condition. Multiple sclerosis (MS) is thought to arise as the immune system attacks the nervous system, peppering the brain with tiny holes. Statins can affect the immune system, and have been shown to ease symptoms in mice with a version of MS. In the first trial of its kind, Inderjit Singh from the Medical University of South Carolina, Charleston, and colleagues tested the therapy on human patients. Thirty patients took the drug simvastatin each day. Six months later, the number and size of lesions within their brains had decreased by around 40%, the team report in the Lancet1. © Nature News Service / Macmillan Magazines Ltd 2004

Keyword: Multiple Sclerosis
Link ID: 5467 - Posted: 06.24.2010

— Howard Hughes Medical Institute researchers have used a combination of brainpower and computer power to identify a multitude of new genes that control the formation of tiny, hair-like cilia that stipple the surfaces of many organs in a wide variety of creatures. The genes are considered important because of the ubiquity of cilia, which are critical for transport and sensory structures located throughout the human body — including the brain, nose, ears, eyes, lung, kidneys and sperm. Led by Howard Hughes Medical Institute investigator Charles S. Zuker, the researchers reported their findings in the May 14, 2004, issue of the journal Cell. Zuker and his colleagues at the University of California, San Diego, collaborated on the studies with a co-author from the Max Planck Institute of Biochemistry in Germany. ©2004 Howard Hughes Medical Institute

Keyword: Pain & Touch; Hearing
Link ID: 5466 - Posted: 06.24.2010

Having empathy for other people is a much more simple and basic emotion than thought, scientists have found. The research, by a group of Dutch scientists, may be the first step to tackling the causes of autism, and may even suggest the idea that animals can sense their owners' feelings is not entirely myth. Experiments by scientists at the University of Groningen have shown that developing empathy is just a matter of learning which emotions go with certain events. The brain then becomes conditioned to trigger the same response when those events involve other people. "It's fairly basic," Dr Nerender Ramnani, a neurobiologist and research scientist at Oxford University, told BBC World Service's Outlook programme. "We light up the motor system [in the brain], not only when we predict the actions of others, but also when we plan our own actions."

Keyword: Emotions; Autism
Link ID: 5465 - Posted: 05.13.2004

By David Usborne Two weekends ago, 38-year-old David Reimer told his parents in their shared hometown of Winnipeg, Canada, that although he was going through a rough patch - recovering from the death of his twin brother two years ago and from his separation from his wife - things would getter better very soon. He didn't explain how. Now his family knows. On 4 May, Reimer took his own life. While his recent ills surely contributed to the despair, his mother knows there was more to it than that. His death was the final coda to a life that became a world-renowned case study in the perils of tampering with gender. During the span of his life he had been a boy, then a girl and then a boy again. "I thought I was an it," he once said. The wrenching story of David (baptised as Brian) Reimer began with a freak snowstorm in 1966. His parents, working-class people from the plains of Manitoba, drove him to the local hospital for a routine circumcision. He was eight months old. But the regular surgeon had not made it in and an assistant took over. She botched the job. A cauterising implement burned David's penis - and it fell off. A witness later said that when the mistake was made there was a sizzling sound, like a steak being seared. © 2004 Independent Digital (UK) Ltd

Keyword: Sexual Behavior
Link ID: 5464 - Posted: 06.24.2010

By Jennifer Viegas, Discovery News — Two types of ants from the family that includes carpenter ants, as well as the common "sidewalk" ants that often march through gardens, serve as the poison source for certain poisonous frogs, according to a new study. The ants generate alkaloids, which are powerful substances that can produce physiological effects in humans and animals. The study, published in the current Proceedings of the National Academy of Sciences, presents the first evidence for alkaloids in the ant subfamily Formicinae. Poisonous frogs are able to eat loads of the toxin-generating ants and are able to concentrate the ants' alkaloids into their bodies and skin. The frogs come from the dendrobatid family, a group commonly referred to as poisonous dart frogs, which are the frogs that Central and South American Emberá and Noanamá Chocó Indians use to create poison darts for their blowguns. Copyright © 2004 Discovery Communications Inc.

