New research performed in rats suggests that orexin, a brain chemical involved in feeding behavior, arousal, and sleep, also plays a role in reward function and drug-seeking behavior. Dr. Glenda Harris and her colleagues at the University of Pennsylvania showed that the activation of orexin-secreting brain cells in the hypothalamus, a brain region that controls many vital functions such as eating, body temperature, fat metabolism, etc. is strongly correlated with food- and drug-seeking behaviors. Past anatomical studies have shown that these cells in the lateral hypothalamus also project to adjacent reward-associated areas of the brain. This study suggests that orexin may be a factor in modulating reward-seeking characteristic of substance abuse. The findings help to better identify neural pathways involved in drug abuse, craving and relapse, which may ultimately help scientists find more effective therapies. This study is published online August 14, 2005 in the journal Nature.

Keyword: Drug Abuse; Obesity
Link ID: 7800 - Posted: 08.26.2005

Roxanne Khamsi The discovery of a group of pitch-sensitive cells in the brain has sent reverberations through the field of music perception. Researchers think that studying these neurons will reveal how our minds grasp songs and speech. Most people can hear that two instruments are playing the same note, even if they sound as different as a trumpet and a piano. Our perception of fundamental sound frequency or 'pitch' remains constant despite differences in an instrument's acoustical traits. This holds true even when the fundamental frequency is actually missing from a complex sound. If several strings are plucked such that they vibrate at their higher harmonics, at 800, 1,000 and 1,200 hertz for example, we will perceive the sound as belonging to the same pitch as the primary harmonic of those strings: 200 hertz. For centuries scholars have puzzled over how the brain does this. In recent years, researchers have looked at the role played by the primary auditory cortex, the brain region known to digest sounds. Human brain scans have indicated that a peripheral bit of this brain region is active when we try to identify pitch. But no one could find cells that responded to specific frequencies, leaving it a mystery how we interpret them. ©2005 Nature Publishing Group

Keyword: Hearing
Link ID: 7799 - Posted: 06.24.2010

Carina Dennis Women have long been known to experience more pain than men. And the idea that sex hormones are to blame has just been bolstered by a study into pain thresholds in a unique study group: people undergoing sex-change operations. Men taking female hormones often start to experience chronic pain, says Anna Maria Aloisi, a physiologist from the University of Siena in Italy. In a study of 54 men taking oestrogen and anti-androgens as treatment to become women, 30% reported developing pains, primarily chronic headaches, during their treatment. "We found that oestrogen in high amounts induced pain in these men," says Aloisi, who presented her work at the 11th World Congress on Pain in Sydney, Australia, this week. In another study of women taking testosterone to become men, says Aloisi, more than half found their aches and pains improved. "They seemed to feel better generally," she adds. The results back up previous research on sex differences in pain. Although no one knows exactly how sex hormones affect pain tolerance, researchers think testosterone dulls pain by muting the excitatory pain pathways in the central nervous system, while oestrogen heightens pain by blocking the inhibitory mechanisms that damp pain sensing. ©2005 Nature Publishing Group

Keyword: Pain & Touch; Sexual Behavior
Link ID: 7798 - Posted: 06.24.2010

IN INTERNET chat rooms, veterans ask if anyone else is having a similar experience. "I had an incident where a small Iraqi boy had his leg blown off. His screams haunt my thoughts. Is what I am experiencing normal?" asks IraqCowboy. "They gave me sleeping pills, but it doesn't stop the nightmares," says Chucky. "The doctor says my husband has PTSD," posts Sam. "Does that count as a combat-related illness?" What is now known as PTSD, or post-traumatic stress disorder, was called shell shock back in the days of the first world war. Sufferers have harrowing flashbacks, and alternate between emotional numbness and outbursts of rage, guilt and depression. Previously well-adjusted soldiers suffer impaired memory and attention, insomnia and anxiety, and are more likely to take drugs and alcohol later in life. That much is well recognised. What is less well known is that PTSD can trigger physical as well as psychological ill health. And as the US agonises over how long its soldiers should stay in Iraq, New Scientist has pieced together evidence showing that veterans will be paying the price of combat for decades to come. Recent and soon-to-be published research reveals that soldiers who fought in theatres as diverse as Vietnam and Lebanon are not only more likely to die from an accident on their return, but are also twice as likely to develop cardiovascular disease, diabetes and even cancer later in life. And these problems are particularly likely to afflict troops who experience the close-quarters fighting taking place in Iraq. © Copyright Reed Business Information Ltd.

