Biological Psychology Links

By Brian Alexander The 69-year-old man saw the spider clearly, whacked at it, yet the spider wouldn’t die. At night, people he knew started visiting his bedroom, sitting in the armchair beside his night table. But he hadn’t invited them. Oh, and there were animals roaming around his house. A different patient saw a double decker bus in the living room. Another saw fire hydrants just like the one that used to sit in front of her childhood home. Then there was the woman who saw small children sitting atop her piano. She didn’t know them and had no kids of her own, but there they were. These people, whose cases were documented in medical journals, are not crazy. They are affected by a condition called “Charles Bonnet syndrome,” (pronounced bow-NAY), a somewhat common hallucinatory condition among people suffering various forms vision loss. The condition was named for an 18th-century naturalist who described it in his grandfather. Recently, Ed Connors, a 61-year-old software engineer near Boston saw a woman walking her dog on his street. In reality, it was just a shadow. Sometimes when in a shopping mall, Connors thinks he sees people and will move to get out of their way. Except nobody is there. © 2010 Microsoft

By Katherine Harmon Hunting for a misplaced set of keys or a dead cell phone can be a nuisance. But for people who search for concealed weapons or malignant tumors, finding a target—and one they're not sure is even there—could be a matter of life or death. Unfortunately, research has shown that the rarer an item has proved to be, the less likely people are to find it when it is there. "We know that if you don't find it often, you often don't find it," Jeremy Wolfe, a professor of ophthalmology at Harvard Medical School, said in a prepared statement. Likewise, searches for common objects tend to turn up way more false positives. So are people as hasty to judge that an inspected bag doesn't contain a weapon (a rare item), as they are to assume it has a more common item? Wolfe and his colleague, Michael Van Wert of the Brigham and Women's Hospital in Cambridge, were determined to hunt down an answer to how reaction times changed based on what people were used to finding. Their results were published online January 14 in Current Biology. Their experiment, in which two dozen participants looked for weapons in simulated baggage, showed that people do not adapt their searching time equally to different odds of finding items. Individuals were given a consistent likelihood of finding an object, say 98 percent, and were judged both on the time it took them to declare whether a bag contained a weapon—and whether they were correct. Those in experiments who are faced with consistently 50-50 odds of finding a target might be expected to take the longest to arrive at an answer, and those with very rare or very frequent incidences of finding weapons should be the fastest. That is, with similarly slim odds of finding or not finding a target, people might be expected to make decisions rapidly about whether they see it or not. © 2010 Scientific American

The visual pathway that underlies a migraine sufferer's sensitivity to light has been uncovered by Harvard scientists. The researchers studied two groups of blind people who suffered migraine headaches. They found light triggered a reaction in a group of brain neurons that remained active for some time. Migraines are one-sided throbbing headaches that cause nausea and affect up to six million people in the UK. The researchers, writing in the journal Nature Neuroscience, said they noted that even blind people who had migraines experienced sensitivity to light or photophobia. The observation led them to the idea that the signals transmitted from the retina via the optic nerve were somehow triggering worsening of the pain. They looked at 20 blind people who fell into two groups - the first were totally blind due to eye diseases such as retinal cancer and glaucoma. They were unable to see images or to sense light and therefore could not maintain normal sleep-wake cycles. Patients in the second group were legally blind due to retinal degenerative diseases, such as retinitis pigmentosa. Although they were unable to perceive images, they could detect the presence of light and maintain normal sleep-wake cycles. The patients in the second group described intensified pain when they were exposed to light, in particular to blue or grey wavelengths. Rami Burstein, professor of anaesthesia and critical care medicine at the Beth Israel Deaconess Medical Centre in Boston, US, led the study. (C)BBC

