By Mary Bates It's an oft-repeated idea that blind people can compensate for their lack of sight with enhanced hearing or other abilities. The musical talents of Stevie Wonder and Ray Charles, both blinded at an early age, are cited as examples of blindness conferring an advantage in other areas. Then there's the superhero Daredevil, who is blind but uses his heightened remaining senses to fight crime. It is commonly assumed that the improvement in the remaining senses is a result of learned behavior; in the absence of vision, blind people pay attention to auditory cues and learn how to use them more efficiently. But there is mounting evidence that people missing one sense don't just learn to use the others better. The brain adapts to the loss by giving itself a makeover. If one sense is lost, the areas of the brain normally devoted to handling that sensory information do not go unused — they get rewired and put to work processing other senses. A new study provides evidence of this rewiring in the brains of deaf people. The study, published in The Journal of Neuroscience, shows people who are born deaf use areas of the brain typically devoted to processing sound to instead process touch and vision. Perhaps more interestingly, the researchers found this neural reorganization affects how deaf individuals perceive sensory stimuli, making them susceptible to a perceptual illusion that hearing people do not experience. These new findings are part of the growing research on neuroplasticity, the ability of our brains to change with experience. A large body of evidence shows when the brain is deprived of input in one sensory modality, it is capable of reorganizing itself to support and augment other senses, a phenomenon known as cross-modal neuroplasticity. © 2012 Scientific American

Related chapters from BP6e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 7: Vision: From Eye to Brain
Link ID: 17281 - Posted: 09.19.2012

Sandrine Ceurstemont, editor, New Scientist TV It's not yet possible to make Silvio Berlusconi disappear, but now a new illusion can shrink his head. Created by Tim Meese and colleagues at Aston University in Birmingham, UK, the animation tricks our brain with moving circles of different sizes before presenting the mind-altering images of his face. To perceive the effect, fix your eyes on the cross in the center of the video. Once the motion stops and the head pictures are flashed on-screen, the image on the left should appear smaller than the one on the right. If you pause the video, you'll notice that in fact both heads are the same size. According to Daniel Baker, a member of the team, the trick occurs because our brain adapts to the size of the moving circles, tiring out the mechanisms that respond to those sizes. So after viewing the large circle on the left, the head presented in its place looks smaller and vice versa. The same type of effect can also alter an object's orientation after staring at tilted patterns. The team was surprised to find that the illusion takes place with any image, regardless of the pattern it's filled in with. "It's rare for an effect to be so general," says Baker. "You could adapt to pictures of kittens and it would still work." © Copyright Reed Business Information Ltd.

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 17260 - Posted: 09.15.2012

by Sara Reardon You can run from a crow that you've wronged, but you can't hide. Wild crows remember human faces in the same way that mammals do. Crows can distinguish human faces and remember how different people treated them, says John Marzluff of the University of Washington in Seattle. To work out how the crows process this information, Marzluff had members of his team wear a latex mask as they captured 12 wild American crows (Corvus brachyrhynchos). The crows learned to associate the captor's mask with this traumatic experience. While in captivity, the crows were fed and looked after by people wearing a different mask. After four weeks, the researchers imaged the birds' brains while they were looking at either the captor or feeder mask. The brain patterns looked similar to those seen in mammals: the feeder sparked activity in areas involved in motivation and reward, whereas the captor stimulated regions associated with fear. The result makes sense, says Kevin McGowan of Cornell Lab of Ornithology in Ithaca, New York. Crows don't mind if humans are in their habitat – but they need to keep a close eye on what we do. Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1206109109 © Copyright Reed Business Information Ltd.

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 7: Vision: From Eye to Brain; Chapter 14: Attention and Consciousness
Link ID: 17243 - Posted: 09.11.2012

