DALLAS – Researchers at UT Southwestern Medical Center have discovered a mechanism that causes a protein to clump together in brain cells of people with Parkinson's disease, pointing toward a possible treatment for the condition. The protein clumping is part of a "vicious cycle," the researchers said. As the proteins cluster, they inhibit an enzyme that normally breaks them down, leading to the formation of even more masses. "It's a disease involving accumulation of a protein in an aberrant form," said Dr. Philip Thomas, professor of physiology at UT Southwestern and senior author of the study. The research, available online, was published in the June 17 issue of The Journal of Biological Chemistry. The findings have parallels to other diseases in which protein clusters form in and around nerves, such as Huntington's and Alzheimer's disease. The culprit in Parkinson's is the protein alpha-synuclein, which normally appears in a long, folded form in cells. It's known to be linked to the disease because mutations in it cause rare, inherited cases of early-onset Parkinson's. Normally, if a cell becomes stressed, alpha-synuclein unfolds, and an enzyme degrades it completely into harmless bits to prevent the clumping. In Parkinson's patients, however, some of the degrading enzyme malfunctions and creates truncated fragments of alpha-synuclein rather than the harmless bits.

Keyword: Parkinsons
Link ID: 7533 - Posted: 06.24.2010

The human brain is a complicated organ and the last to be deciphered by medicine. Although we are continually gaining new understanding about the intricacies of how the brain works ? especially what happens in the brain when things stop working and how to treat those issues ? but science still has a long way to go. The tremors that Steve Tarence, from Milford, Connecticut, suffered in his right arm because of Parkinson's Disease became so severe there was little he could still do by himself. "It's what they call flapping, where? the hand just takes off on you," he explains. "I couldn't go out, I couldn't turn around? life was changed completely because of it. It was really bad." He says deep brain stimulation (DBS) gave him back much of the life Parkinson's had taken away. "I am not afraid to go out, I'm not afraid to eat soup, I'm not afraid to do so many things? it's really, really wonderful," says Tarence. It was so successful in calming the tremors in his right arm that he plans to have it done for the tremors that have now begun on his left side. In DBS, surgeons implant electrodes ? with millimeter precision ? into the brain to stimulate the areas causing the tremors. But how pulses of electrical stimulation relieve the uncontrolled movement, why it doesn't help some patients, and what the long-term consequences of it might be, are not fully understood. © ScienCentral, 2000-2005.

Keyword: Parkinsons
Link ID: 7532 - Posted: 06.24.2010

The Foxp2 gene plays an essential role in the development of social communication, according to a study led by researchers at Mount Sinai School of Medicine. The association between Foxp2 and language was first identified in a family in which half the members had severe speech and grammar impairments. Studies showed that all the affected family members had a mutation in the Foxp2 gene. The gene is found on a region of chromosome 7 that is linked to other disorders that affect speech, including autism and specific language impairment (a broad diagnosis used to describe communication difficulties in the absence of mental retardation, hearing loss, or emotional disorders). In the study, the team engineered mice with either one or both disrupted copies of Foxp2 in order to examine the role of this gene in social communication. These are the first mice to be engineered with this particular genetic defect. Disruption of Foxp2 affected the ability of infant rodents to emit ultrasonic vocalizations (USVs) when separated from their mother and littermates, according to the study leader, Joseph D. Buxbaum, PhD, Associate Professor of Psychiatry, of Neuroscience, and of Geriatrics and Adult Development at Mount Sinai. Mice with two disrupted copies of Foxp2 had a complete absence of USVs, while mice with one disrupted gene emitted USVs at a significantly reduced rate. Mice with two disrupted copies of the gene also displayed severe motor skill impairment and premature death, while single-copy mice had more modest, but still noticeable, developmental delays.

Keyword: Language; Autism
Link ID: 7531 - Posted: 06.22.2005

The world's first cannabis-based drug has gone on sale in Canada, and the UK firm which developed it says it remains committed winning a UK sales licence. Sativex is a mouth spray for multiple sclerosis (MS) sufferers, who can use it to alleviate pain. GW Pharmaceuticals said it remains "committed to securing approval of Sativex across Europe and elsewhere". GW Pharmaceuticals has been asked to provide more data to support its application for a UK licence. Sativex contains the same active ingredients as cannabis - tetrahydrocannabinol and cannabidiol. GW Pharmaceuticals said the Canadian market launch of Sativex was a "transforming event" for the company. It marked "not only our first successful product launch but the first launch of a cannabis derived prescription medicine anywhere in the world", the Salisbury-based firm said. GW Pharmaceuticals also announced its pre-tax losses narrowed to £5.9m in the six months to 31 March, compared to £7.9m year-earlier. It is now looking forward to getting its first sales revenues. (C)BBC

