MacGregor Campbell, consultant Want to get rid of destructive lampreys? In this video, you can see how the smell of death can be a particularly effective repellant. Michael Wagner of Michigan State University exposed a group of lampreys to a mixture of chemicals from putrefying carcasses and ethanol. Another group was subjected to a similar amount of plain ethanol as a control. The animals exposed to the death-scented chemicals jumped out of the tank with a panic-like response. Sea lampreys are an invasive species in the US Great Lakes. They live as parasites on the bodies of lake trout and other commercially-important fish and have contributed to collapsing fish stocks in the region. Currently, wildlife officials use pheromones to lure lampreys into large cages where they can be destroyed or sterilised. These are the same chemicals the lampreys rely on to attract mates or to find good spawning grounds. But using natural cues to attract lampreys can be inefficient since a variety of scents in natural waterways compete for their attention. According to Wagner, repellants could be a better alternative to divert them since even tiny quantities can provoke a response. The smell of death could be used to form a chemical dam to steer lampreys away from environmentally-sensitive waterways. The chemicals could also be used to corral the animals into groups, making them easier to eliminate. © Copyright Reed Business Information Ltd.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 15719 - Posted: 08.25.2011

By LYNN ZINSER Pat Summitt, the longtime women’s basketball coach at Tennessee who has won more games than any other major college coach, said she forgot things at crucial points in games at times last season and struggled to keep track of when meetings were scheduled. She grew so confused that on a few days she simply stayed home from work. It was not until after the season ended that she sought a medical diagnosis and learned she has symptoms of early onset Alzheimer’s disease. Ms. Summitt, 59, revealed the diagnosis on Tuesday, and said she planned to continue to coach. She said her doctor at the Mayo Clinic in Rochester, Minn., encouraged her to continue as long as she felt up to it. “I plan to continue to be your coach,” Ms. Summitt said in a videotaped statement posted on the university’s Web site. “Obviously, I realize I may have some limitations with this condition since there will be some good days and some bad days.” Ms. Summitt built a powerhouse program in Knoxville that often outshone the university’s men’s team, amassing 1,079 victories that make her the most successful Division I coach of either gender. She will enter her 38th season at Tennessee in pursuit of her ninth national title. Long known for a steely, intense coaching style, Ms. Summitt will now also be the public face of a debilitating disease. © 2011 The New York Times Company

Keyword: Alzheimers
Link ID: 15718 - Posted: 08.25.2011

A new atlas of gene expression in the mouse brain provides insight into how genes work in the outer part of the brain called the cerebral cortex. In humans, the cerebral cortex is the largest part of the brain, and the region responsible for memory, sensory perception and language. Mice and people share 90 percent of their genes so the atlas, which is based on the study of normal mice, lays a foundation for future studies of mouse models for human diseases and, eventually, the development of treatments. Researchers from the National Human Genome Research Institute (NHGRI), part of the National Institutes of Health, and from Oxford University in the United Kingdom, published a description of the new atlas in the Aug. 25, 2011, journal Neuron. The study describes the activity of more than 11,000 genes in the six layers of brain cells that make up the cerebral cortex. To map gene activity in all six layers of the mouse cerebral cortex, the research team first micro-dissected the brains of eight adult mice, separating the layers of the cortex. They then purified processed RNAs, including messenger RNA, from each cortical layer. The international collaborators have made the new atlas freely available at http://genserv.anat.ox.ac.uk/layers.

Keyword: Genes & Behavior; Development of the Brain
Link ID: 15717 - Posted: 08.25.2011

