Wriggling worms are motivated by their sense of smell - lingering when they detect the tempting aroma of their favorite bacterial snack, or twisting and turning to explore new territory when that aroma fades. In new studies, Howard Hughes Medical Institute scientists have now shown how odor-sensing neurons in the worm can activate or inhibit other neurons that control crawling and turning. The studies have begun to explain how neurons are capable of carrying information over minutes or even hours - timescales that are much longer than the millisecond timeframes measured by many neuroscience experiments. The research team, led by Howard Hughes Medical Institute investigator Cornelia Bargmann, published its findings in the November 1, 2007, issue of the journal Nature. Bargmann is at The Rockefeller University, and other co-authors were from Stanford University. The scientists say their findings demonstrate that transient changes in sensory cues can trigger sustained behaviors like food-seeking and mating. The keen sense of smell in C. elegans has provided a unique opportunity for Bargmann to understand the interface between genetics and experience. On the one hand, many responses to odors are genetically determined, like the favorable response by human infants to the smell of vanilla. On the other hand, a bad experience, like getting sick after eating a particular food, can create a lifetime aversion to its smell. © 2007 Howard Hughes Medical Institute

Keyword: Chemical Senses (Smell & Taste)
Link ID: 10922 - Posted: 06.24.2010

Evidence is building that the cold sore virus may be linked to Alzheimer's disease, an expert says. In lab tests, Manchester University found brains infected with the herpes simplex virus, HSV-1, saw a rise in a protein linked to Alzheimer's. Scientists believe the discovery could pave the way for a vaccine that may help prevent the brain disorder, New Scientist magazine reported. But such a breakthrough was a long-time off, experts said. The researchers infected cultures of human brain cells with the virus and found a "dramatic" increase in levels of the beta amyloid protein - the building blocks of deposits, or plaques, which form in the brains of people with Alzheimer's. A similar increase was seen in the brains of mice infected with HSV-1. In a separate experiment, the team stained brain slices taken from dead Alzheimer's patients and found DNA from HSV-1 attached to the plaques. Previous research has established that HSV-1 is found in the brains of up to 70% of people with Alzheimer's. And a team from the University of Rochester Medical Center in New York found that it was more likely to cause a problem in people who carry a mutant version of a specific gene called ApoE4, which is involved in the breakdown of fats by the body. They found the vast majority of Alzheimer's patients they examined carried the gene - and suspect that it works to make HSV-1 more active. Scientists have still to establish a direct link between the virus and the disease, but the Manchester team believe the findings offer hope for the future. (C)BBC

Keyword: Alzheimers
Link ID: 10921 - Posted: 11.02.2007

A new study finds that neural stem cells may be able to save dying brain cells without transforming into new brain tissue, at least in rodents. Researchers from the University of California, Irvine, report that stem cells rejuvenated the learning and memory abilities of mice engineered to lose neurons in a way that simulated the aftermath of Alzheimer's disease, stroke and other brain injuries. Researchers expect stem cells to transform into replacement tissue capable of replacing damaged cells. But in this case, the undifferentiated stem cells, harvested from 14-day-old mouse brains, did not simply replace neurons that had died off. Rather, the group speculates that the transplanted cells secreted protective neurotrophins, proteins that promote cell survival by keeping neurons from inducing apoptosis (programmed cell death). Instead, the once ill-fated neurons strengthened their interconnections and kept functioning. "The primary implication here is that stem cells can help rescue memory deficits that are due to cell loss," says Frank LaFerla, a professor of neurobiology and behavior at U.C. Irvine and the senior author on a new study published in The Journal of Neuroscience. If the therapeutic benefit was indeed solely due to a neurotrophic factor, the door could be opened to using that protein alone as a drug to restore learning ability. LaFerla's team genetically engineered mice to lose cells in their hippocampus, a region in the forebrain important for short-term memory formation. These mice were about twice as likely than unaltered rodents to fail a test of their ability to discern whether an object in a cage had been moved since their previous visit. © 1996-2007 Scientific American, Inc.