Keyword: Drug Abuse
Link ID: 7530 - Posted: 06.21.2005

By RICHARD A. FRIEDMAN, M.D. Hippocrates' injunction to physicians, "First, do no harm," is not always easy to follow. Sometimes doing the right thing medically means risking lesser harm to avoid greater harm. When I first met Larry, he was 40 pounds overweight, hypertensive and in a bind. His internist had just told him that if he could not kick his two-pack-a-day smoking habit, he would surely kill himself. His doctor was right, Larry said to me, but he also felt he could not live without cigarettes, either. Larry had already tried to quit and failed four times in the last five years. Now, he was desperate to succeed. The last time he supposedly quit, he was sneaking a cigarette on the porch in his bathrobe on a freezing winter morning so his wife would not discover that he had relapsed, when the door accidentally locked behind him. Shivering and chastened, he decided when his wife finally let him in that it really was time to quit. But from our first meeting, I knew that his habit would be hard to beat. Every aspect of his waking life, from morning coffee to nighttime television, was entwined with smoking. And when he described the effects of smoking, he lapsed into a dreamy adoration usually reserved for lovers. He waxed eloquent about its relaxant and pleasurable effects, as well as the positive effects it had on his concentration and alertness. To me, he was a walking textbook on the pharmacologic effects of nicotine. Copyright 2005 The New York Times Company

Keyword: Drug Abuse
Link ID: 7529 - Posted: 06.21.2005

By BENEDICT CAREY Political scientists have long held that people's upbringing and experience determine their political views. A child raised on peace protests and Bush-loathing generally tracks left as an adult, unless derailed by some powerful life experience. One reared on tax protests and a hatred of Kennedys usually lists to the right. Inheriting AttitudesBut on the basis of a new study, a team of political scientists is arguing that people's gut-level reaction to issues like the death penalty, taxes and abortion is strongly influenced by genetic inheritance. The new research builds on a series of studies that indicate that people's general approach to social issues - more conservative or more progressive - is influenced by genes. Environmental influences like upbringing, the study suggests, play a more central role in party affiliation as a Democrat or Republican, much as they do in affiliation with a sports team. The report, which appears in the current issue of The American Political Science Review, the profession's premier journal, uses genetics to help answer several open questions in political science. They include why some people defect from the party in which they were raised and why some political campaigns, like the 2004 presidential election, turn into verbal blood sport, though polls find little disparity in most Americans' views on specific issues like gun control and affirmative action. Copyright 2005 The New York Times Company

Keyword: Genes & Behavior
Link ID: 7528 - Posted: 06.21.2005

Talk about melting away the pounds. Researchers have developed a new mouse that sheds its fat when injected with a certain chemical. The mouse's creators hope the animal will offer insights not only into the biology of fat, but also into diseases driven by obesity and even the genesis of certain cancers. The fatless mouse, dubbed FAT-ATTAC, isn't the first of its kind. Scientists had generated other genetically modified mice that are fatless from birth. But those animals often have an array of other defects, such as severe insulin resistance, which makes it difficult to isolate the role played by fat--or its absence. Physiologist Philipp Scherer of the Albert Einstein College of Medicine in New York City, with his colleagues, set out to create animals that developed normally into adulthood and whose fat stores could then be melted away at will. To accomplish this, the team genetically altered the fat cells of mice so that a certain chemical would lock on to a molecule inside fat cells, setting off a chain reaction that compels the cells to commit suicide. FAT-ATTAC mice injected with the chemical lost all their fat within 3 or 4 days, says Scherer. Their appetites also surged, suggesting a link between rapid fat loss and high metabolism (since the mice couldn't store the energy they were consuming), though Scherer isn't sure what's behind that change. The mice also have far lower levels of inflammatory markers in their blood, the group reports in the 19 June online edition of Nature Medicine. Scherer says that suggests that obesity helps mediate inflammation and adds credence to the idea that obesity-related diseases, such as type 2 diabetes, are partly inflammatory in origin. Copyright © 2005 by the American Association for the Advancement of Science