by Dan Hurley 10:19 p.m. on a Monday evening in October, I sat in a booth at Chevys Fresh Mex in Clifton, New Jersey, reviewing the latest research into the neurobiology of hunger and obesity. While I read I ate a shrimp and crab enchilada, consuming two-thirds of it, maybe less. With all this information in front of me, I thought, I had an edge over my brain’s wily efforts to thwart my months-long campaign to get under 190 pounds. But even as I was taking in a study about the powerful lure of guacamole and other salty, fatty foods, I experienced something extraordinary. That bowl of chips and salsa at the edge of the table? It was whispering to me: Just one more. You know you want us. Aren’t we delicious? In 10 minutes, all that was left of the chips, and my willpower, were crumbs. I am not alone. An overabundance of chips, Baconator Double burgers, and Venti White Chocolate Mochas have aided a widespread epidemic of obesity in this country. Our waists are laying waste to our health and to our health-care economy: According to a study published by the Centers for Disease Control and Prevention in 2010, nine states had an obesity rate of at least 30 percent—compared with zero states some 10 years earlier—and the cost of treatment for obesity-related conditions had reached nearly 10 percent of total U.S. medical expenditure. So-called normal weight is no longer normal, with two-thirds of adults and one third of children and adolescents now classified as overweight or obese. Dubbed the “Age of Obesity and Inactivity” by the Journal of the American Medical Association, this runaway weight gain threatens to decrease average U.S. life span, reversing gains made over the past century by lowering risk factors from smoking, hypertension, and cholesterol. We all know what we should do—eat less, exercise more—but to no avail. An estimated 25 percent of American men and 43 percent of women attempt to lose weight each year; of those who succeed in their diets, between 5 and 20 percent (and it is closer to 5 percent) manage to keep it off for the long haul. © 2011, Kalmbach Publishing Co.

Keyword: Obesity
Link ID: 15716 - Posted: 08.25.2011

by Elizabeth Norton Time is what keeps everything from happening at once, the American theoretical physicist John Wheeler once said. In the mind, as in the outside world, the flow of events contains individual experiences strung together in sequence yet separated by gaps in time. New research shows that during these gaps, neurons in a part of the brain called the hippocampus encode each "empty" moment as precisely as the surrounding events, allowing the brain to make detailed representations of time. The hippocampus has long been known as a center for navigation and memory. Research into this sea horse-shaped structure shows the importance of "place cells," groups of which fire when a person or animal is at a certain location. The firing pattern provides the neural basis of the mental maps used to find one's way around. But the hippocampus also encodes "episodic" memories of events as they occur in time. Thus, many researchers wondered whether the hippocampus also contains "time cells." To test the idea, Howard Eichenbaum and colleagues at Boston University trained rats to perform a two-part task with a delay in the middle while fitted with surgically implanted electrodes that recorded neural activity in the hippocampus. The rats were taught to associate an object with an odor: a ball with oregano, for example, and a cube with cinnamon. Then they were presented with one of the objects, after which they entered a chamber for 10 seconds. After this delay, a partition opened, leading to a flowerpot full of scented sand. If the scent paired with the object seen earlier, the rats knew to dig for a food reward. If the odor and object didn't match, the rats refrained from digging. (This correct response was rewarded with a treat in another part of the run.) © 2010 American Association for the Advancement of Science

Keyword: Attention
Link ID: 15715 - Posted: 08.25.2011

By Francie Diep To the list of cocaine’s many dangers, health officials have added at least one more: purpura, a rash caused by internal bleeding from small blood vessels. Two recent papers in major medical journals have documented cases of cocaine users showing up in emergency rooms with patches of blackened, dying skin on the ears, face, trunk or extremities. The condition causes scarring and sometimes requires reconstructive surgery. Noah Craft, a dermatologist at the Harbor-UCLA Medical Center who co-authored a paper on the condition published online by the Journal of the American Academy of Dermatology in June, says he now sees about one case per month: “It’s become almost routine.” The cause of the outbreak is a veterinary deworming medication that has become the most common ingredient used to dilute, or cut, cocaine coming into the U.S. from South America. The drug, called levamisole, was once approved for cancer treatment but was later pulled because of its side effects. Three quarters of the cocaine bricks seized by the U.S. Drug Enforcement Administration now contain levamisole. Equally worrying is another of its side effects: a sometimes fatal lowered count of white blood cells that are called neutrophils. Doctors suspect that both conditions are allergic reactions to the drug. In one disease, the body’s immune system attacks the skin; in the other, it attacks the bone marrow. Traffickers may add levamisole to cocaine because it is cheaper than pure cocaine and may contribute to the cocaine high. Papers between the 1970s and 1990s, when levamisole was being suggested and then approved for medical use in the U.S., found it improved mood and caused insomnia and hyperalertness, effects that are similar to cocaine’s. © 2011 Scientific American,

