By Bill Briggs All these years, I thought it was because I was white. And straight. And old. Sure, I’ll get my freak on if I hear “Disco Inferno,” or when Mary J. is in the spot. (Told you I was old. And let me add: Don’t need no hateration.) But my steps aren’t smooth. Those beats and my body never truly connect -- despite what the cocktails tell me. On the dance floor, I'm the male Elaine from "Seinfeld," all kicks, thumbs and no rhythm. Turns out, it’s all in my head, not my hips or feet. A study, released today by researchers at the University of Oxford in England, claims a tiny messenger in the brain is partly to blame for those among us who struggle to grasp the latest dance moves. This is all about GABA (short for gamma-aminobutyric acid). Again: not Gaga, GABA. A naturally occurring chemical, GABA is a bit like the brain’s traffic cop. Nerve cells in the brain are constantly firing and “talking” to each other. GABA helps keep all that chatter from getting out of control. “Our research suggests that an important first step in learning that new skill is a decrease in GABA levels in the motor cortex,” explained Dr. Charlotte Stagg, a junior research fellow at Oxford and at John Radcliffe Hospital. Her study was published online in the journal Current Biology. © 2011 msnbc.com

Keyword: Miscellaneous
Link ID: 15084 - Posted: 03.08.2011

By Neil Bowdler Science reporter, BBC News Scientists say they have found a mechanism which may explain why a poor diet during pregnancy can increase the risk of offspring developing diabetes in later life. They say rat studies indicate an imbalanced diet in the mother can lead to the "silencing" of a gene linked to insulin production in the child. The Cambridge study is in Proceedings of the National Academy of Sciences. Experts said it showed a healthy diet was important during pregnancy. Silent gene Scientists already suspect that a poor diet during pregnancy can result in health problems such as diabetes for the offspring in later life. What the researchers at the University of Cambridge have come up with is a possible explanation. They believe an imbalanced diet in the expectant mother can compromise the long-term functioning of a gene in the child. The gene, called Hnf4a, is thought to play a role in the development of the pancreas and in insulin production. Because of the difficulties of testing the theory on pregnant women, they fed rats a protein-deficient diet and found higher rates of type 2 diabetes in the offspring, as expected. What they also found in the offspring was that this Hnf4a gene appeared to be "silenced" or "switched off" as the rats aged. The researchers suggest this may both cause diabetes, and can be linked back to the maternal diet. BBC © MMXI

Keyword: Obesity; Development of the Brain
Link ID: 15083 - Posted: 03.08.2011

By ANEMONA HARTOCOLLIS Every morning, Kay Brown engages in a ritual similar to a heroin addict’s, or a diabetic’s: she sticks herself with a syringe. Only hers contains hCG, a pregnancy hormone. Ms. Brown, 35, is not taking hCG to help her bear a child. She believes that by combining the hormone injections with a 500-calorie-a-day diet, she will achieve a kind of weight-loss nirvana: losing fat in all the right places without feeling tired or hungry. “I had a friend who did it before her wedding,” Ms. Brown said. “She looks great.” Women like Ms. Brown are streaming into doctors’ offices and weight-loss clinics all over the country, paying upward of $1,000 a month for a consultation, a supply of the hormone and the syringes needed to deliver it. More than 50 years after a doctor at a Roman clinic began promoting hCG as a dieting aid, it is as popular as ever, even though there is scant evidence that it makes any difference. The regimen combines daily injections with a near-starvation diet, and patients, mostly women, are often enticed by promises that they can lose about a pound a day without feeling hungry. Perhaps even more seductively, they are frequently told that the hCG will prompt their bodies to carry away and metabolize fat that has been stored where they least want it — in their upper arms, bellies and thighs. In response to inquiries stirred up by the diet’s popularity, the Food and Drug Administration warned in January that “homeopathic” forms of hCG, like lozenges and sprays, sold over the Internet and in some health food stores, are fraudulent and illegal if they claim weight-loss powers. © 2011 The New York Times Company