Keyword: Obesity
Link ID: 7527 - Posted: 06.24.2010

By Mark H. Lewis, Ph.D., and Martin Lazoritz, M.D. Autism is a pervasive neurodevelopmental disorder characterized by difficulties in social interaction and language and communication, as well as the expression of restricted, repetitive behavior. Prevalence rates of autism have increased significantly, with some estimates in the range of one in 500 individuals affected. Although autism is highly heritable (as high as 90% concordance rate for monozygotic twins), the phenotype is quite variable. Moreover, a large number of potential genetic (e.g., chromosome 7) and environmental (e.g., toxins, viruses, food constituents) factors may be involved suggesting multiple, varying etiologies. Thus, autism is an enormously heterogeneous disorder with a wide range of symptom expression across individuals as well as across disorders on the autism spectrum (high-functioning autism, Asperger's syndrome, pervasive developmental disorder not otherwise specified). In addition, up to 75% of individuals with autism function within the mental retardation range of intellectual development, whereas individuals with high-functioning autism or Asperger's syndrome can be highly intelligent. There is also significant comorbidity in this population, with affective and attention disorders commonly observed. All of these factors make effective pharmacological treatment a challenging proposition. To add to the challenge, no medication is available that effectively treats the core social and communication deficits that define autism. As we shall illustrate in the following sections, that is not the case for restricted, repetitive behaviors. Nonetheless, current drug therapies have been termed palliative treatments (Gerlai and Gerlai, 2004), and behavioral interventions remain the mainstay of treatment. © 2005 Psychiatric Times. All rights reserved.

Keyword: Autism
Link ID: 7526 - Posted: 06.24.2010

By Richard Balon, M.D. The discipline of psychopharmacology has expanded enormously during the last several decades. Psychiatrists and other physicians have been using medications for almost every diagnosis. The pressure from patients, families, insurance companies and the pharmaceutical industry to provide a quick fix for all maladies has been increasing. There is no doubt that our armamentarium has widened and that we have more medications for mental illnesses available. These medications are fairly efficacious and fairly well tolerated. However, as illustrated in several articles in this Special Report, while the treatment of mental illness with medications has definitely advanced, it is neither quick nor easy. Instead, it has become more complex and complicated. The foremost illustration of the complexity of modern-era prescribing of psychotropic medications is the recent U.S. Food and Drug Administration "black box" warning regarding the use of antidepressants in children and adolescents. Some reports suggest that there is an increased risk of suicidality associated with antidepressants compared to placebo. While this issue remains unclear, the FDA felt compelled to warn patients, their families and their physicians about this possible risk. In this Special Report, David A. Brent, M.D., provides us with insight on this issue, suggesting that patients and families should be educated about the benefits and risks of antidepressants, other therapies for depression and monitoring of various symptoms. © 2005 Psychiatric Times. All rights reserved.

Keyword: Schizophrenia; Depression
Link ID: 7525 - Posted: 06.24.2010

By Katherine A. Halmi, M.D. Anorexia nervosa (AN) and bulimia nervosa (BN) are the two major eating disorders. Anorexia nervosa is characterized by weight loss, an intense fear of gaining weight, a distorted body image and amenorrhea. Bulimia nervosa is a disorder in which binge eating is the predominant behavior. People with BN engage in some sort of compensatory behavior to counteract the potential weight gain from calories ingested during bingeing. They are frequently overconcerned about their physical appearance. Why are these disorders difficult to diagnose? Patients with AN do not wish to be diagnosed because they do not wish to be treated. They deny the core symptomatology of their disorder and will often try to mislead their primary care provider into believing there are other medical issues causing their weight loss. Thus, it is very helpful to obtain further information from family members about the patient's behavior, if possible. Furthermore, there are problems with the DSM-IV diagnostic criteria for AN and BN (see Table 1 for an abbreviated version). The DSM-IV criteria are undergoing scrutiny because many patients suffering from eating disorders do not quite fit. For AN, the criterion of weight loss would seem to be noncontroversial. However, there is no consensus as to how weight loss should be calculated. Some investigators emphasize a total weight loss from an original high weight, and others emphasize weight loss below a normal weight for age and height. © 2005 Psychiatric Times. All rights reserved.