Keyword: Drug Abuse
Link ID: 15714 - Posted: 08.25.2011

Adam Kolber Several studies suggest that memories can be pharmaceutically dampened. A few months ago, for instance, researchers showed that a drug called ZIP causes cocaine-addicted rats to forget the locations where they had regularly been receiving cocaine1. Other drugs, already tested in humans, may ease the emotional pain associated with memories of traumatic events. Indeed, the use of memory-altering drugs to treat addicts or victims of assaults, car accidents, natural disasters and terrorist attacks looks increasingly promising. Many are alarmed by the prospect. As far back as 2003, the US President's Council on Bioethics issued a report that largely decried the use of such drugs2. Since then, journal articles and news stories have reiterated concerns that memory manipulators could interfere with the ability to lead true and honourable lives or could undermine a person's sense of identity. The fears about pharmaceutical memory manipulation are overblown. Thoughtful regulation may some day be appropriate, but excessive hand-wringing now over the ethics of tampering with memory could stall research into preventing post-traumatic stress in millions of people. Delay could also hinder people who are already debilitated by harrowing memories from being offered the best hope yet of reclaiming their lives. Various drugs are being investigated3, 4. Propranolol, for instance — which is already approved by the US Food and Drug Administration to treat hypertension — may dull the emotional pain associated with the recall of an upsetting experience by interfering with the release of stress hormones that otherwise strengthen memories. Preliminary studies suggest that propranolol can inhibit the formation of traumatic memories even when taken a few hours after a distressing event5, 6. © 2011 Nature Publishing Group,

Keyword: Learning & Memory; Stress
Link ID: 15713 - Posted: 08.23.2011

Bob Holmes, contributor HUMANS are very good at language. Computers are just beginning to cope with the complexities of speech, but almost every child masters language easily. This remarkable talent has led some anthropologists and psychologists to conclude that we have an innate "language instinct" - that evolution shaped our brains into language-learning devices. In Harnessed, psychologist Mark Changizi turns this argument on its head: instead of our brains adapting to language, he claims, language has evolved to take advantage of sound-processing skills the brain already possessed. Music has done the same, adapting itself to fit our brain's pre-existing talents and borrowing - harnessing - them for a new purpose. Our prelinguistic ancestors used their ears to inform them about events in their surroundings, and we are still good at this. Close your eyes for a moment and listen: not only can you hear a person walking nearby, but you know how close they are, whether they are going up or down stairs, often who they are and what their mood is, and whether they just filled a coffee mug or a water glass. You do that by discriminating many small details of the sounds you hear - the particular "clink" of a coffee mug, the characteristic rhythm of someone's gait, and the like. Crucially, most of this discrimination takes place subliminally, before your conscious mind assembles and labels the perception. © Copyright Reed Business Information Ltd.

Keyword: Hearing; Evolution
Link ID: 15712 - Posted: 08.23.2011

by Sujata Gupta In spring last year, the number of narcolepsy cases in Beijing, China, multiplied threefold. Now, it looks like the swine flu pandemic of the previous winter was to blame. Previously, similar rises in cases of narcolepsy – a disorder that causes sleepiness at inappropriate times – have been linked to use of a swine flu vaccine. The cause was presumed to lie in the drug's adjuvants – additives that boost the immune response to the vaccine. The claim puzzled researchers who saw a concurrent rise in narcolepsy cases in China, where few people had opted to get vaccinated and those who did received a vaccine without adjuvants. Could the flu itself be to blame? To find out, Fang Han and his colleagues at Beijing University People's Hospital studied the medical profiles of 906 people who had come to the hospital with narcolepsy since 1998. The group found that, even in the years before the vaccine was introduced in October 2009, the number of narcolepsy cases followed a seasonal pattern – cases dropped significantly around November and spiked in April. The peak was higher than normal in the spring after the swine flu pandemic (Annals of Neurology, DOI: 10.1002/ana.22587). The idea that flu causes narcolepsy fits in with the theory that narcolepsy is triggered by the immune system's response to airway infections. © Copyright Reed Business Information Ltd.

Keyword: Narcolepsy
Link ID: 15711 - Posted: 08.23.2011

By SINDYA N. BHANOO Acorn woodpeckers are industrious, cooperative birds that live in family groups. Each family has several “helper” woodpeckers that do not breed. These birds devote their time to gathering acorns and other food for the young. Researchers were surprised to find that helpers are more beneficial in the spring after a good crop than in one after a poor harvest. “It makes a lot of intuitive sense that the helpers are a lot more useful when conditions are bad,” said Walter Koenig, an ornithologist at Cornell University. “But in fact it seems to be exactly the opposite.” In the spring after a good acorn crop, the average number of new offspring in a family group increased by about seven-tenths of an offspring per helper. In a bad year, helpers slightly reduced the overall reproductive success. That’s because when an acorn crop is bad, having a helper may not help much, Dr. Koenig said. In fact, helpers might be eating up food that could otherwise go to fledglings. But in a good year, helpers are able to help harvest extra food and contribute to the family’s food reserves. Helper woodpeckers are generally young adults that are actively looking for breeding opportunities, within the family group or outside of it. Until they make a match, they maintain their roles as assistants and help raise their younger siblings and other relatives. © 2011 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 15710 - Posted: 08.23.2011

