A new NIH-funded study shows that a specific gene variant in humans affects both sensitivity to short-term (acute) pain in healthy volunteers and the risk of developing chronic pain after one kind of back surgery. Blocking increased activity of this gene after nerve injury or inflammation in animals prevented development of chronic pain. The gene in this study, GCH1, codes for an enzyme called GTP cyclohydrolase. The study suggests that inhibiting GTP cyclohydrolase activity might help to prevent or treat chronic pain, which affects as many as 50 million people in the United States. Doctors also may be able to screen people for the gene variant to predict their risk of chronic post-surgical pain before they undergo surgery. The results appear in the October 22, 2006, advance online publication of Nature Medicine.* "This is a completely new pathway that contributes to the development of pain," says Clifford J. Woolf, M.D., of Massachusetts General Hospital and Harvard Medical School in Boston, who led the research. "The study shows that we inherit the extent to which we feel pain, both under normal conditions and after damage to the nervous system." Dr. Woolf carried out the study in collaboration with Mitchell B. Max, M.D., of the National Institute of Dental and Craniofacial Research (NIDCR) in Bethesda, Maryland, and colleagues at the National Institute on Alcoholism Abuse and Alcoholism (NIAAA) and elsewhere.

Keyword: Pain & Touch; Genes & Behavior
Link ID: 9516 - Posted: 10.23.2006

Kerri Smith The symptoms of Parkinson's disease have been relieved in rats using a stem-cell treatment. But a potentially cancerous side effect might put the brakes on such therapies for humans. Parkinson's disease kills off neurons that produce the neurotransmitter dopamine, leading to problems with movement and balance. Most treatments currently involve replenishing the dopamine through drugs. But researchers are keen to develop longer-term solutions, using embryonic stem cells to make replacement dopamine neurons. But it has so far proved difficult to produce enough of the right kind of cell; there are several types of dopamine neuron, and only some of them will do the job. "Not all dopamine neurons are created equal," says Steve Goldman of Cornell University Medical College, New York, who leads the study. Goldman and his colleagues now report in Nature Medicine1 that they have found a way to make the right type — neurons of a part of the brain called the substantia nigra, which send signals to cells involved in generating movement. Goldman and his team took human fetal midbrain tissues, in which dopamine cells are made, and extracted glial cells, whose normal role is to support and maintain the growth of neurons. They then cultured stem cells in this glia-rich environment. ©2006 Nature Publishing Group

Keyword: Parkinsons; Stem Cells
Link ID: 9515 - Posted: 06.24.2010

Curators say a Norwegian exhibition on homosexuality among animals has been well received, despite initial indications of strong opposition. The Oslo Natural History Museum opened the show last week and says it has been well attended, not least by families. Organisers reported early criticism of the project, and being told by one opponent they would "burn in hell". But there has been strong interest in an aspect of animal behaviour the museum says is quite common. It says homosexuality has been observed among 1,500 species, and that in 500 of those it is well documented. The exhibition - entitled Against Nature? - includes photographs of one male giraffe mounting another, of apes stimulating others of the same sex, and two aroused male right whales rubbing against each other. We hope to reject the all too well known argument that homosexual behaviour is a crime against nature "Homosexuality is a common and widespread phenomenon in the animal world," says an exhibition statement. Not only short-lived sexual relationships, but even long-lasting partnerships; partnerships that may last a lifetime." The museum says it is the first exhibition in the world to touch on a subject that has been taboo in the past. It says sex between animals - as between humans - is often a matter of enjoyment, rather than procreation, and that this applies to animals of the same sex as well as opposite sexes. While homosexuality would appear to contradict evolutionary imperatives, scientists involved in the exhibition say it appears to do no harm and may actually help in some circumstances. (C)BBC

Keyword: Sexual Behavior
Link ID: 9514 - Posted: 10.21.2006

Phoenix, AZ, -- Researchers at the Translational Genomics Research Institute (TGen) today announced the discovery of a gene that plays a significant role in memory performance in humans. The findings, reported by TGen and research colleagues at the University of Zurich in Switzerland, Banner Alzheimer's Institute, and Mayo Clinic Scottsdale, appear in the October 20 issue of Science. The study details how researchers associated memory performance with a gene called Kibra in over 1,000 individuals --both young and old-- from Switzerland and Arizona. This study is the first to describe scanning the human genetic blueprint at over 500,000 positions to identify cognitive differences between humans. "Using the latest whole-genome association technologies, we have shed light on the fundamental biological process of human memory performance," said Dr. Dietrich Stephan, Director of TGen's Neurogenomics Division and a senior author of the paper. "The capacity to remember is a defining feature of humans and we can now use this new understanding to develop drugs that will improve memory function." Researchers at the University of Zurich, collaborating with colleagues at Arizona's Banner Alzheimer's Institute, Mayo Clinic Scottsdale, and the Arizona Alzheimer's Consortium, collected DNA samples from cognitively healthy people and measured memory performance. TGen researchers screened the collected DNA samples using the whole-genome microarray technology. Researchers then combined the scan data with the memory performance test results and found a connection between Kibra and memory.