Keyword: Obesity
Link ID: 15082 - Posted: 03.08.2011

By RONI CARYN RABIN A leisurely four-course dinner at a fine restaurant can take two hours to eat, while meals eaten at home are usually over in 30 minutes. Does one leave you more satisfied — and less likely to snack afterward — than the other? Researchers in the Netherlands set out to see whether, all other things being equal — meaning people ate the exact same quantities of the exact same food — the speed of consumption had an effect on diners’ feelings of satiety and hunger and on the chemical signals, or hormones, that are involved in appetite regulation. The researchers also wanted to see how the pace of the meal affected postprandial snacking. Though people said they felt more sated and less hungry after a staggered meal that lasted two hours with breaks between courses and didn’t really want to eat more afterward, the experience didn’t change their snacking behavior, said Sofie G. Lemmens, a postdoctoral fellow at Maastricht University in the Netherlands who was the lead author of the paper, published in the March issue of The Journal of Nutrition. Two and a half hours after the beginning of the meal, when the diners were offered an array of traditional Dutch tea treats like apple cake, chocolate-covered marshmallows, peanuts, chips and waffles, they ate almost as much as they did two and a half hours after a meal that they had consumed in 30 minutes. © 2011 The New York Times Company

Keyword: Obesity
Link ID: 15081 - Posted: 03.08.2011

By Deborah Kotz Dianne Sanborn admits that “it didn’t make any sense’’ to take a sugar pill to relieve the severe constipation, abdominal pain, and bloating — attributed to irritable bowel syndrome — that she’d suffered from since college. But eager to try anything, the 64-year-old entered a clinical trial last spring at Beth Israel Deaconess Medical Center, where she was told to take placebo caplets twice a day for three weeks. “Before I took each pill, I had to tell myself that it was going to make me feel better, but I was very skeptical,’’ says the 64-year-old former nurse practitioner who had to quit her job 13 years ago because of her medical problems. “I certainly knew placebos could work but only if you didn’t know it was a placebo.’’ When her symptoms dissipated three days after she started taking the placebos, however, she became a believer. So did many of the other 36 volunteers who were randomly assigned placebos along with any of their usual treatments in the December study published in the journal PLoS ONE. Nearly 60 percent of them reported an improvement in their irritable bowel symptoms compared to 35 percent of the 43 volunteers who weren’t given placebos but were just told to continue their standard therapy. Other research had already demonstrated that sham treatments could dull pain, alleviate depression, and even quell Parkinson’s tremors. But this study was the first to show that placebos have power even when patients know they’re taking them. And now placebo researchers are gearing up to figure out ways to move side-effect-free sugar pills into mainstream clinical practice — that’s the goal of a placebo-studies program that Harvard Medical School is launching in July with 30 faculty members. “We’d like to eventually see placebo treatments become a full partner in medical care along with active medications, procedures, and surgery,’’ says PLoS ONE study author Dr. Ted Kaptchuk, who will head the program. © 2011 NY Times Co.

Keyword: Pain & Touch; Stress
Link ID: 15080 - Posted: 03.08.2011

By BENEDICT CAREY For years scientists have dreamed of developing a genuine memory booster, a drug that could tune the brain’s biological search engine so that it’s better at retrieving not only recently learned facts, like last night’s dinner menu, but details that seem all but lost in the fog of time, like childhood classmates’ names and antics. Such a substance would have obvious appeal — for people at risk of dementia, to name just one group — but the search has been very slow going. Stimulants like caffeine and nicotine can sharpen the memory, but like other temporary enhancers, they need to be taken when the information is learned or retrieved to make a difference. Now, researchers in Israel and New York report that they have been able to strengthen memories formed well in the past, using a brain substance involved in anchoring and maintaining the memory in the first place. The finding, reported last week in the journal Science, is one of two recent studies in which neuroscientists used molecules active in memory formation to, in effect, goose the system and improve recall. Both studies were conducted in rats, which provide a very rough model for human memory. “The idea that an older memory can be strengthened is a novel and exciting finding,” said Jim McGaugh, a neuroscientist at the University of California, Irvine, who was not involved in the research. “But it also raises the question: How does this work? And, does it apply to all memories?” © 2011 The New York Times Company