By AMANDA SCHAFFER For years, scientists thought they understood the skeleton. It serves as structural support for the body. It stores calcium and phosphate. It contributes to blood cell development. And it serves, indispensably, as the creepy mascot of Halloween. But as it turns out, there may be still more to bone. A few years ago, researchers at Columbia University Medical Center discovered, to everyone’s surprise, that the skeleton seems to help regulate blood sugar. Now the team, led by Dr. Gerard Karsenty, geneticist and endocrinologist at Columbia University, has found that bone may play an unexpected role in reproduction. If the work pans out, it may help to explain some cases of low fertility in men. “It’s definitely an attention-grabber,” Dr. William Crowley of Harvard Medical School, who was not involved in the research, said of the new finding regarding fertility. “I think it will turn out to be a seminal observation.” (No pun intended, presumably.) It is well known that the hormones estrogen and testosterone, produced in the ovaries and testes, help to regulate bone growth. When women reach menopause, estrogen levels decrease along with bone mass, putting them at increased risk for osteoporosis. As men age, their testosterone and estrogen levels decline, as well. Men lose bone, but much more slowly than women do. “We thought that if the sex organs talk to the skeleton, then the skeleton should talk back to the sex organs,” Dr. Karsenty said. Apparently it does. © 2011 The New York Times Company

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 15709 - Posted: 08.23.2011

by Caroline Williams A bat would probably have no trouble imagining how it is to see like a human: some species have eyesight that is at least as good as ours, and some see better than us in dim light. For us to imagine their world, though, is somewhat trickier. Insect-eating bats and some fruit-eaters get much of the detail they need to find food through echolocation: clicks, squeals and screams that they belt out at up to 120 decibels. That's the volume of a passing ambulance siren. Thankfully they do it in ultrasound, above the range of human hearing. The echoes of these sounds give them a huge amount of information about their surroundings. The time it takes for an echo to return, for example, reveals the distance of an object, and the changes in the sound's frequency as it bounces off another creature can even reveal the speed and direction of the animal's movement. The sensitivity of echolocation is phenomenal. A study published last year found that some bats can detect differences in the distance between themselves and their prey with an accuracy of between 4 and 13 millimetres (Journal of the Acoustical Society of America, vol 128, p 1467). For an insect-eating bat, that's enough to scoop up the insect with its wings before passing it to its mouth. Subtle differences in the tone of these sounds, meanwhile, reveal a bat's identity to its peers, in much the same way that we recognise someone's speaking voice (PLoS Computer Biology, vol 6, p e1000400). © Copyright Reed Business Information Ltd.

Keyword: Hearing
Link ID: 15708 - Posted: 08.23.2011

by Caroline Williams The idea that animals can navigate using their own internal compass is so startling it was once dismissed as pure fantasy. Now there is good evidence that many species - including pigeons, sea turtles, chickens, naked mole rats and possibly cattle - can detect the Earth's geomagnetic field, sometimes with astonishing accuracy. Young loggerhead turtles, for example, read the Earth's magnetic field to adjust the direction in which they swim. They seem to hatch with a set of directions, which, with the help of their magnetic sense, ensures that they always stay in warm waters during their first migration around the rim of the North Atlantic. Over time they build a more detailed magnetic map by learning to recognise variations in the strength and direction of the field lines, which are angled more steeply towards the poles and flatter at the magnetic equator. What isn't known, however, is how they sense magnetism. Part of the problem is that magnetic fields can pass through biological tissues without being altered, so the sensors could, in theory, be located in any part of the body. What's more, the detection might not need specialised structures at all, but may instead be based on a series of chemical reactions. Even so, many researchers think that magnetic receptors probably exist in the head of turtles and perhaps other animals. These might be based on crystals of magnetite, which align with the Earth's magnetic field and could pull on some kind of stretch receptor or hair-like cell as it changes polarity. The mineral has already been found in some bacteria, and in the noses of fish like salmon and rainbow trout, which also seem to track the Earth's magnetic field as they migrate. © Copyright Reed Business Information Ltd.