Keyword: Neurogenesis; Alzheimers
Link ID: 10920 - Posted: 06.24.2010

By CLAUDIA WALLIS From the earliest months, a healthy baby engages in an astonishing range of social behaviors. Most will begin smiling back at a loved one in the first four months of life. Most will follow a parent's gaze with their own eyes by eight months. Most will also study a caregiver's facial expressions and mimic exhibits of fear, surprise or delight with their own tiny features. They will babble a conversation back and forth by nine months, respond to their names by 10 months, and begin to point to a desired toy or treat by around a year. But some babies won't do these things, and a pattern of such deficits can be an early sign of autism. Despite these and many other early tip-offs, autism spectrum disorders (ASD) are rarely diagnosed before age 3. More subtle forms, such as Asperger's Syndrome, may not be recognized until the child begins school. The American Academy of Pediatrics (AAP) would like to change this. At its annual meeting, held in San Francisco on Monday, the AAP released two reports: one aimed at helping pediatricians recognize autism spectrum disorders — in all their varieties — by age 2 and the other at providing guidance for early intervention. At the same time the AAP formally recommended that all pediatricians routinely screen for autism at ages 18 months and 2 years and announced it was making a new "toolkit" of diagnostic information available to all its members — for about $70. © 2007 Time Inc.

Keyword: Autism
Link ID: 10919 - Posted: 06.24.2010

Nicholas K. Geranios, -- Washoe, a female chimpanzee said to be the first non-human to acquire human language, has died of natural causes at the research institute where she was kept. Washoe, who first learned a bit of American Sign Language in a research project in Nevada, had been living on Central Washington University's Ellensburg campus since 1980. Her keepers said she had a vocabulary of about 250 words, although critics contended Washoe and some other primates learned to imitate sign language, but did not develop true language skills. She died Tuesday night, according to Roger and Deborah Fouts, co-founders of The Chimpanzee and Human Communications Institute on the campus. She was born in Africa about 1965. She was taken to the veterinary hospital at Washington State University on Wednesday for a necropsy. Her memorial will be Nov. 12. "Washoe was an emissary, bringing us a message of respect for nature," Dr. Mary Lee Jensvold, assistant director of the nonprofit institute, said Wednesday. The Fouts went to Central Washington from Oklahoma in 1980 to create a home for Washoe and other chimps. © Discovery Communications

Keyword: Language
Link ID: 10918 - Posted: 06.24.2010

Roxanne Khamsi Football players know that following the position of teammates on the field is a tricky task. New research, however, suggests that people can actually track the position of twice as many moving objects as had been thought. The finding could have implications for everything from video game design to air traffic monitoring. To determine how many objects people can follow at once, scientists show volunteers a screen with many moving dots and indicate which ones the subjects should focus on. Earlier experiments had suggested participants can accurately track the position of up to four dots. "The magical number was thought to be four," explains Steven Franconeri at Northwestern University in Evanston, Illinois, US. But Franconeri and his colleague George Alvarez at the Massachusetts Institute of Technology in Cambridge, Massachusetts, US, both suspected that people could do far better at this task, depending on the speed at which the dots moved. (View some examples of the task here.) The vision researchers recruited a dozen students and asked them to track a specific number of the 16 moving dots that appeared on the computer screen before them. Unlike in previous experiments, the dots came close to one another but did not touch. © Copyright Reed Business Information Ltd.

Keyword: Attention; Vision
Link ID: 10917 - Posted: 06.24.2010

Alison Abbott Dangle a mouse by its tail, and it will wriggle and strain to escape before eventually recognizing the hopelessness of its situation. Measure the time it takes to abandon thoughts of helping itself, and you have one of the classic animal tests for depression. Except it's not, says Laurence Tecott, a research psychiatrist at the University of California, San Francisco. “We can't say that that mouse is depressed, and we can't say you would be if you were strung up by your tail,” he says. The reason we have not seen a genuinely new class of drug in psychiatry for 50 years, he asserts, is largely because animal models are woefully inadequate representations of human-specific disorders. You'll hear the same story from many others. But things are not as hopeless for scientists as they may seem for the dangling mouse; some recent papers offer tantalizing hints of a way forward. “No one is going to create a mouse model of suicidality,” says Eric Nestler, a neuroscientist at the University of Texas Southwestern Medical Center at Dallas. “But sensible models of important aspects of the neurobiology underpinning psychiatric disorders are just around the corner.” Classical animal tests for psychiatric disorders are based on responses to clinically proven drugs. What the tests don't necessarily do, however, is reflect the cause or the biological basis of the disorder they are supposed to mimic. Most researchers agree that it's time to apply recent findings about the human brain to creating more useful mouse models — often by deleting, adding or mutating candidate susceptibility genes. © 2007 Nature Publishing Group