Keyword: Learning & Memory
Link ID: 15079 - Posted: 03.08.2011

Using cannabis as a teenager or young adult increases the risk of psychosis, a report suggests. The study published in the British Medical Journal involved tracking 1,900 people over a period of 10 years. Although the link between cannabis and psychosis is well established, it had been unclear whether cannabis triggered the disorder. This research strongly suggests that cannabis use comes first, rather than people taking it for their symptoms. The research was led by Professor Jim van Os from Maastricht University in the Netherlands, and included researchers from the Netherlands, Germany, Switzerland and the UK. They excluded anyone who reported cannabis use or pre-existing psychotic symptoms at the start of the study, which took place in Germany. The participants in the study, aged between 14 and 24, were assessed for cannabis use and psychotic symptoms at three points over a 10-year period. It found that cannabis use "significantly" increased the risk of psychotic symptoms, even when other factors such as socio-economic status, use of different drugs and other psychiatric conditions were taken into account. Sir Robin Murray, professor of psychiatric research at the Institute of Psychiatry, said the study added "a further brick to the wall of evidence" showing that use of traditional cannabis is a contributory cause of psychoses like schizophrenia. BBC © MMXI

Keyword: Drug Abuse; Schizophrenia
Link ID: 15078 - Posted: 03.07.2011

By GARDINER HARRIS DOYLESTOWN, Pa. — Alone with his psychiatrist, the patient confided that his newborn had serious health problems, his distraught wife was screaming at him and he had started drinking again. With his life and second marriage falling apart, the man said he needed help. But the psychiatrist, Dr. Donald Levin, stopped him and said: “Hold it. I’m not your therapist. I could adjust your medications, but I don’t think that’s appropriate.” Like many of the nation’s 48,000 psychiatrists, Dr. Levin, in large part because of changes in how much insurance will pay, no longer provides talk therapy, the form of psychiatry popularized by Sigmund Freud that dominated the profession for decades. Instead, he prescribes medication, usually after a brief consultation with each patient. So Dr. Levin sent the man away with a referral to a less costly therapist and a personal crisis unexplored and unresolved. Medicine is rapidly changing in the United States from a cottage industry to one dominated by large hospital groups and corporations, but the new efficiencies can be accompanied by a telling loss of intimacy between doctors and patients. And no specialty has suffered this loss more profoundly than psychiatry. Trained as a traditional psychiatrist at Michael Reese Hospital, a sprawling Chicago medical center that has since closed, Dr. Levin, 68, first established a private practice in 1972, when talk therapy was in its heyday. Then, like many psychiatrists, he treated 50 to 60 patients in once- or twice-weekly talk-therapy sessions of 45 minutes each. Now, like many of his peers, he treats 1,200 people in mostly 15-minute visits for prescription adjustments that are sometimes months apart. © 2011 The New York Times Company

Keyword: Depression
Link ID: 15077 - Posted: 03.07.2011

By PERRI KLASS, M.D. Humans are asymmetric animals. Early in our embryonic development, organs turn to one side or the other — heart to the left, liver to the right and so on. In rare cases, an organ may turn up on the “wrong” side with no untoward effects. (I once examined a child with dextrocardia, or heart on the right.) But there is one form of asymmetry that is common and, until quite recently, stigmatized: handedness. Over the centuries, left-handers have been accused of criminality and dealings with the devil, and children have been subjected to “re-education.” In recent years the stigma has largely vanished; among other things, four of our last five presidents — Reagan, the elder Bush, Clinton, Obama — have been left-handed. (Reagan is sometimes cited as ambidextrous.) But the riddle of why about 10 percent of children are born with this essentially human asymmetry remains. “This is really still mysterious,” said Clyde Francks, the lead author of a 2007 study in which Oxford University researchers identified a genetic variant linked to left-handedness. Hand asymmetry (whether left or right) is related to brain asymmetry. And that, Dr. Francks said, “is not at all understood; we’re really at the very beginning of understanding what makes the brain asymmetrical and what goes wrong — we don’t understand that process in the normal case.” © 2011 The New York Times Company

