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By JANE E. BRODY “Feeling My Way Into Blindness,” an essay published in The New York Times in November by Edward Hoagland, an 84-year-old nature and travel writer and novelist, expressed common fears about the effects of vision loss on quality of life. Mr. Hoagland, who became blind about four years ago, projected deep-seated sadness in describing the challenges he faces of pouring coffee, not missing the toilet, locating a phone number, finding the food on his plate, and knowing to whom he is speaking, not to mention shopping and traveling, when he often must depend on the kindness of strangers. And, of course, he sorely misses nature’s inspiring vistas and inhabitants that fueled his writing, though he can still hear birds chatter in the trees, leaves rustle in the wind and waves crash on the shore. Mr. Hoagland is hardly alone in his distress. According to Action for Blind People, a British support organization, those who have lost some or all sight “struggle with a range of emotions — from shock, anger, sadness and frustration to depression and grief.” When eyesight fails, some people become socially disengaged, leading to isolation and loneliness. Anxiety about a host of issues — falls, medication errors, loss of employment, social blunders — is common. A recent study from researchers at the Wilmer Eye Institute at Johns Hopkins University School of Medicine found that most Americans regard loss of eyesight as the worst ailment that could happen to them, surpassing such conditions as loss of limb, memory, hearing or speech, or having H.I.V./AIDS. Indeed, low vision ranks behind arthritis and heart disease as the third most common chronic cause of impaired functioning in people over 70, Dr. Eric A. Rosenberg of Weill Cornell Medical College and Laura C. Sperazza, a New York optometrist, wrote in American Family Physician. © 2017 The New York Times Company

Related chapters from BP7e: 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: 23253 - Posted: 02.20.2017

By Michael Price BOSTON--Among mammals, primates are unique in that certain species have three different types of light-sensitive cone cells in their eyes rather than two. This allows humans and their close relatives to see what we think of as the standard spectrum of color. (Humans with red-green color blindness, of course, see a different spectrum.) The standard explanation for why primates developed trichromacy, as this kind of vision is called, is that it allowed our early ancestors to see colorful ripe fruit more easily against a background of mostly green forest. A particular Old World monkey, the rhesus macaque (pictured), has a genetic distinction that offers a convenient natural test of this hypothesis: a common genetic variation makes some females have three types of cone cells and others have two. Studies with captive macaques has shown that trichromatic females are faster than their dichromatic peers at finding fruit, but attempts to see whether that’s true for wild monkeys has been complicated by the fact that macaques are hard to find, and age and rank also play big roles in determining who eats when. A vision researcher reported today at the annual meeting of AAAS, which publishes Science, that after making more than 20,000 individual observations of 80 different macaques feeding from 30 species of trees on Cayo Santiago, Puerto Rico, she can say with confidence that wild trichromatic female monkeys do indeed appear to locate and eat fruit more quickly than dichromatic ones, lending strong support to the idea that this advantage helped drive the evolution of trichromacy in humans and our relatives. © 2017 American Association for the Advancement of Science.

Related chapters from BP7e: 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: 23252 - Posted: 02.20.2017

By LISA SANDERS, M.D. The 3-year-old girl was having a very bad day — a bad week, really. She’d been angry and irritable, screaming and kicking at her mother over nothing. Her mother was embarrassed by this unusual behavior, because her husband’s sister, Amber Bard, was visiting. Bard, a third-year medical student at Michigan State, was staying in the guest room while working with a local medical practice in Grand Rapids so that she could spend a little time with her niece. The behavior was strange, but the mother was more concerned about her child’s left eye. A few days earlier it was red and bloodshot. It no longer was, but now the girl had little bumps near the eye. The mother asked Bard whether she could look at the eye. “I’m a third-year medical student,” Bard told her. “I know approximately nothing.” But Bard was happy to try. She turned to the girl, who immediately averted her face. “Can you show me your eye?” she asked. The girl shouted: “No! No, no, no!” Eventually Bard was able to coax her into allowing her a quick look at the eye. She saw a couple of tiny pimples along the lower lid, near the lashes, and a couple more just next to the eye. The eye itself wasn’t red; the lid wasn’t swollen. She couldn’t see any discharge. Once the child was in bed, Bard opened her laptop and turned to a database she’d been using for the past week when she started to see patients. Called VisualDx, it’s one of a dozen or so programs known as decision-support software, designed to help doctors make a diagnosis. This one focuses mostly on skin findings.