Keyword: Stress
Link ID: 7797 - Posted: 06.24.2010

Researchers have discovered how the abnormal repetition of a genetic sequence can have disastrous consequences that lead to the death of neurons that govern balance and motor coordination. The studies bolster the emerging theory that neurodegenerative disorders can be caused by having extra copies of a normal protein, not just a mutated one. People who are afflicted with the rare neurodegenerative disorder spinocerebellar ataxia type 1 (SCA1) suffer damage to cerebellar Purkinje cells caused by a toxic buildup of the protein Ataxin-1. Researchers knew that SCA1, Huntington's disease and other related disorders arise because of a “genetic stutter,” in which a mutation causes a particular gene sequence to repeat itself. These abnormal genetic repeats cause the resulting proteins to contain unusually long repetitive stretches of the amino acid glutamine. The new findings, which are published in the August 26, 2005, issue of the journal Cell, provide a molecular explanation for Ataxin-1's assault on cerebellar Purkinje cells. The findings should help to understand a range of diseases, including Huntington's disease, which are caused by an abnormal number of repetitive gene sequences. The discovery may also offer a new conceptual approach to understanding the pathology of Parkinson's disease and Alzheimer's disease, according to Huda Y. Zoghbi, a Howard Hughes Medical Institute investigator at the Baylor College of Medicine. © 2005 Howard Hughes Medical Institute.

Keyword: Movement Disorders
Link ID: 7796 - Posted: 06.24.2010

Using muscle tissue from tarantulas, an HHMI international research scholar and his colleagues have figured out the detailed structure and arrangement of the miniature molecular motors that control movement. Their work, which takes advantage of a new technique for visualizing tissues in their natural state, provides new insights into the molecular basis of muscle relaxation, and perhaps its activation too. “We have solved the structure of the array of miniature motors that form our muscles and found out how they are switched off,” said Raúl Padrón, a HHMI international research scholar in the Department of Structural Biology at the Venezuelan Institute for Scientific Research (Instituto Venezolano de Investigaciones Científicas or IVIC) in Caracas, Venezuela. The findings are reported in the August 25, 2005, issue of the journal Nature. Padrón and his colleagues focused their studies on striated muscle—the type of muscle that controls skeletal movement and contractions of the heart. Striated muscles are made of long cylindrical cells called muscle fibers. Within the fibers, millions of units known as sarcomeres give rise to movement of skeletal muscles. Sarcomeres are composed mainly of thick filaments of myosin, the most common protein in muscle cells, responsible for their elastic and contractile properties. The thick filaments are arranged in parallel with thin filaments of another muscle protein, actin. When the actin and myosin filaments slide along one another, the muscle contracts or relaxes. © 2005 Howard Hughes Medical Institute.

Keyword: Biomechanics; Muscles
Link ID: 7795 - Posted: 06.24.2010

By Shankar Vedantam The brain areas involved in daydreaming, musing and other stream-of-consciousness thoughts appear to be the same regions targeted by Alzheimer's disease, researchers are reporting today in an unusual study that offers new insights into the roots of the deadly illness. The strong correlation between the two suggests there might be a link between the sort of thinking that people regularly do when not involved in purposeful mental activity and the degenerative disease that is characterized by forgetfulness and dementia, said scientists who conducted the federally funded study. Randy Buckner, a neuroscientist at Washington University in St. Louis, said the implications of the finding are far from clear. It is too early to suggest that daydreaming is dangerous, he said, or that avoiding such musings could affect the risk of Alzheimer's disease. Rather, he and others said, the study adds to the evidence that everyday mental and physical activities play an important role in the course of neurological disease. "It suggests an avenue between brain activity patterns and Alzheimer's disease that we just hadn't been thinking about," said Buckner, who led the study. "It is going to take some time to understand the relative potential of this link." © Copyright 1996-2005 The Washington Post Company

