The hormone that controls the body's hunger pangs may also boost the memory, according to Scottish scientists. Researchers at Dundee University have found a link between the hormone leptin and the brain's memory and learning process. Leptin controls food intake and body weight and staves off the urge to eat. The study was carried out by a team which specialises in the braincell processes that produce learning and memory. Jenni Harvey, one of the researchers, said: "The hormone leptin, which is known to control food intake and body weight, has been shown to exert a profound influence on learning and memory processes in a region of the brain called the hippocampus. "Leptin enhances the level of communication between brain cells in the hippocampus in a process known as long-term potentiation (LTP)." It has been shown previously that people suffering from obesity have defects in their leptin levels and in the LTP process. The group's findings could therefore shed light on how obesity affects learning and memory. Dr Harvey said: "Defects in either leptin or genes that regulate leptin result in obesity and also cause impairments in LTP." (C)BBC

Keyword: Obesity; Learning & Memory
Link ID: 7659 - Posted: 07.19.2005

By NICHOLAS BAKALAR In recent years, many anticonvulsant drugs have been widely prescribed not only for seizure disorders, but for various kinds of chronic pain and for several different psychiatric illnesses, even though few have been approved by the Food and Drug Administration for those purposes. Now researchers are reporting a case of brain swelling, or cerebral edema, after abrupt withdrawal from pregabalin (Lyrica), a new antiepileptic drug that will be available this fall. The report appears online and in the August issue of Annals of Neurology. The patient, an 80-year-old woman, was in a clinical trial testing the drug for the severe pain of shingles, or postherpetic neuralgia. About a day after abruptly discontinuing it, she suffered nausea, headache and loss of balance, which progressed to delirium and hallucinations a week later. An M.R.I. scan revealed swelling in the same part of the brain that is affected in some epileptic patients who suddenly stop their drugs. Dr. Anne Louise Oaklander, the lead author on the paper, acknowledged that a single case did not constitute proof. "Maybe it's completely coincidental that she had M.R.I. abnormalities and a neurological illness, and that she'd recently stopped the drug," she said. "But the more likely explanation is that these things are linked." Copyright 2005 The New York Times Company

Keyword: Epilepsy
Link ID: 7658 - Posted: 07.19.2005

By NICHOLAS WADE Biologists have been making considerable progress in identifying members of a special class of genes - those that shape an animal's behavior toward others of its species. These social behavior genes promise to yield deep insights into how brains are constructed for certain complex tasks. Some 30 such genes have come to light so far, mostly in laboratory animals like roundworms, flies, mice and voles. Researchers often expect results from these creatures to apply fairly directly to people when the genes cause diseases like cancer. They are much more hesitant to extrapolate in the case of behavioral genes. Still, understanding the genetic basis of social behavior in animals is expected to cast some light on human behavior. Last month researchers reported on the role of such genes in the sexual behavior of both voles and fruit flies. One gene was long known to promote faithful pair bonding and good parental behavior in the male prairie vole. Researchers discovered how the gene is naturally modulated in a population of voles so as to produce a spectrum of behaviors from monogamy to polygamy, each of which may be advantageous in different ecological circumstances. The second gene, much studied by fruit fly biologists, is known to be involved in the male's elaborate suite of courtship behaviors. New research has established that a special feature of the gene, one that works differently in males and females, is all that is needed to induce the male's complex behavior. Copyright 2005 The New York Times Company