Related chapters from BP7e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 23242 - Posted: 02.17.2017

By Sam Wong Here’s looking at you, squid. Cock-eyed squid have one huge, bulging eye and another normal-sized eye, but the reason has remained a mystery. Now we have an answer. Kate Thomas of Duke University in North Carolina studied 161 videos of the creatures collected over 26 years by remotely operated submarines in Monterey Bay, California. The findings provide the first behavioural evidence that the two eyes are adapted to look in different directions. The large one points upwards to spot prey silhouetted against the sky. The smaller one points downwards to spot bioluminescent organisms against the darkness below. The squid, from the histioteuthid family, live at depths of 200 to 1000 metres, where little light penetrates. The videos show that the squid normally swims with its tail end pointing upwards, but tilted so the large eye is consistently oriented towards the sky. Based on measurements of the eyes and the light levels they would be exposed to, Thomas and her colleagues calculated that having a big upward-pointing eye greatly improves visual perception, while a downward-pointing eye would gain little from being large. “That gives you the context for how this trait might have evolved,” says Thomas. Some of the squid’s prey, such as lanternfish and shrimp, have luminescent undersides so they are camouflaged against the sunlight when seen from below. Yellow pigmentation in the lens of the squid’s large eye may help it distinguish between sunlight and bioluminescence. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: 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: 23222 - Posted: 02.14.2017

By GRETCHEN REYNOLDS Being nearsighted is far more common than it once was. The prevalence of myopia, the condition’s medical name, in Americans has soared by 66 percent since the early 1970s, according to a 2009 study by the National Eye Institute; in China and other East Asian countries, as many as 90 percent of recent high school graduates are thought to be nearsighted. Myopia results when eyeballs are longer than normal, changing the angle at which light enters the eye and therefore the ability to focus on distant objects. The disorder involves a complex interplay of genetics and environment and usually begins before adolescence, when the eye is growing, but it can worsen in early adulthood. Some experts connect the elevated rates of myopia to the many hours young people stare at computers and other screens. But a recent study published in JAMA Ophthalmology suggests that a greater factor may be a side effect of all that screen-watching — it’s keeping children inside. This new study joins a growing body of research indicating that a lack of direct sunlight may reshape the human eye and impair vision. Researchers at King’s College London, the London School of Hygiene and Tropical Medicine and other institutions gave vision exams to more than 3,100 older European men and women and interviewed them at length about their education, careers and how often they remembered being outside during various stages of their lives. This biographical information was then cross-referenced with historical data about sunlight, originally compiled for research on skin cancer and other conditions. © 2017 The New York Times Company

Related chapters from BP7e: 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: 23125 - Posted: 01.19.2017

By Anna Azvolinsky Hummingbirds are efficient hoverers, suspending their bodies midair using rapid forward and backward strokes. Aside from their unique ability to hover, the tiny avians are also the only known birds that can fly in any direction, including sideways. Hummingbird brains appear to be adapted for this flying ability, researchers have now shown. According to a study published today (January 5) in Current Biology, a highly conserved area of the brain—the lentiformis mesencephali (LM), which receives panoramic visual motion information directly from the retina—processes the movement of objects from all directions. In contrast, the LMs of other bird species and all other four-limbed vertebrates studied to date predominantly sense back-to-front motion. While the authors had predicted the neurons of this hummingbird brain region would be tuned to slow motion, they in fact found the opposite: LM neurons were sensitive to quick visual motion, most likely because hummingbirds must process and respond to their environments quickly to avoid collisions, both during hovering and in other modes of flight. “This ancient part of the brain the authors studied has one job: to detect the motion of the image in front of the eyes,” explained Michael Ibbotson, a neuroscientist at the University of Melbourne who penned an accompanying editorial but was not involved in the research. The results of this study suggest that “hummingbirds evolved this area of the brain to have fine motor control to be able to hover and push in every direction possible,” Ibbotson said. © 1986-2017 The Scientist

Related chapters from BP7e: Chapter 10: Vision: From Eye to Brain; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 7: Vision: From Eye to Brain; Chapter 5: The Sensorimotor System
Link ID: 23064 - Posted: 01.07.2017