Keyword: Alzheimers
Link ID: 7794 - Posted: 06.24.2010

CHICAGO (Reuters) - A human fetus is unlikely to feel pain before the third trimester, when consciousness begins to form, researchers said on Tuesday in a report that could fuel debate over proposed U.S. abortion legislation. Even if a fetus feels pain, doctors may not be able to anesthetize it without endangering the mother's health, including during an abortion, the researchers wrote in the Journal of the American Medical Association. Legislation under consideration by the U.S. Congress and some U.S. states would require doctors to inform women seeking abortions after the 22nd week of gestation that their fetus feels pain and offer to anesthetize the fetus. Supporters of the legislation say that when a fetus displays a withdrawal reflex or hormonal stress response, that is evidence of fetal pain. But the researchers at the University of California, San Francisco, questioned that view, saying the responses may be automatic and not signs of discomfort. Drawing on findings from thousands of medical-journal articles on the subject of fetal pain and related topics, the report's author, Susan Lee, wrote that "pain is a subjective sensory and emotional experience that requires the presence of consciousness." Copyright © 2005 Reuters Limited.

Keyword: Pain & Touch
Link ID: 7793 - Posted: 06.24.2010

The finding comes from a study of 200 parents (100 men and 100 women). The parents, who were about 38 years old and lived in the U.K., were asked how tall they are. "On average, males overestimated height while females reported their height relatively accurately," write the researchers in the Archives of Disease in Childhood. How far off were the men's estimates? That varied, but 27 percent overestimated their height by an inch or more, compared with 13 percent of the women, the study shows. Parents' height is often used to help predict a child's future height. Based on this study, it might be worth double-checking parents' self-reported height. "We recommend that efforts should be made to measure both parents at the earliest opportunity and record their heights in the child health record," write the researchers. They included W.F. Paterson of the child health department at the Royal Hospital for Sick Children in Glasgow, Scotland. ©MMV, CBS Broadcasting Inc.

Keyword: Sexual Behavior; Evolution
Link ID: 7792 - Posted: 06.24.2010

BUFFALO, N.Y. -- Neuroscientists from the University at Buffalo have described for the first time how rotenone, an environmental toxin linked specifically to Parkinson's disease, selectively destroys the neurons that produce dopamine, the neurotransmitter critical to body movement and muscle control. Microtubules, intracellular highways that transport dopamine to the brain area that controls body movement, are the crucial target, they report. Damage to microtubules prevents dopamine from reaching the brain's movement center, causing a back-up of the neurotransmitter in the transport system, the researchers found. The backed-up dopamine accumulates in the body of the neuron and breaks down, causing a release of toxic free radicals, which destroy the neuron. The study appeared in the Aug. 9 issue of the Journal of Biological Chemistry. "This study shows how an environmental toxin affects the survival of dopamine neurons by targeting microtubules that are critical for the survival of dopamine-producing neurons," said Jian Feng, Ph.D., assistant professor of physiology and biophysics in the UB School of Medicine and Biomedical Sciences and senior author on the study.