Keyword: Neurotoxins
Link ID: 5463 - Posted: 06.24.2010

(Kingston, ON) – A surprising discovery by Queen's researchers helps explain why fish swimming in icy sea water don't freeze. The team, led by Biochemistry Professor Peter Davies, has identified a new "antifreeze" protein found in the blood of winter flounder enabling the fish to withstand temperatures as low as -1.9 degrees Celsius: the freezing point of sea water. The antifreeze plasma proteins (AFPs) do this by binding irreversibly to ice crystals and preventing them from growing. Until now, it has been a mystery how these fish survive in polar oceans, since the previously identified "type I" AFP associated with winter flounder only provides 0.7oC of freezing point depression, which in combination with blood solutes, only protects the fish down to -1.5 degrees Celsius. "This finally explains the 'critical gap' of 0.4 degrees," says Dr. Davies, a Queen's Canada Research Chair in Protein Engineering. "The winter flounder has been studied extensively by a number of laboratories over the past 30 years, but this antifreeze protein escaped everyone's notice. We're excited to have found it."

Keyword: Evolution
Link ID: 5462 - Posted: 06.24.2010

Migrating birds stay on track because of chemical reactions in their bodies that are influenced by the Earth’s magnetic field, a UC Irvine-led team of researchers has found. The birds are sensitive even to rapidly fluctuating artificial magnetic fields. These fields had no effect on magnetic materials such as magnetite, indicating that the birds do not rely on simple chunks of magnetic material in their beaks or brains to determine direction, as experts had previously suggested. The results are reported in the May 13 issue of Nature. The study is the first to reveal the mechanism underlying magnetoreception – the ability to detect fluctuations in magnetic fields – in migratory birds. In the study, Thorsten Ritz, assistant professor of physics and astronomy, and colleagues exposed 12 European robins to artificial, oscillating magnetic fields and monitored the orientation chosen by these birds. The stimuli were specially designed to allow for responses that could differ depending on whether birds used small magnetic particles on their bodies or a magnetically sensitive photochemical reaction to detect the magnetic field. © Copyright 2002-2004 UC Regents

Keyword: Animal Migration
Link ID: 5461 - Posted: 06.24.2010

Levels of testosterone in the womb may have profound effects on a person's social development. The findings might also explain why men are four times as likely as women to suffer from autism. The study is the latest in a series on a group of 58 children born in 1996 and 1997. Simon Baron-Cohen's team at the Autism Research Centre in Cambridge, UK, measured testosterone levels in the amniotic fluid of the babies' mothers while pregnant. This is presumed to reflect levels in the babies themselves. The team has already found that the babies with higher fetal testosterone levels had a smaller vocabulary and made eye contact less often when they were a year old. And a study by another group has shown that eight-year-old girls who had high fetal levels of the hormone performed better at tasks such as mentally rotating a two-dimensional figure. © Copyright Reed Business Information Ltd.

Keyword: Hormones & Behavior; Autism
Link ID: 5460 - Posted: 06.24.2010

DURHAM, N.C. -- Until now, primatologists believed lemurs to be primitive, ancient offshoots of the primate family tree, with far less intelligence than their more sophisticated cousins, monkeys, apes and humans. But at the Duke University Primate Center, with the gentle touch of his nose to a computer screen, the ringtail lemur called Aristides is teaching psychologist Elizabeth Brannon a startling scientific lesson -- that lemurs are, indeed, intelligent creatures. Brannon is using touch-screens, Plexiglas boxes holding raisins and buckets hiding grapes to establish that ringtails such as Aristides and his mongoose lemur cousins possess a surprising ability to learn sequences of pictures and to discriminate quantities. While Brannon's work is still only at a preliminary stage, its initial results lead her to believe that such studies could mark the dawning of a new appreciation of lemur intelligence. Such research could offer important evolutionary insights into the nature of intelligence in primates, Brannon said, since lemurs are living models for the ancient primate mind. "Prosimians," including lemurs and related species split off from the primate line some 55 million years ago, evolving independently from the line that led to anthropoids and humans.

