Researchers at the Salk Institute for Biological Studies have identified an important circuit in the spinal cord that controls the speed with which our leg muscles contract and relax. Their findings mark an important milestone in understanding the neural circuitry that coordinates walking movements - one of the main obstacles in developing new treatments for spinal cord injuries. "Knowing which circuits are important and understanding how they control the essential aspects of walking should put us in a better position to design treatments or implants that restore or activate these pathways," said Martyn D. Goulding, Ph.D., a professor in the Molecular Neurobiology Laboratory. The Salk research team – led by Goulding– published their findings in the March 9, 2006 issue of the journal Nature. Joint lead authors were Simon Gosgnach, Ph.D. and Guillermo M. Lanuza, Ph.D. in Goulding's laboratory. Whether fish or fowl, the muscle contractions that allow us to move generally have certain rhythmic properties. It has been known for some time that a central pattern generator (CPG) – specialized groups of neurons in the spinal cord – functions as the control and command center for these rhythmic movements. As such, the CPG lies at the heart of all locomotion. Remarkably, this circuitry functions without any input from the brain, which explains why headless chickens run away from the butcher's block.

Keyword: Miscellaneous
Link ID: 8637 - Posted: 06.24.2010

CAMBRIDGE, Mass.--Researchers at MIT and Harvard Medical School have identified a compound that interferes with the pathogenic effects of Huntington's disease, a discovery that could lead to development of a new treatment for the disease. There is no cure for Huntington's, a neurodegenerative disorder that now afflicts 30,000 Americans, with another 150,000 at risk. The fatal disease, which is genetically inherited, usually strikes in midlife and causes uncontrolled movements, loss of cognitive function and emotional disturbance. "There are now some drugs that can help with the symptoms, but we can't stop the course of the disease or its onset," said Ruth Bodner, lead author on a paper appearing online the week of Mar. 6 in the Proceedings of the National Academy of Sciences (PNAS). Bodner is a postdoctoral fellow in MIT's Center for Cancer Research. The compound developed by Bodner and others in the laboratories of MIT Professor of Biology David Housman, Harvard Medical School Assistant Professor Aleksey Kazantsev and Harvard Medical School Professor Bradley Hyman might lead to a drug that could help stop the deadly sequence of cellular events that Huntington's unleashes. "Depending on its target, any one compound will probably block only a subset of the pathogenic effects," Bodner said.

Keyword: Huntingtons
Link ID: 8636 - Posted: 03.09.2006

By Thomas Oberst Imagine seeing a former high school classmate you always wanted to know better. Then imagine seeing that kid who used to push you in the hallways. Do you react differently? What happens in your brain during these encounters? In fact, different areas of the brain react differently when recognizing others, depending on the emotions attached to the memory, a team of Cornell University research psychologists has found. The team, led by professor of psychology Robert Johnston, has been conducting experiments to study individual recognition. But rather than crash high school reunions with an MRI machine in tow, the researchers stayed in their laboratory and created social encounters between golden hamsters. Then they examined the animals' brains for evidence of those encounters. Last year Johnston's team conducted the first experiment to demonstrate the neural basis of individual recognition in hamsters and identify which areas of the brain play a role. The results were published in the Dec. 7, 2005, issue of the Journal of Neuroscience. Better understanding these mechanisms, Johnston said, may be of central importance in treating certain forms of autism, Asperger syndrome, psychopathy and social anxiety disorders.

Keyword: Sexual Behavior; Chemical Senses (Smell & Taste)
Link ID: 8635 - Posted: 03.09.2006

By Jennifer Viegas, Discovery News — Many reptiles in the wild can survive for days, even when over half of their body water is frozen, and now scientists have identified three groups of genes that help keep these animals from sustaining damage or death during this near-Popsicle condition. The discovery not only helps to solve the reptile freezing mystery, but scientists also hope the research could one day lead to improved methods for freezing human cells and organs so that tissues in cryostorage could remain alive and viable after thawing. When the temperature dips, some reptiles cannot escape to warmer areas, so several species instead have evolved incredible tolerance to cold. "Over the past 20 or more years of working in the field, various researchers, including ourselves, have come to realize that animals that survive long-term freezing as an integral part of their winter survival strategy have to be able to deal with ice penetration throughout their whole body and with the many consequences of this, including blood plasma freezing, heart beat and breathing stopping, etc.," said Janet Storey, a research associate at Carleton University's Institute of Biochemistry in Canada. © 2006 Discovery Communications Inc.