By Steve Connor The ancient Egyptian pyramids, the Parthenon of Athens, Mona Lisa’s face and the head of George Clooney all have one thing in common. Their attractiveness is said to be based on the “golden ratio”, which is supposed to be the most aesthetically pleasing shape to the human eye. The golden ratio, also known as the divine proportion, produces a shape similar to a widescreen television or a cinema screen and describes a rectangle with a length roughly one and half times its width. The proportion is said to pervade art, architecture and nature. The modernist architect Le Corbusier used the golden ration for conferring harmonius proportions on everything from door handles to high-rise buildings, whereas the surrealist painter Salvadore Dali deliberately incorporated the rule into his painting Sacrament of the Last Supper. Now a theoretical mathematician has come up with what he believes is a possible reason why the human eye finds shapes in these proportions so particularly appealing. It comes down to how easy it is for the eye and the brain to scan such an image for important details, based on our evolutionary history. Professor Adrian Bejan of Duke University in North Carolina said that the golden ratio – which was first identified mathematically by Euclid in 3rd Century BC – just happens to be the most efficient shape for visual scanning, which could explain why it is behind so many works of art and architectural wonders. ©independent.co.uk

By Nathan Seppa It looks like nearsightedness is on the rise in the United States. Researchers tapped into a wide-ranging health survey to rate vision in the population in the early 1970s and roughly 30 years later. They compared eyesight information for more than 4,400 people tested in 1971 and 1972 with data from another set of 8,300 people tested from 1999 to 2004. This broad survey showed that 25 percent of those examined in the early 1970s were deemed to be nearsighted, compared with 42 percent examined three decades later, the researchers report in the December Archives of Ophthalmology. That’s an increase of 66 percent. Myopia severity also increased, with moderate nearsightedness doubling between the two time periods and severe cases, although uncommon, also rising sharply. Mild myopia cases increased slightly, from about 13 percent to 18 percent. This group included some people who did not need corrective lenses, says study coauthor Susan Vitale, an epidemiologist at the National Eye Institute in Bethesda, Md. When analyzing the more recent eye-exam data, the scientists used only diagnoses that were made with the same technology used in the 1970s — mainly standard eye tests and trial lenses. Including diagnoses made with more advanced technology that has become available only recently might have biased the comparison, Vitale says.. The cause of nearsightedness is poorly understood. Past research has linked added risk to both a genetic predisposition to nearsightedness and to excessive amounts of near work, the kind of tasks that require peering at written words or small objects. © Society for Science & the Public 2000 - 2009

By Vilayanur S. Ramachandran and Diane Rogers-Ramachandran Spanish painter El Greco often depicted elongated human figures and objects in his work. Some art historians have suggested that he might have been astigmatic—that is, his eyes’ corneas or lenses may have been more curved horizontally than vertically, causing the image on the retina at the back of the eye to be stretched vertically. But surely this idea is absurd. If it were true, then we should all be drawing the world upside down, because the retinal image is upside down! (The lens flips the incoming image, and the brain interprets the image on the retina as being right-side up.) The fallacy arises from the flawed reasoning that we literally “see” a picture on the retina, as if we were scanning it with some inner eye. No such inner eye exists. We need to think, instead, of innumerable visual mechanisms that extract information from the image in parallel and process it stage by stage, before their activity culminates in perceptual experience. As always, we will use some striking illusions to help illuminate the workings of the brain in this processing. Compare the two faces shown in a. If you hold the page about nine to 12 inches away, you will see that the face on the right is frowning and the one on the left has a placid expression. But if you move the figure, so that it is about six or eight feet away, the expressions change. The left one now smiles, and the right one looks calm. © 1996-2009 Scientific American Inc

By Jennifer Ouellette From the annals of "How did I miss that story?": While reading a news snippet about how scientists hope to mimic the structure of a mantis shrimp's eyes to improve on the next generation of Blu-Ray players, I stumbled on the fact that there is an X-ray space telescope under development using technology based on lobster vision. It's called the Lobster All-Sky X-Ray Monitor (LASXM), and according to Nigel Bannister of the University of Leicester, the telescope would be "ideal for use as an all-sky X-ray monitor" because of its unlimited field of view." It's not a new idea: in fact, it was first proposed in the 1970s by a scientist at the University of Arizona named Roger Angel, but it's taken 30 years for optics to advance to the point where building such a technology is even possible. What makes lobsters special? Well, they have these pea-sized compound eyes made up of long, narrow square cells that give the creature a 180-degree field of view. This allows for maximum reflectivity; each cell captures a tiny amount of light, but the light enters the eye from many different angles and only then is the light focused into a single image. Lobsters don't have great image resolution, but they don't really need it. What they do have is ultra-sensitivity to detect movement, and even the polarization of light. LASXM would mimic that structure with a new technology called microchannel plates: six nested modules -- each a bundle of 3 million parallel glass channels -- that would combine to give the instrument that same 180-degree field of view. Put it orbit around the Earth aboard a satellite or the International Space Station, such that it completes its orbit every 90 minutes, and you would quickly compile a complete x-ray picture of the sky. © 2009 Discovery Communications, LLC

