Heidi Ledford Surgeons have managed to give an amputee not only a prosthetic arm that moves as directed by her thoughts, but also the feeling of touch — albeit in the wrong part of her body. When Claudia Mitchell presses an area on her chest, where surgeons re-wired the nerves that used to run to her hand, it feels to her as if her fingers are being touched. The technique opens the door to additional technologies that could one day relay signals from the prosthesis back to the 'fingers' on the chest, allowing an amputee to get sensory information such as touch and temperature from their artificial limb. Mitchell's success story was revealed in a press conference last year, but now the details have been published: they are reported this week in the Lancet.1 Mitchell was only 24 years old when a motorcycle accident robbed her of her left arm. She got a prosthesis five months later, but wore it infrequently and then only for cosmetic reasons. It just wasn't useful enough to make the discomfort worthwhile, she said. ©2007 Nature Publishing Group

Keyword: Robotics; Pain & Touch
Link ID: 9911 - Posted: 06.24.2010

"Time" is the most popular noun in the English language, yet how would we tell time if we didn’t have access to the plethora of watches, clocks and cell phones at our disposal? For decades, scientists have believed that the brain possesses an internal clock that allows it to keep track of time. Now a UCLA study in the Feb. 1 edition of Neuron proposes a new model in which a series of physical changes to the brain’s cells helps the organ to monitor the passage of time. "The value of this research lies in understanding how the brain works," said Dean Buonomano, associate professor of neurobiology and psychiatry at the David Geffen School of Medicine at UCLA and a member of the university’s Brain Research Institute. "Many complex human behaviors -- from understanding speech to playing catch to performing music -- rely on the brain’s ability to accurately tell time. Yet no one knows how the brain does it." The most popular theory assumes that a clock-like mechanism – which generates and counts regular fixed movements -- underlies timing in the brain. In contrast, Buonomano suggests a physical model that operates without using a clock. He offers an analogy to explain how it works. "If you toss a pebble into a lake," he explained, "the ripples of water produced by the pebble’s impact act like a signature of the pebble’s entry time. The farther the ripples travel the more time has passed.

Keyword: Attention; Biological Rhythms
Link ID: 9910 - Posted: 06.24.2010

By Nikhil Swaminathan Zeroing in on a group of cells in a high layer of the cortex, a team of researchers from Mount Sinai School of Medicine, Columbia University and the New York State Psychiatric Institute may finally have found the cause of the swirling textures, blurry visions and signal-crossing synesthesia brought on by hallucinogenic drugs like LSD, peyote and "'shrooms." The group, which published its findings in this week's issue of Neuron, may have settled a long-simmering debate over how psychedelic drugs distort human perception. "There's this huge body of literature about these compounds, and I think this paper begins to nail down how the heck they're working in the brain," says Bryan Roth, a pharmacologist at the University of North Carolina at Chapel Hill. "It's not the end of the story, but I'd say it's the end of the beginning of the story." Since the 1980s researchers in this field have agreed that LSD, which was first synthesized by Swiss scientists in 1938, likely affects serotonin 2A receptors in the brain (serotonin is a neurotransmitter suspected to play a role in the communication of mood and consciousness). These receptors show up in many places in the brain, including several areas in the cortex (known for sensory perception), and the thalamus (an interior region known for relaying messages to the cortex as well as regulating arousal and awareness). © 1996-2007 Scientific American, Inc.

Keyword: Drug Abuse
Link ID: 9909 - Posted: 06.24.2010

WESTCHESTER, Ill. -- Parasomnias in children are common, and often more frequent than in adults. It is important for parents to take an active approach in helping their child overcome a sleep disorder, to consult with their child’s pediatrician, and for an office evaluation of a child with any parasomnia to be thorough, according to a study published in the February 1st issue of the journal SLEEP. Thornton B.A. Mason of The Children’s Hospital of Philadelphia, and Allan I. Pack of the University of Pennsylvania, advise pediatricians to question the parents regarding what events typically occur, how soon after sleep onset these events are noted, and whether episodes take place during naps as well as at night. Parents should, in turn, describe in detail the movements and behaviors that are typically seen, said Mason and Pack. In addition, the authors noted, to complement the parents’ descriptions, home videos often prove very useful for identifying and classifying parasomnias. A detailed history may also be supported through the completion of sleep diaries, in which parents record sleep periods, arousals/awakenings and parasomnia events, added Mason and Pack. "The sleep history should be accompanied by a comprehensive physical and neurological exam, to look for features that would be associated with an underlying sleep disruptor: for obstructive sleep apnea, features such as adenotonsillar hypertrophy, retrognathia, and mid-face hypoplasia; for periodic lib movements in sleep, features such as peripheral neuropathy or myelopathy," the authors wrote.

