By BENEDICT CAREY Variations in two genes may increase the likelihood that a person will report suicidal thoughts after taking an antidepressant, researchers reported yesterday. The finding could help doctors develop tests to predict which patients will do well on such medications and which will react badly. The authors of the study, which was released to reporters yesterday and will appear in The American Journal of Psychiatry on Monday, said that the findings were preliminary and would need to be verified by further testing. The study focused on reactions to only one drug, Celexa from Forest Laboratories, and found no link between the gene variations and dangerous behavior like suicide attempts. This distinction is critical, because doctors do not know whether people who report thoughts of ending their lives are at increased risk to act on them. The one patient in the study who attempted suicide consistently denied having any suicidal thoughts. The findings come at a time when psychiatrists, regulators and some former patients are locked in a furious debate about the risks of antidepressant drugs, which include products like Prozac from Eli Lilly and Zoloft from Pfizer. In recent years, health regulators have required that drug makers post strong warnings on antidepressant labels, saying that some young patients may be at increased risk of suicidal thoughts and behavior. Copyright 2007 The New York Times Company

Keyword: Depression; Genes & Behavior
Link ID: 10789 - Posted: 09.28.2007

Susana Martinez-Conde DB is a 67-year-old man who has been blind to the left half of his visual field since age 26, following a neurosurgical operation. The operation, which was necessary to remove a vascular malformation in his occipital lobe, unfortunately destroyed the part of DB's right hemisphere corresponding to the primary visual cortex. The primary visual cortex, also called area V1, is the brain's largest area and one of over two dozen regions dedicated to vision. V1 serves many important functions. Among them, it relays visual information from the eyes to higher cortical visual areas. Since DB lost the right half of area V1, it did not surprise his doctors that he became blind in the left half of his visual field. (The right part of the brain processes visual information from the left half of the visual field, and vice versa.) But they were astounded that, although DB denied seeing any visual targets presented to the left visual field, he was nevertheless able to accurately "guess" many properties of targets presented there, such as shape, specific location and other aspects one could only know of by seeing them. DB's ability to provide accurate information about unseen targets is called "blindsight." Blindsight is thought to be due to information flow through secondary neural pathways that bypass area V1 but which nevertheless convey a small amount of visual information to higher visual cortices. For some unknown reason, these secondary routes are not sufficient to maintain the feeling of sight. Thus the blindsight patient has the subjective feeling that he or she is blind, and reports visual information only when forced to take a guess. © 1996-2007 Scientific American, Inc. Al

Keyword: Vision
Link ID: 10788 - Posted: 06.24.2010

By Matt Kaplan Whereas most animals run away from the dangers of the African savannas, meerkats, brave little souls that they are, race toward them. Large groups run headlong at venomous snakes and other potential predators, harassing them with jeering noises and pokes from their tiny claws. Scientists have long thought the meerkats were somehow protecting their colony, but new research suggests that the odd behavior may also be a way for younger meerkats to learn more about their enemies. If so, then it may lead biologists to take a second look at other social species, such as prairie dogs and vervet monkeys, which behave similarly. Biologists Beke Graw and Marta Manser of the University of Zurich in Switzerland studied meerkats in the wild. When they released cobras and other predators near the colony, the meerkats mobbed the snakes and became aggressive. They also mobbed innocuous critters, such as moles and squirrels--even empty cages--but eventually lost interest and drifted away. Meerkats responded differently according to their age. Adults between 1 and 2 years of age mobbed intruders longer and growled, barked, and poked more intensely than did younger and older animals, the team reports in this month's issue of Animal Behaviour. This age pattern has also been found in several other cooperative behaviors in meerkats such as baby-sitting and colony guarding, in which youngsters follow adults and over time mimic them. "It would seem that mobbing is also a part of social learning, a kind of class in predator recognition, if you like, and that hasn't been demonstrated in mammals before," says Graw. © 2007 American Association for the Advancement of Science