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 7657 - Posted: 07.19.2005

The controversy over whether the herbicide atrazine affects sexual differentiation in frogs is hopping again. A study in this issue of ES&T (pp 5255–5261) reports that gonadal abnormalities—in particular the presence of immature female egg cells, or oocytes, in the testes of male frogs—are common in Xenopus laevis, the “lab rat” of amphibian species. The research, funded by atrazine manufacturer Syngenta, suggests that such abnormalities may be a normal part of development, according to the authors. But other amphibian experts describe the results as “amazing” or “surprising” and say that they have never seen such abnormalities in laboratory studies. Normal or not? Oocytes—immature female egg cells—have been found in the testes of male X. laevis frogs that lived in outdoor tanks in South Africa.Atrazine is one of the most commonly used herbicides in the world, although it is banned in the EU. In 2002, University of California, Berkeley, amphibian endocrinologist Tyrone Hayes reported that atrazine exposure as low as 0.1 parts per billion induced gonadal abnormalities—multiple gonads or multiple testes and ovaries—in male X. laevis (Proc. Natl. Acad. Sci. U.S.A. 2002, 99, 5476–5480). The paper set off a heated and acrimonious debate between Hayes and Syngenta-funded scientists over atrazine’s effects on frogs. In October 2003, U.S. EPA experts and a special pesticide scientific advisory panel concluded that studies supporting and refuting the finding all suffered from confounding effects (Environ. Sci. Technol. 2004, 38, 107A–108A). Despite the controversy, atrazine was re-registered for another three years by EPA in October 2003. Copyright © 2005 American Chemical Society

Keyword: Sexual Behavior
Link ID: 7656 - Posted: 06.24.2010

Whether or not an animal can recognize itself in the mirror has long been used by scientists as a means of self-awareness. Apes pass the test, but monkeys have been thought to perceive a stranger in their reflection. The results of a new study suggest that what monkeys see is not so simple: although they don't recognize themselves, they also treat their mirror twins differently than they do real animals. Primatologist Frans B. M. de Waal and his colleagues at Emory University studied how 14 adult capuchin monkeys responded to their reflections. They exposed the animals to both familiar and unfamiliar monkeys of the same sex and to a large mirror. Adult females acted friendly toward the mirror and made eye contact more often with their reflection than they did with a stranger. Males, on the other hand, had both friendly and negative reactions to the mirror monkeys but still treated the reflection differently than they did a live animal. The animals' reactions to the three situations were consistent and specific enough that human observers unaware of the experimental set-ups correctly categorized the testing conditions. The results indicate that capuchins know almost immediately that a reflection is not a regular stranger. It's possible, the authors argue in a report in the Proceedings of the National Academy of Sciences, that the monkeys are in an intermediate stage of recognizing that the mirror image as themselves and seeing it as another animal. --Sarah Graham © 1996-2005 Scientific American, Inc.

Keyword: Miscellaneous
Link ID: 7655 - Posted: 06.24.2010

COLUMBUS , Ohio – The tongue's ability to differentiate between sweet and bitter tastes may reside in the same taste bud cells, a new study reports. The study explains the discovery of a chemical messenger called neuropeptide Y (NPY) in taste bud cells. Though researchers have long known that NPY is active in the brain and gut, this is the first study to show that it is also active in taste bud cells. That finding gives scientists a deeper understanding of how the human brain may distinguish between different types of tastes, said Scott Herness, the study's lead author and a professor of oral biology and neuroscience at Ohio State University . The current study builds on previous work by Herness and his colleagues. A few years ago, the team found that another chemical messenger, cholecystokinin (CCK), is active in some taste bud cells. They think that these two peptides – small proteins that let cells talk to one another – have different effects in the same cells. The researchers report their findings in this week's online edition of the Proceedings of the National Academy of Sciences. CK may send opposite signals to the brain, depending on what kind of substance is on the tongue. Given the current findings, Herness thinks that CCK tells the brain that something bitter is on the tongue, while NPY sends a message that something sweet is being eaten.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 7654 - Posted: 06.24.2010

STEAMBOAT SPRINGS, Colorado – As animal models go, the vole isn't near the top of the list. In fact, it wasn't even on the list until relatively recently. Not to be confused with the mole, a much smaller and scientifically less-interesting rodent, voles are about the size of hamsters, but more squat. Nevertheless, along with their cousins the mouse and rat, voles have quickly become an invaluable animal model for social behavior and have helped open up the field of study to very complex issues including romance and even more recently, autism. Larry Young, professor of psychiatry at Emory University, began studying the vole in the mid-1990s "unrelated to autism, just for their unusual behavior. Prairie voles are monogamous and form life-long social attachments, while montane and meadow voles are promiscuous breeders and don't form social attachments at all," Young says. Soon, "using comparative molecular approaches, I began to investigate the molecular mechanisms underlying the species behavior differences. Now, by gaining an understanding of the mechanisms underlying social attachment, we hope to gain insight in human disorders characterized with social impairments, such as autism." But to paraphrase Michael Douglas in the "American President": "Autism isn't easy." Young says there are two specific problems in studying autism. First, "there aren't any animal models of autism. Animals just don't get autism. Second, autism is itself a disrupted social phenotype with a broad spectrum of interrelated disorders" that is almost uniquely variable in each individual patient.