Keyword: Animal Migration
Link ID: 15707 - Posted: 08.23.2011

by Caroline Williams When a bee flies into your garden, it doesn't see what you and I see. Flowers leap out from much darker-looking leafy backgrounds, and they have ultraviolet-reflecting landing strips that show the way to the nectar. Some spiders might even have evolved to exploit these displays, spinning UV patterns into their webs that could work to fool a bee into thinking that it was making a beeline for a tasty treat. If the bee manages to resist the spider's trap, she finds her way back home by checking the pattern of polarised light in the sky. All this is seen through the pixellated window of mosaic vision, with each unit of the insect's compound eye providing one of the 5000 dots that make up an image. It's a world of vision that it is difficult to imagine, but we might get some clues from people with aphakia: a condition in which the lens of the eye - which normally absorbs UV light before it can reach the retina - has been removed in surgery or lost in an accident. Bill Stark, an insect-vision researcher at Saint Louis University in Missouri, lost the lens in his left eye after an accident when he was 10 years old. He says he can see UV light as a kind of "whitish blue", which he would see washing the scenery at a funfair, for example. Because the sight in his left eye is not great, however, he cannot see the subtle patterns in flowers that bees do. © Copyright Reed Business Information Ltd.

Keyword: Vision; Evolution
Link ID: 15706 - Posted: 08.23.2011

By LISA TUCKER I was in a neurologist’s office to discuss the results of my brain scan. For the past month and a half, I’d had headaches that felt as if my skull was underwater, punctuated by frequent electric jolts through the right side of my brain. Two CT scans and an M.R.I. had revealed nothing. All the drug treatments tried by my doctor had failed to change me back into myself. But the new test, magnetic resonance angiography, had uncovered something. “You have a cerebral aneurysm,” the neurologist announced. “It’s small. You’ll have to see a neurosurgeon, but it probably won’t require surgery.” He handed me a card for a specialist at a stroke and vascular center. I took the card, though I was focused on the headaches. At least we had a cause for them now, I thought — until he explained that my aneurysm was an “incidental finding.” “It has nothing to do with the pain you’ve been experiencing,” said the neurologist. He offered me another drug. Multiple Google searches later, I understood what he meant. Most experts think that small aneurysms do not cause any symptoms unless they are about to rupture. Even more surprising, given the fear the word “aneurysm” strikes in patients with new diagnoses and their families, is that many small unruptured aneurysms are not treated. © 2011 The New York Times Company

Keyword: Stroke
Link ID: 15705 - Posted: 08.23.2011

By Laura Sanders Widely used antidepressants may reduce the ominous brain plaques associated with Alzheimer’s disease, a new study in mice and humans finds. Brain scans of people who have taken antidepressants reveal fewer clumps of the protein amyloid-beta, a target of Alzheimer’s prevention strategies, when compared with people who have not taken the drugs. Many in the field voiced caution about the results. But if borne out by further study, the findings may point to a new, relatively safe way to treat and prevent Alzheimer’s disease, which is the sixth leading cause of death in the United States. “I think this is a wonderful piece of news, and I think there’s going to be a lot of excitement about this,” says internist Michael Weiner, who leads the Alzheimer’s Disease Neuroimaging Initiative at the Veterans Affairs Medical Center campus of the University of California, San Francisco. “It points the way towards a possible approach to treating Alzheimer’s disease that people have not been talking about very much.” In the study, mice genetically engineered to overproduce amyloid-beta, or A-beta, were given one of three selective serotonin reuptake inhibitors, a class of antidepressants that boost circulating levels of the chemical messenger serotonin in the brain. After a single dose of the antidepressants, A-beta levels dropped in the fluid that surrounds mouse brain cells, researchers report online the week of August 22 in the Proceedings of the National Academy of Sciences. A full day after receiving the drug, the mice’s A-beta levels fell by nearly a quarter. © Society for Science & the Public 2000 - 2011

