While the brain center called the nucleus accumbens (NAc) has been called a key component of the brain's "reward" pathways, researchers' experiments with rats have now shown that the center processes not only rewarding stimuli, but also aversive stimuli. The researchers found that not only does the NAc decide whether stimuli--in this case sweet sucrose or bitter quinine--are rewarding or aversive, but the center's neurons also encode learning associated with the stimuli. The NAc is located in the brain's limbic system, which generates feelings and emotions. It is the key brain center involved in reinforcing the taking of drugs of abuse. In their experiments, researchers led by Mitchell F. Roitman and Regina M. Carelli at Dr. Carelli's laboratory at University of North Carolina in Chapel Hill used recording microelectrodes to measure the electrophysiological response of neurons in the NAc of rats when they fed the rats small squirts of sucrose or quinine. The rats actively responded to the two tastes. For sucrose, they immediately licked and moved their mouths to ingest the sugar. In response to quinine, they gaped their mouths and rubbed their chins--the rat equivalent of "ptui."

Keyword: Chemical Senses (Smell & Taste); Drug Abuse
Link ID: 6883 - Posted: 02.17.2005

Rossella Lorenzi, Discovery News — Sleep helps young birds master the art of song, according to a study that analyzed and recorded every vocalization made by young male zebra finches through cycles of wakefulness and sleep. The study, which appears in the current issue of Nature, showed that just woken up zebra finches are dramatically worse singers than they were the day before. But surprisingly, after intense morning singing, the worst performers become the best singers of all. Zebra finch males are active in the daytime, do not sing in darkness and develop their song during a critical window of "brain plasticity" between 30 and 90 days after hatching. In order to investigate how sleep affects developmental learning in these colorful songbirds, behavioral neuroscientists Ofer Tchernichovski and Sébastien Deregnaucourt from City College New York, recorded the entire song development of zebra finches. Copyright © 2005 Discovery Communications Inc.

Keyword: Learning & Memory; Sleep
Link ID: 6882 - Posted: 06.24.2010

Emma Marris Birds that live in bunches work each other up into a reproductive frenzy with their songs, according to research that confirms an old hypothesis. As far back as the 1930s, ornithologists proposed that large, sociable colonies of birds would tend to have earlier, bigger and more closely synchronized clutches of eggs. Known as the Darling hypothesis, after F. Fraser Darling who first suggested the idea, it has finally been supported by experiments in the laboratory, and the research appears online in the Proceedings of the Royal Society1. To test Darling's hypothesis, the researchers set up two indoor colonies of the zebra finch (Taeniopygia guttata), a smart little Australian bird often seen in pet shops. The first group of birds was played recorded sounds of its own colony, but the second group heard a playback that blended its own colony sounds with noises from extra finches.Females in the second group had more eggs, laying them earlier and more synchronously than controls, confirming the theory. ©2005 Nature Publishing Group

Keyword: Sexual Behavior; Language
Link ID: 6881 - Posted: 06.24.2010

Pregnant women are attracted to healthier looking faces in what scientists believe is a subconscious effort to avoid illness. Teams from the universities of St Andrews and Aberdeen showed pregnant women two pictures of computer- generated faces. The faces were tweaked to show one unhealthy pallor and the other healthy. Women with high levels of the progesterone hormone chose the healthier face. Dr Ben Jones, of the University of Aberdeen, said pregnant women and those with raised progesterone are more attracted to men who appear healthier. He said: "Our findings suggest that pregnancy, or when a woman is in a similar hormonal state, trigger strategies within the body for avoiding illness during social interactions. "These could compensate for weakened immune system responses at these times and reduce the risk of maternal illness disrupting the development of the unborn child." The tests were carried out at the Perception Lab at St Andrews University. (C)BBC

Keyword: Sexual Behavior; Evolution
Link ID: 6880 - Posted: 02.16.2005

Birdsong delights listeners and intrigues evolutionary ecologists. Female birds are thought to preferentially mate with males with more complex or extravagant songs. But why should females prefer these males? What information does a male's song convey? Jane M. Reid and fellow researchers studied a population of song sparrows inhabiting Mandarte Island, British Columbia, Canada, where males sing elaborate repertoires of songs. They found that male sparrows with larger song repertoire sizes contributed more offspring and grand-offspring to the breeding population on Mandarte. This was because these males lived longer and reared more hatched chicks to independence from parental care, not because the females who mated to males with larger repertoires laid or hatched more eggs. Furthermore, they discovered that independent offspring of males with larger repertoires were more likely to survive to breed and then to leave more grand-offspring than independent offspring of males with small repertoires. This effect of paternal repertoire size on offspring performance was stronger in sons than in daughters.