Keyword: Aggression
Link ID: 10787 - Posted: 06.24.2010

David Robson A computer program that emulates the human brain falls for the same optical illusions humans do. It suggests the illusions are a by-product of the way babies learn to filter their complex surroundings. Researchers say this means future robots must be susceptible to the same tricks as humans are in order to see as well as us. For some time, scientists have believed one class of optical illusions result from the way the brain tries to disentangle the colour of an object and the way it is lit. An object may appear brighter or darker, either because of the shade of its colour, or because it is in bright light or shadows. The brain learns how to tackle this through trial and error when we are babies, the theory goes. Mostly it gets it right, but occasionally a scene contradicts our previous experiences. The brain gets it wrong and we perceive an object lighter or darker than it really is – creating an illusion. Subtle similaritiesUntil now there has been no way of knowing whether this theory is correct. Beau Lotto and David Corney at University College London, UK, think they have finally done it. They created a program that learns to predict the lightness of an image based on its past experiences – just like a baby. And just like a human, it falls prey to optical illusions. © Copyright Reed Business Information Ltd.

Keyword: Vision; Robotics
Link ID: 10786 - Posted: 06.24.2010

"Very unpleasant. As if I've just buried my nose in a t-shirt that's just been taken off by a guy who's been exercising, just unbelievably, unbelievably strong and then our collaborators who can't smell it at all. It's an amazing, it's an amazing difference in opinion."Genetics researcher Leslie Vosshall is talking about a component of male sweat-- the sex hormone androstenone. She and her colleagues found that some people love it, some hate it and some can't smell it at all-- and that it all depends on what form of a particular gene they possess. Scientists have long known there is some kind of genetic link to odor perception based on studies such as those done with twins. But no one had ever proved that a particular gene caused a difference in peoples' perception of a specific odor. Associate professor Vosshall and research associate Andreas Keller of The Rockefeller University, along with their collaborators at Duke University, are the first to do just that, with a component of male sweat. The substance they studied, a hormone called androstenone, is a derivative of the sex hormone testosterone. The lining of the nose has millions of smell receptor cells (olfactory sensory neurons). Each of these cells has one of about 400 types of differently shaped receptors. Each receptor will accept one odor molecule with a matching shape. In the artist's rendition to the right, you can see a receptor molecule inserting itself into a receptor. This triggers signals to the brain allowing a person to smell it. © ScienCentral, 2000-2007.

Keyword: Chemical Senses (Smell & Taste); Genes & Behavior
Link ID: 10785 - Posted: 06.24.2010

R. Douglas Fields A recent study used brain scans to examine both the effects that both one-time and cumulative high-altitude climbing have on the human brain. The findings are not elevating for those of us who love to climb. Climbing Mount Everest is not so difficult; the hard part is getting down intact. According to a recent brain imaging study, almost no one does. Of thirteen climbers in the study who attempted Mount Everest, none returned without brain damage. The study also scanned the brains of climbers who attempted less extreme summits. For those of us who love to climb, the results are less than elevating. It seems that almost no one, whether the weekend warrior chaperoned to the summit or the seasoned mountaineer, will return from the high peaks with a brain in the same condition it was in beforehand. The first scientific study of the effects of high altitude on the human brain were made by nineteenth century Italian physiologist Angelo Mosso, who made direct observations on a man whose brain was partly exposed as a result of an accident. Mosso, peeking into the man's skull, observed vague changes in swelling of the brain, but the crude methods available at the time limited his analysis. Now a similar experiment has been done with modern noninvasive brain imaging. In the study reviewed here, "Evidence of Brain Damage After High-Altitude Climbing by Means of Magnetic Resonance Imaging," neurologists Nicholas Fayed and colleagues at the Clinica Queron and Miguel Servet University Hospital in Zarogoza, Spain, gave MRI brain scans to 35 climbers (12 professionals and 23 amateurs) who had returned from high-altitude expeditions, including 13 who had attempted Everest. © 1996-2007 Scientific American, Inc.