Keyword: Laterality
Link ID: 15076 - Posted: 03.07.2011

by Gisela Telis A would-be mom worried about Down syndrome faces an unpleasant choice: undergo an invasive test that can kill her fetus, or forgo a definitive answer until after birth. But a new method that involves tracing differences between a mother's DNA and her baby's could provide doctors with a safe and inexpensive way to diagnose the condition, one practical enough to become a part of routine prenatal care. Down syndrome is the world's most common genetic condition, affecting about one in every 700 live births. Babies with the disorder carry an extra copy of chromosome 21, which causes cognitive disabilities, heart defects, and other problems. Although certain markers in a mother's blood can tip off doctors that a fetus is at higher risk of Down syndrome, only invasive and expensive procedures such as amniocentesis—which requires poking a needle into the uterus to obtain a fluid sample—can give a 99% accurate answer. But these invasive tests are risky: They can cause miscarriage in 1% to 2% of cases. In an attempt to find a safer alternative, researchers have turned to the mother's blood. In a recent study, scientists ferreted out the fragments of fetal DNA that leak into a mother's bloodstream and then sequenced both genomes to check for extra copies of chromosome 21. Those attempts were successful, but they were time-consuming and required specialized and expensive DNA-sequencing equipment that would put the process out of reach for most people. Philippos Patsalis wanted something more accessible. A geneticist at the Cyprus Institute of Neurology and Genetics in Nicosia, Patsalis has provided diagnostic prenatal testing for 20 years and has long lamented that women who want accurate testing face greater risk and expense. © 2010 American Association for the Advancement of Science.

Keyword: Development of the Brain; Genes & Behavior
Link ID: 15075 - Posted: 03.07.2011

By Daniel Strain In “Memory,” a song from the musical Cats, an aging feline invites old memories to live again. Now, that power may be in the hands of the cat’s worst enemy — the rat. Increased levels of one natural brain enzyme supercharge rat memories, a study suggests. And it’s not just new, short-term memories. The enzyme — called PKM-zeta — gives rats better recall of old remembrances, too, a U.S.-Israeli team reports in the March 5 Science. So far, existing memory boosters mostly help animals like rats store lessons or events more efficiently. It’s a lot harder to give furry critters better recall of memories already sitting in long-term cold storage, says study coauthor Yadin Dudai. In a number of recent studies, researchers showed that they could make rats forget a range of old learned behaviors by blocking the protein in the brain. Rodents with too little PKM-zeta, for instance, didn’t know to avoid liquids that had made them sick in the past. So Dudai’s team tackled the next big question. “If you, indeed, can block the memory by blocking the enzyme, can you enhance the memory by enhancing the enzyme?” says Dudai, a neurobiologist at the Weizmann Institute of Science in Rehovot, Israel. Spoiler alert: You can. Dudai’s team injected rats with viruses carrying loads of PKM-zeta–producing genes, shooting the infectious agents right into the wrinkly, outer region of the brain called the neocortex. Cells in the cortex then churned out lots of the protein. The rodents didn’t instantly recall where they left that cheese, though. Researchers trained the rats to associate certain tastes — like sugary or salty — with gross feelings akin to mild food poisoning. Rats that received the enzyme boost remembered to steer clear of those tastes much better than control rats did. © Society for Science & the Public 2000 - 2011