Keyword: Anorexia & Bulimia
Link ID: 7524 - Posted: 06.24.2010

The route to a treatment for Alzheimer's disease may have become more straightforward with the discovery that a key enzyme known to have a major role in this disease is in fact part of a family of enzymes. Only some family members play a role in the progression of this brain-wasting illness, new research at the University of Toronto has found. "It was previously thought that an enzyme called gamma-secretase contributed to the development of protein deposits in the Alzheimer's brain. This study shows that this enzyme is more accurately described as a family of enzymes, each with its own specialization," explains Professor David Westaway of U of T's Centre for Research in Neurodegenerative Diseases and senior author of a paper in the June 21 issue of the Proceedings of the National Academy of Sciences. Gamma-secretase enzymes generate toxic molecules called amyloid-beta peptides. These peptides produce deposits called amyloid plaques, the brain lesions that are a defining feature of Alzheimer's disease. If scientists can stop these enzymes from working, they will be able to stop their resulting toxic molecules from forming in the brain. Complicating the situation is the fact that the gamma-secretase enzyme was also thought to be involved in healthy functioning of other tissues; therefore, therapies would have to inhibit the negative effects while maintaining the normal functioning of other cells. Westaway and his research colleagues used genetically-engineered mice to show that toxic activity of gamma-secretase could be separated from its other benign activities.

Keyword: Alzheimers
Link ID: 7523 - Posted: 06.21.2005

For women, it seems, sex is a big turn-off, reveals a brain scanning study. It shows that many areas of the brain switch off during the female orgasm - including those involved with emotion. “At the moment of orgasm, women do not have any emotional feelings,” says Gert Holstege of the University of Groningen in the Netherlands. His team recruited 13 healthy heterosexual women and their partners. The women were asked to lie with their heads in a PET scanner while the team compared their brain activity in four states: simply resting, faking an orgasm, having their clitoris stimulated by their partner’s fingers, and clitoral stimulation to the point of orgasm. The results of the study are striking. As the women were stimulated, activity rose in one sensory part of the brain, called the primary somatosensory cortex, but fell in the amygdala and hippocampus, areas involved in alertness and anxiety. During orgasm, activity fell in many more areas of the brain, including the prefrontal cortex, compared with the resting state, Holstege told a meeting of the European Society for Human Reproduction and Development in Copenhagen on Monday. In one sense the findings appear to confirm what is already known, that women cannot enjoy sex unless they are relaxed and free from worries and distractions. "Fear and anxiety levels have to go down for orgasm. Everyone knows this but we can see it happening in the brain," he explains. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior; Brain imaging
Link ID: 7522 - Posted: 06.24.2010

By John Fauber, Milwaukee Journal Sentinel Middle-aged sons and daughters of people with Alzheimer's disease may be able to reduce their risk of getting the disorder through lifestyle measures such as exercise, avoiding gum disease, moderate alcohol consumption and drinking fruit and vegetable juice, according to new research. Taken as a whole, the research suggests that even though family history may predispose a person to developing Alzheimer's, various behaviors -- if started early enough in life -- may help preserve cognitive function and delay the onset of the disease. "The best time to intervene is at birth," said Mark Sager, a professor of medicine at the University of Wisconsin at Madison. "What we are hoping is that 55 is not too late." The lifestyle measures, many of which are also good for the heart, were presented in several studies in Washington yesterday at the Alzheimer's Association's first International Conference on the Prevention of Dementia. The findings come amid growing concern about a looming surge in Alzheimer's cases in the years ahead as the U.S. population ages. Nearly 5 million people have the disease, and with the vanguard of the baby boom generation turning 60 this year, the number of cases is expected to increase 70 percent by 2020. © 2005 The Washington Post Company

Keyword: Alzheimers
Link ID: 7521 - Posted: 06.24.2010

RICHMOND, Va. – People with bigger brains are smarter than their smaller-brained counterparts, according to a study conducted by a Virginia Commonwealth University researcher published in the journal “Intelligence.” The study, published on line June 16, could settle a long-standing scientific debate about the relationship between brain size and intelligence. Ever since German anatomist and physiologist Frederick Tiedmann wrote in 1836 that there exists “an indisputable connection between the size of the brain and the mental energy displayed by the individual man,” scientists have been searching for biological evidence to prove his claim. “For all age and sex groups, it is now very clear that brain volume and intelligence are related,” said lead researcher Michael A. McDaniel, Ph.D., an industrial and organizational psychologist who specializes in the study of intelligence and other predictors of job performance. The study is the most comprehensive of its kind, drawing conclusions from 26 previous – mostly recent – international studies involving brain volume and intelligence. It was only five years ago, with the increased use of MRI-based brain assessments, that more data relating to brain volume and intelligence became available.

