By REED ABELSON For many doctors, it’s an irresistible pitch: a $250 profit from a 15-minute test. With that lure, some 12,000 of the nation’s physicians have purchased an automated device that checks patients for nerve disease. Such a diagnosis might otherwise require extensive testing by specialists. Indeed, many neurologists, who stand to lose money and patients from the growing popularity of the device, say that the general practitioners who use it are not always capable of discovering the true cause of a patient’s symptoms. Some insurers and other doctors also have qualms about use of the automated test to diagnose possible nerve damage. One neurologist cites an extreme case, in which a general practitioner diagnosed arm numbness as carpal tunnel syndrome but missed the main cause: a brain tumor. The system, made by a company called Neurometrix, “is being marketed to and utilized by physicians who are not qualified to do these tests,” said Dr. John D. England, a neurologist at the Billings Clinic in Montana who is also an officer for a national professional society of specialists and was the doctor who discovered the brain tumor. The popularity of Neurometrix’s nerve-testing system, called the NC-stat, speaks to the zealous sales practices that some makers of medical devices employ to build the largest possible market for their products. Copyright 2006 The New York Times Company

Keyword: Miscellaneous
Link ID: 9508 - Posted: 06.24.2010

By Greg Miller ATLANTA, GEORGIA--You and your date just had a lovely dinner, but the popcorn at the movie theater snack counter still looks oh-so tempting. If you break down and buy that bucket of buttery goodness, it may be because your brain's reward centers have been sensitized by ghrelin, a peptide a new study implicates in anticipating food rewards. Ghrelin is secreted by the gut, and its levels peak just before meal times. Injections of the peptide prompt feeding in lab animals, but exactly how isn't known. Previous studies found that ghrelin targets receptors in the hypothalamus, a brain region important for regulating food intake and maintaining a healthy physiological status quo. But ghrelin receptors have also been found in other brain regions, including the ventral tegmental area (VTA), part of the feel-good circuitry that's activated by food, sex, and some illicit drugs--or even just by the expectation of such rewards. To investigate ghrelin's effects on the brain, a team of neuroscientists led by Tamas Horvath of Yale University School of Medicine in New Haven, Connecticut, and Alfonso Abizaid, now at Carleton University in Ottawa, Canada, exposed slices of rat and mouse brain tissue to the peptide. The treatment made dopamine-releasing neurons in the VTA more excitable, and it reorganized their synapses with other neurons to make this excitability last. These findings suggest that ghrelin stimulates the brain's reward pathways and may make them more sensitive to future rewards, Abizaid says. © 2006 American Association for the Advancement of Science

Keyword: Obesity
Link ID: 9507 - Posted: 06.24.2010

Fruit flies get 'drunk,' just like humans, when exposed to large amounts of alcohol and may in future help to explain why some people are genetically predisposed to alcohol abuse. Humans and fruit flies respond to alcohol in a very similar way at the gene level, according to a study published today in the open access journal Genome Biology. The researchers show that, in the fruit fly, the expression of many genes is modified by exposure to alcohol, and that mutations in some of these genes affect the flies' sensitivity to alcohol. Many of the genes analysed are also found in humans and the authors of the study conclude that studies in the fruit fly Drosophila could shed light on the genetic basis of human response to alcohol, including the susceptibility to alcohol abuse. Tatiana Morozova, Robert Anholt and Trudy Mackay, from North Carolina State Univeristy, USA, analysed the activity of all Drosophila genes after exposure to alcohol. Using microarray analysis, a technique that enables to measure gene expression levels, they compared the gene expression levels in flies before they were exposed to ethanol, directly after exposure and two hours after exposure. The results of Morozova et al.'s study show that one single exposure to ethanol is enough to modify the expression of some genes in the fruit fly. Morozova et al. identified a total of 582 genes whose expression is modified by exposure to ethanol. Some of these genes are down-regulated, while others are up-regulated, and a different set of genes is up-regulated as the flies become more tolerant to alcohol. Such genes include genes involved in biosynthesis and the regulation of fatty acid metabolism.

