A toy that can't stand still helps explain how we move, and how robots might do the same.
PHILIP BALL Cyclists, stilt-walkers and drunks know the feeling: you're okay moving, but fall over when you stop. Robot engineers will be pleased to hear that motion alone - not friction, slip or any other effect - could be the drunkard's secret1. Michael Coleman of Cornell University, New York and his colleagues have finally found mathematical equations to describe the model they made using a child's Tinkertoy set in 19982, which gains stability from walking. 1.Coleman, M. J., Garcia, M., Mombaur, K. & Ruina, A. Prediction of stable walking for a toy that cannot stand. Physical Review E, 64, 022901, (2001). 2.Coleman, M. J., & Ruina, A. An uncontrolled walking toy that cannot stand still. Physical Review Letters, 80, 3658 - 3661, (1998). © Nature News Service / Macmillan Magazines Ltd 2001

Keyword: Miscellaneous
Link ID: 354 - Posted: 10.20.2001

Our Left-Handed Cousins
Researchers say they have the first good evidence that genes play a significant role in chimp handedness, just as they are believed to in humans. They also say that--as in humans--left-handedness is often associated with developmental anomalies. William Hopkins and colleagues at the Yerkes Regional Primate Research Center in Atlanta determined handedness by watching chimps scoop peanut butter out of a tube. They then measured similarity in hand preferences between mothers and offspring in 134 family pairs. --CONSTANCE HOLDEN Copyright © 2001 by the American Association for the Advancement of Science.

Keyword: Evolution; Laterality
Link ID: 351 - Posted: 10.20.2001

Paxil treats major depression in adolescents, study
Paxil is a safe and effective treatment for major depression in adolescents, suggests a Brown-led study in the current Journal of the Academy of Child and Adolescent Psychiatry. No antidepressant is currently labeled for use in teens. PROVIDENCE, R.I. - The largest clinical trial studying the use of antidepressants for treating major depression in adolescents suggests that paroxetine, sold under the brand name Paxil, may be successful. "This is the first substantial evidence of a safe and effective treatment with an antidepressant for adolescents," said Martin B. Keller, M.D., who led the study, which appears in the July issue of the Journal of the Academy of Child and Adolescent Psychiatry.

Keyword: Depression
Link ID: 350 - Posted: 10.20.2001

by Laura Spinney
If you want to find what causes Parkinson's disease (PD), look to the environment, not to the genes. That was the message delivered by PD expert Donald Calne to a large audience at the WCN. PD affects more than 1 percent of the population over the age of 65, although it can affect younger people too. Between 15 and 20 percent of cases are familial, while the remainder are sporadic. Some researchers have argued that the sporadic cases are in fact caused by a genetic mutation that has low penetrance in the population, so that it appears randomly. But Calne, head of the Neurodegenerative Disorders Centre at Vancouver Hospital and the University of British Columbia, disagrees. © Elsevier Science Limited 2000

Keyword: Parkinsons
Link ID: 348 - Posted: 10.20.2001

by Melissa Mertl The pull of the moon is too strong for neurologists to resist. Conflicting evidence was presented today on the moon's role in triggering neurological disorders. The moon has been associated with epilepsy and mental disorder since ancient times, said Giorgio Zanchin, associate professor in the Department of Clinical Neurology at the University of Padua in Italy. The word "lunacy" itself is derived from the Latin name for the moon, he noted, in an historical overview on the moon's influence on the human brain. © Elsevier Science Limited 2000

Keyword: Epilepsy; Biological Rhythms
Link ID: 347 - Posted: 11.06.2001

Irregular emergence may foil insects' predators.
ERICA KLARREICH Bob Dylan immortalized the rare appearance of periodic cicadas in his 1970 song Day of the Locusts. But he may not have realized that he was honouring a mathematical event as well as a biological one. Periodic cicadas emerge from their underground homes to mate every 13 or 17 years. Both of these numbers are prime - they can only be divided by one. Evolution could have selected for appearance in prime cycles, a new model suggests1. 1.Goles, E., Schulz, A.B. & M., A.B.Prime number selection of cycles in a predator-prey model. Complexity, 6, 33 - 38, (2001). © Nature News Service / Macmillan Magazines Ltd 2001

Keyword: Evolution
Link ID: 345 - Posted: 10.20.2001

PHILIP BALL If you're always late for work you could try a new excuse. An out-of-kilter body clock may be down to darwinian evolution, suggests research from Japan. The mismatch in minutes between the day-night cycle and our internal clock may be a legacy from the struggle for survival1. Our internal clock, the so-called circadian rhythm, gears the body's activity to a 24-hour cycle. But the clock is not precisely attuned to the Earth's daily rotation. Our circadian pacemaker has a period of about 24 hours 18 minutes, varying slightly from person to person2. 1.Daido, H. Why circadian rhythms are circadian: competitive population dynamics of biological oscillators. Physical Review Letters, 87, 048101, (2001). 2.Czeisler, C. A. et al. Stability, precision, and near-24-hour period of the human circadian pacemaker. Science, 284, 2177 - 2181, (1999). © Nature News Service / Macmillan Magazines Ltd 2001

Keyword: Evolution; Biological Rhythms
Link ID: 343 - Posted: 11.06.2001

Both smells and pheromones may arouse instinctive behaviors in mammals
BLOOMINGTON, Ind. -- Ever notice how male dogs come from the other side of the neighborhood when a female dog is in heat? All it takes is a few molecules of a certain chemical to enable mammals to smell their own species up to a half-mile away, said Milos Novotny, Distinguished Professor of Chemistry and director of the Institute for Pheromone Research at Indiana University. The chemicals, called pheromones, are detected by the vomeronasal organ (VNO) in the animal's nose.