Keyword: Parkinsons; Neurotoxins
Link ID: 7791 - Posted: 08.24.2005

Researchers have found a drug that, in monkeys, offsets mental lapses caused by sleep deprivation without the edginess of other stimulants. The finding heightens prospects for a future pill that could restore performance in military pilots, shift workers, and others who function on minimal or irregular sleep. The drug belongs to a class of compounds called ampakines, which amplify the signal of glutamate, a neurotransmitter important for learning and memory. Unlike caffeine and other stimulants that haphazardly rev up the brain's arousal system, ampakines only work on nerve cells that are already communicating. When given the drug, rats more quickly remember where they've been, and people track moving targets with greater accuracy. However, few have considered testing the brain boosters in those who don't get enough zzz's. If not for a timely convergence, Sam Deadwyler, a neuroscientist at Wake Forest University School of Medicine in Winston-Salem, North Carolina, probably wouldn't have either. But several years ago, Deadwyler decided to merge the research tools of a collaborator with the goals of a funder. His lab had done rat experiments with ampakines made by Cortex Pharmaceuticals in Irvine, California. He also had U.S. military funds to research strategies for preventing sleep deprivation in pilots. "Well, we have this drug from Cortex," he remarked at the time. "Let's see how it works in the context of sleep deprivation." Copyright © 2005 by the American Association for the Advancement of Science.

Keyword: Sleep
Link ID: 7790 - Posted: 06.24.2010

A team of scientists at UCL (University College London) has discovered why we often miss major changes in our surroundings - such as a traffic light turning green when we're listening to the radio. Our inability to notice large changes in a visual scene is a phenomenon often exploited by magicians - but only now can scientists put their finger on the exact part of the brain that is so often deceived. The UCL team shows, in a research paper published in the September issue of the journal Cerebral Cortex (which goes online on 24th August) that the part of the brain called the parietal cortex, the area responsible for concentration, is also critical to our ability to detect changes. The exact critical spot lies just a few centimetres above and behind the right ear – the area many people scratch when concentrating. Using Transcranial Magnetic Stimulation (TMS), the team switched off the parietal cortex part of the brain temporarily by applying magnetic stimulation to the head via a magnetic coil which produces small electrical currents to the brain. Without help from this region of the brain, subjects failed to notice even major visual changes– in this case a change of a person's face.

Keyword: Vision
Link ID: 7789 - Posted: 06.24.2010

It seems that placebos have a real physical, not imagined, effect – activating the production of chemicals in the brain that relieve pain, a new study suggests. Placebos are treatments that use substances which have no active ingredient. But if people are told that what they are being given contains an active painkiller, for example, they often feel less pain – an effect that has normally been considered psychological. Recent studies, though, suggest otherwise. For example, when a placebo was secretly mixed with a drug that blocks endorphins – the body’s natural painkillers – there was no placebo effect, showing that endorphins are involved in the placebo painkiller process (New Scientist print edition, 26 May 2001, p 34). Now Jon-Kar Zubieta’s team at the University of Michigan at Ann Arbor, US, has confirmed that placebos relieve pain by boosting the release of endorphins. Fourteen healthy males in their twenties volunteered to try what they were told was “a medication that may or may not relieve pain”. To induce pain, the researchers gave the young men infusions into the jaw that made them ache. © Copyright Reed Business Information Ltd.

Keyword: Pain & Touch
Link ID: 7788 - Posted: 06.24.2010

Researchers who used five different medical imaging techniques to study the brain activity of 764 people, including those with Alzheimer's disease, those on the brink of dementia, and healthy individuals, have found that the areas of the brain that young, healthy people use when daydreaming are the same areas that fail in people who have Alzheimer's disease. On the basis of their data, the researchers are proposing a new hypothesis that suggests that Alzheimer's disease may be due to abnormalities in the regions of the brain that operate the “default state.” This is the term used to describe the cognitive state people defer to when musing, daydreaming, or thinking to themselves. Writing in the August 24, 2005, issue of the Journal of Neuroscience, the researchers state that “the default activity patterns of the brain may, over many years, augment a metabolic- or activity-dependent cascade that participates in Alzheimer's disease pathology.” “The regions of the brain we tend to use in our default state when we are young are very similar to the regions where plaques form in older people with Alzheimer's disease,” said the lead author of the study, Randy L. Buckner, a Howard Hughes Medical Institute (HHMI) investigator at Washington University in St. Louis. “This is quite a remarkable convergence that we did not expect,” Buckner adds. © 2005 Howard Hughes Medical Institute.

