It is often the quiet, supportive types who wield real power. Star-shaped brain cells called astrocytes, usually dismissed as support cells for the attention-grabbing neurons, now seem to control the growth of new neurons in adult brains. The find brings scientists closer to understanding the forces that control neuron growth in adults and could lead to ways to treat neurodegenerative diseases or spinal cord injuries. Astrocytes reside throughout the nervous system, filling in the spaces between neurons, the "wires" that pass the system's messages. Astrocytes were thought to constitute protective scaffolding and a nutrition source that help keep neurons healthy. But recently astrocytes have begun to shed their inert image. In the last few years, scientists have found that the supposedly placid cells help neurons form connections with each other (ScienceNOW, 26 January 2001) and might even be stem cells themselves (ScienceNOW, 15 June 1999). Copyright © 2002 by the American Association for the Advancement of Science.

Keyword: Glia; Neurogenesis
Link ID: 2001 - Posted: 06.24.2010

Females stray when mates lose song battles. JOHN WHITFIELD Female birds that overhear their partner lose a singing contest are more likely to mate sneakily with another male, researchers have found1. Just two defeats send a female looking for alternative mates. "Females are deciding who's going to father their children on the basis of a six-minute interaction," says zoologist Tom Peake of the University of Copenhagen, Denmark. "That's got to worry pretty much every male on the planet." Female eavesdropping shows that there's more to fighting than letting the combatants know who's boss - everyone within earshot is also picking up information. * Mennill, D. J., Ratcliffe, L. M. & Boag, P. T. Female eavesdropping on male song contests in songbirds. Science, 296, 873, (2002). © Nature News Service / Macmillan Magazines Ltd 2002

Keyword: Sexual Behavior
Link ID: 2000 - Posted: 06.24.2010

Scientists from The Center for Hearing and Balance at Johns Hopkins have discovered how tiny cells in the inner ear change sound into an electrical signal the brain can understand. Their finding, published in a recent issue of Nature Neuroscience, could improve the design and programming of hearing aids and cochlear implants by filling in a "black hole" in scientists' understanding of how we hear, say the researchers. "Sound itself is mechanical, a wave that moves, just like the ripples fanning out from a pebble dropped in a lake," says Paul Fuchs, Ph.D., professor of otolaryngology at the Johns Hopkins School of Medicine. "When the inner ear detects this wave, a burst of chemicals is released and a nerve sends an electrical signal to the brain that carries information about the original sound. But the nature of the chemical burst has been a mystery until now." Nature Neuroscience February 2002: 5 (2); 147-154.

Keyword: Hearing
Link ID: 1999 - Posted: 05.03.2002

Possible insight to multiple sclerosis and other neurodegenerative diseases that destroy nerve cell 'insulation' In the May 3 issue of Science, scientists at Rockefeller University and New York University School of Medicine report that the nerve damage that leads to a loss of sensation and disability of people with leprosy occurs in the early stages of infection. The nerve damage, a hallmark of leprosy previously thought to be a byproduct of the immune system’s response to the leprosy bacteria, now seems to be a direct result of the leprosy bug attaching itself to specialized nerve cells called Schwann cells, the glial, or supporting, cells of the peripheral nervous system (PNS). The findings suggest that the body’s immune response does not play a significant role in the early stage of neurological injury.

Keyword: Multiple Sclerosis; Neuroimmunology
Link ID: 1998 - Posted: 06.24.2010

In the first hours and days following a stroke, stem cells leave the bone marrow to help the injured brain repair damaged neurons and make new neurons and blood vessels, according to researchers at the Medical College of Georgia. The research, reported in the May issue of Stroke, used a mouse model in which the animal’s marrow was replaced with that of a transgenic mouse with cells that make a jellyfish protein that fluoresces green so they could trace the cells and the natural repair process that apparently occurs after stroke. The researchers are now looking for the right factors to enhance the normal repair mechanism, improve stroke recovery and, since the patient’s own cells would be used, avoid issues such as the compatibility of donated stem cells and the ethical controversy surrounding embryonic stem cells.