Keyword: Learning & Memory
Link ID: 10784 - Posted: 06.24.2010

By Nikhil Swaminathan You may be hard-pressed to recall events after a night of binge drinking, but a new report suggests that low to moderate alcohol consumption may actually enhance memory. "There are human epidemiological data of others indicating that mild [to] moderate drinking may paradoxically improve cognition in people compared to abstention," says Maggie Kalev, a research fellow in molecular medicine and pathology at the University of Auckland in New Zealand and a co-author of an article in The Journal of Neuroscience describing results of a study she and other researchers performed on rats. "This is similar to a glass of wine protecting against heart disease, however the mechanism is different." Kalev and Matthew During, a professor of molecular virology, immunology and medical genetics at The Ohio State University College of Medicine and a principal investigator of gene therapy at Auckland, initially set out to study the role of N-methyl-D-aspartic acid (NMDA) receptors in the neuronal processes of normal and diseased animals. (NMDA receptors are critical to memory, because they regulate the strength of synapses (spaces) between nerve cells through which the cells communicate.) But during their research, they discovered that memory was enhanced when one of its subunits, known as NR1, was strengthened in the hippocampus (a central brain region implicated in episodic memory). They then reviewed previous experiments, which had turned up a link between alcohol consumption and NR1 activity. © 1996-2007 Scientific American, Inc.

Keyword: Learning & Memory; Drug Abuse
Link ID: 10783 - Posted: 06.24.2010

LOS ANGELES, -- A mercury-based preservative once used in many vaccines does not raise the risk of neurological problems in children, concludes a large federal study that researchers say should reassure parents. The study did not examine autism, however. A separate study due out in a year will look at that issue, said scientists at the U.S. Centers for Disease Control and Prevention, who published the results in Thursday's New England Journal of Medicine. Discussion PolicyDiscussion Policy CLOSEComments that include profanity or personal attacks or other inappropriate comments or material will be removed from the site. Additionally, entries that are unsigned or contain "signatures" by someone other than the actual author will be removed. Finally, we will take steps to block users who violate any of our posting standards, terms of use or privacy policies or any other policies governing this site. Please review the full rules governing commentaries and discussions. You are fully responsible for the content that you post. They found no clear link between early exposure to the preservative thimerosal and problems with brain function and behavior in children ages 7 to 10. The results are in line with past research. Thimerosal has not been used in childhood vaccines since 2001, although it is still found in some flu vaccine. © 2007 The Washington Post Company

Keyword: Autism; Neurotoxins
Link ID: 10782 - Posted: 06.24.2010

Alison Preston Memory consolidation can occur at many organizational levels in the brain. Cellular and molecular changes typically take place within the first minutes or hours of learning and result in structural and functional changes to neurons (nerve cells) or sets of neurons. Systems-level consolidation, involving the reorganization of brain networks that handle the processing of individual memories, may then happen, but on a much slower time frame that can take several days or years. Memory does not refer to a single aspect of our experience but rather encompasses a myriad of learned information, such as knowing the identity of the 16th president of the United States, what we had for dinner last Tuesday or how to drive a car. The processes and brain regions involved in consolidation may vary depending on the particular characteristics of the memory to be formed. Let's consider the consolidation process that affects the category of declarative memory—that of general facts and specific events. This type of memory relies on the function of a brain region called the hippocampus and other surrounding medial temporal lobe structures. At the cellular level, memory is expressed as changes to the structure and function of neurons. For example, new synapses—the connections between cells through which they exchange information—can form to allow for communication between new networks of cells. Alternately, existing synapses can be strengthened to allow for increased sensitivity in the communication between two neurons. Consolidating such synaptic changes requires the synthesis of new RNA and proteins in the hippocampus, which transform temporary alterations in synaptic transmission into persistent modifications of synaptic architecture. © 1996-2007 Scientific American, Inc.