Keyword: Drug Abuse; Genes & Behavior
Link ID: 9506 - Posted: 10.20.2006

By Alex Wilde, ABC Science Online — Charles Dickens was so good at describing neurological disease in his characters that the symptoms were used word-for-word in medical text books of the day, says an Australian neurologist. The 19th century novelist's interpretations of diseases of the nervous system even predated formal medical classification, some by more than a century. In a paper to be published in the Journal of Clinical Neuroscience, Kerrie Schoffer of the Austin Hospital in Melbourne said his observations have helped develop our modern understanding of neurological disorders. "In Dickens's day, they didn't really understand much about these disorders, things like Tourette syndrome; there was no name for that and no understanding of the biological basis of it," she said. Yet Dickens described details in his novel "David Copperfield." His description of the tics, teeth grinding and grimaces of the character Mr Bell, now known as symptoms of Tourette syndrome, was published more than 40 years before Gilles de la Tourette clinically described the disorder in 1885. In "The Pickwick Papers," Schoffer notes that Dickens links Parkinson's disease and dementia in an old man whose "limbs were shaking with disease and the palsy had fastened on his mind." © 2006 Discovery Communications Inc.

Keyword: Miscellaneous
Link ID: 9505 - Posted: 06.24.2010

Toni Baker If you’ve ever wondered how you recognize your mother’s voice without seeing her face or how you discern your cell phone’s ring in a crowded room, researchers may have another piece of the answer. Their work indicates that once you figure out your mother’s voice is a good thing – most days - fairly significant changes occur in the sensory cortex, the part of the brain that responds to sound. “When something starts to predict a good outcome is going to happen, the sensory part of the brain that responds to those events starts to respond more strongly, making it easier for the brain to cause a behavioral response,” says Dr. David T. Blake, neuroscientist at the Medical College of Georgia and lead author on a study in the Oct. 19 issue of Neuron. By monitoring the action potentials of about a dozen key neurons in monkey test subjects, researchers found neuronal responsiveness increases dramatically after just a few training sessions. These neuronal fireworks were short-lived, replaced by a rewiring of the brain that shows the animal has learned, Dr. Blake says. © Medical College of Georgia

Keyword: Learning & Memory
Link ID: 9504 - Posted: 06.24.2010

Emma Young Women told that female under-achievement in mathematics is due to genetic factors perform much worse on maths tests than those told that social factors are responsible. These new findings could have serious implications not only for the way the subject is taught in schools, but for public discussions about genetic influences on behaviour. It may also inform debates about why women are under-represented in university mathematics and science departments. The question of whether there might be gender differences in mathematical ability remains contentious. Earlier this year, Lawrence Summers, then president of Harvard University, Massachusetts, US, resigned in response to an outcry over his speculation on the topic. He said one reason women are under-represented in science and engineering jobs could be because of a “different availability of aptitude at the high end”. “As our research demonstrates, just hearing about that sort of idea is enough to negatively affect women’s performance, and reproduce the stereotype that is out there,” says Steven Heine at the University of British Columbia, Canada, who led the new study. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior
Link ID: 9503 - Posted: 06.24.2010

COLUMBUS , Ohio – New research shows how simply varying the length of daylight to which mice are exposed to can change how aggressively they react to other mice. The study found that in the short days of winter, the class of hormones called estrogens acts to increase aggression in males of a particular type of mouse called the Oldfield Mouse (Peromyscus polionotus). However, in the long days of summer, estrogen decreases aggression among male Oldfield mice, a species commonly found in the southeastern United States . “We found that estrogen has totally opposite effects on behavior in these mice depending only on how much light they got each day,” said Brian Trainor, co-author of the study and postdoctoral fellow in psychology and neuroscience at Ohio State University. “It is quite a surprising finding.” The study is also important because it is one of the few that has shown how hormones other than testosterone can affect aggression in mammals. “This goes against the common belief that testosterone is the hormone that regulates aggression,” said Randy Nelson, co-author and professor of psychology and neuroscience at Ohio State. “There are now several studies showing that in some species estrogen plays a key role in aggressiveness as well.”