Keyword: Biological Rhythms
Link ID: 8634 - Posted: 06.24.2010

Andy Coghlan THE immune cells that attack the brains and nerves of people with multiple sclerosis could be turned into a weapon against the disease. This month sees the beginning of a trial of a personalised vaccine for MS, designed to rein in and destroy the renegade white blood cells that attack myelin cells lining the brain and nerves of patients. To make the vaccine, PharmaFrontiers of Woodlands, Texas, takes blood from an MS patient and extracts a sample of these renegade cells. The cells are then multiplied and weakened with radiation before being re-injected into the patient, whose immune system will then recognise them as damaged and attack them, sometimes wiping them out completely, according to the results of earlier trials. The immune system will also attack healthy renegade cells, which have the same markers on their surface. In one trial of 15 people with MS the rate of new flare-ups was reduced by 92 per cent. If this success is repeated in the new trial it might mean that regular shots could slow or even arrest progression of the disease. "If that's the case, the earlier we can do it after diagnosis the better," says David McWilliams of PharmaFrontiers. In the current trial, 100 patients will receive the treatment and 50 a dummy treatment. The vaccine would only need to be injected four times a year, while other MS drugs need to be given on a weekly or daily basis. © Copyright Reed Business Information Ltd.

Keyword: Multiple Sclerosis; Neuroimmunology
Link ID: 8633 - Posted: 06.24.2010

Bob Holmes The differences between humans and chimpanzees, which are genetically quite similar, may be down to the differences in the activity of individual genes in each species. That was the theory, but until now little has been known about how gene activity differs in different primates. To find out, Yoav Gilad, a human geneticist now at the University of Chicago, US, and his colleagues prepared a "gene chip" (a large array of genes) containing the same 1056 genes from humans, chimps, orang-utans and rhesus macaques. The researchers used the chip to measure the activity level of each of those genes in the four species. Any given pair of species differed in activity levels for 12% to 19% of the 907 genes for which they had good data for all four species. In particular, genes coding for transcription factors (proteins that regulate the activity of other genes) tended to be especially active in the human lineage. Gilad speculates that this may underlie the dramatic changes in body form and behaviour of humans compared to the other primates. © Copyright Reed Business Information Ltd

Keyword: Evolution; Genes & Behavior
Link ID: 8632 - Posted: 06.24.2010

Jacqueline Ruttimann Imitation may be the sincerest form of flattery, but for some it's about survival. Animals often avoid predators by copying the appearance of poisonous creatures. Usually the impostor tries to look like the most toxic species around, or imitates a range of toxic animals. But this is not so in the case of Ecuadorian frog Allobates zaparo. This frog chooses to mimic the less toxic of two local species. "It runs counter to traditional models," says Molly Cummings of the University of Texas, Austin, who describes the frog's strategy in this week's Nature1. The poison frogs Epipedobates bilinguis and Epipedobates parvulus share a similar warning sign: a bright red back. But the less poisonous and rarer of the two, E. bilinguis, also has yellow markings on its upper arms and thighs. Cummings found that when A. zaparo was found in the same region as one of these poisonous species, it would imitate that one. But in areas where all three species lived, A. zaparo tended to mimic E. bilinguis. This is odd. Mimics usually evolve to imitate the more abundant or more toxic species, says Cummings, because that normally guarantees the most protection. ©2006 Nature Publishing Group

Keyword: Neurotoxins; Evolution
Link ID: 8631 - Posted: 06.24.2010

By STEPHANIE SAUL With a tendency to stare zombie-like and run into stationary objects, a new species of impaired motorist is hitting the roads: the Ambien driver. Ambien, the nation's best-selling prescription sleeping pill, is showing up with regularity as a factor in traffic arrests, sometimes involving drivers who later say they were sleep-driving and have no memory of taking the wheel after taking the drug. In some state toxicology laboratories Ambien makes the top 10 list of drugs found in impaired drivers. Wisconsin officials identified Ambien in the bloodstreams of 187 arrested drivers from 1999 to 2004. And as a more people are taking the drug — 26.5 million prescriptions in this country last year — there are signs that Ambien-related driving arrests are on the rise. In Washington State, for example, officials counted 78 impaired-driving arrests in which Ambien was a factor last year, up from 56 in 2004. Ambien's maker, Sanofi-Aventis, says the drug's record after 13 years of use in this country shows it is safe when taken as directed. But a spokeswoman, Melissa Feltmann, wrote in an e-mail message, "We are aware of reports of people driving while sleepwalking, and those reports have been provided to the U.S. Food and Drug Administration as part of our ongoing postmarketing evaluation about the safety of our products." Copyright 2006 The New York Times Company