There is a tiny period of time between the registration of a visual stimulus by the unconscious mind and our conscious recognition of it — between the time we see an apple and the time we recognize it as an apple. Our minds lag behind our eyes, but by how long? And how does this affect our reactions to the world around us? Some estimates say the time delay lasts only 100 milliseconds, others say 500 milliseconds. A new study by Tel Aviv University psychologists says that the answer is somewhere close to the latter, but can vary depending on the complexity of the stimulus. Researcher Moti Salti and his supervisors Dominique Lamy and Prof. Yair Bar-Haim of TAU's Department of Psychology reported their findings in the Journal of Cognitive Neuroscience. "We are hunting for the brain activity associated with conscious perception," says Salti. "When you wander through this world, you see and hear things that may reveal themselves to your conscious mind — and others that don't. We are interested in what cues the brain gives us to open that unconscious perception to the conscious mind — what makes our conscious mind tick." This basic science, Salti says, won't immediately provide marketers with the basis for a new and advanced kind of subliminal advertising. But it may answer long-debated questions about the mysterious nexus between our conscious and unconscious minds. © 2002-2009 redOrbit.com.

By Jody Bourton Why do hammerhead sharks have such a famously strange-shaped head? One hypothesis is that having eyes on either side of such a wide 'hammer' allows the sharks to see better. But even this idea divides scientific opinion, as researchers argue over whether the hammerhead design makes it more or less difficult to see. The mystery may now be solved by a study showing that a hammerhead gives sharks outstanding binocular vision and an ability to see through 360 degrees. The finding is published in the Journal of Experimental Biology. Debate over why hammerheads are shaped as they are goes back centuries, and arguments over their visual capabilities goes back decades, says Dr Michelle McComb from Florida Atlantic University in Boca Raton, Florida, US. For example, in 1948, zoologist Gordon Walls, a leading authority on vertebrate eye evolution, suggested that the position of a hammerhead shark's eye precluded it from having binocular vision. Yet in 1984, leading shark expert Leonard Campagno countered by suggesting that the distance between a hammerhead's eyes would actually give it excellent binocular vision. Binocular vision occurs when the fields of two eyes overlap, allowing the accurate perception of depth and distance. It is especially important for predators which need to judge the distance to their prey. BBC © MMIX

By Mary Bates The discovery of mirror neurons in the brains of macaques about ten years ago sent shockwaves through the neuroscience community. Mirror neurons are cells that fire both when a monkey performs a certain task and when it observes another individual performing that same task. With the identification of networks of similarly-behaving cells in humans, there was much speculation over the role such neurons might play in phenomena such as imitation, language acquisition, observational learning, empathy, and theory of mind. Several research groups have observed the activity of mirror neuron networks indirectly in humans through the use of functional magnetic resonance imaging (fMRI). This technology allows scientists to correlate changes in blood flow in specific brain areas to particular behaviors or mental operations. Experiments using fMRI have demonstrated that there is more activation in the human mirror system when people observe movements with which they are familiar; for instance, experienced dancers had larger mirror network activations when they viewed steps from their own repertoire compared to moves from a different style of dance. Studies of the human mirror system have also revealed that it can be activated by the sounds of actions alone, in the absence of any visual cues. While evidence along these lines suggests that hearing can activate mirror neurons as well as vision, it is not clear if aurally-presented stimuli evoke visual imagery that then recruits the mirror system. These studies did not address whether a functional visual system was a necessary prerequisite for the development of the mirror system. © 1996-2009 Scientific American Inc.

