By Gretchen Vogel The body's internal clock is set by both light and food signals--that's one reason doctors recommend fighting jetlag with sunlight and regular meals. But just how these signals dictate our circadian rhythms is still being sorted out. In this week's online edition of Proceedings of the National Academy of Sciences, scientists report that they have identified the region of the brain that seems to adjust a body's circadian clock in response to food. If confirmed, the find might help scientists explain a little-understood connection between obesity and late-night eating. Mice are nocturnal animals, sleeping much of the day and feeding and moving around at night. But when researchers offer food only during daylight hours, the animals quickly switch their day-night patterns, sleeping more in the dark and exploring and eating when it's light. These patterns persist even when the brain's main clock-setting area, the suprachiasmatic nucleus (SCN), is damaged or destroyed. Therefore, scientists have been searching for what they call a food-entrainable oscillator, a region of the brain that sets daily rhythms in response to food. To find the region, geneticist Masashi Yanagisawa and his colleagues at the University of Texas Southwestern Medical Center in Dallas looked at gene-expression patterns in two groups of mice. One group had been trained to expect food only during the day; the other could eat any time they were hungry. The researchers found that, in the day-eaters, the levels of a clock gene called mPer1 oscillated in a strong daily pattern in a brain region called the dorsomedial hypothalamic nucleus (DMH), which doesn't normally do that. The gene expression in the SCN, however, looked normal. When mice are fed during the day, says Yanagisawa, DMH hijacks the SCN signals, making food the primary arbiter of the circadian clock. © 2006 American Association for the Advancement of Science

Keyword: Biological Rhythms; Obesity
Link ID: 9194 - Posted: 06.24.2010

WEST LAFAYETTE, Ind. —Mice that couldn't be dissuaded from the object of their attention by a piece of sweet, crunchy cereal may help researchers find new treatments and cures for human disorders like autism and Parkinson's disease. For the first time, a psychiatric test for monitoring many human mental abnormalities has been adapted for use in mice, according to researchers at Purdue University, University of California-Davis and Justus-Liebig University in Giessen, Germany. The test involves the ability to switch attention from one task to another, a skill often impaired in people with autism and similar illnesses. "Without a measure of cognitive deficit in mice that is relevant to such disorders in humans, research into new diagnostic methods, treatments and cures is severely hindered," said Joseph Garner, a Purdue assistant professor of animal sciences and the study's lead author. "The level of complexity at which we assess mouse behavior is often very rudimentary, and it just does not match up with subtleties of the cognitive deficits in human mental dysfunction or with the tools we use to study the mechanisms that underlie disorders in people." Garner and his colleagues designed a task to measure a process called set shifting in which a focus on one object must be abandoned in favor of another object or task. This test long has been used to monitor brain processes involved in human psychiatric disorders and also has been tailored to a few other animals. However, researchers previously had not adapted it to the most-used of research mammals, the common laboratory mouse.

Keyword: Autism; Parkinsons
Link ID: 9193 - Posted: 06.24.2010

Michael Hopkin A survey of primate IQ has cemented apes' reputation as our most intelligent cousins. An analysis of a slew of studies designed to spot smartness has concluded that orang-utans and chimps are the chief eggheads, with monkeys and lemurs trailing in their intellectual wake. The study has produced a league table of overall cognitive ability among primates. Previous research had attempted to compare different primates' abilities at specific tasks, but no one had ever combined this data into an overall measure of intelligence. The researchers compiled results from dozens of problem-solving puzzles given to different types of primates by researchers. These included tests of ability to navigate mazes, to untangle a jumble of differently coloured threads to find food, and to spot the odd-one-out in a series of images. They ranked each species and calculated the overall average intelligence of each. Orang-utans emerged at the top of the heap, just edging out chimpanzees. Both species share a prodigious ability to use tools and impart traditional wisdom to their young. "Orang-utans are more patient and deliberative," says Robert Deaner, who led the research while at Duke University Medical Center in Durham, North Carolina. "And they're the master escape artists from zoos." ©2006 Nature Publishing Group