Keyword: Intelligence; Evolution
Link ID: 5459 - Posted: 05.13.2004

When jet lag or oft-changing work shifts make you feel out of synch, it's probably not your imagination. New research led by a University of Washington biologist demonstrates that there are at least two circadian clocks in the mammal brain, one that sticks strictly to an internal schedule and another that can be altered by external influences such as light and dark. Typically the two clocks are synchronized so that various physical functions are in tune with each other, said Horacio de la Iglesia, a UW assistant professor of biology. But make a long plane trip or switch your 8-to-5 work schedule to begin at midnight and things can get out of kilter. "When you travel to Europe, the rest-activity cycle will adjust relatively quickly. In two or three days you'll probably be sleeping when it's dark," de la Iglesia said. "But your temperature or hormone-release cycles might still be on Seattle time, affecting for instance how well you sleep." A bit of brain tissue called the suprachiasmatic nucleus, a daily pacemaker that regulates rhythms such as sleep and wakefulness, has thousands of cells called neurons with synchronized circadian activities. But the neurons in the nucleus can be grouped into at least two secondary clocks that can become disconnected from one another when exposed to artificial day-night cycles.

Keyword: Biological Rhythms
Link ID: 5458 - Posted: 05.13.2004

Human beings are more aroused by rewards they actively earn than by rewards they acquire passively, according to brain imaging research by scientists at Emory University School of Medicine. Results of the study, led by first author Caroline F. Zink and principal investigator Gregory S. Berns, MD, PhD, of Emory’s Department of Psychiatry and Behavioral Sciences, are published in the May 13 issue of the journal Neuron. The Emory scientists used functional magnetic resonance imaging (fMRI) to measure brain activity in the striatum, which is a part of the brain previously associated with reward processing and pleasure. Although other experiments have studied and noted brain activity associated with rewards, until now these studies have not distinguished between the pleasurable effects of receiving a reward and the "saliency" or importance of the reward. Study volunteers in the Emory experiment were asked to play a simple target-detection computer game. During the game, a money bill appeared occasionally and automatically dropped into a bag of money on the screen. The participant was given the amount of money that dropped in the bag at the end of the game, but because receiving the money had nothing to do with their performance on the computer game, it was not particularly arousing or salient to them. In another version of the game, a money bill occasionally appeared on the screen and the participant had to momentarily interrupt the target detection game and push a button to make the bill drop into the bag.

Keyword: Attention; Learning & Memory
Link ID: 5457 - Posted: 06.24.2010

For the first time, researchers have used a technique called optical imaging to visualize changes in nerve connections when flies learn. These changes may be the beginning of a complex chain of events that leads to formation of lasting memories. The study was funded in part by the NIH's National Institute of Neurological Disorders and Stroke (NINDS) and appears in the May 13, 2004, issue of Neuron.1 Scientists have long been captivated by the questions of how memories form and how they are represented in the brain. The answers to these questions may help researchers understand how to treat or prevent memory problems, drug addiction, and other human ailments. Thousands of changes in gene expression, neuron formation, nerve signaling, and other characteristics may be involved in the formation of just a single memory. Scientists refer to any learning-induced change in the brain as a "memory trace." In the new study, Ronald L. Davis, Ph.D., and colleagues at Baylor College of Medicine in Houston developed fruit flies with special genes that caused the flies' neuronal connections to become fluorescent during nerve signaling (synaptic transmission). They then exposed the flies to brief puffs of an odor while they received a shock. This caused them to learn a new association between the odor and the shock — a type of learning called classical conditioning.

Keyword: Learning & Memory
Link ID: 5456 - Posted: 06.24.2010

BY JAMIE TALAN Scientists have transplanted adult stem cells from the bone marrow of rats into the brains of rat embryos and found that thousands of the cells survive into adulthood, raising the possibility that someday developmental abnormalities could be prevented or treated in the womb. Dr. Ira Black, chairman of the department of neuroscience at the University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, said the cells took on the properties of brain cells, migrating to specific regions and taking up characteristics of neighboring cells. "They exhibited the same flexibility in the living brain as we had observed in culture," said Black, director of the school's Stem Cell Center. His findings were published today in the Journal of Neuroscience. Copyright © Newsday, Inc. Produced by Newsday Electronic Publishing.