Keyword: Learning & Memory
Link ID: 15074 - Posted: 03.05.2011

By Bruce Bower The Go-Go’s had a 1982 hit record with “We Got the Beat,” but a 23-year-old man named Mathieu never got their message. Researchers have identified Mathieu as the first documented case of beat deafness, a condition in which a person can’t feel music’s beat or move in time to it. Mathieu flails in a time zone of his own when bouncing up and down to a melody, unlike people who don’t dance particularly well but generally move in sync with a musical beat, according to a team led by psychologists Jessica Phillips-Silver and Isabelle Peretz, both of the University of Montreal. What’s more, Mathieu usually fails to recognize when someone else dances out of sync to a tune, the researchers report in a paper that will appear in Neuropsychologia. “We suspect that beat deafness is specific to music and is quite rare,” Phillips-Silver says. She and her colleagues plan to investigate whether Mathieu takes an offbeat approach to nonmusical activities, such as conversational turn-taking and adjusting one’s gait to that of someone else. Language lacks the periodic rhythms found in music, so it’s unlikely that Mathieu’s problem affects speech perception, remarks cognitive scientist Josh McDermott of New York University. If periodic sounds of all kinds confuse Mathieu, this problem may loom large when he confronts complex musical beats, McDermott suggests. © Society for Science & the Public 2000 - 2011

Keyword: Hearing; Language
Link ID: 15073 - Posted: 03.05.2011

by Carrie Arnold Why does the rustle of sheets wake us up on some nights, but we sleep through the sound of our alarm clocks going off on others? A new study implicates a type of brain activity known as alpha waves. With better monitoring of these waves, researchers might be able to develop therapies that could help all of us get a better night's sleep. Our brain activity changes throughout the day. When we're awake, our neurons chatter in short, frequent bursts. Measured on an electroencephalogram (EEG), these "alpha waves" look a lot like earthquake squiggles on a seismograph. When we sleep, our neuron chatter slows down, resulting in less squiggly theta and delta waves. Scientists have shown that alpha waves help us respond to the sights and sounds of our environment. Yet they seem to disappear during sleep, even though we are still able to respond to environmental cues, such as smoke or a passing police siren. So do alpha waves really disappear when we slumber? Sleep scientists Scott McKinney and Jeffrey Ellenbogen of Massachusetts General Hospital in Boston and colleagues used a sophisticated computer program to find out. Rather than eyeballing EEGs, as researchers had done in the past, the program teases apart the complicated patterns of brain activity. During sleep, the researchers found, alpha waves are still present—they're just drowned out by the theta and delta waves, like the din of a noisy restaurant drowns out individual conversations. © 2010 American Association for the Advancement of Science.

Keyword: Sleep
Link ID: 15072 - Posted: 03.05.2011

by Ferris Jabr Alzheimer's disease kills brain cells that are vital for memory – but now we can make new ones from human embryonic stem cells in the lab. The breakthrough opens the way for testing new anti-Alzheimer's drugs, and raises the hope that one day people with Alzheimer's could receive transplants of lab-grown neurons into their brains to improve their memory. A type of brain cell called basal forebrain cholinergic neurons is among those that Alzheimer'sMovie Camera hits hardest. They die off early in the progress of the disease, a loss which devastates memory and our ability to fully understand our environment. Christopher Bissonnette and colleagues at Northwestern University in Evanston, Illinois, took the first step in growing new ones by studying the genetics of these neurons. Once the team had deciphered the genetic signals that guide the development of these cells, they were able to coerce human embryonic stem cells into developing in the same way. To initiate the metamorphosis, they created pores in the walls of the stem cell nuclei and slipped in segments of DNA and gene-regulating proteins called transcription factors that are associated with the neurons. When the researchers transplanted the neurons they had engineered into slices of mouse brain, the cells wove themselves into the tissue of the hippocampus, a brain region involved in the formation of memories. They then began producing the neurotransmitter acetylcholine, which is necessary for memory retrieval. © Copyright Reed Business Information Ltd.