Keyword: Learning & Memory
Link ID: 10781 - Posted: 06.24.2010

Catherine Brahic Far from being lethargic and lazy creatures, crocodiles will travel hundreds of miles to return home, the first satellite-tracking experiment of the reptile has confirmed. Australian scientists tracked three saltwater crocodiles after moving them between 56 and 126 kilometres away from their home territory. The study confirms that the world's largest reptile has a remarkable homing instinct and will cover great distances in order to get home. It also suggests that airlifting problematic crocs to new areas may be ineffective at keeping them away. Aided by crocodile expert and TV presenter Steve Irwin, who died in September 2006, Craig Franklin of the University of Queensland and colleagues captured the three large male saltwater crocodiles (Crocodylus porosus) from coastal areas between August and September 2004. After fitting each with a satellite tracking device, the researchers airlifted each of the animals by helicopter to a new stretch of coastline either 56 km, 99 km or 126 km away. All three animals behaved in roughly the same way. After a few weeks of exploring their new habitats, each set off home, travelling around the coast back to their point of departure, taking between 5 and 20 days to get home. © Copyright Reed Business Information Ltd.

Keyword: Animal Migration
Link ID: 10780 - Posted: 06.24.2010

Scientists have discovered a link between a mutated gene and a protein found in dead brain cells of people who suffer from a form of dementia and other neurological disorders. The finding, reported in the Sep. 26, 2007, issue of the Journal of Neuroscience, demonstrates for the first time a pathological pathway that ultimately results in cell death related to frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig's disease). The discovery could eventually play a role in the design of new drug therapies. The study was funded by the National Institute on Aging (NIA) at the National Institutes of Health (NIH). Leonard Petrucelli, Ph.D., and Dennis W. Dickson, M.D, of the Mayo Clinic in Jacksonville, Fla., led the international team of scientists in the study supported by the Mayo Clinic Foundation. The study, in cell cultures, showed that a cell death pathway is involved. A cascade of events begins with a mutation in the gene progranulin (PGRN) located on chromosome 17. Normally, high levels of PGRN exist in a cell to promote cell growth and survival. But when progranulin gene mutations occur, low levels of PGRN result. The investigators showed that this causes a protein called TDP-43 to be cut into two fragments. These fragments then migrate from their usual location in the nucleus into the surrounding cytoplasm of the cell where they form inclusions, or insoluble clumps of protein. This abnormal process results in the neurodegeneration in people with FTD and ALS.

Keyword: Alzheimers; Apoptosis
Link ID: 10779 - Posted: 09.27.2007

When you have Tourette Syndrome, you get used to the physical and vocal tics that others often view as faux pas. I know, I have it. When I interviewed 14-year-old Andrew Youngen, who participated in a study designed to find out if the neurological disorder affects the brain in other ways, I began by asking him to tell me some things about himself for background. I wanted to see if he would mention his Tourette Syndrome in his description of himself. He didn't. He told me how he enjoys coin collecting, but in a way that I thought was pretty unique-- he makes sure to get one of those kitschy-touristy penny presses at every attraction he visits. But, while people with Tourette may not think of the neurological disorder as one of the most important parts of themselves, having it has made Andrew into a sort of ad-hoc Tourette ambassador. He does "in-service" visits to classrooms to explain that his sudden or repetitive motions and sounds are involuntary. "After we watch the video, I say in my own words what Tourette is and how it affects me, and I can't help anything about it… And then they usually have some questions, like, actually last year, I got a question, 'What can we do to help?'" "It was the first time I've ever gotten that, it was a very nice one," Andrew says. © ScienCentral, 2000-2007

Keyword: Tourettes
Link ID: 10778 - Posted: 06.24.2010

Katharine Sanderson How do migrating birds perceive which way is north? Research now points to the idea that they actually 'see' the Earth's magnetic fields, rather than feeling or sensing them in some other way. Previous work has suggested that the Earth's magnetic field might act on the sensitivity of a migratory bird's eye, so that sight might be involved in finding magnetic north. Now researchers have firmed that up with evidence that molecules in the eyes of migratory birds are connected to the part of the brain that guides their direction of flight. Dominik Heyers, at the University of Oldenburg, Germany, and colleagues injected migratory garden warblers (Sylvia borin) with a tracer capable of travelling along neuronal fibres along with nerve signals. They injected one tracer into the part of the forebrain known to be the only active area when birds orient themselves (known as Cluster N), and a different tracer into the retina. After a bird experienced a desire to migrate, both tracers ended up in the same place, the researchers report in the Public Library of Science One1 — a part of the thalamus responsible for vision. This anatomical link strongly supports the notion that the birds probably experience magnetic fields as a visual sensation, say the researchers. ©2007 Nature Publishing Group