Keyword: Aggression; Biological Rhythms
Link ID: 9502 - Posted: 06.24.2010

By Greg Miller ATLANTA, GEORGIA--Going a night without sleep may cause your hippocampus to go on strike. A new study has caught this crucial memory-encoding brain region slacking off in college students the day after they've pulled an all-nighter. The study is one of the first to investigate how sleep deprivation interferes with memory mechanisms in the human brain. Neuroscientist Matthew Walker of Harvard University and his colleagues paid 10 undergraduate students to forgo a night's sleep. The next day, the students viewed a series of 30 words, and two days later--after having two nights to catch up on their sleep--the students returned to the lab and took a test to see how well they remembered the words they'd seen. The students recalled about 40% fewer words overall than a group of 10 students who had slept normally, Walker reported here yesterday at the annual meeting of the Society for Neuroscience. But the researchers also found that the emotional content of the words made a big difference in what people remembered. Previous studies have found that both positive and negative emotions bolster memory, but in the current study, negatively charged words (such as cancer or jail) seemed to penetrate the sleep-deprived brain more deeply than positive ones (such as happy or sunshine). Indeed, sleep-deprived students were only 19% worse than their well-rested counterparts at remembering negative words, but 59% worse for positive words. Walker suspects the difference may reflect an evolutionary safeguard against forgetting potential threats. © 2006 American Association for the Advancement of Science.

Keyword: Sleep; Learning & Memory
Link ID: 9501 - Posted: 06.24.2010

WEDNESDAY, (HealthDay News) -- A study in mice suggests a connection between sunlight, estrogen and aggression in male mammals. During short winter days, estrogen prompts male Oldfield mice to be more aggressive, but the hormone decreases aggression during long summer days, says a team from Ohio State University. Oldfield mice are commonly found in the southeastern United States. "We found that estrogen has totally opposite effects on behavior in these mice, depending only on how much light they got each day. It was quite a surprising finding," study co-author Brian Trainor, a postdoctoral fellow in psychology and neuroscience, said in a prepared statement. The study is one of only a few that have shown how hormones other than testosterone influence aggression in mammals. "This goes against the common belief that testosterone is the hormone that regulates aggression. There are now several studies showing that, in some species, estrogen plays a key role in aggressiveness as well," study co-author Randy Nelson, a professor of psychology and neuroscience, said in a prepared statement. © Forbes.com Inc.™

Keyword: Aggression; Hormones & Behavior
Link ID: 9500 - Posted: 06.24.2010

ANN ARBOR, Mich. -- For years, the brain chemical dopamine has been thought of as the brain's "pleasure chemical," sending signals between brain cells in a way that rewards a person or animal for one activity or another. More recently, research has shown that certain drugs like cocaine and heroin amplify this effect – an action that may lie at the heart of drug addiction. Now, a new study from the University of Michigan adds a new twist to dopamine's fun-loving reputation: pain. Using sophisticated brain-scanning and a carefully controlled way of inducing muscle pain, the researchers show that the brain's dopamine system is highly active while someone experiences pain – and that this response varies between individuals in a way that relates directly to how the pain makes them feel. It's the first time that dopamine has been linked to pain response in humans. The finding, published in the October 18 issue of the Journal of Neuroscience, may help explain why people are more likely to acquire a drug addiction during times of intense stress in their lives. It may also yield clues to why some, but not other chronic pain patients may be prone to developing addictions to certain pain medications. And, it gives further evidence that vulnerability to drug addiction is a very individual phenomenon – and one that can't be predicted by current knowledge of genetics and physiology.

Keyword: Pain & Touch
Link ID: 9499 - Posted: 06.24.2010

Roxanne Khamsi A compound derived from marijuana might one day help fight the memory loss associated with Alzheimer’s disease, a new study suggests. Researchers have shown that a synthetic drug similar to cannabis can help older rats perform better on a spatial memory task. Over a period of three weeks, Gary Wenk at Ohio State University in Columbus, US, and colleagues injected the brains of young and old rats with an inflammatory molecule that created an immune response in the animals’ brains which mimics that seen in Alzheimer’s patients. During the same period the researchers also injected some of the rats with a synthetic drug similar to cannabis, called WIN-55212-2, which stimulates the brain receptors that normally respond to cannabis compounds. The team then tested the rats by having the animals navigate through a water maze. Because rodents dislike water they will do their best to find the dry platform hidden in the maze. "The maze task is sensitive to memory impairment and also to ageing," Wenk says. "Old rats tend to be pretty bad at navigating the maze. It's kind of like an elderly person trying to find his way around a house that he's not familiar with.” Researchers gave the animals three days to learn the maze and then timed them on the fourth day. © Copyright Reed Business Information Ltd