Keyword: Alzheimers; Stem Cells
Link ID: 15071 - Posted: 03.05.2011

Catherine de Lange, reporter Want to see an illusion that will get your cogs turning? In the video above, you can see three versions of a new illusion by Sung Ho-Kim at Rutgers University, New Jersey, that trick your brain into thinking circular patterns that shift across a screen are actually spinning. Make sure you are close to the screen to see the full effect. In the first animation, the top and bottom halves of the shape should look like they are rotating in opposite directions. They switch directions as the motion of the pattern changes from left to right. In the second version of the illusion, a block covers half of the shape. This time it looks like the spokes of a wheel are rotating as the whole pattern travels left and right across the screen. In the final animation, two gears connected by a chain appear to be rotating together. If you're convinced that these shapes are actually turning, try tracking each of the short lines, and you'll see that it's an illusion. The physical trajectory of each line segment is purely horizontal and none of the circles are rotating. Do you know why our brains trick us in this way? If you think you know the answer, let us know in the comments below and we will reveal all next week. © Copyright Reed Business Information Ltd.

Keyword: Vision
Link ID: 15070 - Posted: 03.05.2011

By Nina Bai When asked recently on The Today Show how he cured himself of his addiction, Two and a Half Men sitcom star Charlie Sheen replied, "I closed my eyes and made it so with the power of my mind." Until last month, he was the highest paid actor on TV, despite his well-known bad-boy lifestyle and persistent problems with alcohol and cocaine. After the rest of his season's shows were canceled by producers, Sheen has gone on an interview tear with many bizarre statements, including that he is on a "winning" streak. His claims of quitting a serious drug habit on his own, however, is perhaps one of his least eccentric statements. A prevailing view of substance abuse, supported by both the National Institute on Drug Abuse and Alcoholics Anonymous, is the disease model of addiction. The model attributes addiction largely to changes in brain structure and function. Because these changes make it much harder for the addict to control substance use, health experts recommend professional treatment and complete abstinence. But some in the field point out that many if not most addicts successfully recover without professional help. A survey by Gene Heyman, a research psychologist at McLean Hospital in Massachusetts, found that between 60 to 80 percent of people who were addicted in their teens and 20s were substance-free by their 30s, and they avoided addiction in subsequent decades. Other studies on Vietnam War veterans suggest that the majority of soldiers who became addicted to narcotics overseas later stopped using them without therapy. © 2011 Scientific American

Keyword: Drug Abuse
Link ID: 15069 - Posted: 03.05.2011

By Clara Moskowitz The latest neuroscience research is presenting intriguing evidence that the brains of certain kinds of criminals are different from those of the rest of the population. While these findings could improve our understanding of criminal behavior, they also raise moral quandaries about whether and how society should use this knowledge to combat crime. In one recent study, scientists examined 21 people with antisocial personality disorder – a condition that characterizes many convicted criminals. Those with the disorder "typically have no regard for right and wrong. They may often violate the law and the rights of others," according to the Mayo Clinic. Brain scans of the antisocial people, compared with a control group of individuals without any mental disorders, showed on average an 18 percent reduction in the volume of the brain's middle frontal gyrus, and a 9 percent reduction in the volume of the orbital frontal gyrus — two sections in the brain's frontal lobe. Another brain study, published in the September 2009 Archives of General Psyciatry, compared 27 psychopaths — people with severe antisocial personality disorder — to 32 non-psycopaths. In the psychopaths, the researchers observed deformations in another part of the brain called the amygdala, with the psychopaths showing a thinning of the outer layer of that region called the cortex and, on average, an 18-percent volume reduction in this part of brain. © 2011 LiveScience.com.