Keyword: Animal Migration
Link ID: 10777 - Posted: 06.24.2010

Acupuncture - real or sham - is more effective at treating back pain than conventional therapies, research suggests. A German team found almost half the patients treated with acupuncture felt pain relief. But the Archives of Internal Medicine study also suggests fake acupuncture works nearly as well as the real thing. In contrast, only about a quarter who received drugs and other Western therapies felt better. The researchers, from the Ruhr University Bochum, say their findings suggest that the body may react positively to any thin needle prick - or that acupuncture may simply trigger a placebo effect. One theory is that pain messages to the brain can be blocked by competing stimuli. Researcher Dr Heinz Endres said: "Acupuncture represents a highly promising and effective treatment option for chronic back pain. "Patients experienced not only reduced pain intensity, but also reported improvements in the disability that often results from back pain and therefore in their quality of life." More than 1,100 patients took part in the study. They were given either conventional therapy, acupuncture or a sham version. Although needles were used in the sham therapy, they were not inserted as deeply as in standard acupuncture. Neither were they inserted at points thought key to producing a therapeutic effect, or manipulated and rotated once in position. After six months 47% of patients in the acupuncture group reported a significant improvement in pain symptoms, compared to 44% in the sham group, and just 27% in the group who received conventional therapy. (C)BBC

Keyword: Pain & Touch
Link ID: 10776 - Posted: 09.25.2007

They're embedded in everything from mattresses to insoles for shoes to wrist bands — but there is no definitive scientific evidence that static magnets can relieve chronic pain, researchers say. Products that incorporate static magnets are a multibillion-dollar business worldwide, and many chronic pain sufferers are drawn by the promise they hold for alleviating such nagging conditions as arthritis, fibromyalgia and low back discomfort. The theory from proponents is that a magnetic field increases blood flow, causing increased oxygen, nutrients, hormones and painkilling endorphins to be distributed to tissues in the affected area. 'There is no definite grounds of being absolutely sure that a magnet works or not.' —Dr. Max Pittler, researcherResearchers at the universities of Exeter and Plymouth in England decided to search the medical literature to determine whether there is any proof magnets can reduce pain. In their analysis of nine randomized trials comparing products containing magnets with those containing either no magnet or very weak ones, the researchers found that the data did not support the use of magnetic therapy for pain control. "There is no definite grounds of being absolutely sure that a magnet works or not," lead author Dr. Max Pittler, a complementary medicine specialist, said Monday. © CBC 2007

Keyword: Pain & Touch
Link ID: 10775 - Posted: 06.24.2010

If you want to have lots of kids, look for a Barry White instead of a Justin Timberlake. Men with a deep voices have more offspring, a new study suggests. Previous studies conducted by David Feinberg of McMaster University in Canada have shown that women are more attracted to men with deeper voices, judging them to be older, healthier and more masculine than their higher-pitched rivals. Men, on the other hand, go for women with higher pitched voices because they find them more attractive, subordinate, feminine, healthier and younger-sounding. In the new study, detailed in a recent issue of the journal Biology Letters, Feinberg set out to see how that attraction to deeper-voiced men affected reproduction and the survival of offspring. "While we find in this new study that voice pitch is not related to offspring mortality rates," Feinberg said, "we find that men with low voice pitch have higher reproductive success and more children born to them." To look for any relationship between voice pitch and birth rates, the researchers studied the Hadza tribe of Tanzania, one of the last true hunter-gatherer cultures. Because the Hadza have no modern birth control, the researchers were able to compare birth rates without any outside influencing factors. © 2007 MSNBC.com © 2007 Microsoft