Keyword: Alzheimers; Brain imaging
Link ID: 7787 - Posted: 06.24.2010

By HARRIET BROWN Two brains are better than one. At least that is the rationale for the close - sometimes too close - relationship between the human body's two brains, the one at the top of the spinal cord and the hidden but powerful brain in the gut known as the enteric nervous system. Dr. Michael D. Gershon, the author of "The Second Brain" and the chairman of the department of anatomy and cell biology at Columbia, the connection between the two can be unpleasantly clear. "Every time I call the National Institutes of Health to check on a grant proposal," Dr. Gershon said, "I become painfully aware of the influence the brain has on the gut." In fact, anyone who has ever felt butterflies in the stomach before giving a speech, a gut feeling that flies in the face of fact or a bout of intestinal urgency the night before an examination has experienced the actions of the dual nervous systems. The connection between the brains lies at the heart of many woes, physical and psychiatric. Ailments like anxiety, depression, irritable bowel syndrome, ulcers and Parkinson's disease manifest symptoms at the brain and the gut level. "The majority of patients with anxiety and depression will also have alterations of their GI function," said Dr. Emeran Mayer, professor of medicine, physiology and psychiatry at the University of California, Los Angeles. Copyright 2005 The New York Times Company

Keyword: Emotions; Stress
Link ID: 7786 - Posted: 08.23.2005

By DONALD G. McNEIL Jr. You remember Isaac Newton, his apple and the "Why didn't it fall up?" question. In the olfactory sciences, a crucial line of inquiry was opened up some years ago when a friend of a psychologist who was studying food asked, "If I hate the smell of Limburger cheese, why is it so delicious?" Researchers at Yale, the John B. Pierce Laboratory and the University of Dresden may now be closer to a biological answer. They got 11 volunteers to lie inside magnetic brain scanners with separate straws leading to the fronts of their noses (the part above the lip) and the backs (above the palate). The subjects were taught to make facial motions that closed off their palate and kept the experiment from being clouded by any sense of taste. Four odors were pumped in: butanol, farnesol (both described as "pleasantly musky"), lavender and chocolate. Only chocolate activated two different regions. Smelled from up front, it lighted up pleasure-anticipation neurons; from the back, it lighted up food-reward neurons. The scientists are unsure why only chocolate had that effect. Prof. Dana Small of the Yale team said it suggested that the brain changed smell perceptions based on eating, which is rarely done with lavender or musk. Another nasal expert, Dr. Leslie Vosshall of Rockefeller University, suggested confirmation with liver and brussels sprouts. Copyright 2005 The New York Times Company

Keyword: Chemical Senses (Smell & Taste)
Link ID: 7785 - Posted: 08.23.2005

By David Reid The quest to simulate the mammalian brain on the world's most powerful supercomputer is neuroscience's most ambitious project yet. David Reid went to Lausanne in Switzerland to find out how the line is being blurred between man and machine. Inside your head nestles a forest of millions of neurons which weave together to make your thoughts. Man has long wanted to discover the secrets of the brain, and has done so with varying degrees of success. Recently advancements in this area of science have been limited by the power of computers. But at Switzerland's École Polytechnique Fédérale de Lausanne, the Blue Brain Project aims to change this by simulating the structures and functions of the brain. The project's head, Professor Henry Markram, says that in the past there was no software environment capable of simulating the brain. "We haven't had the computing power to really address the complexity of the brain. Why is the brain so complex? We need to be able to do simulations addressing the question of complexity." Now, Blue Gene, a commercially available supercomputer, will help scientists to peer into the most inscrutable part of ourselves."We are not trying to build an intelligent device or robot or anything like that," explains Professor Markram. "We are trying to understand the brain, and one pathway is to take our available knowledge of the brain and put it to a test inside a model. "That process, we believe, will reveal where our gaps are; what we do understand and what we don't understand." (C)BBC