Keyword: Aggression; Emotions
Link ID: 15068 - Posted: 03.05.2011

by Rowan Hooper Neuroengineer Ed Boyden is best known for his pioneering work on optogenetics, which allows brain cells to be controlled using light. A speaker at the TED2011 conference this week, his vision, he tells Rowan Hooper, is nothing less than to understand the brain, treat neural conditions and figure out the basis of human existence. Give us your elevator pitch. I run the synthetic neurobiology group. We develop software, electrical and optical tools to allow people to analyse brain dynamics. Unlike a computer, the brain is made of thousands of different types of cell, and we don't know how they work. We need to be able to turn the cells on and off to see how they cooperate to implement brain computations, and how they go awry in brain disorders. What we're doing is making genetically encoded neurons that we can turn on and off with light. By shining light on these cells we can activate them and see what they do. What brain functions will this allow you to study? Scientists now have unprecedented abilities to perturb and record from the brain, and that's allowing us to go after complex ideas like thought and memory. Our tools will help us parse out emotion, memory, attention and consciousness. Put psychology and neuroscience together with neuroengineering, and some of the biggest questions in neuroscience become tractable. Tell us about your tools. The core idea is to take molecules that sense light and convert it into electrical energy, and put them in neurons. We can take a given class of brain cells and develop a virus to deliver genes to these cells. Then we can shine light on these cells and activate them and see what they do. © Copyright Reed Business Information Ltd.

Keyword: Miscellaneous
Link ID: 15067 - Posted: 03.05.2011

NEW YORK — People who regularly use ibuprofen to ease their aches and pains may be less likely to develop Parkinson's disease than those who do not use the painkiller, researchers reported Wednesday. In a study of more than 136,000 U.S. men and women, researchers found that the more ibuprofen tablets people took each week, the lower their odds of developing Parkinson's, a disorder in which movement-regulating brain cells degenerate over time. Ibuprofen, sold as name-brands like Advil and Motrin in the U.S., is a non-steroidal anti-inflammatory drug (NSAID). But the study found no connection between Parkinson's risk and other NSAIDS, like aspirin or naproxen (Aleve), or with acetaminophen (Tylenol). Experts caution, however, that the findings do not prove that ibuprofen itself can help ward off Parkinson's. "It's too early to recommend use of ibuprofen to prevent or treat Parkinson's disease," lead researcher Dr. Xiang Gao, of Harvard Medical School in Boston, told Reuters Health in an email. Instead, Gao said, the findings lay the groundwork for clinical trials to look at whether the painkiller, which costs only a few cents per pill, might help slow SOURCE: http://bit.ly/Q5TNl Neurology, online March 2, 2011. Copyright 2011 Thomson Reuters

Keyword: Parkinsons
Link ID: 15066 - Posted: 03.03.2011

By Katherine Harmon Wandering the neighborhood randomly is not usually the best strategy to find a great dinner—especially if you live in a place where such meals are few and far between. The resulting trajectory, known in mathematics as "a random walk," does not always make for the best use of time and energy, particularly in locations where resources can be scarce, such as the open ocean. But a more purposeful "directed walk" to a destination takes a pretty sophisticated memory and spatial sense (or a device with GPS) that many animals don't have. New research, however, shows that thresher and tiger sharks are actually quite adept at highly directed swimming, with tiger sharks finning it over to a familiar spot from six to eight kilometers away within a home territory that covers hundreds or even thousands of square kilometers. Demonstrating that an animal is traveling directly to a desired destination—rather than stumbling on it accidentally—is challenging, given communication barriers and the fact that even straight paths are not always part of a purposeful travel pattern. To find out whether sharks were always circling their home range randomly or were intentionally returning to a place they remembered to offer food, shelter or mates, a team of researchers used fractal analysis to assess old GPS tracking data from three shark species: tiger sharks (Galeocerdo cuvier), thresher sharks (Alopias vulpinus) and blacktip reef sharks (Carcharhinus melanopterus). Tracking for each individual shark lasted for at least seven hours. © 2011 Scientific American,

Keyword: Animal Migration
Link ID: 15065 - Posted: 03.03.2011