Keyword: Alzheimers; Drug Abuse
Link ID: 9498 - Posted: 06.24.2010

ATLANTA, - New research into how sex influences brain function shows surprising and important implications for understanding and treating a variety of neurological diseases, that strike one sex more than another, such as autism, Alzheimer's disease, depression, and schizophrenia. It's also helping to explain why women tend to experience pain more intensely than men -- and why they require higher doses of morphine and other analgesics to relieve that pain. Other new research is shedding light on the age-old observation that men and women's brains often work differently -- such as in how they select cues when navigating from one destination to another. "Sex is a major variable influencing the brain's basic physiology and the risk for disease," says Arthur Arnold, PhD, of the University of California, Los Angeles. "Studying sex differences in the brain therefore is a major tool in helping us understand the basic processes underlying such things as cognitive performance, emotional memory, pain perception, and the onset and time course of diseases." For more than half a century, scientists believed that gonadal steroid hormones -- "sex" hormones such as testosterone and estrogen -- were solely responsible for differences between male and female brains. Higher levels of testosterone during fetal development, for example, are known to cause the male brain to develop differently than the female brain, triggering cell death in some regions and fostering cell development in others. Copyright © 2006 Society for Neuroscience

Keyword: Sexual Behavior
Link ID: 9497 - Posted: 06.24.2010

By Gregg Easterbrook Last month, I speculated in Slate that the mounting incidence of childhood autism may be related to increased television viewing among the very young. The autism rise began around 1980, about the same time cable television and VCRs became common, allowing children to watch television aimed at them any time. Since the brain is organizing during the first years of life and since human beings evolved responding to three-dimensional stimuli, I wondered if exposing toddlers to lots of colorful two-dimensional stimulation could be harmful to brain development. This was sheer speculation, since I knew of no researchers pursuing the question. Today, Cornell University researchers are reporting what appears to be a statistically significant relationship between autism rates and television watching by children under the age of 3. The researchers studied autism incidence in California, Oregon, Pennsylvania, and Washington state. They found that as cable television became common in California and Pennsylvania beginning around 1980, childhood autism rose more in the counties that had cable than in the counties that did not. They further found that in all the Western states, the more time toddlers spent in front of the television, the more likely they were to exhibit symptoms of autism disorders. The Cornell study represents a potential bombshell in the autism debate. "We are not saying we have found the cause of autism, we're saying we have found a critical piece of evidence," Cornell researcher Michael Waldman told me. Because autism rates are increasing broadly across the country and across income and ethnic groups, it seems logical that the trigger is something to which children are broadly exposed. 2006 Washington Post.Newsweek Interactive Co. LLC

Keyword: Autism
Link ID: 9496 - Posted: 10.18.2006

To a cognitive neuroscientist, success in life depends largely on how well your brain shapes actions to fit both your goals and the context in which you act. If you need to cross the street, first check the traffic. If you're feeding your new in-laws, serve better wine--and different jokes --than you do for your poker buddies. Such context-driven "cognitive control," thought to reside in the brain's prefrontal cortex, has lately become one of neuroscience's hottest topics, inspiring hundreds of papers regarding its role in everything from academic and sports performance to depression and gambling. Yet it remains unclear just how the prefrontal cortex exerts this control. Researchers have explored models emphasizing (not necessarily to mutual exclusion) attentional control, conversations between the prefrontal cortex and limbic areas, and the prefrontal cortex's sensitivity to context. On Monday at the Society for Neuroscience conference in Atlanta, David Badre, a post-doc at the University of California, Berkeley, described an experiment bolstering another emerging model, that of a "hierarchy" of control. In this view, Badre says, "we respond to increasing cognitive challenges not on a continuum, but in leaps as different areas of the prefrontal cortex activate." That is, we throw more light on a problem not by sliding a dimmer switch, but by flipping a series of toggles that successively activate chunks of the prefrontal cortex from back to front. Recognizing this is an important early step in understanding how cognition works, and it could help lead to better treatment for patients who have suffered strokes or other injury to the prefrontal cortex. © 1996-2006 Scientific American, Inc.