Keyword: Sleep; Development of the Brain
Link ID: 9908 - Posted: 06.24.2010

Tracy Staedter, Discovery News — Part human and part robot, an interface made of lab-grown nerve tissue and a microchip could one day help patients control artificial limbs with their thoughts. The tissue interface could help make prosthesis motion, now awkward and cumbersome, smoother. It could also replace lost sensory feedback, such as that from touch, to reproduce natural limb responses. "We want to hook a nerve system up to a device and create bidirectional communication," said Douglas Smith, professor of neurosurgery at the University of Pennsylvania and director of its Center for Brain Injury and Repair. And since "a nerve doesn't like to be poked and prodded by things it's unfamiliar with," sticking an electronic device directly into the tissue isn't option. In this case, a hybrid device is the way to go. Smith and his team published their results in this month's issue of Neurosurgery. At the heart of the research is a technique Smith and his team are pioneering for growing, or rather stretching, nerve tissue to a particular length. © 2007 Discovery Communications Inc.

Keyword: Robotics
Link ID: 9907 - Posted: 06.24.2010

Heidi Ledford A man walks around the neighbourhood with his family, and stops to admire a particularly lovely house. He turns to his family and asks who built it. "You did," they reply. It was the first sign that something was wrong, he would later recount to researchers at the University of California, San Francisco. But it was another half a year before he developed the classical erratic behaviour and unsteady gait typical of Creutzfeldt-Jakob disease (CJD) — a neurodegenerative condition caused by an infectious protein called a prion. A diagnosis of CJD is a death sentence, and researchers around the world are looking for a cure. But that cure is unlikely to do much good if doctors can't diagnose the condition in its early stages, before the patient develops severe brain damage. Now, researchers have characterized the early signs of a similar prion disease in mice. In results presented this week in Neuron1, the researchers show that shutting off production of the pathogenic protein during these early stages allowed mice to not only survive, but also recover normal brain function. ©2007 Nature Publishing Group

Keyword: Prions
Link ID: 9906 - Posted: 06.24.2010

By Sarah Waldron As the government attacks "fashion and the tyranny of thinness" for undermining the confidence of girls, experts are seeing younger and younger children with eating disorders. But blaming stick-thin models might be too simplistic. Rhodes Farm is a clinic dealing with children suffering from anorexia nervosa. Opened 16 years ago, it has seen the average age of clients drop and children as young as eight are now being treated. Culture Secretary Tessa Jowell has pledged to tackle "the cult of size zero" by establishing a task force with fashion leaders, but for many girls at the clinic the issue is more about control. Twelve-year-old Natasha was admitted to Rhodes Farm after her weight fell to less than four-and-a-half stone. She says the furore over "size zero" models and celebrities has nothing to do with why she stopped eating. "[The media's] story is people get anorexia because they want to be thin and they see other people in magazines and on the catwalk and they think 'I want to be like that'," she says. "That's a really good story and why would they change it - it's a perfect story. But it's not the truth. Maybe for some people it is, but I know that for me it's not. I haven't got anorexia because I've been inspired to look like other people. It's the image in my head. There's no one that's my idol. (C)BBC