by Nora Schultz The decline was rapid. I got my first pair of glasses aged 9, and by my mid-teens could no longer read the title on the cover of New Scientist at arm's length. With my mum's eyes just as bad, I always assumed that I'd inherited my short-sightedness from her and that I could do little to stop my vision from becoming a little blurrier each year. Around the same time, however, rates of short-sightedness, or myopia, were rising to epidemic proportions around the world. Today, in some of the worst-affected countries such as Singapore, Hong Kong and Taiwan, around 80 per cent of young adults are myopic, compared to only 25 per cent a few decades back. Rates are lower in western countries - between 30 and 50 per cent - but myopia seems to be rising steadily here too. What could be causing this mysterious epidemic? It is clear that genetics alone can't explain the condition, and the long-standing theory that reading was to blame has failed to play out in subsequent studies. Large-scale epidemiological surveys ensued, which have pinned down the specific aspects of modern lifestyles that cause children's eyesight to deteriorate. With just a few simple measures, it now looks like we could easily prevent future generations from descending into my blurry world. While the causes have been elusive, the anatomy of myopia has been well understood for decades. In the normal eye, the lens focuses light squarely on the retina, which records the image and sends it to the brain. We myopes, however, have eyeballs that are elongated, increasing the distance between the light-sensitive retina at the back of the eye and the lens at the front. The result is that light from distant objects is focused in front of the retina, so a blurred image is transmitted to the brain. © Copyright Reed Business Information Ltd

By PAM BELLUCK By the time Corey Haas was 7, the retinal disease he was born with had already stolen much of his vision. “He always clung to me or my wife,” said Corey’s father, Ethan Haas. The boy relied on a cane and adults to guide him, and, unable to see blackboard writing, sat in back with a teacher’s aide, large-type computer screen and materials in Braille. Legally blind, Corey was expected eventually to lose all sight. Then, 13 months ago, after his eighth birthday, he underwent an experimental gene therapy procedure, receiving an injection in his left eye. His vision in that eye improved quickly. Now 9, Corey plays Little League baseball, drives go-carts, navigates wooded trails near his home in Hadley, N.Y., and reads the blackboard in class. “It’s gotten, like, really better,” he said. Experts in vision problems say that while it is unclear how many visually impaired people gene therapy could help, they consider the research promising for some types of blinding diseases, and an achievement for gene therapy, which has had many setbacks. The study, reported in the journal Lancet, involved five children and seven adults, from Belgium, Italy and the United states, with a type of Leber’s congenital amaurosis, rare but serious congenital retinal diseases. Copyright 2009 The New York Times Company

By Richard Alleyne, Science Correspondent One of the charms of the world's most famous painting is that she appears radiant one moment and then serious and sardonic the next. Now scientists claim to have come up with an answer to her changing moods - our eyes are sending mixed signals to the brain. They believe Mona Lisa's smile depends on what cells in the retina pick up the image and what channel the image is transmitted through in the brain. Sometimes one channel wins over the other, and you see the smile, sometimes others take over and you do not see the smile. Different cells in the eye are designed to pick up different colours, contrasts, backgrounds and foregrounds. Some deal with central vision while others with peripheral. Depending on what cells picks up the image first depends on what channel they are sent to the brian for interpreting. These channels encode data about an object's size, clarity, brightness and location in the visual field. "Sometimes one channel wins over the other, and you see the smile, sometimes others take over and you don't see the smile," said Dr Luis Martinez Otero, a neuroscientist at Institute of Neuroscience in Alicante, Spain, who conducted the study, told New Scientist. To get a fuller picture of the reasons behind Mona Lisa's vanishing smile, Dr Martinez Otero varied different aspects of the Mona Lisa that are processed by different visual channels, and then asked volunteers whether they saw a smile or not. © Copyright of Telegraph Media Group Limited 2009