Keyword: Stem Cells; Regeneration
Link ID: 5455 - Posted: 06.24.2010

A large dose of caffeine may be the way many of us start the day, but researchers say little and often would do more to help us stay awake. Harvard University researchers say the morning cuppa boosts caffeine levels, but these fall away during the day. They say frequent low doses of caffeine would give people such as shift workers who need to stay awake more of boost. Writing in the journal Sleep, they say caffeine works by interfering with one of the systems which governs sleep. When we sleep, and for how long, is regulated by both the circadian system and the homeostatic system. The circadian system is tuned in to the difference between night and day, and promotes sleep rhythmically, with an internal clock releasing melatonin and other hormones in a cyclical fashion. But the homeostatic system is demand driven - it tells the body it needs more sleep the longer someone has been awake. (C)BBC

Keyword: Sleep
Link ID: 5454 - Posted: 05.12.2004

By RICHARD PÉREZ-PEÑA In the wake of huge tobacco tax increases and a ban on smoking in bars, the number of adult smokers in New York City fell 11 percent from 2002 to 2003, one of the steepest short-term declines ever measured, according to surveys commissioned by the city. The surveys, to be released today, show that after holding steady for a decade, the number of regular smokers dropped more than 100,000 in a little more than a year, to 19.3 percent of adults from 21.6 percent. The decline occurred across all boroughs, ages and ethnic groups. The surveys also found a 13 percent decline in cigarette consumption, suggesting that smokers who did not quit were smoking less. Like similar local and national polls, the surveys counted as smokers all people who said that they had smoked more than 100 cigarettes in their lives and that they now smoked every day or "some days." Copyright 2004 The New York Times Company |

Keyword: Drug Abuse
Link ID: 5453 - Posted: 05.12.2004

By THE ASSOCIATED PRESS WINNIPEG, Manitoba, — David Reimer, a man who was born a boy but raised as a girl in a famous medical experiment, only to reassert his male identity in the last 20 years of his life, died on May 4. He was 38. His family says he committed suicide. Mr. Reimer shared his story about his life in the pages of a book and on Oprah Winfrey's television show. His mother, Janet Reimer, said she believed that her son would still be alive had it not been for the devastating experiment, which led to much emotional hardship. "He managed to have so much courage," she said Sunday. "I think he felt he had no options. It just kept building up and building up." After a botched circumcision operation when he was a toddler, David Reimer became the subject of a study that became known as the John/Joan case in the 60's and 70's. His mother said she was still angry with the Baltimore doctor who persuaded her and her husband, Ron, to give female hormones to their son and raise him as a daughter. Copyright 2004 The New York Times Company

Keyword: Sexual Behavior
Link ID: 5452 - Posted: 06.24.2010

By Jennifer Viegas, Discovery News — Australian scaly cricket males can copulate 50 to 58 times within three to four hours with the same female, which sets the world record for the most copulations per unit time of any creature within the animal and insect kingdom, according to a report in the current Royal Society Biology Letters. The finding puts the insect Ornebius aperta ahead of the previous record holders, lions and tigers. Tigers can mate up to 50 times a day at a rate of five to 15 minutes over the course of five or six days. The research also suggests that "extreme repeated mating" can develop in response to female-imposed limits on copulation. In this case, the limit is due to female crickets that remove sperm and eat it after about three seconds following insertion. Copyright © 2004 Discovery Communications Inc.

Keyword: Sexual Behavior; Evolution
Link ID: 5451 - Posted: 06.24.2010

Epidemic reflects rise in refined sugars. HELEN PEARSON The startling rise in diabetes is perfectly mirrored by our mounting consumption of refined carbohydrates, a new analysis reveals. The study adds to evidence that sugary foods should be eschewed and that public health advice to cut back on fat may have backfired. Levels of obesity and late onset diabetes have risen slowly over the last century and accelerated in the last 40 years. While the problem is most acute in developed countries, there is evidence that rates are starting to increase in developing countries too. Most experts agree that worsening diets and increasingly inactive lifestyles are responsible, but the exact cause is hard to pin down. Simin Liu of the Harvard School of Public Health, Boston, and his co-workers collected information on consumption and food composition for the period between 1909 and 1997. They compared this with data on disease incidence rates from the US Centers for Disease Control and Prevention. © Nature News Service / Macmillan Magazines Ltd 2004

Keyword: Obesity
Link ID: 5450 - Posted: 06.24.2010