Keyword: Learning & Memory; Alzheimers
Link ID: 9513 - Posted: 10.21.2006

Brain-derived neurotrophic factor (BDNF) has been a subject of keen interest in neuroscientific circles for several years, turning up in studies of conditions ranging from central hypoventilation syndrome to obsessive-compulsive disorder, depression, bipolar disorder and schizophrenia -- a range of disorders uncannily parallel to those produced by mutations in the "Rett gene," MeCP2. In 2003, two groups found that MeCP2 regulates BDNF transcription, but sorting out the complex relationship between the two proteins has been quite challenging. New studies from the labs of Michael Greenberg at Children's Hospital Boston and David Katz at Case Western School of Medicine have begun to shed light on the interplay of MeCP2 and BDNF. Because Rett syndrome (RTT) develops during early childhood, when sensory experiences normally stimulate the development of synaptic circuits, some researchers hypothesized that the fundamental defect in RTT is a failure of synaptic plasticity or maturation. Early support for this hypothesis came from studies showing that MeCP2 expression normally increases as neurons mature. Conversely, RTT patients and mice lacking MeCP2 suffer defects in synaptic plasticity, learning and memory, all of which are dependent on experience – so there is some link between experience and the change in neuronal function it would normally produce that is missing when MeCP2 is not functioning properly. Zhou et al. (Greenberg lab) have found at least part of that missing link. In a paper just published in Neuron, they show that increases in neuronal activity result in phosphorylation of MeCP2 at a particular residue (S421) which, in turn, increases transcription of certain genes, including Bdnf, that are required for experience-dependent brain maturation.

Keyword: Trophic Factors; Learning & Memory
Link ID: 9512 - Posted: 06.24.2010

Bruce Bower Scientists have taken a promising step forward in untangling the genetic roots of autism. Inheritance of a common variant of a gene that influences immunity, gastrointestinal repair, and brain growth substantially raises the chances of developing autism, at least in families with more than one child diagnosed with the severe brain disorder, a study finds. Children with autism show severe social difficulties, language problems, and repetitive behaviors. The gene, called MET, regulates production of a protein that influences cell proliferation in various parts of the body. "This is a moderate-to-high-risk autism-vulnerability gene," reports developmental neurobiologist Pat Levitt of Vanderbilt University in Nashville. Certain variants of the gene, which contain minor alterations in their genetic code, cause several cancers. Levitt's group had explored how MET contributes to brain development. After learning that the gene lies on a stretch of chromosome 7 that other investigators had linked to autism, the group began its new study. Consulting a large database, the researchers obtained genetic information from members of 204 families in which one or more children had autism. These children ranged from below average to average in intelligence. ©2006 Science Service.

Keyword: Autism
Link ID: 9511 - Posted: 06.24.2010

A silicon chip that faithfully mimics the neural circuitry of a real retina could lead to better bionic eyes for those with vision loss, researchers claim. About 700,000 people in the developed world are diagnosed with age-related macular degeneration each year, and 1.5 million people worldwide suffer from a disease called retinitis pigmentosa. In both of these diseases, retinal cells, which convert light into nerve impulses at the back of the eye, gradually die. Most artificial retinas connect an external camera to an implant behind the eye via a computer (see 'Bionic' eye may help reverse blindness). The new silicon chip created by Kareem Zaghloul at the University of Pennsylvania, US, and colleague Kwabena Boahen at Stanford University, also in the US, could remove the need for a camera and external computer altogether. The circuit was built with the mammalian retina as its blueprint. The chip contains light sensors and circuitry that functions in much the same way as nerves in a real retina – they automatically filter the mass of visual data collected by the eye to leave only what the brain uses to build a picture of the world. "It has potential as a neuroprosthetic that can be fully implanted," Zaghloul told New Scientist. The chip could be embedded directly into the eye and connected to the nerves that carry signals to the brain's visual cortex. © Copyright Reed Business Information Ltd.

Keyword: Vision; Robotics
Link ID: 9510 - Posted: 06.24.2010

From The Economist print edition KEEPING mentally agile protects against dementia but until now no one has known exactly why. One possible reason was revealed at this week's annual Society for Neuroscience conference in Atlanta—at least, for rats. Thousands of new brain cells or neurons grow each day in the brains of rats and, presumably, in the brains of people, too. But only those animals that actively engage in learning get to keep the new cells. In their mentally lazy companions new cells die after a couple of weeks. Until relatively recently, scientists thought that no new neurons grew in the brains of adults and that every blow on the head or glass of wine after adolescence cut the number of brain cells. Over the past decade, though, neuroscientists have realised that young neurons do continue to appear in the brains of mature mammals—but what they might do is only now being pieced together. Many of these new brain cells are found in the hippocampus, a structure used to remember events, people and places. This suggested to Tracey Shors, of Rutgers University in New Jersey, that the cells might be involved in forming such memories. To learn the fate of these new neurons, Dr Shors and her team used a chemical tag that attaches itself to cells that are dividing. On a given day, the researchers injected this chemical into the brains of rats. As a result, only the new brain cells that were born that day were labelled and thus the team could follow a cohort of new neurons over time. Copyright © The Economist Newspaper Limited 2006

Keyword: Learning & Memory; Neurogenesis
Link ID: 9509 - Posted: 06.24.2010

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