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 342 - Posted: 10.20.2001

NEW YORK (Reuters Health) - Some people who are addicted to alcohol or drugs may have problems with their decision-making skills, researchers suggest. Their findings give weight to the idea that addiction involves a flaw in the brain's decision-making center. In a study conducted at the University of Iowa in Iowa City, a majority of alcoholics and drug addicts scored as poorly on a test measuring the ability to make decisions as people with damage to a brain region that helps control decision-making. People who abuse alcohol or drugs often behave similarly to people who have experienced damage to a part of the brain called the ventromedial prefrontal cortex (VM), which is involved in decision-making. For instance, both groups of people often deny they have a problem or are unaware of it. And when given a choice to do something that will bring them immediate pleasure but will lead to negative consequences later, they often opt for instant gratification. SOURCE: Neuropsychologia 2001;39:376-389. © 2001 Reuters Limited. All rights reserved. Republication and redissemination of the contents of this screen are expressly prohibited without Reuters prior written consent. ©2001 At Home Corporation.

Keyword: Drug Abuse
Link ID: 341 - Posted: 10.20.2001

Mother hens dictate diet Ptarmigans teach their brood healthy eating habits. JOHN WHITFIELD The maternal command to eat your greens now has a feathered equivalent. Female ptarmigans steer their chicks away from junk food towards a high-protein diet. Teaching such as this is known for only a few species, including chimpanzees and cheetahs, says Jennifer Clarke of the University of Northern Colorado, Greeley. "To find it in a little chicken-like bird is very surprising," she says. © Nature News Service / Macmillan Magazines Ltd 2001

Keyword: Evolution
Link ID: 340 - Posted: 10.20.2001

Tomboys bred in the womb The sex of a baby's twin may effect their development The way a girl twin's brain develops may be in part influenced by the sex of her fellow twin. Researchers have discovered that girls who grow inside the womb with their twin brothers may develop slightly more "masculine" brains than girls with twin sisters. The scientists believe this may be because the girls with twin brothers are exposed to higher levels of the male sex hormone testosterone in the womb. (c) BBC

Keyword: Hormones & Behavior
Link ID: 337 - Posted: 10.20.2001

Caloric Restriction New research is creating much food for thought. Increasing evidence in animals suggests that a special diet involving a sharp reduction in calories, termed caloric restriction, helps the brain battle old age and disease. These findings may lead to creative, new ways to improve the health of the human brain. Here's the skinny. Since the 1930s, when researchers found that rats placed on a low-calorie diet lived longer, many suspected that the benefits of reducing food intake surpassed keeping a slim waist. So they put down their PB & J and got cooking in the lab. Increasing evidence from animal studies now indicates that, indeed, low-cal perks are far-reaching, even extending to the brain. Cutting back calories, termed caloric restriction, appears to slow age-related changes in the brain and helps ward off brain destruction from neurological ailments. This new research may lead to: Copyright © 2001 Society for Neuroscience. All rights reserved. No portion of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise without permission of the Society for Neuroscience.

Keyword: Obesity
Link ID: 336 - Posted: 10.20.2001

Birds feel the rub Phony phallus puts sperm ahead in bird orgasm first. HELEN PEARSON "These birds would be at it for 10-20 minutes," says ecologist Tim Birkhead of the red-billed buffalo weaver and its remarkable false phallus. A male uses his organ to rub females up the right way and improve his sperm's chance of success1. By massaging his member the male also reaches what looks like an orgasm - a first in the bird world. Few birds are blessed with a phallus; most couples achieve fertilization by pushing together their rear ends for a functional exchange of fluids. So 19th-century reports of a mock member in the buffalo weaver sent Birkhead and his team from the University of Sheffield, UK on a field trip to drought-struck Namibia. 1.Winterbotton, M., Burke, T. & Birkhead, T.R.The phalloid organ, orgasm and sperm competition in a polygandrous bird: the red-billed buffalo weaver. Behavioural Ecology and Sociobiology, pre-published online, (2001). © Nature News Service / Macmillan Magazines Ltd 2001

