Alzheimer's Disease and Plaques
For years researchers have known that the brains of those with the memory-robbing disorder, Alzheimer's disease, are mottled with deposits or plaques, which are formed mainly of a fiber-like substance termed amyloid. While the plaques clearly are a sign of the disease, their exact role has been unclear. Some scientists believe that the deposits are merely the consequence of other, more important factors. Other researchers believe that the plaques are central to the disease. Now new research efforts that are finding ways to reduce the burden of amyloid plaques in the brain may clarify the role plaques and, more importantly, may lead to ways to prevent or treat Alzheimer's disease.

Keyword: Alzheimers
Link ID: 364 - Posted: 10.20.2001

Narcolepsy
The incurable sleep disorder, narcolepsy, has long mystified scientists. But recently, several discoveries culled from animal research indicate that molecular brain malfunctions may participate in the development of the ailment. The new insights are focusing the search for targeted human treatments for narcolepsy as well as other types of sleeping problems. Dramatically drowsy during calculus class? Maybe it's the monotone teacher, an overdose of David Letterman or, perhaps, narcolepsy. This brain disorder, which afflicts an estimated 200,000 Americans, is marked by an uncontrollable, overwhelming desire to sleep during the day. The attacks can occur at any time, even in the middle of a conversation about yesterday's homework.

Keyword: Narcolepsy
Link ID: 363 - Posted: 10.20.2001

Brain-development timeline for mammalian species
ITHACA, N.Y. -- A team of Cornell University neurobiologists has modeled key milestones in brain development across nine mammalian species, from hamsters to humans. They have, for example, pinpointed the date after conception when the cells that make up the retina of the eye are formed. The neurobiologists found pretty much what they expected -- an evolutionarily conserved pattern of sequence and timing. But they also found a few curious exceptions, such as the discovery that the human brain is relatively developed at birth. Knowing precisely how development in rodent brains can be translated to other species, the researchers hope, might reduce the number of higher animals required for research and should make transgenic mice an even more valuable animal model in biomedical research. And because brain (neural) development milestones are remarkably consistent in mammals, the researchers' mathematical model is able to fill in the blanks in one species, Homo sapiens , where experimentation is unthinkable.

Keyword: Evolution
Link ID: 361 - Posted: 10.20.2001

BLOOMINGTON, Ind. -- The birth control pill can have significant adverse effects on sexuality and mood in some women, increasing the likelihood of early discontinuation, according to a study by the Kinsey Institute for Research in Sex, Gender and Reproduction at Indiana University. Results of the study will be reported in the July issue of the journal Contraception. Stephanie Sanders, associate director of the Kinsey Institute and an IU faculty member in gender studies, directed the study of 80 women. The research team included John Bancroft and Jennifer Bass of the Kinsey Institute and Cynthia Graham of the IU Department of Psychology.

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 360 - Posted: 10.20.2001

The Stammering Brain
For the first time, researchers have spotted unique features of the brain anatomy of stutterers. The findings could help predict who is at risk for stuttering and perhaps lead to treatments based on the particular features of a stutterer's brain. A team led by neurologist Anne Foundas at Tulane University Health Science Center in New Orleans, Louisiana, used magnetic resonance imaging to measure the volume of speech-related brain regions in 13 men and three women who had stuttered since childhood, and in a control group of 16 nonstutterers. The controls were matched for sex (male stutterers outnumber females 4 to 1) and handedness (stutterers are about twice as likely to be lefties), as well as age and education. The researchers then compared two brain areas associated with speech and language--Broca's area in the front of the brain, and parts of Wernicke's area in the back. --ALKA AGRAWAL Copyright © 2001 by the American Association for the Advancement of Science.

Keyword: Development of the Brain
Link ID: 359 - Posted: 10.20.2001

Early Success Seen With 2nd Type of Stem Cell
By NICHOLAS WADE A second kind of human embryonic stem cell appears to have demonstrated promise in repairing damaged tissues by helping paralyzed mice regain some powers of movement. Dr. John D. Gearhart, a biologist at Johns Hopkins University, said the mice, whose spinal nerve cells had been destroyed by a virus, managed to move again, though not perfectly, after receiving injections of human embryonic cells. Copyright 2001 The New York Times Company

Keyword: Stem Cells
Link ID: 358 - Posted: 10.20.2001

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