Keyword: Intelligence; Evolution
Link ID: 9192 - Posted: 06.24.2010

Michael Day Smoking marijuana at the time of conception could cause pregnancies to fail, new research in mice suggests. The same problem may occur as a result of taking the slimming drug, rimonabant. The warnings come from embryologists who have discovered key factors that govern an embryo’s chances of successful implantation. After fertilisation in humans and mice, the egg faces a perilous path from the place of conception in the fallopian tube down into the womb. The team from Vanderbilt University Medical Centre, Tennessee, US, has shown that precisely the right levels of a chemical called anandamide are required for this passage to be completed safely. Increasing or decreasing the amount of anandamide drastically harms mouse embryos’ chances of normal implantation and survival. Their research reveals that anandamide levels in the fallopian tubes are governed by two enzymes: one called NAPE-PLD increases levels of anandamide, while NAAH reduces them. Significantly, the team also found that exposing the mice to certain drugs disrupted this delicate balance, thereby impeding an embryo's ability to pass into the womb. One such substance is tetrahydrocannabinol (THC), the major psychoactive component of marijuana. © Copyright Reed Business Information Ltd

Keyword: Drug Abuse
Link ID: 9191 - Posted: 06.24.2010

Measuring the brain development of premature babies in their first weeks of life can show those likely to have difficulties, scientists suggest. An Imperial College team found babies with less brain surface development had poorer mental skills at the age of two. If confirmed in larger studies, the researchers say it may be possible to identify which children need more support and to provide it earlier. The research is published in the Public Library of Science Medicine. Half of all babies who survive after being born very early go on to develop a disability or learning difficulty, past research has found. The cortex, the surface area of the brain, should change from looking like a coffee bean to looking like a walnut while a foetus is in the womb. If a baby is born prematurely, that development needs to take place outside the womb - with all the different stresses the baby will be under at that time. The researchers used MRI (magnetic resonance imaging) scanning to measure brain growth of 113 babies born prematurely between 22 and 29 weeks gestation. A baby is normally born at 40 weeks. The premature babies were scanned up to the point when they would have been eight weeks old, if the pregnancies had gone to term. (C)BBC

Keyword: Development of the Brain
Link ID: 9190 - Posted: 08.01.2006

By Jennifer Couzin A new vaccine helps rats stay svelte no matter what they eat, a study has found. The findings represent the first published animal research on an "obesity vaccine." Meanwhile, a Swiss company is testing a related vaccine on people. Obesity is a major challenge for the pharmaceutical industry. But some progress has been made. Since the early 1990s, scientists have managed to identify naturally occurring molecules that control energy expenditure, satiation, and other elements that govern weight gain and loss. One of these, the hormone ghrelin, was identified 7 years ago and is produced in the stomach (ScienceNOW, 10 November 2005). Rodents given ghrelin eat more and gain weight. Puzzlingly, however, mice that lack ghrelin don't eat less: They have normal appetites, although they burn excess fat. Choosing the hormone as their target, chemical biologist Kim Janda of the Scripps Research Institute in San Diego, California, and colleagues at Scripps and Osaka City University in Japan, crafted three antighrelin vaccines. Each was designed to recognize and inactivate different parts of the hormone. The team immunized 14 male rats with one of the three vaccines; three others got a placebo. The rats received five shots over 12 weeks. © 2006 American Association for the Advancement of Science.

Keyword: Obesity
Link ID: 9189 - Posted: 06.24.2010

Richard Van Noorden Which is the most harmful: ecstasy, alcohol or tobacco? Ecstasy features in the highest class of most countries' drug legislation, but a report released today by British parliamentarians says that the current system for classifying drugs is based more on policy considerations than on science. The report, by the House of Commons Science and Technology Committee, suggests that ecstasy should be placed lower than both alcohol and tobacco in a league table based on a drug's capacity to cause harm. But pharmacologists argue that such an approach may still be difficult to implement in a scientifically rational way. In Britain, illegal drugs are classed in three categories, with class A (including heroin and ecstasy) being the most harmful, and class C (including cannabis) the least. Criminal penalties for supplying or possessing a drug depend on the drug's classification. But committee member Evan Harris has branded the current system of drug classification, instigated in 1971, an "evidence-free zone". Leslie King, a member of Britain's Advisory Council on Misuse of Drugs (ACMD), agrees: "The current system is just scientific anecdotes floating round a table," he says. ©2006 Nature Publishing Group