Keyword: Autism; Hormones & Behavior
Link ID: 7653 - Posted: 06.24.2010

Scientists say they have discovered a gene linked to diabetes and obesity, offering hope for a diagnostic test. Faulty versions of the gene ENPP1 disrupt the way the body stores energy and handles sugar by blocking the hormone insulin. Children with faulty versions were obese at as young as five years old. The Imperial College London team told Nature Genetics that spotting the problem early and intervening could save lives. Experts have already predicted that the UK is facing an obesity and diabetes time bomb, with rates soaring among children and adults alike. The number of people in the UK with diabetes is predicted to reach three million by 2010. Diabetes and obesity increase the likelihood of potentially fatal diseases such as heart attacks. While inactivity and poor diets are much to blame for obesity and the metabolic problems that can lead to full-blown diabetes, the authors of the latest study say some people are genetically prone as well. In these individuals - up to 20% of Caucasians and 50% of black communities - leading a healthier lifestyle from the outset is imperative if they are to avoid problems in later life, say Dr Philippe Froguel and his team. They looked at French families with a strong history of diabetes and obesity and compared them with families that did not. When they compared the genes of 1,225 children who were grossly obese or overweight at ages five and 11 with 1,205 normal weight children they found an obvious pattern - many of the obese children possessed culprit versions of ENPP1. (C)BBC

Keyword: Obesity; Genes & Behavior
Link ID: 7652 - Posted: 07.18.2005

STEAMBOAT SPRINGS, Colorado – Maternal aggressive/protective behavior is recognized throughout mammalian species, especially during lactation. When hiking, we warn our kids not to approach bear cubs, or to get between a cub and the mother. While driving and you see a fawn, you know a doe can't be too far away and will run headlong to protect it. The same neurohypophyseal (NH) hormone, oxytocin (OT), is responsible for both the physiological and behavioral changes, but the site of action is quite different. OT is released during parturition and in lactation not only from NH terminals into the bloodstream in order to support reproductive systems, but also within the brain, into the supraoptic nucleus (SON) and paraventricular nucleus (PVN), where it has marked behavioral impact. OT release in the brain is involved with such reproductive events as "morphological plasticity, autoregulation of OT neuronal activity and promotion of maternal behavior, including maternal aggressive behavior to protect offspring," Inga D. Neumann of the University of Regensburg, Germany, notes. "Thus in lactating rats from a line bred for high-anxiety behavior, or HAB, OT release within both the central amygdala and the PVN was positively correlated with the level of maternal offensive behavior against an intruder." In addition, the lactating HAB dams display higher aggression and central OT release compared with a low-anxiety line.

Keyword: Aggression; Hormones & Behavior
Link ID: 7651 - Posted: 06.24.2010

Hypnosis brings to mind thoughts of swinging watches and some stage hypnotist making people walk around acting like chickens, but how much can it really change the way we think and act? Hypnotic suggestion seems to be able to put novel ideas into our heads, making us do and say unusual things. But some psychologists believe it is powerful enough to override some of the most ingrained and automatic processes of the brain, such as reading. Reading is a skill that once learned becomes unconscious and automatic. Even so, brain researcher Amir Raz has shown that a form of hypnotic suggestion can make some people undo automatic behaviors, even to the point of viewing their native language as meaningless. "It tells us a little bit about what we can and cannot do to certain deeply ingrained processes," says Raz from the New York State Psychiatric Institute. "In a way, this is very much like 'unringing' the bell if you're thinking about Pavlov and his dogs. Pavlov would ring a bell and the dogs would salivate because Pavlov would condition them to give them food right after the bell was rung," Raz explains. "What we're doing here is we're taking a process that is already deeply ingrained in people, reading, in this case. When we start reading this process is not at all automatic but after a few years of training, particularly when we're adults and particularly as readers, we read effortlessly. As soon as something is in front of us, we read it immediately. What I'm showing is that you can actually make people unlearn the reading process." © ScienCentral, 2000-2005.