Keyword: Alzheimers; Depression
Link ID: 15704 - Posted: 08.23.2011

By Bruce Bower LAS VEGAS — Soldiers fighting at the tip of the spear — the leading edge of combat — confront fighting, suffering and dying. But the success of those soldiers’ operations depends on a huge network of service and support personnel who themselves face considerable and often overlooked war stress, says military sociologist Wilbur Scott of the U.S. Air Force Academy in Colorado Springs. After returning from one or more deployments, National Guard combat service personnel — including clerks, truck drivers, medics and supply officers — displayed slightly less emotional resilience and described having experienced more stress while overseas and after returning home than their comrades engaged in combat, Scott reported August 20 at the annual meeting of the American Sociological Association. In particular, combat service personnel cited deployment stress triggered by exposure to danger, life-threatening situations and death. Their responses reflect the changed nature of warfare, Scott suggested. In Iraq and Afghanistan, counterinsurgency efforts have replaced conventional warfare. “While those in combat arms typically are thought of as being at the tip of the spear, this thinking applies more accurately to conventional settings rather than those encountered in Iraq and Afghanistan,” Scott said. Combat units not only fight and kill but establish relationships with local officials, head local building projects and encourage trust in local governments. Service personnel work in the midst of operations, where they can encounter guerilla attacks or roadside bombs. © Society for Science & the Public 2000 - 2011

Keyword: Stress
Link ID: 15703 - Posted: 08.23.2011

A breakdown of a recycling system in cells appears to be the underlying cause of a fatal nerve disease. Amyotrophic lateral sclerosis (ALS), the most common form of motor neuron disease, causes paralysis. A US team, writing in Nature, found the flaw in the way nerve cells in the brain recycle protein building blocks, which means cells cannot repair themselves and become damaged. Experts in the UK said that the findings were significant. ALS affects an estimated 350,000 people around the world, including children and adults, with about half of people dying within three years of its onset. The breakdown occurs in the recycling system in the nerve cells of the spinal cord and the brain. In order to function properly, the protein building blocks in the cells need to be recycled. But in ALS, that system is broken. The cell cannot repair or maintain itself and becomes severely damaged. The scientists found a protein, ubiquilin2, which should be directing the recycling process, does not work in people with ALS. BBC © 2011

Keyword: ALS-Lou Gehrig's Disease
Link ID: 15702 - Posted: 08.23.2011

By ALEXANDRA HOROWITZ and AMMON SHEA HUMANS have long been fascinated with animal intelligence. Scientific studies have asked if animals use language or tools; have culture; can imitate, cooperate, empathize or deceive. Inevitably, the results of these studies invite comparison with our own cognitive faculties. In such comparisons, humans nearly always come out on top. An impartial observer might suggest that the deck is stacked. After all, we are the ones running these tests. But if we look at some of the subtler aspects of animal behavior, the beasts begin to offer surprisingly stiff competition. A few recent research papers describe animal competence at social and cognitive tasks that humans often struggle with — mastering conversational etiquette, understanding botanical classification, competing on game shows and figuring out how to get a drink when you’re thirsty and the only glass of water is glued to the table and your hands are tied behind your back. “Aping Expressions? Chimpanzees Produce Distinct Laugh Types When Responding to Laughter of Others,” in the journal Emotion (2011). You’re at a dinner party. Your hostess regales you with a long, meandering tale of her recent back surgery. It ends with attempted humor: she laughs and glances at you. You laugh in response, trying to convey an appreciation for her humor that you don’t actually feel. Congratulations: you are now at the level of social politeness of chimpanzees. © 2011 The New York Times Company

Keyword: Evolution; Intelligence
Link ID: 15701 - Posted: 08.23.2011

By Laura Sanders A new kind of visual illusion confirms that people are not masters of perception. Observers are oblivious to peripheral visions of a woman’s face dissolving into a fountain, a stroller becoming a blob, and windows melding into trees, researchers report online August 14 in Nature Neuroscience. By studying these visual oversights, scientists hope to understand how the brain culls the flood of visual data that constantly streams into the eyes. Jeremy Freeman of New York University and Howard Hughes Medical Institute investigator Eero Simoncelli, also of NYU, started the project by developing a mathematical description of how information moves through the visual system in the brain. Their model predicted that the visual system tosses unnecessary information that comes from the periphery. “Your visual system is giving you the information that you need, and it’s throwing away information that you really don’t need,” Simoncelli says. To see whether this information loss actually happens, the team showed eight people quick flashes — a fifth of a second — of various scenes, scrambled in a way the math model predicted would be undetectable to humans. While fixating on a point in the middle, people couldn’t tell the difference between two very different van Gogh-esque scrambles of a normal scene of a crowd at Washington Square Park in New York City, for example. These scrambles went undetected even when people were allowed to stare at the images for nearly half a second, the team reports. © Society for Science & the Public 2000 - 2011

Keyword: Vision; Attention
Link ID: 15700 - Posted: 08.20.2011