Keyword: Drug Abuse
Link ID: 9188 - Posted: 06.24.2010

Like detectives trying to solve a murder case, researchers searching for the biological cause of autism have come up with some surprising suspects. They've found that different genes may be responsible for causing autism in boys than in girls. In addition, the researchers also have discovered that other genes may play a role in the early onset form of the developmental disorder and in the recently verified regression, or late onset, type of autism, according to a new study published today in the online edition of the journal Molecular Genetics. The study also provides new evidence for the idea that multiple genes contribute to autism, said lead author Gerard Schellenberg, a researcher at the Puget Sound Veterans Affairs Medical Center and a research professor of medicine at the University of Washington. The research team was headed by Schellenberg, Ellen Wijsman, a UW research professor of medical genetics and Geraldine Dawson, director of the UW's Autism Center. "It is highly unlikely that there is only one gene responsible for autism," said Schellenberg. "There may be four to six major genes and 20 to 30 others that might contribute to autism to a lesser degree. "If an individual only gets three high-risk variants of these genes, it could mean a less-severe form of autism. And because autism is rarer in females, it may take more risk genes for a female to have autism. There also is the possibility that there might be a biological difference in autism for females versus males," he said.

Keyword: Autism; Genes & Behavior
Link ID: 9187 - Posted: 08.01.2006

Researchers have developed a "man-made" scorpion venom to be used in the treatment of brain tumours. The venom is used as a carrier to deliver radioactive iodine into tumour cells left behind after surgery has removed the bulk of the tumour. So far the technique has been tested in 18 patients and further trials are under way, a report in the Journal of Clinical Oncology says. Initial findings suggest the treatment is well-tolerated and may be effective. Gliomas are a particularly aggressive form of brain tumours, with only 8% of patients surviving two years and 3% surviving five years from the time of diagnosis. Despite advances in surgery, radiotherapy and chemotherapy, there has been little improvement in length of survival for patients with gliomas. Researchers at Cedars-Sinai Medical Center, in California, carried out a study using TM-601, a synthetic version of a peptide, that naturally occurs in the venom of the Giant Yellow Israeli scorpion. Unlike many substances, the peptide can pass through the bloodstream into the brain and can bind to glioma cells. Patients in the study first had surgery to remove their tumour. Then 14 to 28 days later, a single, low dose of TM-601 with radioactive iodine attached was injected into the cavity from which the tumour had been removed. (C)BBC

Keyword: Glia; Neurotoxins
Link ID: 9186 - Posted: 07.31.2006

US scientists have found a way to reverse muscular dystrophy (MD) in mice, offering hope of a cure for humans with muscle-wasting diseases. The animals in the Nature Genetics study had myotonic dystrophy - the most common form of MD in adults. The therapy targets a particular kind of toxic molecule to "silence" its presence in the diseased muscle. The University of Virginia team showed the treatment fully restored heart and skeletal muscle function in mice. In myotonic dystrophy, like the other types of MD, faulty DNA is to blame for the abnormalities that occur. Myotonic dystrophy occurs because of a large expansion of DNA code, which most likely causes an accumulation of toxic messenger RNA molecules in cells. Messenger or mRNA is a copy of the information carried by a gene on the DNA. If the DNA code is faulty then the mRNA will be faulty too. These abnormalities lead to the progressive muscle weakness and wasting and heart problems seen in myotonic dystrophy. Dr Mani Mahadevan and his team reasoned that eliminating the toxic mRNA molecules might help reverse the disease. They created mice with faulty DNA that could be turned on and off by adding or removing an antibiotic to their drinking water. In the "on" phase the mice showed all the cardinal features of myotonic dystrophy. When the DNA was turned off, normal skeletal and cardiac muscle function was restored in many, but not all of the mice. (C)BBC