Keyword: Attention
Link ID: 9495 - Posted: 06.24.2010

By Prashant Nair Scientists have found a way to suppress epileptic seizures in rats by inhibiting the animals' ability to break down sugars. If the approach works in humans, it could herald a novel class of antiepileptic drugs. Epilepsy arises when brain neurons fire in an uncontrolled frenzy, causing seizures. Most current treatments are aimed at decreasing neuronal activity, but these approaches have side-effects, such as drowsiness and cognitive difficulties. Neurobiologists Thomas Sutula and Avtar Roopra at the University of Wisconsin, Madison, decided to tackle epileptic seizures from a different angle. Scientists have long known that seizures can sometimes be kept at bay when people with epilepsy steer clear of sugars and other carbohydrates--the so-called ketogenic diet. In addition, removing glucose from slices of the hippocampus--the brain region activated in epilepsy--leads to a dip in neuronal firing in animal studies. Sutula and Roopra focused on an inhibitor of sugar breakdown--or glycolysis--known as 2DG. When rats predisposed to epileptic seizures were given 2DG, the amount of electric current needed to set off a seizure in these animals was significantly higher than that in animals not given the drug. Furthermore, treated rats required twice as many electric discharges than untreated ones to produce seizures. An analysis of the hippocampus of treated rats revealed that 2DG was blocking the action of a protein complex that drives the expression of seizure-related genes. The activity of this complex is dependent on the end products of glycolysis, the team reports in the October issue of Nature Neuroscience. © 2006 American Association for the Advancement of Science.

Keyword: Epilepsy
Link ID: 9494 - Posted: 06.24.2010

Dartmouth researchers have found areas in the brain that indicate bilingualism. The finding sheds new light on decades of debate about how the human brain's language centers may actually be enhanced when faced with two or more languages as opposed to only one. The study was presented at the Society for Neuroscience's annual meeting on October 14-18 in Atlanta, Ga. The researchers used an optical imaging technology called Near Infrared Spectroscopy (or NIRS) as a new "microscope" into the human brain's higher cognitive capacities, and they are among the first to take advantage of this technology in this way. NIRS has been used in the detection of, for example, breast tumors and heart blood flow. The Dartmouth team used NIRS to measure changes in the brain's oxygen levels while people performed specific language and cognitive tasks. Authors of the study are Mark Shalinsky, former post-doctoral fellow at Dartmouth now a research fellow at Massachusetts General Hospital; Ioulia Kovelman, formerly a Dartmouth graduate student currently a post-doctoral fellow at MIT; Melody Berens, currently a post-doctoral fellow at Dartmouth; and Laura-Ann Petitto, the study's senior scientific director, and professor and chair of the Department of Education at Dartmouth. "NIRS provides much the same information as functional magnetic resonance imaging or 'fMRI,' but has several advantages over fMRI," says Shalinsky, the study's electro-neurophysiologist who created the analysis programs to use NIRS technology in this new way. NIRS technology is quiet, small and portable. It's only about the size of a desktop computer. It's child friendly, and it tolerates a participant's body movements, which makes it ideal for studying language where participants move their mouths to speak." Copyright © 2006 Trustees of Dartmouth College

Keyword: Language; Brain imaging
Link ID: 9493 - Posted: 06.24.2010

A version of a gene has been linked to autism in families that have more than one child with the disorder. Inheriting two copies of this version more than doubled a child's risk of developing an autism spectrum disorder, scientists supported by the National Institutes of Health's (NIH) National Institute of Mental Health (NIMH) National Institute on Child Health and Human Development (NICHD) have discovered. In a large sample totaling 1,231 cases, they traced the connection to a tiny variation in the part of the gene that turns it on and off. People with autism spectrum disorders were more likely than others to have inherited this version, which cuts gene expression by half, likely impairing development of parts of the brain implicated in the disorder, report Drs. Daniel Campbell, Pat Levitt, Vanderbilt Kennedy Center at Vanderbilt University, and colleagues, online during the week of the October 16, 2006 in the Proceedings of the National Academy of Sciences. "This common gene variant likely predisposes for autism in combination with other genes and environmental factors," said Levitt. "It exerts the strongest effect detected thus far among autism candidate genes." Autism is one of the most heritable mental disorders. If one identical twin has it, so will the other in nearly 9 out of 10 cases. If one sibling has the disorder, the other siblings run a 35-fold greater-than-normal risk of having it. Still, scientists have so far had only mixed success in identifying the genes involved.