Keyword: Sleep; Drug Abuse
Link ID: 8630 - Posted: 06.24.2010

By Michael Schirber Insects hoping to outsmart their bat predators would do best to hide under a rock. New research shows that even in complex surroundings--where prey is closely interspersed with its environment--bats use a series of rapid calls to break through the clutter and find their quarry. When hunting or navigating, bats send out high-frequency chirps that bounce back from nearby objects, revealing their size and location. Not all of these "echolocating" chirps are the same, however. A bat flying out in the open will emit loud chirps separated by relatively long pauses (100 milliseconds) as it waits for something interesting to bounce back. If that bounce comes from an insect, the bat will focus its calls in the bug's direction and accelerate its chirps as it closes in. But what if the insect is near another object? Psychologist and bat expert Cynthia Moss of the University of Maryland, College Park, wondered if the overlapping echoes would confuse the bat. To find out, she and colleagues recorded the calls and flight patterns of big brown bats (Eptesicus fuscus) in a closed room, called the Batlab. In one set of trials, the bats took just a few seconds to find and capture a worm suspended by string from the ceiling. But when the researchers hung a plant 10 centimeters from the worm, the bats only went for the snack half of the time--taking an average of a minute and a half to do so, the team reports online today in PLoS Biology. The bats fared better when the worm and plant were separated by 20 centimeters or more. © 2006 American Association for the Advancement of Science.

Keyword: Hearing
Link ID: 8629 - Posted: 06.24.2010

Hatchery-reared steelhead trout show increased growth of some parts of the brain when small stones are scattered on the bottom of their tank, according to a new study by researchers at UC Davis. The brains of those young fish were closer to those of salmon reared in the wild, and the fish also showed behavior closer to wild than to hatchery-reared fish. "There's an obvious difference between the hatchery and the wild fish," said graduate student Rebecca Kihslinger, who carried out the study with Gabrielle Nevitt, professor of neurobiology, physiology and behavior at UC Davis. "A simple change affected brain growth in a large-scale way." The results could affect the design of hatcheries for breeding fish to restock wild populations, Kihslinger said. The study is published in the February 2006 issue of the Journal of Experimental Biology. Wild steelhead lay their eggs in gravel nests on the riverbed. After hatching, the fry, called alevins, stay among the gravel and live off their yolk sac until they emerge as free-swimming fry. In hatcheries, the fish are reared in tanks of clean, well-aerated water, but without environmental features or enrichment.

Keyword: Learning & Memory; Intelligence
Link ID: 8628 - Posted: 03.08.2006

Michael Hopkin Humanity's response to the challenges of the past few millennia, from adapting to different environments to taming crops and animals, are writ large in human society. Now geneticists have shown that they are also writ small - in our DNA. Researchers at the University of Chicago, Illinois, have identified the regions of our genetic sequence that show the strongest marks of natural selection. Their work highlights the genes that have been most important in adapting to new lifestyles, and could help to identify the genetic factors involved in complex medical conditions such as high blood pressure and alcoholism. Genes that show the most evidence of recent selection include those involved in milk digestion. Although most mammals drink milk only in infancy, humans seem to have adapted genetically to digest it throughout life. Genes for skin pigmentation also bear the hallmarks of rapid evolution - highlighting the fact that many populations have become more fair-skinned as they have colonized more extreme latitudes with less sunshine. ©2006 Nature Publishing Group

Keyword: Evolution; Genes & Behavior
Link ID: 8627 - Posted: 06.24.2010

An analysis of data from 24 clinical trials suggests that antidepressant medications may be linked to a modest increase in the risk of suicidal thoughts and behaviors in children, according to an article in the March issue of Archives of General Psychiatry, one of the JAMA/Archives journals. For decades, some physicians have suspected that patients' risk of suicidality (suicidal thoughts and behavior) increased when pediatric patients first began taking antidepressants, according to background information in the article. Research indicates that there is no such association in adults. In 2003, a report submitted to the Food and Drug Administration (FDA) suggested a link between the antidepressant paroxetine and suicidality in pediatric patients. The FDA then requested pediatric data from the manufacturers of eight other antidepressant drugs, the authors report. Tarek A. Hammad, M.D., Ph.D., and colleagues at the FDA performed a meta-analysis of data from 23 short-term clinical trials received in response to the request, as well as one trial funded by the National Institute of Mental Health (NIMH). The 24 studies included 4,582 pediatric patients taking one of nine antidepressant medications for depression, anxiety or other psychiatric disorder.