By Susana Martinez-Conde Our perceptual and cognitive systems like to keep things simple. We describe the line drawings below as a circle and a square, even though their imagined contours consist—in reality—of discontinuous line segments. The Gestalt psychologists of the 19th and early 20th century branded this perceptual legerdemain as the Principle of Closure, by which we tend to recognize shapes and concepts as complete, even in the face of fragmentary information. Now at the end of the year, it is tempting to seek a cognitive kind of closure: we want to close the lid on 2016, wrap it with a bow and start a fresh new year from a blank slate. Of course, it’s just an illusion, the Principle of Closure in one of its many incarnations. The end of the year is just as arbitrary as the end of the month, or the end of the week, or any other date we choose to highlight in the earth’s recurrent journey around the sun. But it feels quite different. That’s why we have lists of New Year’s resolutions, or why we start new diets or exercise regimes on Mondays rather than Thursdays. Researchers have also found that, even though we measure time in a continuous scale, we assign special meaning to idiosyncratic milestones such as entering a new decade. What should we do about our brain’s oversimplification tendencies concerning the New Year—if anything? One strategy would be to fight our feelings of closure and rebirth as we (in truth) seamlessly move from the last day of 2016 to the first day of 2017. But that approach is likely to fail. Try as we might, the Principle of Closure is just too ingrained in our perceptual and cognitive systems. In fact, if you already have the feeling that the beginning of the year is somewhat special (hey, it only happens once a year!), you might as well decide that resistance is futile, and not just embrace the illusion, but do your best to channel it. © 2017 Scientific American

Related chapters from BP7e: 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: 23042 - Posted: 01.02.2017

By Stephen L. Macknik Masashi Atarashi, a physics high school teacher from Japan, submitted this wonderful winter illusion to the 2015 Best Illusion of the Year Contest, where it competed as a finalist. Atarashi discovered this effect serendipitously, while watching the snow fall through the venetian window blinds of his school’s faculty lounge—just like his students must sometimes do in the classroom during a lecture! Notice that as the blinds occupy more area on the screen, the speed of the snowfall seems to accelerate. A great illusion to ponder during our white holiday season. Nobody knows how Atarashi’s effect works, but our working hypothesis is that each time the snow disappears behind a blind, or reappears below it, it triggers transient increases in the activity of your visual system’s motion-sensitive neurons. Such transient surges in neural activity are perhaps misinterpreted by your brain as faster motion speed. © 2016 Scientific American,

Related chapters from BP7e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 23022 - Posted: 12.27.2016

Sarah Boseley Health editor The NHS is to pay for 10 people to be implanted with a “bionic eye”, a pioneering technology that can restore some sight to those who have been blind for years. Only a handful of people have undergone surgery in trials so far to equip them to use Argus II, which employs a camera mounted in a pair of glasses and a tiny computer to relay signals directly to the nerves controlling sight. The decision to fund the first 10 NHS patients to be given the bionic eye could pave the way for the life-changing technology to enter the mainstream. Those who will get the equipment can currently see nothing more than the difference between daylight and darkness. The system allows the brain to decode flashes of light, so that they can learn to see movement. One of three patients to have had the implant into the retina in trials at Manchester Royal Eye hospital is Keith Hayman, 68, from Lancashire, who has five grandchildren. He was diagnosed with retinitis pigmentosa in his 20s. The disease causes cells in the retina gradually to stop working and eventually die. Hayman, who was originally a butcher, was registered blind in 1981, and forced to give up all work. “Having spent half my life in darkness, I can now tell when my grandchildren run towards me and make out lights twinkling on Christmas trees,” he said. “I would be talking to a friend, who might have walked off and I couldn’t tell and kept talking to myself. This doesn’t happen anymore, because I can tell when they have gone.” They may seem like little things, he said, but “they make all the difference to me”. © 2016 Guardian News and Media Limited

Related chapters from BP7e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 23015 - Posted: 12.23.2016

Betsy Mason With virtual reality finally hitting the consumer market this year, VR headsets are bound to make their way onto a lot of holiday shopping lists. But new research suggests these gifts could also give some of their recipients motion sickness — especially if they’re women. In a test of people playing one virtual reality game using an Oculus Rift headset, more than half felt sick within 15 minutes, a team of scientists at the University of Minnesota in Minneapolis reports online December 3 in Experimental Brain Research. Among women, nearly four out of five felt sick. So-called VR sickness, also known as simulator sickness or cybersickness, has been recognized since the 1980s, when the U.S. military noticed that flight simulators were nauseating its pilots. In recent years, anecdotal reports began trickling in about the new generation of head-mounted virtual reality displays making people sick. Now, with VR making its way into people’s homes, there’s a steady stream of claims of VR sickness. “It's a high rate of people that you put in [VR headsets] that are going to experience some level of symptoms,” says Eric Muth, an experimental psychologist at Clemson University in South Carolina with expertise in motion sickness. “It’s going to mute the ‘Wheee!’ factor.” Oculus, which Facebook bought for $2 billion in 2014, released its Rift headset in March. The company declined to comment on the new research but says it has made progress in making the virtual reality experience comfortable for most people, and that developers are getting better at creating VR content. All approved games and apps get a comfort rating based on things like the type of movements involved, and Oculus recommends starting slow and taking breaks. But still some users report getting sick. © Society for Science & the Public 2000 - 2016.