Keyword: Schizophrenia; Depression
Link ID: 10916 - Posted: 06.24.2010

Alison Abbott It's not often that research results look this good. An elegant new way to visualize individual brain cells not only provides a major boost to scientists trying to understand how the brain works, but has also won one of its developers a major prize in science photography. The method — described by neuroscientists at Harvard University in Cambridge, Massachusetts, in today’s Nature 1 — allows researchers to see more clearly how individual neurons connect with each other by colouring each one from a palette of about 90 shades. In this way they will be able to build up a detailed diagram of the brain's wiring, which will help to study how it computes. More than a century ago, neuroscientists developed the first method of staining individual neurons — with silver chromate. Work with this technique was the basis of the Nobel Prize in Physiology or Medicine in 1906. But this could only stain neurons with one colour. Only in the last decade have scientists improved on this technique, using genetic engineering to transfer genes for fluorescent proteins into mice such that they are expressed in neurons. But until now they could transfer no more than two florescent-protein genes at a time, lighting up the brain with two colours. “It was clear that two colours were not enough to map connections efficiently in the brain’s complex tangle of neurons,” says Joshua Sanes, one of the paper’s senior scientists. © 2007 Nature Publishing Group

Keyword: Development of the Brain
Link ID: 10915 - Posted: 06.24.2010

A single gene may control why some people are sensitive to the slightest smell of sweat, while others appear oblivious to the odour. A team from Israel found people who carried at least one working version of a gene called OR11H7P were hypersensitive to the smell. The PLoS Biology study found women were slightly more sensitive to many smells than men. However, they found social factors, as well as genes, were important. Our sense of smell often takes a back seat to our other senses - but humans can perceive up to 10,000 different odours. Like mice, we have about 1,000 different genes for the smell-detecting receptors in our olfactory system. However, over half of these genes have become defunct in the last few million years. Some of these genes are "broken" in all people, while others still function in some of the population. Researchers from the Weizmann Institute asked volunteers to sniff varying concentrations of compounds that smelled like banana, eucalyptus, spearmint, or sweat. They compared their ability to detect each odour with their patterns of receptor gene loss. One gene - OR11H7P - appeared to be associated with the capacity of smelling sweat. (C)BBC

Keyword: Chemical Senses (Smell & Taste); Genes & Behavior
Link ID: 10914 - Posted: 10.31.2007

NEW YORK - It was one of the worst killing rampages in U.S. history. In August 1966, Charles Whitman murdered his wife and his mother, then climbed a tower at the University of Texas and used a high-powered rifle to fatally shoot 14 more people before being killed by police. He left a note that said, "I cannot rationally pinpoint any specific reason for doing this." An autopsy later revealed he had a brain tumor, which some experts said may have affected his actions. At the time, there was no way to detect such a tumor without surgery. But today, scientists have developed noninvasive brain scans that may reveal whether a person has a brain abnormality that could affect decision-making or trigger violence, with huge implications for the law. Neuroscientists use functional magnetic resonance imaging techniques — in which a person's head is put in a machine like a giant magnet — to gaze deep within the brain to view neural regions that monitor behavior and regulate emotions. It is a young field, but one that ultimately could have as dramatic an impact on the legal system as DNA testing, said Michael Gazzaniga, the director of a new project to study the implications of neuroscience for the U.S. judicial system. Copyright 2007 Reuters.