Keyword: Depression; Development of the Brain
Link ID: 8626 - Posted: 03.07.2006

By Stacey Colino When each of her three kids was an infant, Nichole Ahern of Chevy Chase had recurring visions of tumbling down the stairs with the baby in her arms. Last fall, Mindy Walker of Westchester, N.Y., had fleeting thoughts of letting her infant daughter drop out of her arms. Adele Morgan of Hillsborough, N.J., says that the challenges of caring for her first baby made her think about putting him in the microwave or throwing him off the deck when he wouldn't stop crying. None of these women ever harmed their babies, and all are successful, loving mothers. And these kinds of intrusive, unwanted thoughts -- mild versions of those associated with obsessive-compulsive disorder (OCD) -- are extremely common among new parents. In a study of 85 new mothers and fathers conducted at the Mayo Clinic in Rochester, Minn., researchers found that 89 percent experienced distressing, intrusive thoughts related to their infants: images of the baby suffocating or being contaminated with germs, or worries about the baby having an accident, being harmed or kidnapped. © 2006 The Washington Post Company

Keyword: OCD - Obsessive Compulsive Disorder; Development of the Brain
Link ID: 8625 - Posted: 06.24.2010

CHARLOTTESVILLE, Va – It has been well documented that, across human cultures and in most mammals, males are usually more aggressive and less nurturing than females. It’s simple to blame male hormones, like testosterone, for male behavior such as aggression. But maybe it’s in our genes, too. Indeed such social behavior also has a genetic basis, according to new research on mice by neuroscientists at the University of Virginia Health System. “The differences in sex chromosomes, XX versus XY, are also responsible for differences in adult behavior,” explained Emilie Rissman, PhD, a professor of biochemistry and molecular genetics at UVa, who studied aggression and maternal behavior in genetically engineered mice. “Sex chromosome genes may not be the whole story that determines how aggressive or motherly we are, but they are a partof it.” Rissman’s work is published in the Feb. 22 issue of The Journal of Neuroscience, found online at www.jneurosci.org. Co-authors on the paper are scientists at the University of California Los Angeles and the National Institute for Medical Research in London, England. Using mouse models, Rissman and the research team uncoupled the testis-determining gene Sry on the male Y chromosome from other sex chromosome genes. The presence of Sry leads to the development of the testes and high levels of androgens in males, which is partly responsible for aggression. Sry was deleted from the Y chromosome and replaced by a transgenic copy. © 1998 – 2006 by the Rector & Visitors of the University of Virginia

Keyword: Sexual Behavior; Aggression
Link ID: 8624 - Posted: 06.24.2010

By PAUL STEINBERG, M.D. The recent recommendation that Ritalin and other medications for attention-deficit disorder carry the most serious allowable warning will certainly slow the explosive growth in the use of those drugs. That was the intention of some members of the Food and Drug Administration advisory committee that called for the packaging alert, known as a black-box warning. But the recommendation and concerns about growth in the use of these drugs may force us to think about the disorder, known as A.D.H.D., in new and different ways, from an evolutionary and contextual standpoint. Every generation likes to believe that it is witnessing the most dramatic epoch in history. In the case of the current Western world, that belief may indeed be accurate, particularly in light of the striking changes of the last 30 years. As the business writer and consultant Peter Drucker pointed out, most people in the United States, Japan and parts of Europe are "knowledge workers." We live in an information age, in a knowledge-based economy. For those of us who have "attention-surplus disorder" — a term coined by Dr. Ned Hallowell, a psychiatrist in Boston who has A.D.H.D. — this knowledge-based economy has been a godsend. We thrive. Copyright 2006 The New York Times Company

Keyword: ADHD
Link ID: 8623 - Posted: 06.24.2010

BAR HARBOR, Maine - When it comes to the price of mice, you pay extra for defects. A mouse with arthritis runs close to $200; two pairs of epileptic mice can cost 10 times that. You want three blind mice? That’ll run you about $250. And for your own custom mouse, with the genetic modification of your choosing, expect to pay as much as $100,000. Always a mainstay of scientific research, mice have become a critical tool in the quest for new drugs and medical treatments because their genes are remarkably similar to a person’s. With proper manipulation — either by man or nature — a set of mouse genes can produce an animal with just about any human ailment, or a reasonable facsimile of it. Strains of mice that succumb to Alzheimer’s disease, obesity, diabetes, cancer and countless other conditions are being used to study both the illnesses themselves and potential treatments. As many as 25 million mice are now used in experiments each year. Where do they come from? Where else? Mouse farms. © 2006 MSNBC.com © 2006 Microsoft