Related chapters from BP7e: 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: 22962 - Posted: 12.07.2016

.By JOANNA KLEIN A honey bee gathering pollen on a white flower. Dagmar Sporck/EyeEm, via Getty Images Set your meetings, phone calls and emails aside, at least for the next several minutes. That’s because today you’re a bee. It's time to leave your hive, or your underground burrow, and forage for pollen. Pollen is the stuff that flowers use to reproduce. But it’s also essential grub for you, other bees in your hive and your larvae. Once you’ve gathered pollen to take home, you or another bee will mix it with water and flower nectar that other bees have gathered and stored in the hive. But how do you decide which flowers to approach? What draws you in? In a review published last week in the journal Functional Ecology, researchers asked: What is a flower like from a bee’s perspective, and what does the pollinator experience as it gathers pollen? And that's why we're talking to you in the second person: to help you understand how bees like you, while hunting for pollen, use all of your senses — taste, touch, smell and more — to decide what to pick up and bring home. Maybe you're ready to go find some pollen. But do you even know where to look? © 2016 The New York Times Company

Related chapters from BP7e: 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: 22943 - Posted: 12.03.2016

Hannah Devlin Science Correspondent Blind animals have had their vision partially restored using a revolutionary DNA editing technique that scientists say could in future be applied to a range of devastating genetic diseases. The study is the first to demonstrate that a gene editing tool, called Crispr, can be used to replace faulty genes with working versions in the cells of adults - in this case adult rats. Previously, the powerful procedure, in which strands of DNA are snipped out and replaced, had been used only in dividing cells - such as those in an embryo - and scientists had struggled to apply it to non-dividing cells that make up most adult tissue, including the brain, heart, kidneys and liver. The latest advance paves the way for Crispr to be used to treat a range of incurable illnesses, such as muscular dystrophy, haemophilia and cystic fibrosis, by overwriting aberrant genes with a healthy working version. Professor Juan Carlos Izpisua Belmonte, who led the work at the Salk Institute in California, said: “For the first time, we can enter into cells that do not divide and modify the DNA at will. The possible applications of this discovery are vast.” The technique could be trialled in humans in as little as one or two years, he predicted, adding that the team were already working on developing therapies for muscular dystrophy. Crispr, a tool sometimes referred to as “molecular scissors”, has already been hailed as a game-changer in genetics because it allows scientists to cut precise sections of DNA and replace them with synthetic, healthy replacements. © 2016 Guardian News and Media Limited

Related chapters from BP7e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 22882 - Posted: 11.17.2016

By Simon Oxenham Isy Suttie has felt “head squeezing” since she was young. The comedian, best known for playing Dobbie in the BBC sitcom Peep Show, is one of many people who experience autonomous sensory meridian response (ASMR) – a tingly feeling often elicited by certain videos or particular mundane interactions. Growing up, Suttie says she had always assumed everyone felt it too. Not everyone feels it, but Suttie is by no means alone. On Reddit, a community of more than 100,000 members share videos designed to elicit the pleasurable sensation. The videos, often described as “whisper porn”, typically consist of people role-playing routine tasks, whispering softly into a microphone or making noises by crinkling objects such as crisp packets. The most popular ASMR YouTuber, “Gentle Whispering”, has over 250 million views. To most of us, the videos might seem strange or boring, but the clips frequently garner hundreds of thousands of views. These videos often mimic real-life situations that provoke ASMR in susceptible people. Suttie says her strongest real-world triggers occur during innocuous interactions with strangers, like talking about the weather – “it’s almost as if the more superficial the subject the better,” Suttie says. She feels the sensation particularly strongly when someone brushes past her. For Suttie, the feelings are so powerful that she often feels floored by them, and they even overcome pain and emotional distress. During a trip to the dentist, she still experiences the pleasurable tingles when the assistant brushes past her, she says. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: 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: 22843 - Posted: 11.08.2016