By Susana Martinez-Conde and Stephen L. Macknik “There are things in that [wall]paper that nobody knows but me, or ever will. Behind that outside pattern the dim shapes get clearer every day. It is always the same shape, only very numerous. And it is like a woman stooping down and creeping about behind that pattern.” —Charlotte Perkins Gilman, “The Yellow Wallpaper,” 1892 The protagonist in Charlotte Perkins Gilman's short story “The Yellow Wallpaper” suffers from the most notable case of pareidolia in fiction. Pareidolia, the misperception of an accidental or vague stimulus as distinct and meaningful, explains many supposedly paranormal and mystical phenomena, including UFO and Bigfoot sightings and other visions. In Gilman's story, the heroine, secluded in her hideously wallpapered bedroom and having nothing with which to occupy herself, is driven to insanity>—full-blown paranoid schizophrenia>—by the woman behind the yellow pattern. As she descends into madness, she comes to believe that she is imprisoned by the wallpaper. Mental disease can aggravate pareidolia, as can fatigue and sleepiness. After a recent surgery, one of us (Martinez-Conde) noticed faces everywhere, in places as unlikely as the ultrasound images of her left arm during an examination of potential postsurgical blood clots. She realized at once that the ubiquitous faces were the product of lack of sleep and the high titer of pain medication in her bloodstream, so she was more fascinated than concerned. Her doctor agreed but made a note in her file for a different drug regime in the future. Just in case. Luckily, the hospital room's walls were bare, and there was no yellow wallpaper in sight. Our brain is wired to find meaning. Our aptitude to identify structure and order around us, combined with our superior talent for face detection, can lead to spectacular cases of pareidolia, with significant effects in society and in culture. © 2012 Scientific American

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 17241 - Posted: 09.11.2012

Sandrine Ceurstemont, editor, New Scientist TV Impossible objects, like those drawn by artist M. C. Escher, don't seem like they could exist in the real world. But Kokichi Sugihara from Meiji University in Kawasaki, Japan, is well known for building 3D versions of these structures. Now a new video shows his latest construction: a gravity-defying roof that seems to attract and balance balls on its edge. When the house is rotated, its true form is revealed. According to Sugihara, this type of ambiguous shape is interesting because we perceive the illusion again even after we have seen what the object really looks like. After studying a variety of these objects, he concludes that our brain seems to choose the most rectangular configuration when it tries to make sense of features that can have different interpretations. The brain trick was presented this week at the European Conference on Visual Perception in Alghero, Italy. If you would like to build your own impossible objects, check out printable copies of Sugihara's designs. © Copyright Reed Business Information Ltd.

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 17234 - Posted: 09.10.2012

By CLAUDIA DREIFUS The developmental psychologist Daphne Maurer made headlines this year with research suggesting that people born with cataracts could improve their eyesight by playing Medal of Honor, the “first-person shooter” video game. But her fame goes far beyond the video screen. Dr. Maurer, 56, director of the Visual Development Lab at McMaster University in Ontario, is an author, with her husband, Charles, of the pioneering 1988 book “The World of the Newborn,” an inventory of what babies sense and experience. In recent years she has been directing a study tracking infants born with visual impairments into later life. This longitudinal study is her attempt to learn how early sensory deprivation affects vision over a lifetime. We spoke in person earlier this year and again by telephone last month. An edited and condensed version of the two conversations follows. How did computer games enter your life? Are you a gamer? No, not at all. I’m a reader. My husband and I don’t have children. So computer games wouldn’t be a part of our lives. I’ve never played one. I can’t imagine enjoying playing one. For more than 25 years, I’ve been an investigator on a longitudinal study following the visual development of infants born with cataracts in their eyes. These youngsters went through a period of temporary visual deprivation. They didn’t get any of that early patterning in the world that regularly sighted infants get. As soon as possible, they received surgeries and corrective contact lenses at Toronto’s Hospital for Sick Children, after which their vision improved. © 2012 The New York Times Company

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 7: Vision: From Eye to Brain; Chapter 13: Memory, Learning, and Development
Link ID: 17212 - Posted: 08.28.2012

by Gilead Amit The bath of cells in avian eyes could prolong a delicate quantum state that helps to explain how some birds navigate using Earth's magnetic field. It is thought that light reacts with receptors in the birds' eyes to produce two molecules with unpaired electrons, whose spins are linked by a special state called quantum entanglement. If the relative alignment of the spins is affected by Earth's magnetic field, the electron pair can cause chemical changes that the bird can sense. In 2009, researchers at the University of Oxford calculated that such entanglement must last for at least 100 microseconds for the internal compass to work. But how the sensitive state of quantum entanglement could survive that long in the eye was a mystery. Calculations by Zachary Walters of the Max Planck Institute for the Physics of Complex Systems in Dresden, Germany, now show that interactions with cells in the bird's eye allow the electron pairs to stay entangled for longer through a dampening effect. Rather like the way a car with stiff shock absorbers takes longer to stop bouncing after going over a bump, the signal from the electron pair dies away more slowly under strong interactions with the cellular bath. Predicting exactly how long entanglement is sustained won't be possible until the mechanism is better understood, says Walters. But he believes there's a good chance his model could account for the 100 microseconds. © Copyright Reed Business Information Ltd