Keyword: Autism; Genes & Behavior
Link ID: 9492 - Posted: 10.18.2006

Heidi Ledford It is essentially a 'nature versus nurture' argument about how different languages divide colours into categories. For instance, in English, there is a word for red and a word for purple, but is that the case in every language? Some say that the underlying biological basis for how we perceive and categorize colour rules all. These are the 'universalists'. In the other corner, a handful of anthropologists believe that cultural needs shape how we define colours. These are the 'relativists'. Throughout the 1940s to 1960s, the textbook view was that every language chops up the colour spectrum in a different way, says Paul Kay, a linguistics professor emeritus at the University of California, Berkeley. When Kay and his colleagues published a 20-language survey of residents of the San Francisco Bay area in 1969, that predominant view changed. "Since then, there has been a continuing parade of papers that show that the ways people cut up colour space in different languages is not random," says Kay. But as is the case in nearly any debate, many researchers fall somewhere in between, and the argument rages on. Isn't there a way to work this out? ©2006 Nature Publishing Group

Keyword: Vision
Link ID: 9491 - Posted: 06.24.2010

Roxanne Khamsi, Atlanta Initial results from the first human clinical trial of gene therapy treatment for Parkinson’s disease suggest the approach can significantly reduce symptoms of the disease. After a year, the 12 patients in the trial showed an average 25% improvement in motor control. The researchers say the new treatment shows no signs of reducing immunity – gene therapy for other illnesses has caused fatal immune-system complications. There is currently no cure for Parkinson’s disease, a fatal degenerative brain condition that causes tremors, speech difficulties and progressive loss of mobility, among many other symptoms. Sufferers can take medications such as levodopa, which helps by elevating levels of the chemical messenger dopamine in the brain. But people respond less to the drug over time and can experience side effects such as jerky movements. Researchers hoping to develop a cure for Parkinson’s have now turned to gene therapy. They developed the treatment by engineering a harmless virus to carry genes that encode a protein called glutamic acid decarboxylase, or GAD. The protein helps make a key nerve signalling chemical called GABA (gamma aminobutyric acid), which inhibits a brain region known as the subthalamic nucleus. This is important because the subthalamic nucleus is typically overactive in Parkinson’s disease due to a loss of dopamine-producing cells elsewhere in the brain. © Copyright Reed Business Information Ltd.

Keyword: Parkinsons
Link ID: 9490 - Posted: 06.24.2010

Stem cells show potential for treating the debilitating nerve condition motor neurone disease, research suggests. A US team found injecting rats with stem cells delayed the onset of MND. Writing in the Transplantation, the researchers from Johns Hopkins Medical Institutions warned clinical use of stem cells was still a long way off. But they said their findings would help scientists to better understand how stem cells behaved when they were transplanted into the body. Motor neurone disease (MND) affects about 5,000 people in the UK. It is a progressive disorder caused by the break-down of the nerve cells, called motor neurones, which control the muscle activity. It is characterised by muscle-wasting, loss of mobility, and difficulties with speech, swallowing and breathing. To investigate whether stem cells - cells that can transform into any type of cell in the body - could help MND sufferers, scientists injected rats, bred to carry the most common form of MND, amyotrophic lateral sclerosis (AMS), with live human stem cells into their lower spines. They found that 70% of the transplanted cells developed into new nerve cells, and many of them had grown new endings connecting with other cells in the rats' spinal cords. The onset of the disease, marked by weight loss, was also delayed. It began on average at 59 days, in the rats injected with live stem cells, compared with 52 days for control rats that had been injected with dead, and therefore inactive, stem cells. They also discovered the rats with live stem cells grew weaker more slowly and lived longer than those that had received dead stem cell transplants. (C)BBC

Keyword: ALS-Lou Gehrig's Disease ; Stem Cells
Link ID: 9489 - Posted: 10.17.2006