Keyword: Anorexia & Bulimia
Link ID: 9905 - Posted: 01.31.2007

By SHARON BEGLEY It was a fairly modest experiment, as these things go, with volunteers trooping into the lab at Harvard Medical School to learn and practice a little five-finger piano exercise. Neuroscientist Alvaro Pascual-Leone instructed the members of one group to play as fluidly as they could, trying to keep to the metronome's 60 beats per minute. Every day for five days, the volunteers practiced for two hours. Then they took a test. At the end of each day's practice session, they sat beneath a coil of wire that sent a brief magnetic pulse into the motor cortex of their brain, located in a strip running from the crown of the head toward each ear. The so-called transcranial-magnetic-stimulation (TMS) test allows scientists to infer the function of neurons just beneath the coil. In the piano players, the TMS mapped how much of the motor cortex controlled the finger movements needed for the piano exercise. What the scientists found was that after a week of practice, the stretch of motor cortex devoted to these finger movements took over surrounding areas like dandelions on a suburban lawn. The finding was in line with a growing number of discoveries at the time showing that greater use of a particular muscle causes the brain to devote more cortical real estate to it. But Pascual-Leone did not stop there. He extended the experiment by having another group of volunteers merely think about practicing the piano exercise. They played the simple piece of music in their head, holding their hands still while imagining how they would move their fingers. Then they too sat beneath the TMS coil. © 2007 Time Inc.

Keyword: Learning & Memory
Link ID: 9904 - Posted: 06.24.2010

NEW YORK (Reuters Health) - The rate of prostate cancer among men with schizophrenia is lower than in the general population, according to findings published in the journal Urology. "Lower than expected rates of cancer, in general, have been reported for psychiatric patients for almost a century," writes Dr. E. Fuller Torrey, of the Uniformed Services University of the Health Sciences, Bethesda, Maryland. For his study, the researcher performed a search of the MEDLINE database for all studies of "prostate cancer" or "cancer" or "schizophrenia." A total of five studies were included in the current analysis. In all five studies, the prostate cancer rates for schizophrenia patients were lower than expected in the general population. The overall rate of cancer at other body sites varied among the studies. Possible explanations for the decreased rate of prostate cancer include the effect of antipsychotic drugs (either by protecting against cancer or by decreasing testosterone, or both), and genetic factors, Torrey suggests. SOURCE: Urology, December 2006. © 1996-2007 Scientific American, Inc.

Keyword: Schizophrenia; Hormones & Behavior
Link ID: 9903 - Posted: 06.24.2010

Walking while holding a conversation and writing a letter whilst thinking about its content: we perform many actions without even thinking about them. This is possible due to the cerebellum. It regulates the automation of our movements and as a result the cerebrum can perform other tasks. However, how the cerebellum performs this task is not clear. Dutch researcher Angelique Pijpers reconstructed a part of cerebellar functioning in rats and investigated how it mediates in the control of hind limb muscles. Such research might in future provide a better understanding of how the elderly move. Pijpers and her colleagues investigated which processes took place inside and outside of the cerebellum: how does it channel information and process this into a signal to the muscles? Subsequently they investigated which parts of the cerebellum are involved in regulating the activity of a single muscle. Furthermore, they examined the consequences of inactivation of one or more parts of the cerebellum on the functioning of this muscle. Nerve cells in the cerebellum receive two types of signals. Through the climbing fibres, signals from a specific structure in the brain stem are transmitted to Purkinje cells located in the cerebellar cortex. Mossy fibres transmit signals from various parts of the central nervous system to the granule cells of the cerebellar cortex. Pijpers reconstructed the modular anatomy of the cerebellum by injecting small quantities of traceable substances. This allowed mapping of different 'stations' of the information pathway.

Keyword: Movement Disorders
Link ID: 9902 - Posted: 01.31.2007

Jennifer Viegas, Discovery News — What day of the week was January 13, 2000? Donny, considered the world's fastest and most gifted calendar prodigy, could answer correctly (Thursday) in 700 milliseconds. Now researchers think they know how he does it, and why. In addition to explaining autistic savants like Donny and Dustin Hoffman's character in the 1988 movie "Rain Man," the findings shed light on music and language prodigies who may also suffer from autism and sometimes retardation. Scientists previously believed these talents might be innate or involve complicated brain processing, but extensive testing of Donny suggests that at least some autistic people have a disruption in the reward and motivation system for a part of the brain that controls goal-directed behavior and reward-motivated learning. The person becomes obsessed with a certain activity, be it music, language or, in Donny's case, dates. "Donny has a sort of addiction for dates, which probably developed when he was 5 or 6 years old," said Marc Thioux, who led the study. "He spends most of his time repeating dates, asking for dates, answering questions about dates....His first question upon meeting you is to ask for your birth date," added Thioux, who is a scientist at the Behavioral and Cognitive Neurosciences Neuroimaging Center in the Netherlands. © 2007 Discovery Communications Inc.