Keyword: Aggression
Link ID: 10913 - Posted: 06.24.2010

WASHINGTON - Science is getting a grip on people’s fears. As Americans revel in all things scary on Halloween, scientists say they now know better what’s going on inside our brains when a spook jumps out and scares us. Knowing how fear rules the brain should lead to treatments for a major medical problem: When irrational fears go haywire. “We’re making a lot of progress,” said University of Michigan psychology professor Stephen Maren. “We’re taking all of what we learned from the basic studies of animals and bringing that into the clinical practices that help people. Things are starting to come together in a very important way.” About 40 million Americans suffer from anxiety disorders, according to the National Institute of Mental Health. A Harvard Medical School study estimated the annual cost to the U.S. economy in 1999 at roughly $42 billion. Balance is key Fear is a basic primal emotion that is key to evolutionary survival. It’s one we share with animals. Genetics plays a big role in the development of overwhelming — and needless — fear, psychologists say. But so do traumatic events. “Fear is a funny thing,” said Ted Abel, a fear researcher at the University of Pennsylvania. “One needs enough of it, but not too much of it.” © 2007 The Associated Press.

Keyword: Emotions
Link ID: 10912 - Posted: 06.24.2010

By ANAHAD O’CONNOR People who suffer from chronic headaches have been known to try all sorts of pills and home remedies. But cayenne peppers? Behind the folk wisdom is capsaicin, the active ingredient in cayenne. It is said to bring relief by depleting Substance P, a neurotransmitter that helps transmit pain impulses. Sounds unlikely, but a number of studies have tested the claim, and most have found evidence to support it. One prominent study was published in 1998 in The Clinical Journal of Pain by researchers in the department of anesthesia and critical care at the University of Chicago. In it, the researchers analyzed data from 33 prior studies and found that capsaicin seemed to work better than placebos for headaches occurring in clusters. But simply eating hot sauce isn’t going to help. Most studies suggest that capsaicin works just when applied topically. A study by researchers at Massachusetts General Hospital recruited sufferers of chronic headaches and randomly split them. One group had small amounts of diluted capsaicin applied inside the nose for a week. The other received placebo. The study found “a significant decrease in headache severity in the capsaicin group,” but not the placebo group. Other studies, including one this year, published similar results. Copyright 2007 The New York Times Company

Keyword: Pain & Touch
Link ID: 10911 - Posted: 06.24.2010

By Tamara Holt Mark Dewis is a king among flavor scientists. But right now, the director of flavor research and development at International Flavors & Fragrances (IFF), one of the world's biggest flavor companies, resembles nothing so much as a kid who can't wait for show-and-tell. He grins widely as he describes his new million-dollar machine. "There are only five of these in the world," he boasts, throwing open the lab door. Filling the center of the room from floor to ceiling is what looks like a small building with a lot of stainless-steel tubing attached. It's a high-performance liquid chromatograph, an instrument that separates compounds according to their chemical affinity with certain solvents and resins. Dewis calls it a "Sepbox," which is his particular instrument's trade name, and it's one of the largest on the planet. It is, in effect, a giant mouth, and in cabinets along the wall are jars full of the food he feeds it. The labels look familiar—"oregano," "olives," "coffee"—but there are three jars of each, broken down into flakes or waxy pellets by different solvents. Dewis digs up all kinds of things to be tasted by his stainless-steel pet. When food scientists suspect that there might be, for example, a molecule in orange peel that makes citrus taste particularly fresh, Dewis feeds extracts of peel to the Sepbox, and out the other end come hundreds of chemical compounds, separated into groups, for further analysis. Then, a few years later, a new flavor of energy drink hits the market. © 2007 Popular Science

Keyword: Chemical Senses (Smell & Taste)
Link ID: 10910 - Posted: 06.24.2010

Susan Courtney When we choose between two courses of action, are we aware of all the things that influence that decision? Particularly when deliberation leads us to take a less familiar or more difficult course, scientists often refer to a decision as an act of "cognitive control." Such calculated decisions were once assumed to be influenced only by consciously perceived information, especially when the decision involved preparation for some action. But a recent paper by Hakwan Lau and Richard Passingham, "Unconscious Activation of the Cognitive Control System in the Human Prefrontal Cortex," demonstrates that the influences we are not aware of can hold greater sway than those we can consciously reject. We make countless "decisions" each day without conscious deliberation. For example, when we gaze at an unfamiliar scene, we cannot take in all the information at once. Objects in the scene compete for our attention. If we're looking around with no particular goal in mind, we tend to focus on the objects most visually different from their surrounding background (for example, a bright bird against a dark backdrop) or those that experience or evolution have taught us are the most important, such as sudden movement or facial features -- particularly threatening or fearful expressions. If we do have a goal, then our attention will be drawn to objects related to it, such as when we attend to anything red or striped in a "Where's Waldo" picture. Stimulus-driven and goal-driven influences alike, then, bias the outcome of the competition for our attention among a scene's many aspects. © 1996-2007 Scientific American, Inc.