By Jessica Boddy Glasses may be trendy now, but for centuries they were the stodgy accessories of the elderly worn only for failing eyes. Now, new research suggests that aging bonobos might also benefit from a pair of specs—not for reading, but for grooming. Many older bonobos groom their partners at arm’s length instead of just centimeters away, in the same way that older humans often hold newspapers farther out to read. This made researchers think the apes might also be losing their close-up vision as they age. To see whether their hypothesis held, the researchers took photos of 14 different bonobos of varying ages as they groomed one another (above) and measured the distance between their hands and faces. By analyzing how this so-called grooming distance varied from ape to ape, the researchers found that grooming distance increased exponentially with age, they report today in Current Biology. And because both humans and bonobos shows signs of farsightedness around age 40, deterioration in human eyes might not be the mere result of staring at screens and small text, the scientists say. Rather, it might be a deep-rooted natural trait reaching back to a common ancestor. © 2016 American Association for the Advancement of Science.

Related chapters from BP7e: 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: 22841 - Posted: 11.08.2016

By peering into the eyes of mice and tracking their ocular movements, researchers made an unexpected discovery: the visual cortex — a region of the brain known to process sensory information — plays a key role in promoting the plasticity of innate, spontaneous eye movements. The study, published in Nature, was led by researchers at the University of California, San Diego (UCSD) and the University of California, San Francisco (UCSF) and funded by the National Eye Institute (NEI), part of the National Institutes of Health. “This study elegantly shows how analysis of eye movement sheds more light on brain plasticity — an ability that is at the core of the brain’s capacity to adapt and function. More specifically, it shows how the visual cortex continues to surprise and to awe,” said Houmam Araj, Ph.D., a program director at NEI. Without our being aware of it, our eyes are in constant motion. As we rotate our heads and as the world around us moves, two ocular reflexes kick in to offset this movement and stabilize images projected onto our retinas, the light-sensitive tissue at the back of our eyes. The optokinetic reflex causes eyes to drift horizontally from side-to-side — for example, as we watch the scenery through a window of a moving train. The vestibulo-ocular reflex adjusts our eye position to offset head movements. Both reflexes are crucial to survival. These mechanisms allow us to see traffic while driving down a bumpy road, or a hawk in flight to see a mouse scurrying for cover.

Related chapters from BP7e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 22750 - Posted: 10.13.2016

By Colin Barras Subtract 8 from 52. Did you see the calculation in your head? While a leading theory suggests our visual experiences are linked to our understanding of numbers, a study of people who have been blind from birth suggests the opposite. The link between vision and number processing is strong. Sighted people can estimate the number of people in a crowd just by looking, for instance, while children who can mentally rotate an object and correctly imagine how it might look from a different angle often develop better mathematical skills. “It’s actually hard to think of a situation when you might process numbers through any modality other than vision,” says Shipra Kanjlia at Johns Hopkins University in Baltimore, Maryland. But blind people can do maths too. To understand how they might compensate for their lack of visual experience, Kanjlia and her colleagues asked 36 volunteers – 17 of whom had been blind at birth – to do simple mental arithmetic inside an fMRI scanner. To level the playing field, the sighted participants wore blindfolds. We know that a region of the brain called the intraparietal sulcus (IPS) is, and brain scans revealed that the same area is similarly active in blind people too. “It’s really surprising,” says Kanjlia. “It turns out brain activity is remarkably similar, at least in terms of classic number processing.” This may mean we have a deep understanding of how to handle numbers that is entirely independent of visual experience. This suggests we are all born with a natural understanding of numbers – an idea many researchers find difficult to accept. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: 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: 22664 - Posted: 09.17.2016

Tina Hesman Saey Color vision may actually work like a colorized version of a black-and-white movie, a new study suggests. Cone cells, which sense red, green or blue light, detect white more often than colors, researchers report September 14 in Science Advances. The textbook-rewriting discovery could change scientists’ thinking about how color vision works. For decades, researchers have known that three types of cone cells in the retina are responsible for color vision. Those cone cells were thought to send “red,” “green” and “blue” signals to the brain. The brain supposedly combines the colors, much the way a color printer does, to create a rainbow-hued picture of the world (including black and white). But the new findings indicate that “the retina is doing more of the work, and it’s doing it in a more simpleminded way,” says Jay Neitz, a color vision scientist at the University of Washington in Seattle who was not involved in the study. Red and green cone cells each come in two types: One type signals “white”; another signals color, vision researcher Ramkumar Sabesan and colleagues at the University of California, Berkeley, discovered. The large number of cells that detect white (and black — the absence of white) create a high-resolution black-and-white picture of a person’s surroundings, picking out edges and fine details. Red- and green-signaling cells fill in low-resolution color information. The process works much like filling in a coloring book or adding color to a black-and-white film, says Sabesan, who is now at the University of Washington. |© Society for Science & the Public 2000 - 2016