Keyword: Autism
Link ID: 9901 - Posted: 06.24.2010

Aria Pearson Vaginal birth increases the risk of brain haemorrhage in newborns, a new study suggests. But it is unclear if the early bleeding causes problems with subsequent child development, so natural births should not be eschewed in favour of caesarean sections, experts warn. Psychiatrists at the University of North Carolina at Chapel Hill, US, were studying normal brain development in babies as part of their research on schizophrenia when they noticed that some of the newborns had suffered small haemorrhages. “The bleeds were unexpected,” says John Gilmore, who led the study. “So we decided to see what they were correlated with.” The researchers looked at 88 newborns with no outward symptoms, recording information including whether the birth was vaginal or caesarean, the duration of labour, and the infant’s weight, head size and gestational age at birth. They found that 26% of the babies born vaginally had bleeding in the brain, while none of those born through caesarean were affected. No other risk factor seemed to be involved. “It’s purely the process of being born and going through the birth canal,” says Gilmore. Past studies have linked haemorrhages to the trauma of birth, but these involved babies with clear symptoms such as seizures or lethargy. © Copyright Reed Business Information Lt

Keyword: Development of the Brain
Link ID: 9900 - Posted: 06.24.2010

US researchers have discovered a likely reason why people find it hard to do two things at once. A "bottleneck" occurs in the brain when people attempt to carry out two simultaneous tasks, the research shows. The study found the brain slows down when attempting a second task less than 300 milliseconds after the first. The findings, published in Neuron, support the case for a complete ban on the use of mobile phones when driving, the team said. Participants were asked to press an appropriate computer key in response to one of eight different sounds and call out a syllable in response to eight different images. The researchers from Vanderbilt University used functional MRI scans to detect changes in oxygenated blood in the brain - a way of monitoring the activity in different brain regions. They found that the lateral frontal and prefrontal cortex, and also the superior frontal cortex, were unable to process two tasks at once, leading to a bottleneck. But when tasks were presented a second apart there was no delay. Study leader Dr Paul Dux said previous studies had shown people were limited in being able to do two simple tasks at once - a phenomenon known as "dual-task interference. We were interested in trying to understand these limitations and in finding where in the brain this bottleneck might be taking place," he said. "We determined these brain regions responded to tasks irrespective of the senses involved, they were engaged in selecting the appropriate response, and, most importantly, they showed 'queuing' of neural activity. "The neural response to the second task was postponed until the response to the first was completed," he added. (C)BBC

Keyword: Attention
Link ID: 9899 - Posted: 01.30.2007

Neurologist and dizziness specialist Kevin A. Kerber of the University of Michigan at Ann Arbor offers the following explanation: In general, the most common causes of dizziness are activities everyone experiences, at least as children, namely running around in circles or riding carnival attractions that spin, loop or twist. These movements cause an asymmetry in the signals that stem from the vestibular system--a sensory system situated on each side of the head in the inner ear compartments--and that are processed in the brain. This alteration leads to the sensation known as dizziness during, and even for some time after, the provoking event. But dizziness can also occur as an unprovoked and severe episodic or even constant occurrence--an understandable source of distress for the person experiencing it. In fact, dizziness is one of the most common reasons for a visit to a doctor's office. The first step in determining the cause of dizziness is to clarify exactly what the individual is experiencing. The most common types of dizziness are vertigo, light-headedness and imbalance. Vertigo refers to the sensation of being in a spinning environment. At rest, continuous and balanced signals from the peripheral vestibular system keep the eyes stationary via connections in the brain. When the head moves, a physiological imbalance in the signals leads to small movements of the eyes that keep vision optimal. When a sudden abnormality in the balance of the signals occurs, the result is a pattern of eye movements referred to as nystagmus. When the eyes move in this fashion, the world is perceived to be rotating even though the person remains still. Benign paroxysmal positional vertigo (BPPV) is a common variety of vertigo that is caused by aberrant stimulation of the vestibular system by small, displaced particles in the inner ear fluid chambers. © 1996-2007 Scientific American, Inc.