Keyword: Intelligence
Link ID: 7784 - Posted: 08.23.2005

Being a drunk in denial can't sound much more morose than the way musician Tom Waits depicts it when he wearily growls in song, "The piano has been drinking, not me." Experts say it's this type of fuzzy headedness that makes it hard to get alcoholics to admit to the excessive behavior that's likely ruining their lives. Even when hardcore drinkers finally do leap for the back of the wagon there's usually a lot of falling off involved. Now scientists say they believe there may be even more reason to stay sober. A brain study of rats fed enough alcohol to turn them into alcoholics, shows that their brains create a new crop of brain cells in early abstinence, suggesting the brain might be repairing itself. "Months after the last dose of alcohol there are new brain cells formed… that, in fact, make more neurons in the brain and we believe that those neurons play a role in the recovery of brain function," says one of the study's authors, pharmacologist Fulton Crews, of the Bowles Center for Alcohol Studies at the University of North Carolina at Chapel Hill. Researchers bent on deciphering the anatomical workings of addiction are looking at the neuronal level because it's there that overall brain function starts. And from what researchers have seen, the damage alcohol does to neurons isn't good. "The damage to the brain that occurs in alcoholics is damage that occurs by inhibiting the repair of the brain and the normal growth of the brain, and as well as stimulating the loss of cells and neurons in the brain," says Crews. © ScienCentral, 2000-2005.

Keyword: Drug Abuse
Link ID: 7783 - Posted: 06.24.2010

ST. LOUIS -- A compound that kills cancer can sneak past the blood brain barrier, which protects the brain from foreign substances, to do its work in fighting a particularly invasive brain cancer, according to a new Saint Louis University animal study published in the Proceedings of the National Academy of Sciences Online Early Edition the week of Aug. 22. "The bottom line is, if you can get drugs into the brain, you can cure brain cancer," says William A. Banks, M.D., professor of geriatrics in the department of internal medicine and professor of pharmacological and physiological science at Saint Louis University School of Medicine and a member of the research team. The compound – JV-1-36 – is an antagonist of the hypothalamic growth hormone- releasing hormone, which has been found to cause cancerous tumors, such as malignant glioblastomas, to grow. The main known purposes of the hypothalamic growth hormone-releasing hormone usually are to trigger the hormone that makes children grow and affect how glucose is used in adults. Researchers found that the P-gp system, an extra guardian located at the blood brain barrier that usually keeps anticancer drugs out of the brain, intercepted some of the JV-1-36 that was injected into mice but let much of it pass into the brain to treat cancer.

Keyword: Miscellaneous
Link ID: 7782 - Posted: 06.24.2010

It has been known for some time that many species of birds use the Earth's magnetic field to select a direction of movement--for example, during migration. However, although such birds clearly have a sense of direction, until now it has not been possible to train birds to move in a certain direction in the laboratory, even if they are motivated by a food reward. The reasons for this failure have been perplexing, but researchers now report that they have been able to successfully accomplish this training task, providing new insight into the evolution of magnetic sensing and opening new opportunities for further study of magnetoreception. In the new work, researchers including Rafael Freire from the University of New England (Australia), Wolfgang Wiltschko and Roswitha Wiltschko from the University of Frankfurt, Germany, and Ursula Munro from the University of Technology in Sydney, demonstrated for the first time that birds could be trained to respond to a magnetic direction. The researchers trained domestic chicks to find an object that was associated with imprinting and was behind one of four screens placed in the corners of a square apparatus, and, crucially, showed that the chicks' direction of movement during searching for the hidden imprinting stimulus was influenced by shifting the magnetic field. One important difference between this work and earlier attempts to train birds is that the researchers used a social stimulus to train the birds, whereas most previous attempts have used food as the reward. The authors of the study hypothesize that in nature, birds do not use magnetic signals to find food, and tests involving such a response may be alien to them.

Keyword: Animal Migration
Link ID: 7781 - Posted: 08.23.2005