By ANNE EISENBERG WHEN disease destroys vital parts of the eye, causing degrees of blindness, scientists can sometimes replace damaged tissue with electronic implants that help patients see lines and basic shapes. A model of an eye with a newly designed implant from a Boston group of researchers. The tips of the implant's electrodes, which help replace the work of diseased rods and cones, slide into a snug berth just below the retina. But as with any electrical connection, these implants must fit snugly and not jiggle or shake loose after a few months, like a drooping plug in a wall socket. Now groups of scientists have demonstrated retinal implants that they say will resist the jarring of daily use. The implant contains a tiny array of electrodes whose tips slide into a snug berth just beneath the retina, the nerve tissue lining the back of the eye, and are held in place by natural suction. The electrodes prompt the remains of retinal circuits to transmit signals to the brain, said John L. Wyatt, a professor of electrical engineering at the Massachusetts Institute of Technology and co-founder of the Boston Retinal Implant Project, one of the groups that has developed a prototype of the new design. The research team includes scientists from the Massachusetts Eye and Ear Infirmary, the VA Boston Health Care System and Cornell University. Copyright 2009 The New York Times Company

By Jocelyn Kaiser A single injection of DNA into the eyes of four children born with a blindness-causing disease has given them enough vision to walk without help. The study, published today, confirms that if patients with this disease are given gene therapy early in life, the results can be dramatic. Several clinical trials in the United States and Europe have been using gene therapy to treat a disease called Leber's congenital amaurosis (LCA), which affects about 3000 people in the United States. Those born with LCA start losing their sight at birth and are completely blind by age 40. Children born with one form, LCA2, have defects in a gene called RPE65 that helps the retina's light-sensing cells make rhodopsin, a pigment needed to absorb light. Without rhodopsin, the photoreceptor cells gradually die. In 2001, researchers at the University of Pennsylvania (Penn) showed that they could partially restore sight to blind dogs with this defect by injecting a good copy of RPE65 into their eyes. Two years ago, the Penn team began a small safety study of the therapy in humans with collaborators at the Children's Hospital of Philadelphia. They injected each patient's worse eye with a modified virus carrying the RPE65 gene. Early results from this trial and a similar study in the United Kingdom published in April 2008 showed that four of six young adults with LCA2 who received the treatment could later sense more light and perform better in an obstacle course. But the Penn researchers knew from their studies in animals that children should improve even more because they have more intact retinal tissue than adults do. Today in an online paper in The Lancet, their team and collaborators in Europe report full study results for three of the adults they treated earlier and nine more patients, including four children ages 8 to 11. © 2009 American Association for the Advancement of Science.

By Laura Sanders CHICAGO — The Halle Berry fan club is expanding one brain cell at a time. By eavesdropping on the activity of single neurons in the human brain, scientists have figured out which brain cells go wild for superstars such as the popular actress. And the newest research shows that people can activate those cells selectively. “This study is the first demonstration of humans’ ability to control the activity of single neurons,” the researchers wrote in a summary of their study. The results, presented October 19 at the Society for Neuroscience’s annual meeting by Moran Cerf of the California Institute of Technology in Pasadena, may help researchers understand how each cell in the brain sees and responds to the world. “This type of work gives us some clues about what’s going on in the brain,” comments Christoph Weidemann of the University of Pennsylvania, who studies how the brain processes information. “It’s quite an amazing feat for the brain to make sense of its input and reliably recognize people and objects.” The new study was conducted on people with epilepsy. Doctors had implanted electrodes in these patients’ brains to track where seizures originate. The researchers used these same electrodes to eavesdrop on the activity of single brain cells in a part of the brain called the medial temporal lobe, which is important for “memory, attention, perception — the things that we care about the most,” Cerf said in his presentation. © Society for Science & the Public 2000 - 2009