Keyword: Miscellaneous
Link ID: 9898 - Posted: 06.24.2010

If you bend a knee or an elbow, the nerves in your limbs stretch but do not break. A University of Utah study suggests why: A gene produces a springy protein that keeps nerve cells flexible. When the gene was disabled in tiny nematode worms, their nerve cells literally broke. The discovery may provide a new explanation for spinocerebellar ataxia type 5 (SCA5) – a disease previously tied to a human version of the gene and identified in 11 generations of U.S. President Abraham Lincoln's family, starting with his paternal grandparents. SCA5 may have afflicted Lincoln himself. The new study suggests how. "Were Lincoln's nerves shattered? We don't know. But our study raises the possibility that they were," says biology Professor Michael Bastiani, the study's senior author and a member of the Brain Institute at the University of Utah. The new study will be published in The Journal of Cell Biology on Jan. 29, two weeks before Lincoln's birthday on Feb. 12. The study involved a worm gene named unc-70 that makes a protein named beta spectrin. Humans have four beta spectrin genes, and mutations in one of them was identified previously as the cause of SCA5, a neurodegenerative disease that develops between ages 10 and 68; destroys nerve cells in the part of the brain that controls movements; causes loss of coordination in walking, speaking, writing and swallowing; and puts some patients in wheelchairs.

Keyword: Development of the Brain; Movement Disorders
Link ID: 9897 - Posted: 06.24.2010

Michael Hopkin They say you are what you eat. And that's especially true of Rhabdophis tigrinus — zoologists have discovered that this snake eats poisonous toads and keeps their venom for itself. Rather than going to the trouble of making its own venom to use against predators, R. tigrinus, which is found in Asia, takes the venom from its prey and transports it to its own venom glands for storage and use. The snakes eat a wide range of prey, often including toads that secrete defensive poisons called bufadienolides through their skin. When fed a diet featuring these toads, the snakes' venom glands fill up with an almost chemically identical venom, report Deborah Hutchinson of Old Dominion University in Norfold, Virginia, and her colleagues. Snakes lacking toads in their diet do not gather the poison, the researchers add. Their findings are published in Proceedings of the National Academy of Sciences1. Many invertebrates, such as sea slugs, collect and store toxins from their plant food to make themselves unpalatable to predators. A few species of poisonous frogs also get their toxins from insects in their diet. But examples of vertebrate predators using venom from vertebrate prey are rare, and the only other species known to do it only stores venom temporarily. ©2007 Nature Publishing Group

Keyword: Neurotoxins
Link ID: 9896 - Posted: 06.24.2010

Rowan Hooper The monthly mood swings experienced by many women may serve an evolutionary purpose, researchers say, by helping to get them pregnant. Levels of sex hormones such as oestrogen and progesterone fluctuate throughout a woman’s monthly menstrual cycle. During the follicular phase at the start of the cycle, the egg is maturing and the body releases oestrogen, while during the luteal phase, when a fertilised egg might implant, progesterone is secreted. To see how these influence the brain, Jean-Claude Dreher and colleagues at the National Institute of Mental Health in Bethesda, Maryland, US, used functional magnetic resonance (fMRI) imaging to examine the changes in brain activity over the course of the month. The team scanned the brains of 15 women at different stages of menstruation as they played a game with hypothetical prizes of money at the end. During the follicular phase, both the orbitofrontal cortex and the amygdala showed higher activity both when the women were anticipating a reward and when the reward was delivered. The orbitofrontal cortex is associated with decision making, reward and emotion processing, and the amygdala mediates emotional reactions. This means the women were probably experiencing greater feelings of reward during the first half of their menstrual cycles than during the second half, although they were not specifically asked to report this. “Our work specifies the brain networks that are modulated by the menstrual cycle,” says Dreher. © Copyright Reed Business Information Ltd