Keyword: Sexual Behavior; Evolution
Link ID: 6879 - Posted: 02.16.2005

Oliver Wendell Holmes coined the term "anesthesia" in 1846 to describe drug-induced insensibility to sensation (particularly pain), shortly after the first publicized demonstration of inhaled ether rendered a patient unresponsive during a surgical procedure. Two broad classes of pharmacologic agents, local and general, can result in anesthesia. Local anesthetics, such as Novocain, block nerve transmission to pain centers in the central nervous system by binding to and inhibiting the function of an ion channel in the cell membrane of nerve cells known as the sodium channel. This action obstructs the movement of nerve impulses near the site of injection, but there are no changes in awareness and sense perception in other areas. In contrast, general anesthetics induce a different sort of anesthetic state, one of general insensibility to pain. The patient loses awareness yet his vital physiologic functions, such as breathing and maintenance of blood pressure, continue to function. Less is known about the mechanism of action of general anesthetics compared to locals, despite their use for more than 150 years. The most commonly used general anesthetic agents are administered by breathing and are thus termed inhalational or volatile anesthetics. They are structurally related to ether, the original anesthetic. Their primary site of action is in the central nervous system, where they inhibit nerve transmission by a mechanism distinct from that of local anesthetics. The general anesthetics cause a reduction in nerve transmission at synapses, the sites at which neurotransmitters are released and exert their initial action in the body. But precisely how inhalational anesthetics inhibit synaptic neurotransmission is not yet fully understood. It is clear, however, that volatile anesthetics, which are more soluble in lipids than in water, primarily affect the function of ion channel and neurotransmitter receptor proteins in the membranes of nerve cells, which are lipid environments. © 1996-2005 Scientific American, Inc

Keyword: Pain & Touch
Link ID: 6878 - Posted: 06.24.2010

Here's what Mary Jo O'Kelley avoids thanks to a warehouse accident that left her with chronic back pain: bending, squatting, exercising and lifting anything of almost any kind. But that might not be all the damage her injury caused. For the first time, researchers have found evidence that chronic back pain may be at least partially responsible for shrinking the brain. Neuroscientist Vania Apkarian of Northwestern University used magnetic resonance imaging (MRI) scans to collect 26 brain images from people who reported suffering back pain that lasted for a year or more and 26 images from pain-free subjects matched for age and sex. After looking at average brain size across each group, he compared the pain subjects with subjects free of pain and found significant differences in brain density in gray matter—the tissue in the brain that houses neurons, or nerve cells, that communicate with each other to help us process information. With age, we naturally lose some gray matter but Apkarian notes a difference when pain comes into play. "The amount of gray matter decrease per year that we see for normal aging is about 2.5 ccs in volume; that's about a teaspoon," he explains. "The chronic back pain condition has an additional half a teaspoon, about 1.5 cc of additional of gray matter brain atrophy on top of the normal aging effect." Loss of gray matter that results from chronic pain—he's found it's generally in the pre-frontal cortex and the thalamus—can bring cognition problems, as Apkarian explains: "Neurons are probably not functioning as well as they should be functioning, all of which will decrease that ability of that area of the brain to process the kinds of things that are involved in processing in everyday behavior." © ScienCentral, 2000- 2005.