Keyword: Learning & Memory; Emotions
Link ID: 10909 - Posted: 06.24.2010

A new analysis suggests that about 3.4 million Americans age 71 and older — one in seven people in that age group — have dementia, and 2.4 million of them have Alzheimer's disease (AD). The study, supported by the National Institutes of Health (NIH), is the latest in a series of analyses attempting to assess the prevalence of dementia and AD, the most common form of dementia. Published online this week in Neuroepidemiology, the study is the first to estimate rates of dementia and AD using a nationally representative sample of older adults across the United States. Brenda L. Plassman, Ph.D., of Duke University Medical Center, with Kenneth M. Langa, M.D., Ph.D., and David R. Weir, Ph.D., of the University of Michigan, Robert B. Wallace, Ph.D., of the University of Iowa, and others, conducted the analysis as part of the Aging, Demographics and Memory Study (ADAMS). ADAMS is a sub-study of the larger Health and Retirement Study (HRS), the leading resource for data on the combined health and economic circumstances of Americans over age 50. ADAMS and the HRS are sponsored by the National Institute on Aging, a component of NIH, under a cooperative agreement with the University of Michigan. The study highlights the nationwide reach of dementia, which affects not only those with the disease, but their families and communities as well. "As the population ages during the next few decades, the prevalence of Alzheimer's disease will increase several-fold unless effective interventions are discovered and implemented," said NIA Director Richard J. Hodes, M.D. "These data underscore the urgency of research in this area."

Keyword: Alzheimers
Link ID: 10908 - Posted: 06.24.2010

By Jocelyn Kaiser SAN DIEGO, CALIFORNIA--Variants in two genes may explain why psychotherapy helps only some people with depression, according to a preliminary study presented here Friday at the annual meeting of the American Society of Human Genetics. Researchers are uncovering more and more evidence that genetics play a role in how people respond to psychotropic drugs. In 2006, for example, scientists identified a gene variant that seems to explain why some patients respond better to antidepressants than others (ScienceNOW, 20 March 2006). And just last month, researchers found that variants in two genes could account for the increased suicide risk associated with antidepressants (ScienceNOW, 28 September). Psychiatrist John Kelsoe and colleagues at the University of California (UC), San Diego, wanted to know if genetic variants could also account for why some people respond better to psychotherapy. Graduate student Amelia Kotte gathered therapy records and blood samples for 65 volunteers who had completed 16 weeks of psychotherapy, some of whom were also taking antidepressants. Kelsoe's team then analyzed DNA in the patients' blood for five genes thought to be involved in responses to antidepressants, because some brain-imaging studies have suggested biological similarities in responses to both antidepressants and psychotherapy. Two of these genes seem to affect responses to psychotherapy, Kotte reported at the meeting. Patients with two copies of a particular variant of a gene called NTRK2 showed more improvement from psychotherapy than did those with one or no copy of the variant, dropping eight points on a 63-point assessment called the Beck Depression Inventory compared with a five-point drop for those with one or no copy of the variant. © 2007 American Association for the Advancement of Science

Keyword: Depression; Genes & Behavior
Link ID: 10907 - Posted: 06.24.2010

Roxanne Khamsi You may not want a monkey to balance your chequebook, but you still have to give them credit – new research supports the idea that not only can monkeys understand written numbers, but that individual brain cells may become dedicated to specific numbers. The small study of two rhesus monkeys reveals that cells in their brains respond selectively to specific number values – regardless of whether the amount is represented by dots on a screen or an Arabic numeral. For example, a given brain cell in the monkey will respond to the number three, but not the number one. The results suggest that individual cells in human brains might also have a fine-tuned preference for specific numerical values. While monkeys might not yet have mastered calculus, recent studies have shown that they can learn understand some basic aspects of arithmetic and, in a rare case, multiplication. Andreas Nieder at the University of Tübingen in Germany and colleagues trained two rhesus monkeys to count by showing them various numbers of dots on a screen followed by Arabic numerals. The monkeys had to pull a lever to indicate when the numeral matched the preceding count of dots. An accurate response earned the animals a cup of apple juice, which they consider a treat. The researchers also reversed the task, showing the Arabic numerals several seconds before the dots. © Copyright Reed Business Information Ltd.