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 9895 - Posted: 06.24.2010

By MICHAEL POLLAN Eat food. Not too much. Mostly plants. That, more or less, is the short answer to the supposedly incredibly complicated and confusing question of what we humans should eat in order to be maximally healthy. I hate to give away the game right here at the beginning of a long essay, and I confess that I’m tempted to complicate matters in the interest of keeping things going for a few thousand more words. I’ll try to resist but will go ahead and add a couple more details to flesh out the advice. Like: A little meat won’t kill you, though it’s better approached as a side dish than as a main. And you’re much better off eating whole fresh foods than processed food products. That’s what I mean by the recommendation to eat “food.” Once, food was all you could eat, but today there are lots of other edible foodlike substances in the supermarket. These novel products of food science often come in packages festooned with health claims, which brings me to a related rule of thumb: if you’re concerned about your health, you should probably avoid food products that make health claims. Why? Because a health claim on a food product is a good indication that it’s not really food, and food is what you want to eat. Uh-oh. Things are suddenly sounding a little more complicated, aren’t they? Sorry. But that’s how it goes as soon as you try to get to the bottom of the whole vexing question of food and health. Before long, a dense cloud bank of confusion moves in. Sooner or later, everything solid you thought you knew about the links between diet and health gets blown away in the gust of the latest study. Copyright 2007 The New York Times Company

Keyword: Obesity
Link ID: 9894 - Posted: 06.24.2010

Heidi Ledford By learning from patients who nod off unexpectedly during the day, researchers have pinpointed a chemical that could help people who can't sleep at night. One out of every 10 people in the United States suffers from chronic insomnia, making for a big sleeping-pill market. The most popular pills work by strengthening the effects of a brain chemical that slows the nervous system and promotes relaxation. But these drugs can also carry unpleasant side effects, including memory loss and grogginess the next day. The race for a better sleeping pill is still on. Now, a new approach targets brain hormones called orexins. Orexins are known to be linked to sleepiness; patients with a sleeping disorder called narcolepsy have low levels of these hormones and are chronically sleepy during the day, sometimes falling asleep on the job or while driving. The new chemical, known as ACT-078573, blocks the action of orexins. When given to dogs, rats and humans, it decreased alertness in all three species, while shortening the time it took for them to fall asleep. François Jenck, of the Swiss biotech company Actelion Pharmaceuticals in Allschwil, and his colleagues report the findings in the journal Nature Medicine1. Orexins aren't an obvious target for developing new sleeping pills. Narcoleptics suffer not only from sleepiness, but also from sudden loss of muscle tone that, in extreme cases, can cause them to collapse and remain frozen - fully conscious - for minutes at a time. Laughter often triggers a collapse in human narcoleptics, whereas narcoleptic dogs can crumple from the thrill of dinnertime or being let loose to play in the yard. "They get excited and run out the door and just go 'thump'," says Jerome Siegel, a sleep researcher at the University of California, Los Angeles. ©2007 Nature Publishing Group

Keyword: Narcolepsy; Sleep
Link ID: 9893 - Posted: 06.24.2010

A new love song CD with a difference could make a splash by featuring sea creatures including an amorous haddock. The British Library collection includes marine mating calls. Whale and dolphin sounds may be familiar but deeper in the North Sea the recorded sounds include a male haddock searching for a mate. The haddock courting noises start as slow knocks and turn into a quicker hum that sounds similar to a small motorcycle revving its engine. The CD contains the noises of North Sea haddock recorded in laboratory conditions in Aberdeen. The experts believe that replicates the "at sea" sound. Sounds of the Deep also features a walrus diving for food and the clicks, whistles and buzzes of the Atlantic Spotted Dolphin. The British Library sound archive's wildlife curator, Cheryl Tipp, said of the haddock: "It really is quite a novel sound, it's fascinating. "The knocks turn into a hum. "We are thrilled to present these captivating new collections of marine life and coastal wildlife sounds and hope that wildlife enthusiasts will find them fascinating." (C)BBC

Keyword: Sexual Behavior; Hearing
Link ID: 9892 - Posted: 01.27.2007