Keyword: Pain & Touch
Link ID: 6877 - Posted: 06.24.2010

Robots that act like rat pups can tell us something about the behavior of both, according to UC Davis researchers. Sanjay Joshi, assistant professor of mechanical and aeronautical engineering, and associate professor of psychology Jeffrey Schank have recorded the behavior of rat pups and built rat-like robots with the same basic senses and motor skills to see how behavior can emerge from a simple set of rules. Seven to 10-day-old rat pups, blind and deaf, do not seem to do a whole lot. Videotaped in a rectangular arena in Schank's laboratory, they move about until they hit a wall, feel their way along the wall until their nose goes into a corner, then mostly stay put. Because their senses and responses are so limited, pups should be a good starting point for building robots that can do the same thing. Joshi's laboratory built foot-long robots with tapered snouts, about the same shape as a rat pup. The robots are ringed by sensors so that they "feel" when they bump into a wall or corner. They are programmed to stay in contact with objects they touch, as rats do. But when the robotic "rats" were put into a rectangular arena like that used for experiments with real rats, the robots showed a new behavior. They scuttled along the walls and repeatedly bumped into one corner, but favored one wall. Instead of stopping in a corner they kept going, circling the arena.

Keyword: Robotics
Link ID: 6876 - Posted: 02.16.2005

By Sandra G. Boodman From the time her son was born, Jennifer DeWeese said, she suspected something was wrong. As an infant he cried inconsolably and slept mostly in hour-long snatches. At 3, he was always irritable and had prolonged tantrums triggered by the slightest change in his routine. A therapist told his mother he was emotionally disturbed and suggested she read a popular book about childhood bipolar disorder. A year later a child psychiatrist in Virginia Beach made the diagnosis: the 4 1/2 -year-old was manic-depressive. A few months later, when his even-tempered sister grew moody and volatile, DeWeese took her to the same psychiatrist. They sat down with DeWeese's well-thumbed book about bipolar children and went through its symptom checklist. Based largely on those results and the family's history -- DeWeese said she learned during her divorce that the children's father had been diagnosed as bipolar in high school -- the psychiatrist told DeWeese her 5 1/2-year-old daughter was bipolar, too. "I feel relieved to know there is something causing their symptoms and something we can do about it," said DeWeese, 34. She is convinced, she said, that her children's problems are inherited, not a reaction to their father's permanent departure, a bitter divorce marked by allegations of spousal abuse, a bankruptcy that resulted in the loss of the family's house and car, DeWeese's frequent hospitalizations for kidney disease and the arrival of a new stepfather. Now 6 and 8, DeWeese's son and daughter exemplify a trend that is roiling mental heath: the burgeoning number of children diagnosed with bipolar illness, also known as manic depression, which affects about 2.3 million Americans. © Copyright 1996-2005 The Washington Post Company

Keyword: Schizophrenia; Depression
Link ID: 6875 - Posted: 06.24.2010

By JANE E. BRODY My surgeon did a marvelous job replacing my arthritic knees and, at the same time, straightening my terribly bowed legs when, at 63, I decided to have knee replacement surgery. Although a class given at the hospital before the operation repeatedly emphasized the importance of adequate pain control, the surgeon and his helpers were not experts in treating prolonged, debilitating postoperative pain. They are hardly alone. Pain management is not generally taught as a part of medical education, not even to residents in orthopedic surgery. As a result, most doctors are clueless or unnecessarily cautious about treating pain, especially chronic pain like that caused by incurable neurological or muscular disorders. They are especially ill-informed about opioids, which are synthetic versions of morphine, the most potent painkillers that can be taken by mouth. As Dr. Jennifer P. Schneider writes about opioids in her book "Living With Chronic Pain" (Healthy Living Books, $15.95), "Fear and lack of knowledge of these drugs prevent many doctors from prescribing them for people whose pain is caused by anything other than cancer." Copyright 2005 The New York Times Company