Keyword: Language
Link ID: 7650 - Posted: 06.24.2010

Intelligence may lead to a better paid job and quality of life but, in old age, cleverness has no effect on happiness, new research suggests. A happy old age is what many people spend their lives preparing for, aiming for financial security and good health in their dotage. But one thing people need not worry about, it seems, is how clever they are. A study of more than 400 pensioners reveals that cognitive ability is unrelated to happiness in old age. The Scottish research looked at a group of 416 people born in 1921, who underwent intelligence tests at the ages of 11 and 79. At the age of 80, the group was also sent a “satisfaction with life” questionnaire, which had them assess their current level of happiness. “We found no association between levels of mental ability and reported happiness, which is quite surprising because intelligence is highly valued in our society,” says Alan Gow, who carried out the research with colleagues at the University of Edinburgh, UK. Participants were asked to respond to five statements about their happiness and give a rating on a scale of 1 to 7 according to how strongly they agreed. The statements referred mainly to their current life, but also asked if, given the chance, they would like to have done anything differently with their lives. © Copyright Reed Business Information Ltd.

Keyword: Intelligence; Emotions
Link ID: 7649 - Posted: 06.24.2010

By NICHOLAS WADE If stem cells ever show promise in treating diseases of the human brain, any potential therapy would need to be tested in animals. But putting human brain stem cells into monkeys or apes could raise awkward ethical dilemmas, like the possibility of generating a humanlike mind in a chimpanzee's body. No such experiments are planned right now. But in a paper today in the journal Science, a group of scientists and ethicists is advising researchers to exercise care with such experiments, particularly if they should lead to a large fraction of a chimpanzee's brain's being composed of human neurons. The group, led by Ruth R. Faden, a biomedical ethicist at Johns Hopkins University, acknowledged the view that monkeys and apes should not be experimented on at all, but nevertheless considered what kinds of research should be permitted if the experiments were required by regulatory authorities. Clinical trials often depend on previous tests with rats or mice that have some equivalent of the human disease. But for some diseases that affect the human brain, the rodent models may not serve so well. If stem cell therapies for Alzheimer's or Parkinson's disease were to be developed, the Food and Drug Administration might require tests in monkeys or apes before permitting clinical trials. Copyright 2005 The New York Times Company

Keyword: Stem Cells
Link ID: 7648 - Posted: 07.15.2005

Writing in the journal Nature, Michael Kosfeld and colleagues reported that intranasal administration of oxytocin, a human neuropeptide involved in maternal bonding, “causes a substantial increase in trusting behavior, thereby greatly increasing the benefits from social interactions.”1 The double-blind study involved a trust game with real monetary stakes, in which the subjects played the role of either an investor or a trustee. Investors could choose whether and how much money to invest with an anonymous trustee, and the trustees could choose whether to honor or violate the investors’ trust. The investors who had inhaled the oxytocin invested 17% more money than those who received the placebo. In what is becoming an increasingly tantalizing form of neuroscience, researchers in this study obtained consent not to study the phenomenon about which they were interested, trust, but rather the effect of a hormone more generally. The seemingly subtle shift in language, with its attendant deception, was obviously necessary for the researchers to conduct their study. But did they, and do researchers who would study phenomena of character more generally, have a special responsibility to inform subjects about the risks of “shifts in subject consciousness?” It is more than a question of informed consent that is at hand. For just as there is an obvious irony in manipulating subjects’ inclination to trust in order to study the biochemical basis of that trust, there is a broader safety—and indeed human—concern about whether trust should be scientifically manipulated in clinical studies in this way at all.