Keyword: Muscles
Link ID: 9185 - Posted: 07.31.2006

A visually impaired artist and poet at the Massachusetts Institute of Technology has collaborated with an optics expert to create a visionary new "Seeing Machine" that could assist people who are visually impaired due to eye diseases like macular degeneration. This ScienCentral News video has more. A combination of eye diseases left M.I.T. poet and artist Elizabeth Goldring with only partial eyesight. During one exam, doctors used a device called a Scanning Laser Ophthalmoscope, or "SLO," that projects images onto the retina - the part of the eye that turns light into sight. It's used for determining the severity of vision loss, but Goldring "saw" it could do much more. "I asked them if they could write a word, and they wrote the word 'sun,' she recalls. "I saw that too, and it was the first word I'd seen for many months." Goldring collaborated with the machine's inventor, Robert Webb of the Schepens Eye Research Institute, 30 M.I.T. students, and some of her personal eye doctors to create a smaller, more affordable device they call a "Seeing Machine." "I was a poet before I became visually challenged and part of the reason I felt so strongly about developing the Seeing Machine was in an effort to keep my visual sense alive and active so that I could continue to be a visual artist and poet," says Goldring. © ScienCentral, 2000-2006.

Keyword: Vision
Link ID: 9184 - Posted: 06.24.2010

Helen Pearson On that dream date, something really might be in the air. Results from a mouse study may bolster the evidence for human pheromones, the long-debated chemical signals thought to unconsciously sway our behaviour. A team at the Fred Hutchinson Cancer Research Center in Seattle, Washington, has identified a class of protein receptor in the lining of mouse noses that may also operate in humans. Researchers know that certain chemicals in mouse urine can alter the social or sexual behaviour of other mice. These chemicals work partly by binding to receptors in a particular structure in the mouse nose, known as the vomeronasal organ. In humans, however, this organ is thought to be defunct and the role of pheromones is hotly debated. Finding such receptors in the lining of the nose, rather the vomeronasal organ, is a more direct parallel with humans. Stephen Liberles and Linda Buck report their finding online this week in Nature (S. D. Liberles & L. B. Buck Nature doi:10.1038/nature05066; 2006). They isolated a group of receptors that can be triggered by at least one known mouse pheromone. ©2006 Nature Publishing Group

Keyword: Chemical Senses (Smell & Taste)
Link ID: 9183 - Posted: 06.24.2010

Roxanne Khamsi A new type of drug which increases blood flow to the vagina in animal experiments has now been shown to be safe in rats. Derived from an experimental heart drug, the new compounds could one day help treat women who find it difficult or impossible to become sexually aroused, say researchers at the drugs company Pfizer. Previous tests have shown that the new compounds, including the most potent one, called R-13, increased vaginal blood flow in animals. New tests now demonstrate that the drugs are safely tolerated by rats. The ultimate aim is to address female sexual arousal disorder (FSAD) in women. The condition sometimes involves blood flow problems in the pelvic region, which might be restored by a drug intervention. Experts agree the approach might eventually benefit the small subset of women who suffer sexual dysfunction due to a physiological cause, due to nerve damage in the pelvic area from surgery, for example. But they stress that such drugs would not effectively treat FSAD when it is due to purely psychological factors. In fact, some question the very existence of FSAD, adding that some women’s sexual dissatisfaction may have to do with the nature of the relationship the women are in. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior
Link ID: 9182 - Posted: 06.24.2010