Keyword: Pain & Touch; Drug Abuse
Link ID: 6874 - Posted: 02.15.2005

By ANDREW POLLACK Despite all the advances of modern medicine, the main drugs used to fight pain today are essentially the same as those used in ancient times. Hippocrates wrote about the pain-soothing effects of willow bark and leaves as early as 400 B.C. Opium was cultivated long before that. Aspirin and morphine, based on the active ingredients in these traditional remedies, were isolated in the 1800's and helped form the foundation of the modern pharmaceutical industry. But scientists are now trying to find new ways of fighting pain. The effort has been given new impetus by the recent withdrawal of Vioxx and the questions surrounding the safety of similar pills like Celebrex and Bextra. Those concerns come on top of the problems of abuse of narcotic painkillers like OxyContin. "There's a huge void, and no one is filling it," said Remi Barbier, chief executive of Pain Therapeutics, a company in South San Francisco, Calif. But Dr. Barbier's company and dozens of others are trying. And some new treatments may come from things in nature that soothe or sting, like marijuana, hot chili peppers, nicotine and deadly toxins of snails and fish. While the withdrawal of Vioxx leaves more room for newcomers, it also makes their challenge harder. Not only have opioids and aspirin been hard to beat, but the Food and Drug Administration is now expected to demand more evidence that drugs are safe before approving them. Copyright 2005 The New York Times Company

Keyword: Pain & Touch
Link ID: 6873 - Posted: 02.15.2005

The following statement is being released by the Parkinson’s Disease Foundation, located at 710 West 168th Street, New York City. It follows the announcement, earlier today, of a decision by Amgen Incorporated, manufacturer of GDNF, an experimental neural growth factor, to forgo the offer of reinstatement of GDNF to patients who were involved in recent clinical trials of the treatment. The authors of the PDF statement are Stanley Fahn, M.D., the Foundation’s Scientific Director, and Robin Anthony Elliott, its Executive Director. "The Amgen announcement, which followed a resolution by the PDF Board of Directors urging the company to permit patients who participated in the company’s clinical trials the option of continued access to GDNF, is deeply disappointing to PDF, to the Parkinson’s community, and to the participating patients," the statement reads. "However well-intentioned the company may have been in wrestling with this issue, we believe it has reached the wrong decision – whether judged in terms of science, or the desires of the people who participated in the clinical trials, or the issues of safety." "In terms of the science, we would argue that the reinstatement of GDNF, if accompanied by the continuing collection of efficacy and safety data, would enable scientists and regulatory authorities to monitor the long-term aspects of safety and efficacy of the treatment. Furthermore, the observation of increased fluorodopa uptake in PET scans needs to be carefully followed over time to determine if this will eventually translate into clinical improvement. Giving up this opportunity to learn is, in our view, a mistake." © 2005 The Parkinson’s Disease Foundation

Keyword: Parkinsons; Trophic Factors
Link ID: 6872 - Posted: 06.24.2010

The supersensitivity to dopamine that is characteristic of schizophrenia can be caused by mutations to a wide variety of genes, rather than alterations to just two or three specific genes, says a University of Toronto researcher. In research published in the Feb. 15 edition of the Proceedings of the National Academy of Sciences, University of Toronto pharmacology professor Philip Seeman and his 16 colleagues in eight universities show that mutations to genes that have no relation to the brain's dopamine receptors can still cause those receptors to become highly sensitive to their own dopamine, a condition that leads to psychosis. By examining brain tissue from mice with various gene mutations, the researchers determined that the brain appears to compensate for the altered gene by becoming supersensitive to dopamine. Dopamine is a neurotransmitter that allows people to move, think and feel. "The altered genes may provoke the brain to respond and compensate, and compensation often involves the dopamine system going into high gear," says Seeman. "The brain knows about mistakes, and to protect itself, it makes sense for the compensation to re-adjust the dopamine system to preserve the functions – such as movement and thought – that the body and brain needs."

Keyword: Schizophrenia; Genes & Behavior
Link ID: 6871 - Posted: 06.24.2010

Your parents may have told you about the birds and bees, but scientists are learning a bit about love from fruit flies. As this ScienCentral News video explains, biologists studying flirtatious flies are learning how our genes shape sex appeal—and everything else. For a certain species of male fruit fly, the wing's the thing—male sex appeal boils down to a black spot on the suitor's wings. "The species that have these spots have an elaborate courtship ritual where they dart out in front of the females and they extend their wings and do a little dance while they display these spots," says Sean Carroll, genetics professor at the University of Wisconsin-Madison and Howard Hughes Medical Institute. "It's quite clear that these spots are a visual cue that the females are picking up on in the selection of mates, and the success of mating of males being linked to their possession of this trait—that process is called sexual selection and it's a very powerful evolutionary force." Since fruit flies have long been the workhorses of genetics, Carroll and his colleagues used them to study how such traits evolve at the genetic level. Biologists already knew that every gene has two parts—the DNA that does the work, and the DNA that tells the gene where to work. "And one of the biggest questions in evolution," says Carroll, "is what parts are evolving, is it the part that does the work, or is it the instructions for where that work's going to be done?" © ScienCentral, 2000- 2005.