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain; Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain; Chapter 5: The Sensorimotor System
Link ID: 17190 - Posted: 08.22.2012

Analysis by Jesse Emspak A glass inspired by spider's webs is being used to keep birds from smacking into windows. Birds can't see glass well, and so many of them die when they hit picture windows. Humans can't see glass well either, which might explain why some people try to walk through glass doors. But most people know that the refection of the sky and landscape in a window isn't real -- unfortunately, birds don't. According to the Fatal Light Awareness Program, a building with glass walls or windows can kill up to 10 birds per day, and estimates of worldwide deaths from such collisions reach hundreds of millions of birds each year. On Lindisfarne Island, off the northeastern coast of England, local authorities wanted to do something about it. Hundreds of species of migratory birds pass through every year. So officials decided to cover a lookout tower with glass designed by Arnold Glas, a German company. Called Ornilux, the glass has a spiderweb-like pattern that humans can't see unless they stand very close (see image below, right). But because glass reflects ultraviolet light, birds can see the pattern very well. Spider webs, particularly those of orb weaver spiders, work the same way, reflecting UV and alerting the bird that there is something there. While flying through a web wouldn't hurt a bird, the bird doesn't know that. So they avoid them. The glass was tested in a flight tunnel in the United States. Birds were allowed to fly to one end of the tunnel which was covered with two types of glass, one with the UV-reflective coating. The birds avoided hitting the coated glass up to 68 percent of the time. © 2012 Discovery Communications, LLC.

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 17166 - Posted: 08.15.2012

By Susan Milius COLLEGE PARK, Md. — A mantis shrimp, which has one of the most elaborate visual systems ever discovered, turns out to be pretty lousy at distinguishing one color from another. The puzzling underachievement may mean that the mantis shrimp brain perceives color in a way new to science, says Hanne Thoen of the University of Queensland in Brisbane, Australia. She presented results from her ongoing study August 6 at the 10th International Congress of Neuroethology. The stalked eyes of mantis shrimp species that live in shallow water can have up to 16 kinds of photoreceptor cells, 12 of which are specialized for different colors. People make do with four kinds, three of which pick up colors. Yet tests with pairs of increasingly similar colors found that the mantis shrimp Haptosquilla trispinosa flunks out when choices narrow to colors 15 nanometers apart in wavelength, Thoen said. At sweet spots in the color spectrum, people can distinguish between colors only 1 or 2 nanometers apart. “Hanne’s results are a bit of a shock to us,” says Thomas Cronin of the University of Maryland, Baltimore County, whose lab also studies mantis shrimp vision. Thoen tested the color vision of mantis shrimp by training them to scoot out of their burrows toward a pair of optical fibers and punch at the one glowing a particular color. As she narrowed the color gap between the two fibers, she could tell when the animals no longer discerned a difference. © Society for Science & the Public 2000 - 2012

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 17165 - Posted: 08.15.2012

Prosthetic retina helps to restore sight in mice Geoff Brumfiel Two neuroscientists have created a prosthesis that can partially restore the sight to blind mice. The device could eventually be developed for use in humans. More than 20 million people worldwide become blind owing to the degeneration of their retina, the thin tissue at the back of the eye that turns light into a neural signal. Only one prosthesis has been approved for treatment of the condition — it consists of an array of surgically implanted electrodes that directly stimulate the optic nerve and allow patients to discern edges and letters. Patients cannot, however, recognize faces or perform many everyday tasks. Sheila Nirenberg, a physiologist at the Weill Medical College at Cornell University in New York thinks that the problem is at least partially down to coding. Even though the retina is as thin as tissue paper, it contains several layers of nerves that seem to encode light into neural signals. "The thing is, nobody knew the code," she says. Without it, Nirenberg believes that visual prostheses will never be able to create images that the brain can easily recognize. Now, she and her student, Chethan Pandarinath, have come up with a code and developed a device that uses it to restore some sight in blind mice. The duo began by injecting nerve cells in the retinas of their mice with a genetically engineered virus. The virus had been designed to insert a gene that causes the cells to produce a light-sensitive protein normally found in algae. When a beam of light was then shown into the eye, the protein triggered the nerve cells to send a signal to the brain, performing a similar function to healthy rod and cone cells. © 2012 Nature Publishing Group