By Michael Balter If you've ever worried about leaving the safety of one job for the excitement of another, or contemplated an extramarital affair, chances are you experienced conflict anxiety--the nervousness that occurs when we have to choose between competing impulses. Now, researchers working with mice believe they have identified the part of the brain responsible for this mental anguish. The discovery may aid the search for better drugs for anxiety and other emotional disorders. The neural basis of anxiety first began to become clear in the 1980s, when researchers discovered that a drug used to treat anxiety stimulates receptors for a neurotransmitter called serotonin. More recent research has confirmed this connection (ScienceNOW, 27 March 2002), but scientists still know very little about the role that serotonin plays and where in the brain it acts. To explore this role further, a team led by neurobiologist Jay Gingrich of Columbia University knocked out a gene in mice that encodes a serotonin receptor called 5HT2A, one of more than a dozen such receptors identified to date. 5HT2A is abundant in several areas of the brain and is thought to be involved in conflict anxiety. The researchers put the mice through a battery of tests designed to induce a conflict between safety and novelty-seeking behavior. In one experiment, the team recorded how much time the mice spent in dark versus brightly lit spaces. In another, the researchers placed the mice in an elevated maze, where some sections were completely open and others had walls. Compared to control mice, the knockout animals spent significantly more time engaged in novelty-seeking behavior. For example, they spent twice as much time in the brightly lit part of the cage, which mice usually avoid, Gingrich and his colleagues report in tomorrow's Science. © 2006 American Association for the Advancement of Science.

Keyword: Emotions
Link ID: 9181 - Posted: 06.24.2010

Ann Arbor, Mich. -- Obsessive-compulsive disorder tends to run in families, causing members of several generations to experience severe anxiety and disturbing thoughts that they ease by repeating certain behaviors. In fact, close relatives of people with OCD are up to nine times more likely to develop OCD themselves. Now, new research is shedding new light on one of the genetic factors that may contribute to that pattern. And while no one gene "causes" OCD, the research is helping scientists confirm the importance of a particular gene that has been suspected to play a major role in OCD's development. In two papers published simultaneously in the Archives of General Psychiatry, researchers from the University of Michigan, the University of Illinois at Chicago, the University of Chicago and the University of Toronto report finding an association between OCD patients and a glutamate transporter gene called SLC1A1. The gene encodes a protein called EAAC1 that regulates the flow of a substance called glutamate in and out of brain cells. So, variations in the gene might lead to alterations in that flow, perhaps putting a person at increased risk of developing OCD. The new findings are especially important not only because of the simultaneous discoveries reported in the papers, but also because of previous studies that show a functional link between glutamate and OCD. Brain imaging and spinal fluid studies have shown differences in the glutamate system between OCD patients and healthy volunteers, including in areas of the brain where the EAAC1 protein is most common.

Keyword: OCD - Obsessive Compulsive Disorder; Genes & Behavior
Link ID: 9180 - Posted: 07.28.2006

A drug made to enhance memory appears to trigger a natural mechanism in the brain that fully reverses age-related memory loss, even after the drug itself has left the body, according to researchers at UC Irvine. Professors Christine Gall and Gary Lynch, along with Associate Researcher Julie Lauterborn, were among a group of scientists who conducted studies on rats with a class of drugs known as ampakines. Ampakines were developed in the early 1990s by UC researchers, including Lynch, to treat age-related memory impairment and may be useful for treating a number of central nervous system disorders, such as Alzheimer’s disease and schizophrenia. In this study, the researchers showed that ampakine drugs continue to reverse the effects of aging on a brain mechanism thought to underlie learning and memory even after they are no longer in the body. They do so by boosting the production of a naturally occurring protein in the brain necessary for long-term memory formation. The study appears in the August issue of the Journal of Neurophysiology. “This is a significant discovery,” said Gall, professor of anatomy and neurobiology. “Our results indicate the exciting possibility that ampakines could be used to treat learning and memory loss associated with normal aging.” © Copyright 2002-2006 UC Regents

Keyword: Learning & Memory; Alzheimers
Link ID: 9179 - Posted: 06.24.2010

Doctors are testing a radical new way to help smokers quit: a shot that "immunizes" them against the nicotine rush that fuels their addiction. More than 300 people around the country are testing an experimental vaccine that makes the immune system attack nicotine in much the same way it would fight a life-threatening germ. The treatment keeps nicotine from reaching the brain, making smoking less pleasurable and theoretically, easier to give up. The small amount that still manages to get in helps to ease withdrawal, the main reason most quitters relapse. If it works — and this has not yet been proved — the vaccine could become part of a new generation of smoking cessation treatments. They attack dependency in the brain instead of just replacing the nicotine from cigarettes in a less harmful way, like the gum, lozenges, patches and nasal sprays sold today. One such drug, Pfizer Inc.'s Chantix, is due on the market any day now. Another, Sanofi-Aventis SA's Acomplia, recently won approval in Europe as a weight-loss drug. If U.S. regulators follow suit, some doctors say they also will use it to help smokers quit, especially those concerned about gaining weight. © 2006 Discovery Communications Inc.