Keyword: Sexual Behavior; Evolution
Link ID: 6870 - Posted: 06.24.2010

A highly sensitive post-mortem test could help scientists more accurately determine if a person died of Creutzfeldt-Jakob disease (CJD), a human neurological disorder caused by the same class of infectious proteins that trigger mad cow disease, according to a new study supported in part by the National Institutes of Health (NIH). The finding opens the possibility that such testing might be refined in the future so it can be used to detect prion disease in living people and animals before the onset of symptoms. The test, called conformation-dependent immunoassay (CDI), was originally developed to detect various forms of disease-causing proteins called prions in cows, sheep, deer and other animals. In the new study, researchers led by Jiri Safar, M.D., Bruce Miller, M.D., Michael Geschwind, M.D., Stephen DeArmond, M.D., and Nobel Laureate Stanley B. Prusiner, M.D., of the University of California, San Francisco, found that CDI not only identifies prions in human brain tissue but is faster and far more precise than the standard immunological detection methods, which only detect a small fraction of the infectious prions that may be in the brain. The finding appears in the March 1, 2005 issue of the Proceedings of the National Academy of Sciences, www.pnas.org. Two components of the NIH, the National Institute of Neurological Disorders and Stroke (NINDS)* and the National Institute on Aging (NIA), supported the study. Additional support was provided by the John Douglas French Foundation for Alzheimer's research, the McBean Foundation, and the Alzheimer's Disease Research Center of California.

Keyword: Prions
Link ID: 6869 - Posted: 02.15.2005

By Jennifer Viegas, Discovery News — If a man and a woman are in love, the bewitched fellow loses testosterone — a hormone linked to strength and aggressiveness — while his female partner actually gains some of the potent male hormone and its effects, according to a recent study. The findings, published in the current Harvard Health Letter, suggest that love brings members of the opposite sex together by reducing some of their differences. Researchers made the determination after comparing 24 young adults who had recently fallen in love with the same number of people currently not feeling love pangs. Blood was drawn from all of the test subjects. It then was analyzed for hormonal contents, which revealed the testosterone female spike and male drop. Donatella Marazziti and colleague Domenico Canale, University of Pisa scientists who conducted the study, are not sure why men in love lose testosterone while women in love gain it. Marazziti told Discovery News that the changes might be linked to sexual behavior. The blood test also revealed that all people in love, both men and women, gain heightened levels of cortisol, a hormone linked to stress. Copyright © 2005 Discovery Communications Inc

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 6868 - Posted: 06.24.2010

A pioneering form of gene therapy has apparently cured deafness in guinea pigs, raising hopes that the same procedure might work in people. "It's the first time anyone has biologically repaired the hearing of animals," says Yehoash Raphael at the University of Michigan in Ann Arbor, Michigan, and head of the US-Japanese team that developed the technique. The therapy promotes the regrowth of crucial hair cells in the cochlea, the part of the inner ear which registers sound. After treatment, the researchers used sensory electrodes around the animals' heads to show that the auditory nerves of treated - but not untreated - animals were now registering sound. Deafness is a major problem in people: millions of people worldwide become deaf or hearing impaired every year. This can occur if a person's inner-ear hair cells are destroyed by exposure to loud noise, to some antibiotic drugs, or simply through old age. The hair cells act like miniature microphones, capturing sound vibrations from fluid in the ear and translating the movement into nerve signals. Raphael says one future possibility would be to use the therapy to improve hearing in people who already wear cochlear implants. These electrical devices are of some help to people lacking hair cells, but the regrowth of even some hairs could boost their hearing further. Raphael says that the next experiments in guinea pigs will focus on this combination. © Copyright Reed Business Information Ltd.