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 17162 - Posted: 08.14.2012

By Cheryl Murphy Liliputs and little people, cartoon characters dancing on your desk, a civil war soldier in your living room, a zebra walking down the street. Typically not what we’d expect to see with our own eyes. But for some, it happens almost every day…for a year or so anyway. The “visions” aren’t always complex or bizarre. Sometimes they can “blend in” to our everyday lives a bit more. One case study was recently published in the Canadian Journal of Ophthalmology described a patient having visual hallucinations of small children popping up in her vision. She didn’t try to speak or interact with them in any way and they never spoke to her. She didn’t recognize them. She knew that they weren’t real and she wasn’t frightened of them but there they were. She saw them. Why? It turns out she had Charles Bonnet Syndrome, a condition in which visual hallucinations are caused by recent visual field loss… and, in her case, a brain tumor. People who have suffered newly acquired vision loss from eye conditions such as macular degeneration, diabetic retinopathy or cataracts (or from damage to other parts of the visual pathway in the brain) can have new visual field defects as a result and sometimes they begin to “see” things that really aren’t there. These people have no prior history of dementia or cognitive impairment, have never had any hallucinations in the past and are not taking medications known to have hallucinations as one of their side effects. Typically, no other sense (taste, touch, smell, or hearing) is affected in Charles Bonnet Syndrome other than sight. It can affect the young as well as the old in that there have been cases of Charles Bonnet Syndrome reported in young children who suffered vision loss from retinopathy of prematurity. In some cases, the vision loss is only to a part of their whole field of vision and their vision can sometimes remain as sharp as 20/40. © 2012 Scientific American,

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 7: Vision: From Eye to Brain; Chapter 14: Attention and Consciousness
Link ID: 17147 - Posted: 08.11.2012

By RONI CARYN RABIN Older people who have eye surgery to remove cataracts and improve their vision also significantly reduce their risk of breaking a hip in a fall, with the sickest among them and those in their early 80s experiencing nearly 30 percent fewer hip fractures in the first year, a large study reports. The study adds to findings from earlier papers indicating that the benefits of cataract surgery, a relatively safe outpatient procedure with a high success rate, may significantly enhance the quality of life for the elderly, improving sleep, enabling them to be more engaged and mentally alert and curbing depression. “This is elective surgery, and sometimes people think, ‘I’m too sick to have my cataracts out,’ or ‘I’m too old,’ ” said Dr. Anne L. Coleman, the study’s lead author and a professor of ophthalmology at the Jules Stein Eye Institute at the University of California, Los Angeles. “But the take-home message from this study is that if you’re starting to have vision problems and the doctor says you have cataracts, you should probably think of having them removed.” Hip fractures, which become more common with age, are serious injuries for elderly people, with complications that can be life-threatening. The new study, published on Tuesday in The Journal of the American Medical Association, examined the incidence of hip fractures within a year of cataract surgery in a random sample of 1.1 million Medicare beneficiaries age 65 and older who were given a cataract diagnosis from 2002 to 2009. © 2012 The New York Times Company

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 7: Vision: From Eye to Brain; Chapter 13: Memory, Learning, and Development
Link ID: 17113 - Posted: 08.01.2012

The cause of a type of hereditary blindness has been traced to a genetic mutation, a discovery that potentially opens a new treatment approach, Canadian and international researchers say. The inherited eye disease, called Leber congenital amaurosis, usually shows its first signs at birth or in the months following. It affects about one in 80,000 newborns. About 1,000 Canadians live with the effects. The researchers' genetic discovery helps provide families with a firm diagnosis, Robert Koenenkoop says.The researchers' genetic discovery helps provide families with a firm diagnosis, Robert Koenenkoop says. (CBC) Scientists at Montreal's McGill University and their co-authors have identified that a gene called NMNAT1 can cause LCA. "We're getting closer to finding 100 per cent of the genes causing Leber congenital amaurosis," said Dr. Robert Koenekoop, director of the McGill Ocular Genetics Laboratory, who led the research team. "That gives an immediate relief to the families, because it confirms the diagnosis [and] gives you a treatment avenue." The disease was considered untreatable, but that is no longer the case for some subtypes, Koenekoop said. For the study in this week's issue of Nature Genetics, scientists analyzed the genomes of 60 infants with LCA of unknown cause. They discovered a mutation on the NMNAT1 gene, which is found in all human cells. It produces a coenzyme called NAD that is involved in hundreds of reactions. © CBC 2012