Keyword: Stroke; Stem Cells
Link ID: 1997 - Posted: 06.24.2010

Genetic test might identify ex-drinkers most likely to relapse under stress Why does stress make some people reach for a drink, but not others? Variations in a key stress-response gene may be at least one reason, suggests a German study on mice. The scientists report their findings in the journal Science, published by the American Association for the Advancement of Science. Rainer Spanagel of the University of Heidelberg and the Max Planck Institute of Psychiatry found that mice lacking the "CRH1" gene drank more alcohol than normal mice did after stressful experiences. If humans with variations in this gene behave the same way, a fairly simple test may identify recovering alcoholics likely to relapse under stress, according to Spanagel.

Keyword: Drug Abuse; Stress
Link ID: 1996 - Posted: 05.03.2002

Women are more likely to give up cigarettes if they take smoking cessation drugs rather than depend on nicotine replacement therapy, research suggests. A study by doctors at Oregon Health and Science University in the US found women who took the anti-smoking drug bupropion were more successful in kicking the habit. Bupropion is marketed as the anti-smoking drug Zyban. However, it is also prescribed as an anti-depressant under the name Wellbutrin. The authors believe the anti-depressant features of the drug may particularly benefit women who are more likely to start smoking again than men. They suggest the drug helps to relieve depression, irritability and other negative feelings which many women say leads them to take up the habit once more. (C) BBC

Keyword: Drug Abuse; Depression
Link ID: 1994 - Posted: 05.02.2002

By HOWARD MARKEL, M.D. Recently one morning, I received an urgent call from the mother of an 18-year-old named Daniel, whom I treat for marijuana abuse. For most of the past few years, Daniel had smoked more than a quarter of an ounce of marijuana daily and was almost always high, except, perhaps, when he was asleep. His marijuana problem has led to many others: he has been hospitalized, fired from jobs and thrown out of high school. He has faced run-ins with the police and lost the trust of most of his family members and friends. Copyright 2002 The New York Times Company

Keyword: Drug Abuse
Link ID: 1993 - Posted: 05.02.2002

Desire drives remote-controlled rodents. TOM CLARKE Remote-controlled rats could soon be detecting earthquake survivors or leading bomb-disposal teams to buried land mines. Signals from a laptop up to 500 metres away make the rats run, climb, jump and even cross brightly lit open spaces, contrary to their instincts. The rodents carry a backpack containing a radio receiver and a power source that transmits the signals into their brains through electrical probes the breadth of a hair. "They work for pleasure," says Sanjiv Talwar, the bioengineer at the State University of New York who led the research team. One electrode stimulates the rat's medial forebrain bundle, or MFB, the 'feelgood' centre of the mammalian brain. "The rat feels nirvana," Talwar says. Talwar, S. K. et al. Rat navigation guided by remote control.. Nature, 417, 37 - 38, (2002). © Nature News Service / Macmillan Magazines Ltd 2002

Keyword: Robotics
Link ID: 1992 - Posted: 06.24.2010

LITTLE ground squirrel has revealed a slumbering secret of hibernating mammals True hibernators, such as ground squirrels, marmots and chipmunks, regularly wake themselves from deep sleep. It didn't seem to make sense because this uses up huge amounts of valuable stored energy. But the answer seems to be they do it to fire up their immune systems and carry out a systems check for parasites and pathogens. Small mammals hibernate to conserve energy when food is scarce during long, cold winters. While larger creatures such as bears and badgers go into a state of torpor, in which their body temperature drops for short periods, true hibernators cool right down. Their temperature often drops as low as 5 ¡C for weeks on end. California's golden-mantled ground squirrel (Spermophilus lateralis) is a champion hibernator. For five to six months each winter it spends most of the time with its heart ticking over at just two beats a minute. But roughly once a week, it wakes up and for 12 to 16 hours its body temperature rises to 37 ¡C. The wake-up periods use up to 80 per cent of the animal's winter energy budget. Researchers wondered if the animals wake to clear waste from their body, but that seemed unlikely given the huge energy costs. To investigate, Brian Prendergast of Ohio State University at Columbus and his team took 31 squirrels into the lab and implanted them with radio transmitters that recorded body temperature every 5 seconds.