Keyword: Sexual Behavior
Link ID: 335 - Posted: 10.20.2001

'The Imitation Factor': Guppy Love By Jon W. Turney Monkey see, monkey do. Does monkey have culture? Yes, according to Lee Alan Dugatkin. And so do rats, pigeons, whales . . . oh, and guppies. Individuals in all these species imitate some aspects of others' behavior. So they have a way of passing on information that is separate from the DNA they bestow on their offspring. Guppies choosing mates are at the heart of Dugatkin's story in ''The Imitation Factor.'' Female guppies' hard-wired preferences for the right male -- one sporting, say, orange scales -- count for little if they see another female mate with a more nondescript specimen. Mr. Average Guppy suddenly is more attractive to the opposite sex. Being desired makes one desirable. Copyright 2001 The New York Times Company | Privacy Information

Keyword: Evolution
Link ID: 334 - Posted: 10.20.2001

Divorce is written in the DNA Hazel Muir A new study of twins suggests that genetic make-up has a strong influence on whether or not your marriage will last - though not whether you'll get married in the first place. Beth Jerskey, Michael Lyons and their colleagues at Boston University in Massachusetts compared marriage and divorce rates in identical and non-identical male twins. © Copyright Reed Business Information Ltd.

Keyword: Genes & Behavior
Link ID: 328 - Posted: 10.20.2001

PHILIP BALL
When we think, our brain lights up - or so we have been led to believe by the now-familiar pictures of the brain in action, which depict a glow around the active area. Now neuroscientists in Germany have finally worked out what these pictures are telling us. Scans obtained using functional magnetic resonance imaging (fMRI) show brain cells (neurons) receiving and processing electrical signals, say Nikos Logothetis and colleagues at the Max Planck Institute for Biological Cybernetics in Tübingen1. 1.Logothetis, N. K., Pauls, J., Augath, M., Trinath, T. & Oeltermann, A.Neurophysiological investigation of the basis of the fMRI signal. Nature, 412, 150 - 157, (2001). © Nature News Service / Macmillan Magazines Ltd 2001

Keyword: Brain imaging
Link ID: 327 - Posted: 10.20.2001

Mating Dances Go On and On By NATALIE ANGIER Fairy tales never reveal exactly what happens once the prince and princess have shaken the rice from their hair, but here's a sample of how other coupled creatures interpret the phrase, "And they lived happily ever after": ¶Any time a pair of great-crested grebes reunites after a separation, the white-cheeked, pointy-beaked water birds celebrate with an aquatic version of the tango. As one bird dives and swims toward the other, its partner arches its back and fluffs itself up, cat-style, until the diver bursts through the water right next to it in the "ghost display," wings extended, body erect. The two part, plunge back under and re- emerge with weeds clutched like roses in their beaks. Pressing their breasts together, they rise up and begin trampling their feet on the water, heads turning back and forth. Copyright 2001 The New York Times Company

Keyword: Sexual Behavior
Link ID: 324 - Posted: 10.20.2001

In both rats and humans, chronic stress early in life can hobble memory during adulthood. Now researchers have identified a substance that might be to blame. Immature rats injected with high levels of a hormone that is produced in response to stress suffer later memory deficits, and parts of their brains are shrunken. Adult rat survivors of stressful puphoods typically are missing neurons in a part of the brain called the hippocampus that's necessary for recording memories. But researchers haven't been sure what depletes these neurons. Stress hormones called glucocorticoids are an obvious possibility, except for the fact that they don't normally interact with the hippocampus. So in the new study, neuroscientists tested another stress-related suspect, called corticotropin-releasing hormone (CRH). --BEN HARDER Copyright © 2001 by the American Association for the Advancement of Science.

Keyword: Stress
Link ID: 323 - Posted: 10.20.2001

Memories in the Mind's Eye When a monkey has to remember something, it holds that thought in its mind's eye, a new study suggests. A low-level part of the visual system just one step removed from the retina buzzes while a monkey maintains a visual memory--a power once ascribed only to more sophisticated parts of the brain. Earlier memory research showed that neurons in higher order brain regions--such as the frontal lobes--fire madly when monkeys (or people) remember something briefly. In contrast, the primary visual cortex was once thought to simply sort incoming lights and shadows before passing basic information on to higher brain centers for interpretation. --LAURA HELMUTH Copyright © 2001 by the American Association for the Advancement of Science.

Keyword: Learning & Memory
Link ID: 322 - Posted: 10.20.2001

Faces of Perception It's tough to explain how people so easily tell one face from another Bruce Bower Newborn babies are wrinkled, wide-eyed strangers in a strange land of light, shadow, and color. Nonetheless, these little bundles of visual innocence take an immediate shine to faces. Just a few hours after birth, infants begin to imitate adults' smiles, frowns, and other expressions. Given a choice, the same babies gaze longer at a picture of their mother's face than at an image of the face of a female stranger. They also boast a budding aptitude for telling strangers' faces apart and give particular notice to faces rated as attractive by adults. From Science News, Vol. 160, No. 1, July 7, 2001, p. 10. Copyright ©2001 Science Service. All rights reserved.

Keyword: Vision
Link ID: 321 - Posted: 10.20.2001