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 7: Vision: From Eye to Brain; Chapter 13: Memory, Learning, and Development
Link ID: 17106 - Posted: 07.31.2012

by Andy Coghlan Treating disease by stimulating brain cells with light is a step closer to reality following the first demonstration that the technique can improve mental performance in monkeys. Two monkeys performed better on simple computer tasks after light was used to boost the activity of brain cells necessary for the task. "For the first time, we were able to change behaviour in primates with our technique," says Wim Vanduffel of Massachusetts General Hospital in Charlestown, who is head of the group that performed the experiment. Known as optogenetics, the method has the potential to treat conditions such as epilepsy, where the light could temporarily deactivate the brain cells that cause seizures, or Parkinson's disease, where it can activate cells that make dopamine, the neurotransmitter vital for controlling mobility that those with Parkinson's lack. Previously, it has been used in nematode worms to trigger them to lay eggs, and mice to relieve depression and paralysis. Researchers have also used it in monkeys, but only on single, isolated neurons. Vanduffel and his colleagues wanted to see if they could extend this to entire networks of cells, boosting a monkey's ability to perform a simple computer-based task. Natural performance enhancers First, Vanduffel's team scanned the two monkeys' brains using functional magnetic resonance imaging while they followed a green dot on a computer screen. From the scans, the researchers could tell that the monkeys relied on an area of the brain called the arcuate sulcus to do the task. © Copyright Reed Business Information Ltd.

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Related chapters from MM:Chapter 7: Vision: From Eye to Brain; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 17098 - Posted: 07.28.2012

By Stephen L. Macknik and Susana Martinez-Conde As both the midget in the country of Brobdingnag and the giant on the island of Lilliput, Lemuel Gulliver—the protagonist of Jonathan Swift's Gulliver's Travels—experienced firsthand that size is relative. As we cast a neuroscientific light on this classic book, it seems clear to us that Swift, a satirist, essayist and poet, knew a few things about the mind, too. Absolute size is meaningless to our brain: we gauge size by context. The same medium-sized circle will appear smaller when surrounded by large circles and bigger when surrounded by tiny ones, a phenomenon discovered by German psychologist Hermann Ebbinghaus. Social and psychological context also causes us to misperceive size. Recent research shows that spiders appear larger to people who suffer from arachnophobia than to those who are unafraid of bugs and that men holding weapons seem taller and stronger than men who are holding tools. In this article, we present a collection of illusions that will expand your horizons and shrink your confidence in what is real. Try them out for size! Do you see tiny objects photographed with a macro lens? Look again. This remarkable illusion combines tilt-shift photography—in which the photographer uses selective focus and a special lens or tilted shot angle to make regular objects look toy-sized—with the strategic placement of a giant coin. Art designers Theo Tveterås and Lars Marcus Vedeler, from the Skrekkøgle group, created the enormous 50-cent euro coin from painted and lacquered wood at a 20:1 scale. At first sight, they look like real-life scenes from the television show Hoarders, precleanup. © 2012 Scientific American

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 17080 - Posted: 07.24.2012

An Ontario study of two drugs — one approved to treat wet age-related macular degeneration, and the other used off-label to fight the eye disease —suggests neither increases the risk of stroke or heart attack, adding to the debate over why both treatments from the same company aren't covered under provincial drug plans when used for AMD. AMD, which affects about one million Canadians mostly over age 65, is a progressive condition that damages the macula in the eye, and is a leading cause of blindness. Researchers from Toronto, Hamilton and Kingston, Ont., followed 91,378 older adults with a history of retinal disease between April 1, 2006 and March 31, 2011, to determine if injections of bevacizumab (trade name Avastin) or ranibizumab (Lucentis) could be linked to increased vascular risks including stroke, heart attack or congestive heart failure. Avastin and Lucentis, both manufactured by Roche, are vascular endothelial growth factor (VEGF) inhibiting drugs, and both have the potential to cause vascular side-effects. However, the research done at Ontario's Institute for Clinical Evaluative Sciences (ICES), and published in Wednesday's edition of BMJ (British Medical Joural) concludes injections of these drugs into the eyes of patients with retinal disease did not increase such risks. © CBC 2012