Keyword: Biological Rhythms; Neuroimmunology
Link ID: 1991 - Posted: 05.02.2002

DURHAM, N.C. -- A Duke University Medical Center pharmacologist is recommending caution when using the insecticide DEET, after his animal studies last year found the chemical causes diffuse brain cell death and behavioral changes in rats after frequent and prolonged use. Mohamed Abou-Donia, Ph.D. has also called for further government testing of the chemical's safety in short-term and occasional use, especially in view of Health Canada's recent decision to ban products with more than 30 percent of the chemical. Every year, approximately one-third of the U.S. population uses insect repellents containing DEET, available in more than 230 products with concentrations up to 100 percent. While the chemical's risks to humans are still being intensely debated, Abou-Donia says his 30 years of research on pesticides' brain effects clearly indicate the need for caution among the general public.

Keyword: Neurotoxins
Link ID: 1990 - Posted: 05.02.2002

The ability to learn a new language is determined by the onset of language experience during early brain development – regardless of the specific form of the language experience. This is the finding of a Canadian study led by Rachel Mayberry of McGill University. Mayberry, director of McGill’s School of Communication Sciences and Disorders, along with Elizabeth Lock of the University of Ottawa and Hena Kazmi of the University of Western Ontario, studied groups of deaf and hearing adults to see how the onset and type of initial language experience affects the ability to learn a new language. The results of the study, which will appear in the May 2 issue of the prestigious journal Nature, show that deaf and hearing adults who experience language in early life perform similarly well in learning a new language later in life – whereas deaf adults who had little language experience in early life showed low levels of performance in a later learned language. These findings are not affected by whether the early language or the later language was signed or spoken.

Keyword: Language; Development of the Brain
Link ID: 1989 - Posted: 06.24.2010

Copyright © 2002 Scripps Howard News Service By LEE BOWMAN, Scripps Howard News Service - Chin up, positive mental attitude, keep plugging along, don't let it get you down. Most aging experts - and most people - figure that being depressed, or anything but chipper, is a ticket toward illness and a shorter life. But a new study challenges this view with a finding that older women with mild depression actually live longer than women who aren't experiencing any symptoms of depression. Copyright © 2001 Nando Media

Keyword: Depression
Link ID: 1988 - Posted: 06.24.2010

Copyright © 2002 AP Online By RICK CALLAHAN, Associated Press - By implanting electrodes in rats' brains, scientists have created remote-controlled rodents they can command to turn left or right, climb trees and navigate piles of rubble. Someday, scientists said, rats carrying tiny video cameras might search for disaster survivors. "If you have a collapsed building and there are people under the rubble, there's no robot that exists now that would be capable of going down into such a difficult terrain and finding those people, but a rat would be able to do that," said John Chapin, a professor of physiology and pharmacology at the State University of New York in Brooklyn. The lab animals aren't exactly robot rats. They had to be trained to carry out the commands. Copyright © 2001 Nando Media

Keyword: Robotics
Link ID: 1987 - Posted: 06.24.2010

By Jennifer Viegas, Discovery News — Until recently, scientists thought human ears were passive devices that detected and processed sounds, but new findings suggest that ears are like perpetually turned on stereo receivers that quiver spontaneously and sing along with incoming sounds. The latest findings, published in the May issue of the journal Physics World, help to explain why some people's ears emit noise that actually can be heard by passers by. According to Thomas Duke, a physicist at The Cavendish Laboratory of Cambridge University in England, at least four major discoveries about how the ear works were made in recent months. The first is that hair bundles — filament-like sensors in the inner ear that are deflected by sound waves — have been found to vibrate spontaneously, which can itself produce noise similar to a stereo speaker. Copyright © 2002 Discovery Communications Inc.