Keyword: Hormones & Behavior
Link ID: 7647 - Posted: 06.24.2010

By Ceci Connolly A government Web site intended to help parents and teenagers make "smart choices about their health and future" includes inaccurate or misleading information that may alienate some families or prompt riskier behavior, according to a team of medical experts who reviewed the material. Three physicians and a child psychologist analyzed the Bush administration's 4Parents.gov Web site and concluded it made many incorrect assertions about condoms, sexual orientation, single-parent households and the dangers of oral sex. They also found omissions of information that could go a long way toward raising healthy young adults, such as warning against the dangers of drinking alcohol. Rep. Henry A. Waxman (D-Calif.), a frequent administration critic who solicited the analyses, said the site is the latest example of "the distortion of scientific information" in favor of a conservative ideology focused predominantly on promoting abstinence-until-marriage programs. "A federally-funded website should present the facts as they are, not as you might wish them to be," Waxman wrote to Health and Human Services Secretary Mike Leavitt. "It is wrong -- and ultimately self-defeating -- to sacrifice scientific accuracy in an effort to frighten teens and their parents." © 2005 The Washington Post Company

Keyword: Sexual Behavior; Drug Abuse
Link ID: 7646 - Posted: 06.24.2010

By Jennifer Viegas, Discovery News — Chickens do not just live in the present, but can anticipate the future and demonstrate self-control, something previously attributed only to humans and other primates, according to a recent study. The finding suggests that domestic fowl, Gallus gallus domesticus, are intelligent creatures that might worry. "An animal with no awareness of 'later' may not be able to predict the end of an unpleasant experience, such as pain, rendering it (the pain) all-encompassing," said Siobhan Abeyesinghe, lead author of the study. "On the other hand, an animal that can anticipate an event might benefit from cues to aid prediction, but may also be capable of expectations rendering it vulnerable to thwarting, frustration and pre-emptive anxiety." She added, "The types of mental ability the animal possesses therefore dictate how they should best be managed and what we might be able to do to minimize psychological stress." Abeyesinghe, a member of the Biophysics Group at Silsoe Research Institute in England, and her colleagues tested hens with colored buttons. When the birds pecked on one of the buttons, they received a food reward. If the chicken waited two to three seconds, it received a small amount of food. If the bird held out for 22 seconds, it received a "jackpot" that paid out with much more to eat. Copyright © 2005 Discovery Communications Inc.

Keyword: Learning & Memory
Link ID: 7645 - Posted: 06.24.2010

Roxanne Khamsi Mice with memory loss have had their condition reversed, a discovery that should help refine the search for a cure for Alzheimer's disease and other dementias. The study also helps clarify the actual cause of dementia, which should give more focus to drug studies. The brains of people with Alzheimer's and some 50 other forms of dementia are known to have certain characteristic features, including messy bundles of fibres in nerve cells called neurofibrillary tangles. But no one has been sure whether the tangles are a cause or symptom of dementia. Mice engineered to massively overproduce a protein called tau tend to grow more of the tangles and display the same problems with memory and learning as humans with dementia. Researchers think that it is a certain version of the tau protein, rather than a simple over-abundance, that leads to the tangles. It has been speculated that these tau proteins, rather than the tangles, kill nerve cells. Karen Ashe, a neurobiologist at the University of Minnesota Medical School in Minneapolis, and her colleagues hoped to untangle this mystery. They trained mice to navigate a maze partly submerged in water, and watched for signs of memory loss. By the age of three months, mice genetically engineered to express 13 times too much tau protein couldn't remember the route to dry land, and had developed tangles in their brains. ©2005 Nature Publishing Group

Keyword: Alzheimers
Link ID: 7644 - Posted: 06.24.2010

A new type of ear-shape analysis could see ear biometrics surpass face recognition as a way of automatically identifying people, claim the UK researchers developing the system. The technique could be used to identify people from CCTV footage, or incorporated into cellphones to identify the user, says Mark Nixon, a biometrics expert at the University of Southampton. Ears are remarkably consistent, he says. Unlike faces, they do not change shape with different expressions or age, and remain fixed in the middle of the side of the head against a predictable background. “Hair is a problem,” Nixon admits. “But that might be solved by using infrared images.” In an initial small-scale study involving 63 subjects – all taken from a database of face profiles – Nixon and his colleague David Hurley found their method to be 99.2% accurate. This is a great starting point, says Nixon, but in theory the method could be greatly improved. “There are more fixed features available in an ear than we have been measuring,” he says. Much larger populations are needed to determine how reliably it could be implemented. But an initial analysis of the decidability index – a measure of how similar or dissimilar each of the ears were – indicates how unique an individual ear might be. © Copyright Reed Business Information Ltd