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 17000 - Posted: 07.05.2012

by Michael Marshall Step from a sunlit hillside into the darkness of a cave, and you immediately have a problem: you can't see. It's best to stand still for a few minutes until your eyes adjust to the dimness, otherwise you might blunder into a hibernating bear that doesn't appreciate your presence. The same thing will happen when you leave again: the brightness of the sun will dazzle you at first. That's because your eyes have two types of receptor: one set works in bright light and the other in dim light. Barring a few minutes around sunset, only one set of receptors is ever working at any given time. Peters' elephantnose fish has no such limitations. Its peculiar eyes allow it to use the two types of receptor at the same time. That could help it to spot predators as they approach through the murky water it calls home. It's electric Peters' elephantnose fish belongs to a large family called the elephantfish, all of which live in Africa. They get their name from the trunk-like protrusions on the front of their heads. But whereas the trunks of elephants are extensions of their noses, the trunks of elephantfish are extensions of their mouths. To find a Peters' elephantnose fish, you must lurk in muddy, slow-moving water. Look closely, because the fish is brown and so is the background. © Copyright Reed Business Information Ltd.

Related chapters from BP6e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 7: Vision: From Eye to Brain
Link ID: 16985 - Posted: 06.30.2012

By JOHN MARKOFF MOUNTAIN VIEW, Calif. — Inside Google’s secretive X laboratory, known for inventing self-driving cars and augmented reality glasses, a small group of researchers began working several years ago on a simulation of the human brain. There Google scientists created one of the largest neural networks for machine learning by connecting 16,000 computer processors, which they turned loose on the Internet to learn on its own. Presented with 10 million digital images found in YouTube videos, what did Google’s brain do? What millions of humans do with YouTube: looked for cats. The neural network taught itself to recognize cats, which is actually no frivolous activity. This week the researchers will present the results of their work at a conference in Edinburgh, Scotland. The Google scientists and programmers will note that while it is hardly news that the Internet is full of cat videos, the simulation nevertheless surprised them. It performed far better than any previous effort by roughly doubling its accuracy in recognizing objects in a challenging list of 20,000 distinct items. The research is representative of a new generation of computer science that is exploiting the falling cost of computing and the availability of huge clusters of computers in giant data centers. It is leading to significant advances in areas as diverse as machine vision and perception, speech recognition and language translation. © 2012 The New York Times Company

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 16977 - Posted: 06.27.2012

by Andy Coghlan Newborn babies have revealed to the world when they start seeing in three dimensions. Babies were thought to begin seeing in stereo at about four months after their due date. They actually learn to do it four months after they are exposed to light, even if they are born early. Ilona Kovács at Budapest University of Technology and Economics in Hungary and her colleagues gave 15 premature and 15 full-term babies goggles that filtered out red or green light. Once a month for eight months, the team sat the babies in a dark room and got them to stare at patterns of dots on a screen. The goggles made the dots invisible unless viewed in 3D. Sensors placed on each baby's head picked up electrical signals that revealed whether they could see the dots. If they could, the sensor registered pulses of 1.875 hertz; if not, there was only a background signal. The babies began to see stereo images about four months after they were born, whether they were premature or full term, showing that the environment, not an internal clock, is the likely trigger for the development of this ability in the brain Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1203096109 © Copyright Reed Business Information Ltd.

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 7: Vision: From Eye to Brain; Chapter 13: Memory, Learning, and Development
Link ID: 16946 - Posted: 06.21.2012

by Veronique Greenwood An average human, utterly unremarkable in every way, can 
perceive a million different colors. Vermilion, puce, cerulean, periwinkle, chartreuse—we have thousands of words for them, but mere language can never capture our extraordinary range of hues. Our powers of color vision derive from cells in our eyes called cones, three types in all, each triggered by different wavelengths of light. Every moment our eyes are open, those three flavors of cone fire off messages to the brain. The brain then combines the signals to produce the sensation we call color. Vision is complex, but the calculus of color is strangely simple: Each cone confers the ability to distinguish around a hundred shades, so the total number of combinations is at least 1003, or a million. Take one cone away—go from being what scientists call a trichromat to a dichromat—and the number of possible combinations drops a factor of 100, to 10,000. Almost all other mammals, including dogs and New World monkeys, are dichromats. The richness of the world we see is rivaled only by that of birds and some insects, which also perceive the ultraviolet part of the spectrum. Researchers suspect, though, that some people see even more. Living among us are people with four cones, who might experience a range of colors invisible to the rest. It’s possible these so-called tetrachromats see a hundred million colors, with each familiar hue fracturing into a hundred more subtle shades for which there are no names, no paint swatches. And because perceiving color is a personal experience, they would have no way of knowing they see far beyond what we consider the limits of human vision. © 2012, Kalmbach Publishing Co.

Related chapters from BP6e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 16928 - Posted: 06.19.2012