Keyword: Hearing
Link ID: 1986 - Posted: 06.24.2010

By Richard Black Scientists in Norway have for the first time managed to turn one sort of human cell into another. Conventional scientific wisdom has been once a skin cell, always a skin cell. All the evidence has been that nerve cells can only produce other nerve cells, muscle cells only produce other muscle cells, and so on. But researchers at the University of Oslo have turned the conventional view on its head. (C) BBC

Keyword: Stem Cells
Link ID: 1985 - Posted: 05.01.2002

STANFORD, Calif. - Using microarray technology, researchers at Stanford University Medical Center have uncovered thousands of genes that may be involved in multiple sclerosis. Although some of the genes are new, others were known genes that had previously been thought to play roles that were unrelated to MS. These results could lead to new treatments and help clarify previous observations about the disease. "We've been bumping around looking at a few genes," said Lawrence Steinman, MD, professor of neurology and neurological sciences. "Now there are hundreds if not thousands of other genes that may be critical." This work will be published in the May issue of Nature Medicine. MS occurs when cells of the immune system target their attack on cells that insulate neurons in the brain. The disease generally progresses in stages with an acute attack followed by a recovery - or chronic phase - in which the insulating cells degenerate and scar tissue builds up. Eventually, the disease can lead to paralysis and sensory disturbances such as blindness or deafness.

Keyword: Multiple Sclerosis; Genes & Behavior
Link ID: 1984 - Posted: 05.01.2002

Whether it's a widely prescribed medication or a placebo, a successful treatment for depression must trigger a common pattern of brain activity changes, suggests a team of researchers funded by the National Institute of Mental Health. Using functional brain imaging, Helen Mayberg, M.D., and colleagues at the University of Texas Health Science Center, San Antonio, have found increased activity in the cortex accompanied by decreases in limbic regions in patients who responded to either the popular antidepressant fluoxetine or to a placebo. They propose that this pattern of changes may be necessary for therapeutic response. However, patients who responded to fluoxetine also experienced unique changes in lower areas -- brainstem, striatum and hippocampus -- thought to confer additional advantage in sustaining the response long term and preventing relapse. The researchers report on their Positron Emission Tomography (PET scan) study in the May 2002 American Journal of Psychiatry.

Keyword: Depression
Link ID: 1983 - Posted: 05.01.2002

(REUTERS) Two new studies could shed more light on why infants who lie on their stomachs are more likely to die of Sudden Infant Death Syndrome. One shows that lying prone can twist a baby's neck so far that the arteries leading to the head become blocked, and another showed that nerve cells near brain arteries may not work properly. Both support the recommendation that babies be put to sleep on their backs. ©MMII, CBS Worldwide Inc, All Rights Reserved

Keyword: Sleep; Development of the Brain
Link ID: 1982 - Posted: 06.24.2010

By JENNIFER HOYT The Associated Press WASHINGTON (AP) -- Concussions are common in soccer, with better training needed for coaches and parents to identify and treat children who may get serious head injuries, according to the Institute of Medicine. "A lot of people -- parents anyway -- found soccer more appealing for their kids because they saw it as less dangerous than football," said Janet Joy, who prepared a review for the institute. "But the fact is, concussions are just as frequent in soccer." Players can get concussions from heading the ball, colliding, running into goalposts or hitting their heads on the ground. A player who has a second concussion before recovering from the first may suffer brain swelling that could lead to brain damage and death. Copyright 2002 Associated Press. All rights reserved

Keyword: Brain Injury/Concussion
Link ID: 1981 - Posted: 05.01.2002