Related chapters from BP7e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 22660 - Posted: 09.15.2016

By Rachel Becker Optical illusions have a way of breaking the internet, and the latest visual trick looks like it’s well on its way. On Sunday afternoon, game developer Will Kerslake tweeted a picture of intersecting gray lines on a white background. Twelve black dots blink in and out of existence where the gray lines meet. In the six hours since he posted the photo to Twitter, it’s been shared more than 6,000 times, with commenters demanding to know why they can’t see all 12 dots at the same time. The optical illusion was first posted to Facebook about a day ago by Japanese psychology professor Akiyoshi Kitaoka, and it has been shared more than 4,600 times so far. But the origin of this bit of visual trickery is a scientific paper published in the journal Perception in 2000. To be clear, there really are 12 black dots in the image. But (most) people can’t see all 12 dots at the same time, which is driving people nuts. "They think, 'It’s an existential crisis,'" says Derek Arnold, a vision scientist at the University of Queensland in Australia. "'How can I ever know what the truth is?'" But, he adds, scientists who study the visual system know that perception doesn’t always equal reality. In this optical illusion, the black dot in the center of your vision should always appear. But the black dots around it seem to appear and disappear. That’s because humans have pretty bad peripheral vision. If you focus on a word in the center of this line you’ll probably see it clearly. But if you try to read the words at either end without moving your eyes, they most likely look blurry. As a result, the brain has to make its best guess about what’s most likely to be going on in the fuzzy periphery — and fill in the mental image accordingly. © 2016 Vox Media, Inc.

Related chapters from BP7e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 22652 - Posted: 09.15.2016

Laura Sanders Despite its name, the newly identified GluMI cell (pronounced “gloomy”) is no downer. It’s a nerve cell, spied in a mouse retina, that looks like one type of cell but behaves like another. Like neighboring retina nerve cells that subdue, or deaden, activity of other nerve cells, GluMI cells have a single arm extending from their body. But unlike those cells, GluMI cells actually seem to ramp up activity of nearby cells in a way that could aid vision. GLuMIs don’t seem to detect light firsthand, but they respond to it, Luca Della Santina of the University of Washington in Seattle and colleagues found. GluMIs are among a growing list of unexpected and mysterious cells found in the retinas of vertebrates, the researchers write August 8 in Current Biology. Citations L. Della Santina et al. Glutamatergic monopolar interneurons provide a novel pathway of excitation in the mouse retina. Current Biology. Vol. 26, August 8, 2016. doi:10.1016/j.cub.2016.06.016. |© Society for Science & the Public 2000 - 2016

Related chapters from BP7e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 22610 - Posted: 08.30.2016

Amy McDermott You’ve got to see it to be it. A heightened sense of red color vision arose in ancient reptiles before bright red skin, scales and feathers, a new study suggests. The finding bolsters evidence that dinosaurs probably saw red and perhaps displayed red color. The new finding, published in the Aug. 17 Proceedings of the Royal Society B, rests on the discovery that birds and turtles share a gene used both for red vision and red coloration. More bird and turtle species use the gene, called CYP2J19, for vision than for coloration, however, suggesting that its first job was in sight. “We have this single gene that has two very different functions,” says evolutionary biologist Nicholas Mundy of the University of Cambridge. Mundy’s team wondered which function came first: the red vision or the ornamentation. In evolution, what an animal can see is often linked with what others can display, says paleontologist Martin Sander of the University of Bonn in Germany, who did not work on the new study. “We’re always getting at color from these two sides,” he says, because the point of seeing a strong color is often reading visual signals. Scientists already knew that birds use CYP2J19 for vision and color. In bird eyes, the gene contains instructions for making bright red oil droplets that filter red light. Other forms of red color vision evolved earlier in other animals, but this form allows birds to see more shades of red than humans can. Elsewhere in the body, the same gene can code for pigments that stain feathers red. Turtles are the only other land vertebrates with bright red oil droplets in their eyes. But scientists weren’t sure if the same gene was responsible, Mundy says. |© Society for Science & the Public 2000 - 2016

Related chapters from BP7e: 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: 22535 - Posted: 08.10.2016