Keyword: Drug Abuse
Link ID: 9178 - Posted: 06.24.2010

Riverside, Calif. -- UCR researchers have made a major leap forward in understanding how the brain programs innate behavior. The discovery could have future applications in engineering new behaviors in animals and intelligent robots. Innate or "instinctive" behaviors are inborn and do not require learning or prior experience to be performed. Examples include courtship and sexual behaviors, escape and defensive maneuvers, and aggression. Using the common fruit fly as a model organism, the researchers found through laboratory experiments that the innate behavior is initiated by a "command" hormone that orchestrates activities in discrete groups of peptide neurons in the brain. Peptide neurons are brain cells that release small proteins to communicate with other brain cells and the body. The researchers report that the command hormone, called ecdysis-triggering hormone or ETH, activates discrete groups of brain peptide neurons in a stepwise manner, making the fruit fly perform a well-defined sequence of behaviors. The researchers propose that similar mechanisms could account for innate behaviors in other animals and even humans. Study results appear as the cover article in this week's issue of Current Biology. "To our knowledge, we are the first to describe how a circulating hormone turns on sequential steps of an innate behavior by inducing programmed release of brain chemicals," said Young-Joon Kim, a postgraduate researcher in UCR's Department of Entomology working with Michael Adams.

Keyword: Hormones & Behavior
Link ID: 9177 - Posted: 07.28.2006

Zeeya Merali PIT vipers and boid snakes strike at prey with uncanny accuracy even when blindfolded, a feat that's been hard to explain given the rudimentary nature of their heat-sensing organs. It seems that some rather spectacular image processing may be the key. To scout for cool shelters, and hunt in complete darkness, pit vipers and boid snakes are known to use infrared sensing organs. But their skill has amazed scientists. "In the lab, blindfolded snakes can strike a running rat behind the ears to avoid its sharp teeth," says physicist Leo van Hemmen of the Technical University of Munich in Germany. "It must be seeing more than just a warm blob." But how, given that the snakes are saddled with very crude heat-sensing apparatus? On each side of their face, they have a pit organ that is little more than a hole with a heat-sensitive membrane stretched across it. "The eye has a lens to focus a visual image, but these holes can't do that," says van Hemmen. Instead, the pit organs are supposed to work as "pinhole" cameras, except that the holes are too large at 1 millimetre or more in diameter. "These must produce images that are just fuzzy blurs," says van Hemmen. "So, how can the snakes strike with such precision?" © Copyright Reed Business Information Ltd.

Keyword: Vision
Link ID: 9176 - Posted: 06.24.2010

By C. CLAIBORNE RAY Q. Is left-handedness less common in women? A. Studies of Western populations usually find that left-handedness is somewhat less common in women, but perhaps because left-handedness is hard to define, the difference varies by several percentage points. One large study in 1971 used a standard called the Edinburgh Handedness Inventory, which asks which hand is used for different tasks, and found that 90 percent of women were right-handed, as against 86 percent of men. But a smaller 1988 study using the same inventory found no significant difference by sex, and a large Internet study done for the BBC for another purpose found sex differences that varied by ethnic group. Anthropologists’ studies of traditional cultures in Africa and elsewhere found a wide range of differences, from no left-handed women at all to levels approximating those in Western studies. Some researchers have suggested that the trend for more men to be left-handed is not universal or may be affected by social norms, with left-handed men stubbornly clinging to left-handedness while left-handed women are more easily persuaded to join the majority. Copyright 2006 The New York Times Company

Keyword: Laterality; Sexual Behavior
Link ID: 9175 - Posted: 06.24.2010