Keyword: Intelligence
Link ID: 7520 - Posted: 06.24.2010

A new study of dementia in identical twins suggests that exposure to inflammation early in life quadruples one's risk of developing Alzheimer's disease. Margaret Gatz, lead author and professor of psychology in the USC College of Letters, Arts and Sciences, is slated to present her findings at the first Alzheimer's Association International Conference on Prevention of Dementia, to be held June 18-21 in Washington, D.C. If confirmed, the link would add inflammatory burden to the short list of preventable risk factors for Alzheimer's. Previous studies by Gatz and others have shown that Alzheimer's is strongly genetic: If one twin has the disease, his or her identical twin has a 60 percent chance of developing it. Stroke and a short period of formal education both increase the odds of dementia, but not of Alzheimer's specifically, the new study found. Dementia is an umbrella term for many conditions, including Alzheimer's. "People can plan a life span that will alter dementia risk," Gatz said. "And these aren't risk factors that are unique to dementia. Many of these are also risk factors for other disorders. This is good news." Gatz's team, which included researchers from the Karolinska Institute in Stockholm, Sweden, sifted the 20,000 participants in the Swedish Twin Registry for the 109 "discordant" pairs where only one twin had been diagnosed with dementia.

Keyword: Alzheimers
Link ID: 7519 - Posted: 06.20.2005

Humans may have evolved during a few rapid bursts of genetic change, according to a new study of the human genome, which challenges the popular theory that evolution is a gradual process. Researchers studying human chromosome 2 have discovered that the bulk of its DNA changes occurred in a relatively short period of time and, since then, only minor alterations have occurred. This backs a theory called “punctuated equilibrium” which suggests that evolution actually occurred as a series of jumps with long static periods between them. Evolutionary stages are marked by changes to the DNA sequences on chromosomes. One of the ways in which chromosomes are altered is through the duplications of sections of the chromosomes. These DNA fragments may be duplicated and inserted back into the chromosome, resulting in two copies of the section. Evan Eichler, associate professor of genomic sciences at the University of Washington in Seattle, US, and colleagues looked at duplicated DNA sequences on a specific section of chromosome 2, to compare them with ape genomes and Old World monkey genomes. They expected to find that duplications had occurred gradually over the last few million years. Instead, they found that the big duplications had occurred in a short period of time, relatively speaking, after which only smaller rearrangements occurred. Eichler found the bulk of the duplications were present in the genomes of humans, chimpanzees, gorillas and orang-utans, but were absent in Old World monkeys - such as baboons and macaques. © Copyright Reed Business Information Ltd

Keyword: Evolution
Link ID: 7518 - Posted: 06.24.2010

By Sandi Doughton As the culture wars rage over gay rights, a flock of sheep at Oregon State University may help answer a key question behind the controversy: Is homosexuality a matter of choice or biology? The Corvallis herd includes a group of rams that scientists delicately refer to as "male-oriented." These animals consistently ignore females and bestow all their amorous attentions on members of their own sex. Researcher Charles Roselli says a decade of study suggests sexual orientation is largely hard-wired into the sheep's brains before birth. Now, he's trying to figure out how that happens, zeroing in on genes and hormones. In a bold test of his ideas, he hopes to engineer the birth of gay rams by altering conditions in the womb. Sheep aren't people, but the Oregon work adds to a growing body of research that bolsters biological explanations for sexual orientation across species — including humans. Despite those scientific findings, some religious groups say homosexuality is a lifestyle that can be treated, if not prevented. One such group, the conservative Christian organization Focus on the Family, is sponsoring a one-day conference in Bothell Saturday. The social and political implications of the research are impossible to ignore, leading to unease on both sides of the gay-rights debate. If science proves homosexuality is innate, is there any basis to deny gays equal treatment — including the right to marry? But if scientists unravel the roots of sexual orientation, will it some day be possible to "fix" people who don't fit the norms or abort fetuses likely to be born gay? Copyright © 2005 The Seattle Times Company