Keyword: Genes & Behavior; Animal Rights
Link ID: 8622 - Posted: 06.24.2010

Scientists at UCL (University College London) have discovered the area of the brain linked to dyscalculia, a maths learning disability. The finding shows that there is a separate part of the brain used for counting that is essential for diagnosis and an understanding of why many people struggle with maths. The paper, published online today in the Proceedings of the National Academy of Sciences (PNAS), explains that an area of the brain widely thought to be involved in processing number information generally, in fact has two very separate, specific functions. One function is responsible for counting 'how many' things are present and the other is responsible for knowing 'how much'. It is the discovery of the part responsible for counting or numerosity that is a major finding for Professor Brian Butterworth, who also published 'The Mathematical Brain' and is an authority on dyscalculia. He believes his finding is the key to diagnosis of dyscalculia. Professor Butterworth, of the UCL Institute of Cognitive Neuroscience, said: "Now that we know where to look for the differences in brain activation between those who suffer from dyscalculia and those who don't have the learning disorder, we will be able to come up with better diagnosis and insights.

Keyword: Miscellaneous
Link ID: 8621 - Posted: 03.07.2006

The dissociation in the visual system between two separate functions – one that enables us to identify objects and the other to interact with them – has been clearly demonstrated for the first time in healthy humans by researchers at the Hebrew University of Jerusalem. These separate vision-related actions have been documented from the beginning of the 20th century in patients who suffered damage to the visual system as a result of illness or injuries in which one or the other function – identification or action – was damaged. For example, persons suffering from ataxia are able to verbally identify an object presented to them but have difficulty in grasping it, while those who have agnosia can grasp an object if handed to them but are unable to name or indicate the position, size or texture of the object. This dissociation between action and perception suggests the existence of two separate visual streams However, despite the wide research triggered by this theoretical concept, it had not been proved in subjects in whom both streams are functioning normally.

Keyword: Vision
Link ID: 8620 - Posted: 06.24.2010

By Betsy Mason, ScienceNOW Daily News When it comes to good recollection, elephants get the lion's share of the glory. But now an animal only slightly larger than an elephant's toenail is giving the largest land mammal a run for its memory. Hummingbirds can keep a running tab of multiple aspects of their visits to at least eight different flowers over the course of several days, displaying a type of memory once attributed solely to humans. Previous studies have shown that birds, rats, and primates can remember where they saw of an item or event, but it's not clear whether they can remember when they saw it. The time question is especially important to hummingbirds, who must be as efficient as possible as they remove nectar from a large number flowers in their territory. Hit the same flower too soon, and it's still empty. Wait too long, and a competitor has made off with the bounty. A team led by biologists Jonathan Henderson and Susan Healy of the University of Edinburgh in the United Kingdom set out to check the birds' record-keeping skills. Using eight artificial flowers, the scientists tested three wild, male rufous hummingbirds in the Canadian Rocky Mountains. The birds were able to recognize the difference between flowers that were refilled with nectar at 10 and 20 minute intervals, remember where the flowers were, and recall when they had last drained them. © 2006 American Association for the Advancement of Science

Keyword: Learning & Memory
Link ID: 8619 - Posted: 06.24.2010

By Jennifer Viegas, Discovery News — Healthy humans cannot tickle themselves or attribute their own voices to those of other people, according to a new study that determined that individuals anticipate their own actions, which can beneficially alter their sense of perception. Since it is now believed that a breakdown in this anticipation process may underlie the delusions of schizophrenics, the finding may lead to a better understanding of this mental disorder. According to the National Institute of Mental Health, around 51 million people worldwide suffer from schizophrenia. The study also solves the long-standing mystery as to why most humans and animals cannot tickle themselves. "It's well known that you can't tickle yourself," said Randy Flanagan, one of the study's authors. "One explanation is that since all the sensations are completely predictable, we do 'sensory attenuation,' which reduces our touch perception." Flanagan, a psychologist at Queen's University in Ontario, Canada, added, "If we try to deal with all the sensory information directed at us at any given time, it's overwhelming. We can't focus attention on crucial changes in our environment that aren't a function of our own motions." © 2006 Discovery Communications Inc.

Keyword: Pain & Touch; Attention
Link ID: 8618 - Posted: 06.24.2010