By Vilayanur S. Ramachandran and Diane Rogers-Ramachandran Humans enjoy stereoscopic vision. As we mentioned in our essay last issue, because our eyes are separated horizontally images we see in the two eyes are slightly different and the difference is proportional to the relative depth. The visual areas in the brain measure these differences, and we experience the result as stereo—what we all have enjoyed as children playing with View-Master toys. Visual-image processing from the eye to the brain happens in stages. Rudimentary features such as the orientation of edges, direction of motion, color, and so on are extracted early on in areas called V1 and V2 before reaching the next stages in the visual-processing hierarchy for a progressively more refined analysis. This stage-by-stage description is a caricature; many pathways go “back” from stage to stage—allowing the brain to play a kind of 20-questions game to arrive at a solution after successive iterations. Returning to the concept of stereo, we can ask: At what stage is the comparison of the two eyes’ images made? If you are looking at a scene with hundreds of features, how do you know which feature in one eye matches with which feature in the other eye? How do you avoid false matches? Until the correct matching is achieved, you cannot measure differences. In stereopsis, this conundrum is called the correspondence problem. © 1996-2009 Scientific American Inc.

By Laura Sanders CHICAGO -- Magicians and neuroscientists may not seem like a likely match, but they have one important thing in common: A fascination with the brain. As Science News pointed out in this article about science and magic in April, neuroscientists delve deep into the human mind to see how things like attention, perception and memory work, while magicians manipulate these very same things to confound their audience. This unlikely alliance was solidified October 17 at the Society for Neuroscience’s Annual Meeting in Chicago as two world-class magicians demonstrated some of their tricks to an audience of thousands of neuroscientists. (The size of the scientist crowd may have rivaled the motley crew of America’s Got Talent hopefuls, who were waiting in a monster line that snaked around a different part of the conference center. Although neuroscientists seem like they might be a tough crowd, everyone in the room was enamored. By all reports, the scientists seemed thrilled to have such interesting new colleagues. Apollo Robbins, known professionally as the “Gentleman Thief,” has an unusual set of skills that allowed him to, among other dastardly deeds, “borrow” Jennifer Garner’s engagement ring, switch Troy Aikman and Jerome Bettis’ licenses, and relieve Jimmy Carter’s secret service agents of their wallets, watches and confidential itineraries. (For more of Robbins’ rap sheet, check out his website Istealstuff.com © Society for Science & the Public 2000 - 2009

Eric Bland, Discovery News -- An artificial retina could restore sight to the blind, according to new research from the Massachusetts Institute of Technology. The device can be plugged directly into the optic nerve and is based on widely used cochlear implants. "We are skipping the rods and cones in the eye," said Shawn Kelly, a professor at MIT who is developing the artificial retina. "Instead, we are using a camera outside the eye to collect the image, transmitting that image to a chip inside the eye, and using an electric current to directly stimulate the nerves." The artificial retina is designed to help people with advanced macular degeneration or retinitis pigmentosa, progressive diseases that permanently blind patients, usually older patients. Some drugs can delay the process, but once the cells that detect light (rods) and color (cones) die, they are gone. The nerves behind the rods and cones do survive, however. For a patient to see again, something needs to stimulate the nerves. A mild electrical charge, applied using a self-contained, surgically implanted device could stimulate the optical nerves and allow a person to see again. © 2009 Discovery Communications, LLC

By Carina Storrs Seeing is believing when it comes to emotions. We smile, we gasp, we yawn when we see others do the same—a phenomenon called emotional contagion. A new study published last week in Proceedings of the National Academy of Sciences finds that emotional contagion occurs even if the "seeing" step is bypassed. The blind patients in the study could not consciously see images of the faces of happy or fearful people that they were shown. Although their eyes and optic nerves were functional, the region of their brains involved in visual processing had been damaged. Instead, other parts of the brain took over, allowing the subjects to still respond normally with their own happy or scared facial expressions. These patients also made the appropriate happy or fearful face in response to emotions that were communicated through bodily expressions, suggesting that blind empathy can happen even without a facial template to imitate. "We're actually infected by the emotions of others. [This study shows] this phenomenon can be carried out in the absence of visual awareness," says Marco Tamietto, a neuroscience researcher at Tilburg University in the Netherlands and lead author of the study. "We can say that emotional contagion cannot be reduced to a simple mimicry." To tease apart the mechanism underlying emotional contagion, Tamietto and his colleagues took advantage of what is known in neuroscience as "blindsight". Starting a few decades ago, researchers found that patients who have damage to the part of the brain called the visual cortex, which processes visual information, retain a sort of sixth sense of sight.

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