Keyword: Miscellaneous
Link ID: 10906 - Posted: 06.24.2010

Declan Butler Two children with a common neurodegenerative disease are seeing early signs of success from a pioneering gene-therapy treatment, researchers report this week. The results raise hopes for a treatment for adrenoleukodystrophy (ALD), and, the researchers add, mark the first successful use of an attenuated HIV virus to carry a therapeutic gene into a patient’s cells. HIV is a promising vector for transferring corrective genes into a host — it can penetrate directly into cell nuclei, making it a theoretically efficient way to introduce new genetic material. But until now it hadn’t been proven in a clinical setting. This early success potentially opens the door to better treatments for many other diseases involving the bone marrow and blood cells, such as leukaemia, thalassemia and sickle-cell disease, the researchers say. The results, from two 7-year-old Spanish children with ALD, were announced on Sunday 28 October at the fifteenth Congress of the European Society of Gene and Cell Therapy in Rotterdam, the Netherlands ALD is caused by a mutation on the X chromosome. This mutation causes degradation of the insulating sheaths that surround neurons and allow them to signal properly. The condition was made famous by Lorenzo's Oil , the Hollywood film outlining one family’s fight to help their son. The most severe, cerebral form of ALD affects one in 17,000 people, with two-thirds of sufferers being children. It progresses slowly at first, but if no bone-marrow transplant is available it can quickly progress to cause brain damage and death. © 2007 Nature Publishing Group

Keyword: Glia; Genes & Behavior
Link ID: 10905 - Posted: 06.24.2010

By MARLENE BELFORT My father killed himself at 46. So not surprisingly, at 46 I felt nervous and a bit depressed. As a scientist, I looked at the facts, the data. Life was fundamentally fine — married to a supportive man, with three healthy sons and a good career. But the anxiety prompted me to seek a psychiatrist. His diagnosis was burnout — dysthymia, to use the clinical term. There was no need for medication, but I could benefit from psychotherapy, to deal with my repressed feelings as the child of a suicide. Skeptical at first — this analytical stuff is not science! — I gradually began to appreciate the parallels between his discipline and mine. In science and in psychotherapy, one approaches a problem from different angles, observes, hypothesizes, discards theories and begins to draw conclusions. When the evidence from various directions converges on a point, that point becomes a discovery, a new “truth.” After four years of therapy, all seemed well. But three years later, I suddenly began to feel profoundly depressed and returned to therapy. “Let’s try an antidepressant, and I bet you’ll come out of it,” my psychiatrist said. Medication loomed large. I had never taken more than aspirin, not even for childbirth. But as the depression deepened, I capitulated, using antidepressants in various combinations and at increasing doses. Copyright 2007 The New York Times Company

Keyword: Depression; Hormones & Behavior
Link ID: 10904 - Posted: 06.24.2010

By GINA KOLATA Clinton T. Rubin knows full well that his recent results are surprising — that no one has been more taken aback than he. And he cautions that it is far too soon to leap to conclusions about humans. But still, he says, what if ... ? Less Fat in Vibrated Mice And no wonder, other scientists say. Dr. Rubin, director of the Center for Biotechnology at the State University of New York at Stony Brook, is reporting that in mice, a simple treatment that does not involve drugs appears to be directing cells to turn into bone instead of fat. All he does is put mice on a platform that buzzes at such a low frequency that some people cannot even feel it. The mice stand there for 15 minutes a day, five days a week. Afterward, they have 27 percent less fat than mice that did not stand on the platform — and correspondingly more bone. “I was the biggest skeptic in the world,” Dr. Rubin said. “And I sit here and say, ‘This can’t possibly be happening.’ I feel like the credibility of my scientific career is sitting on a razor’s edge between ‘Wow, this is really cool,’ and ‘These people are nuts.’” The responses to his work bear out that feeling. While some scientists are enthusiastic, others are skeptical. Copyright 2007 The New York Times Company

Keyword: Obesity
Link ID: 10903 - Posted: 06.24.2010