Keyword: Hearing
Link ID: 6867 - Posted: 06.24.2010

Philip Ball An inability to process language needn't stop you from doing maths, UK researchers have found. They say that three men with severe aphasia, a linguistic impairment, can understand 'grammatical' rules in mathematics even though they cannot handle analogous rules in language. Aphasia leaves people unable to use or comprehend words, and is often triggered by stroke or other brain injuries. The discovery challenges a commonly held view that linguistic and mathematical mental processing draw on the same cognitive resources. "Our findings very strongly turn that idea on its head," says Rosemary Varley, a cognitive neuroscientist at the University of Sheffield, UK. The research is published in Proceedings of the National Academy of Sciences1. According to the view of cognition developed by linguist Noam Chomsky, language processing is a fundamental skill that is used for related grammatical tasks in the brain, such as certain mathematical ones. Previous studies of the relationship between linguistic and mathematical ability have lent some support to this notion. ©2005 Nature Publishing Group

Keyword: Language
Link ID: 6866 - Posted: 06.24.2010

David Perlman, Chronicle Science Editor There stood Jack Dumbacher, innocently trying to trap a gorgeous bird of paradise in the mist net he'd set up for his research in a New Guinea forest, when the net entangled a flying stranger, all vivid orange and black. The unwanted bird clawed Dumbacher's fingers, nipped them with its beak, and when the startled scientist put a bleeding finger to his mouth, he suddenly felt a burning, tingling sensation on his tongue and lips -- which soon became briefly numb. The bird was a hooded pitohui (pronounced PIT-a-hooey), and the encounter in Papua New Guinea 15 years ago led the ornithologist to abandon his research into birds of paradise and to follow a mysterious, deadly poison that links the birds in the highland Papuan villages to frogs in the lowland South American jungles of Colombia -- and to beetles in both far-off habitats. Dumbacher and his colleagues have now discovered that a family of beetles in New Guinea and their distant relatives more than 9,500 miles away, on the other side of the Pacific, are apparently responsible for the toxins in Dumbacher's pitohui birds -- the first poisonous birds discovered anywhere - - and Phyllobates terribilis, the poison-dart frogs of Colombia. The frogs got their name because the Choco Indians use the same poison to tip their arrows and blowpipe darts when they hunt for monkeys and other game animals. ©2005 San Francisco Chronicle

Keyword: Neurotoxins
Link ID: 6865 - Posted: 06.24.2010

Arthur L. Caplan Is the pharmaceutical industry a dangerous and crooked business that federal and state authorities need to bring to heel? Should those who develop, market or prescribe drugs hang their heads in shame when faced with the stark reality of what they do to earn a living? Is Big Pharma in fact the moral equivalent of the tobacco industry? One could well come away from Marcia Angell's The Truth about the Drug Companies or Jerome Kassirer's On the Take thinking so. In both books, the sort of moral opprobrium once directed against Big Tobacco is aimed squarely at the pharmaceutical industry, along with its legions of lobbyists, the politicians awash in its campaign contributions and the doctors it has bought, free meal by free meal, junket by junket, free sample by free sample and trinket by trinket. Kassirer and Angell, who are physicians at Tufts and Harvard, respectively, and who are both former editors of the New England Journal of Medicine, are not the only authors currently taking a critical look at industry excesses. Harvard physician and pharmacoepidemiologist Jerry Avorn also has a new book examining some of the problems with the way prescription drugs are brought to market, the thoughtful and incisive Powerful Medicines. It's not hard to see why demonization of the pharmaceutical industry has become such a popular sport. As Avorn points out, drug companies are now so obsessed with profits that they are no longer willing to pay for the innovative research that they claim justifies the high cost of their products. He and Angell each demonstrate that the numbers do not support the contention that without high prices there would be no money for the next generation of miracle drugs. © Sigma Xi, The Scientific Research Society

Keyword: Drug Abuse
Link ID: 6864 - Posted: 06.24.2010