Keyword: Sexual Behavior
Link ID: 7517 - Posted: 06.24.2010

Men who are no good at wooing the ladies may be able to blame their genes, after researchers have made a discovery in the humble fruit fly. Manipulation of a single gene in male fruit flies made them less adept at courting female mates, a US and an Austrian team have both found. While humans do not possess this gene, we do share many with fruit flies. The research, in the journals Nature and Cell, suggested sexual behaviour has a strong biological basis. Others still argue that it is down to upbringing. Professor Barbara Taylor and colleagues at Oregon State University in the US and Dr Barry Dickson and colleagues at the Austrian Academy of Sciences looked at the 'fruitless' gene, which is present in both male and female fruit flies. Ordinarily, it is only in males that this gene results in the creation of proteins that guide male sexual behaviour patterns, such as approaching females, tapping and singing to them and performing courtship dances. When the researchers manipulated the male fruit flies so that they had a faulty fruitless gene the flies no longer showed typical male sex-related behaviours Conversely, when females had their genes manipulated so that they produced the male proteins, they began to show classic patterns of male sexual behaviour. Professor Taylor said: "In a physical sense, the females looked perfectly normal, but they acted like males and, if they were physically able to, I would not be surprised if they would have attempted to mate other females." "Research of this type is telling us quite a bit about they ways in which things we believe are developmental actually have a biological and genetic underpinning," she said. Co-author of the US study, which appears in Neuron, Dr Jeffrey Hall, said he would not be surprised to learn that human sexual behaviours also had similar mechanisms underpinning them. (C)BBC

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 7516 - Posted: 06.17.2005

St. Paul, Minn. – A new study shows that the prognosis is good for people who have epilepsy surgery, even 30 years after the surgery. The study is published in the June 14 issue of Neurology, the scientific journal of the American Academy of Neurology. “Few studies have looked at the long-term prognosis for epilepsy surgery,” said neurologist and study author William H. Theodore, MD, of the National Institute of Neurological Disorders and Stroke in Bethesda, Md. “We found that 50 percent of the patients were free of seizures 30 years after the surgery.” In epilepsy, surgery is generally considered for those whose seizures do not respond to medication. The study involved people who had a temporal lobectomy, which is the surgical removal of the portion of the brain where seizures most often occur. The study examined 48 people who had a temporal lobectomy at the National Institutes of Health in Bethesda an average of nearly 30 years previously. The patients or their families were questioned about whether they had experienced seizures at one year after the surgery, and at five, 10, and 30 years after the surgery. At 30 years, 14 people were free of seizures and taking no epilepsy drugs; 10 people were free of seizures while taking epilepsy medication. Those who had seizures within the first year after surgery were least likely to be free of seizures in the future.

Keyword: Epilepsy
Link ID: 7515 - Posted: 06.24.2010

Immediate, large rewards cause animals to make fast, correct decisions. But the real world is fettered with choices that don't lead to timely, big bonuses--such as having to slog through cleaning our plate to get to dessert. A new study fingers a region of the brain called the thalamus, which may give us the motivation to eat the green beans of life so we can have our cheesecake. Scientists trying to understand the circuits in the brain that reward animals for making choices have long focused on two regions: the cortex, where the higher functions such as paying attention reside, and the basal ganglia, where the neurotransmitter dopamine acts to make the brain feel rewarded. A third region, the thalamus, connects to both areas, but neuroscientists have long thought that it functions mainly in relaying sensory information. Neuroscientist Minoru Kimura at the Kyoto Prefectural University of Medicine in Japan wondered if the thalamus might play a role in a decision-making that led to smaller, less immediate rewards. To find out, Kimura and colleagues hooked up two rhesus monkeys to electrodes that recorded signals coming from a specific part of the thalamus. Then the team had the monkeys hold down a lever until a button lit up as red or green. When the light was red, the animals were trained to let go of the lever and press the button. When they did this, they got a large amount of water--a big reward. But when the button shone green and the monkeys were trained to hold the lever down, they received significantly less water--a small reward. In addition, a less-compensated task was usually followed by a task that rewarded the big drink of water. The team found that the neurons in the thalamus stayed silent when the red light came on (i.e., when the monkeys anticipated a large reward) but flared when the green light came on (i.e., when the monkeys were resigned to a small reward). To see if the neurons controlled the animals' behavior, the researchers stimulated the nerve cells via implanted electrodes just as the button lit up. Even if the animal was supposed to perform the large reward task, stimulating the neurons caused them to perform the small reward task instead, the team reports 17 June in Science. Copyright © 2005 by the American Association for the Advancement of Science.

Keyword: Drug Abuse
Link ID: 7514 - Posted: 06.24.2010