Keyword: Hearing
Link ID: 7643 - Posted: 06.24.2010

Researchers have constructed a new detailed map of the three-dimensional terrain of a synapse — the junction between neurons which are critical for communication in the brain and nervous system. The “nano-map,” which shows the tiny spines and valleys resolved at nanometer scale, or one-billionth of a meter, has already proven its worth in changing scientists' views of the synaptic landscape. Using the map as a guide, the research team, led by Howard Hughes Medical Institute investigator Terrence Sejnowski, has developed a biologically accurate computer simulation of synaptic function. The simulation combines 3-D electron microscope maps with computer simulation and physiological measurements from real neurons. Their in silico modeling indicates that the synapse may behave more like a shotgun than a rifle when it comes to firing the neurotransmitters involved in neuronal communication. The textbook view of the synapse describes it as a place where rifle-like volleys of neurotransmitter are launched from one defined region of the sending neuron to another defined target on the receiving neuron. In contrast, the new data suggest that synapse can act like a shotgun, firing buckshot-like bursts of neurotransmitter to reach receptors arrayed beyond the known receiving sites. The researchers say that right now they have little idea of how the synaptic shotgun functions. The research was published in the July 15, 2005, issue of the journal Science. Sejnowski, who is at The Salk Institute, and colleagues Darwin Berg and Mark Ellisman, both of the University of California, San Diego, led the research team, which also included co-authors from Carnegie Mellon University and the University of Pittsburgh. © 2005 Howard Hughes Medical Institute

Keyword: Development of the Brain; Learning & Memory
Link ID: 7642 - Posted: 06.24.2010

Howard Hughes Medical Institute researchers have discovered a novel way in which the brain size of developing mammals may be regulated. They have identified a signaling pathway that controls the orientation in which dividing neural progenitor cells are cleaved during development. The way these cells are sliced during development is critical because at later stages of neurogenesis, vertical cleavage gives rise to two mature neurons that are incapable of further division, while horizontal cleavage yields one neuron and one progenitor cell that can continue to support brain growth. The researchers speculate that this type of regulatory decision point may play a powerful role in determining the ultimate size of the mammalian brain. Inherited disorders that cause the brain to develop too small or too large may also influence this developmental pathway. Howard Hughes Medical Institute investigator Li-Huei Tsai and postdoctoral fellow Kamon Sanada, both at Harvard Medical School, published their findings in the July 15, 2005, issue of the journal Cell. The researchers drew on studies by other researchers that showed that the orientation of cleavage planes in dividing neural progenitor cells in the neocortex determines the fate of the resulting daughter cells. However, nothing was known about the molecular signaling mechanism that regulates the decision to cleave one way or another, said Tsai. © 2005 Howard Hughes Medical Institute.

Keyword: Development of the Brain
Link ID: 7641 - Posted: 06.24.2010

Healthy people, including children, might one day take drugs to boost their intelligence, scientists predict. The think-tank Foresight, outlined the scenario in an independent report looking at potential developments over the next 20 years. Such "cognitive enhancers" could become as "common as coffee", they suggest. Scientists did not rule out children taking exams facing drug tests, as sportsmen do, to see if any have taken 'performance enhancing substances'. The report was compiled by 50 experts, who set out their predictions for the next two decades. Some drugs are already known to aid mental performance. Ritalin, now prescribed to children with attention deficit hyperactivity disorder (ADHD), has already been used by some students to improve their performance in exams. Modafinil, used now to treat sleep disorders, has been shown to help people remember numbers more effectively. It can also make people think more carefully before making decisions. There is also a type of molecule called ampakins, which enhance the way some chemical receptors in the brain work, suggesting drugs could be developed to improve people's memory when they are tired. (C)BBC

Keyword: Attention; Learning & Memory
Link ID: 7640 - Posted: 07.14.2005