Keyword: Sexual Behavior; Evolution
Link ID: 10774 - Posted: 06.24.2010

Researchers at the University of Warwick's Warwick Medical School studied 10,308 British civil servants in two different time periods: between 1985 and 1988, and between 1992 and 1993. Study participants who slept longer than eight hours were more than twice as likely to die as those who kept sleeping for seven. Researchers believe depression, low socioeconomic status and cancer-related fatigue could play a part. (CBC) With seven hours seen as the optimal amount of sleep for the average adult, the study subjects who cut the duration of their sleep from seven hours to five hours a night had a 1.7-fold increased risk of death from all causes, according to the research, presented Monday to the British Sleep Society. They also had twice the increased risk of death from a cardiovascular problem. More surprisingly, scientists found those individuals who increased the number of hours they slept per night from seven to eight hours or more were more than twice as likely to die as those who kept sleeping for seven. They were also more likely to die from non-cardiovascular diseases. "Short sleep has been shown to be a risk factor for weight gain, hypertension and Type 2 diabetes sometimes leading to mortality,' said Francesco Cappuccio, an author of the study. © CBC 2007

Keyword: Sleep; Neuroimmunology
Link ID: 10773 - Posted: 06.24.2010

LONDON - People who do not get enough sleep are more than twice as likely to die of heart disease, according to a large British study released on Monday. Although the reasons are unclear, researchers said lack of sleep appeared to be linked to increased blood pressure, which is known to raise the risk of heart attacks and stroke. A 17-year analysis of 10,000 government workers showed those who cut their sleeping from seven hours a night to five or less faced a 1.7-fold increased risk in mortality from all causes and more than double the risk of cardiovascular death. The findings highlight a danger in busy modern lifestyles, Francesco Cappuccio, professor of cardiovascular medicine at the University of Warwick's medical school, told the annual conference of the British Sleep Society in Cambridge. "A third of the population of the U.K. and over 40 percent in the U.S. regularly sleep less than five hours a night, so it is not a trivial problem," he said in a telephone interview. "The current pressures in society to cut out sleep, in order to squeeze in more, may not be a good idea — particularly if you go below five hours." © 2007 MSNBC.com © 2007 Microsoft

Keyword: Sleep; Neuroimmunology
Link ID: 10772 - Posted: 06.24.2010

Jennifer Viegas, Discovery News — Big-headed people could be brainier too, according to a new analysis of a 1939 study comparing head size and intelligence in a group of male prisoners. Although the effect of head size on IQ is minimal, it does exist, says Jeremy Genovese, who conducted the new research and is an associate professor of human development and educational psychology at Cleveland State University. "The correlations between head size and IQ are quite modest, and you cannot determine someone's intelligence with a tape measure," he told Discovery News. "However, the correlation is real and might have some clinical significance, such as predicting susceptibility to dementia." Genovese explained that "larger bodies do require larger brains to support larger nervous systems," but he added that the notable difference in body size between men and women appears to have "no relationship to intelligence." For the study, which has been accepted for publication in the journal Personality and Individual Differences, Genovese obtained copies of the 1939 inmate data, which was collected by Harvard anthropologist Earnest Albert Hooten. Hooten gathered anthropological and sociological records on roughly 12 percent of American prison inmates. © 2007 Discovery Communications

Keyword: Intelligence
Link ID: 10771 - Posted: 06.24.2010

Roxanne Khamsi Hormone replacement therapy massively boosts sexual interest in post-menopausal women, suggests a new study. Women taking HRT therapy, typically used to treat symptoms of menopause such as "hot flashes", reported a 44% increase in sexual interest in the recent trial. Researchers say this finding supports the idea that the hormone treatment, which consists of oestrogen and progesterone, can help women frustrated by a decline in libido following menopause. Experts say, however, that patients must carefully weigh the benefits of such treatment against the possible negative side effects, which include an increased risk of cancer. Menopause has a huge impact on women, leading sometimes to bone loss known as osteoporosis and facial hair growth. The hormonal changes of menopause can also lead to clitoral atrophy and vaginal dryness, which can make sex less pleasurable. Previous studies have estimated that anywhere from 30% to 70% of women report a decline in libido following menopause for various reasons, according to Jim Pfaus at Concordia University in Montreal, Quebec in Canada. Pfaus adds that sex therapy cannot necessarily boost libido in women who have passed menopause since their loss of interest in sex often has a biological cause. “You can't cognitively treat your hormone levels,” he says. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 10770 - Posted: 06.24.2010