By Jessica Hamzelou People who are blind use parts of their brain that normally handle for vision to process language, as well as sounds – highlighting the brain’s extraordinary ability to requisition unused real estate for new functions. Neurons in the part of the brain normally responsible for vision synchronise their activity to the sounds of speech in blind people, says Olivier Collignon at the Catholic University of Louvain (UCL) in Belgium. “It’s a strong argument that the organisation of the language system… is not constrained by our genetic blueprint alone,” he says. The finding builds on previous research showing that the parts of the brain responsible for vision can learn to process other kinds of information, including touch and sound, in people who are blind. Collignon and his colleagues made the discovery using magnetoencephalography (MEG), which measures electrical activity in the brain. Read more: How some blind people are able to echolocate like bats While they were being scanned, groups of sighted and blind volunteers were played three clips from an audio book. One recording was clear and easy to understand; another was distorted but still intelligible; and the third was modified so as to be completely incomprehensible. Both groups showed activity in the brain’s auditory cortex, a region that processes sounds, while listening to the clips. But the volunteers who were blind showed activity in the visual cortex, too. © Copyright New Scientist Ltd.

Related chapters from BN8e: Chapter 10: Vision: From Eye to Brain; Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 7: Vision: From Eye to Brain; Chapter 15: Brain Asymmetry, Spatial Cognition, and Language
Link ID: 24075 - Posted: 09.19.2017

By Emily Chung, CBC News If you were blind and walked into a coffee shop, how would you find the counter so you could order? That's easy for Susan Vaile at 9 Bars Coffee in Toronto — she just needs to listen to her smartphone: "Walk forward six metres to carpet. Service counter at 9 o' clock." Sure enough, there it is, and within minutes, Vaile has ordered and received a small coffee with double cream and double sugar. Similar verbal directions are already available to customers like Vaile at several other businesses in the Yonge and St. Clair neighbourhood, thanks to a pilot project called ShopTalk launched by the CNIB, a charity that provides community-based support for people who are blind or partially sighted. The project installs and programs palm-sized Apple iBeacons that use Bluetooth wireless signals to connect with nearby users' phones via an iPhone app called BlindSquare. It provides directions to help them navigate through doors and vestibules, to service counters, washrooms, and other important parts of buildings such as stores and restaurants. Vaile says the beacons make it possible for customers like herself to find their way independently. ©2017 CBC/Radio-Canada.

Related chapters from BN8e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 24074 - Posted: 09.19.2017

By Catherine Offord | On August 21, the moon will pass between the Earth and the sun, resulting in a total solar eclipse visible across a large strip of the United States. Self-proclaimed eclipse-chaser Ralph Chou, an emeritus professor of optometry at the University of Waterloo, has been working to spread awareness about eye-safety during eclipses for around 30 years. Last year, he put together the American Astronomical Society’s technical guide to eye safety, aimed at everyone from astronomers to educators to medical professionals. The Scientist spoke to Chou to find out what happens to the eye when exposed to too much sunlight, and how to watch next week’s solar eclipse safely. Ralph Chou: Light comes into the eye and goes through all the various layers of cells until it reaches the photoreceptors—essentially, the bottom of a stack of cells. The photoreceptors themselves guide the light towards a specialized structure [of the cells] called the outer segment, where there is a stack of discs that contain the visual pigment. Under normal circumstances, the light would interact with the pigment, which generates an electrical signal that then starts the process of sending an impulse through the optic nerve to the brain. In looking at the sun, you have a very large volume of photons—light energy—coming in and hitting these pigment discs, and it’s more than they can really handle. In addition to generating the electrical signal, [the cell] also starts generating photo-oxidative compounds. So you’re getting oxidative species like hydroxyl radicals and peroxides that will go on to attack the cell’s organelles. © 1986-2017 The Scientist

Related chapters from BN8e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 23969 - Posted: 08.17.2017

By Kai Sinclair It’s hard to see underwater, and not just because of the chlorine. The image-producing light rays that enter our eyes have trouble bending and focusing when the water’s density is almost same as that of eye fluid. Sea creatures experience the same problem, but squid use a type of lens notorious for blurry images to correct that, researchers report today in Science. Spherical lenses, like the squids’, usually can’t focus the incoming light to one point as it passes through the curved surface, which causes an unclear image. The only way to correct this is by bending each ray of light differently as it falls on each location of the lens’s surface. S-crystallin, the main protein in squid lenses, evolved the ability to do this by behaving as patchy colloids—small molecules that have spots of molecular glue that they use to stick together in clusters. The S-crystallins feature a pair of loops that act as the proteins’ sticky patches and attract the loops of other S-crystallins. Globs of six proteins link together during the squid’s larval stage and form a gel that eventually becomes the center of the lens. As the gel becomes too dense with protein clumps, smaller particles struggle to diffuse through, and a new layer of protein packages forms with just under six S-crystallins in each clump. The process continues until the outer edge of the lens is formed with pairs of S-crystallins. This allows light rays to bend a little differently in each region of the lens, which yields a clearer image. Some fish eyes are nearly identical to squids’, but it’s unknown whether their eye proteins exhibit patchy colloidlike behavior. Other cephalopods, like octopuses and nautiluses, lack S-crystallin lens proteins. So they, unlike squid, likely have blurry vision. © 2017 American Association for the Advancement of Science

Related chapters from BN8e: 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: 23945 - Posted: 08.11.2017

By JANE E. BRODY Putting carboxymethylcellulose sodium in one’s eyes two, three or more times a day may not sound like a great experience. But I can assure you that it can be. Drops of this chemical, called a topical lubricant, help to keep my eyes from burning, avoiding bright lights, becoming red and itchy, and generally feeling miserable. Like tens of millions of Americans, especially women older than 50, I have dry eye disease, medically known as keratoconjunctivitis sicca. Fortunately, my problem is not severe, certainly not as bad as that of an elderly woman I know who has to use a nightly ointment of mineral oil and Vaseline, which minimizes the dryness but temporarily blurs her vision. The drops I use, an over-the-counter preservative-free product called Refresh Plus (also sold as generic store brands) that I carry with me at all times, are a crucial measure I take to keep my eyes from becoming overly dry and chronically irritated — but not the only one. To minimize the drying effect of wind when driving, cycling or sitting in a room cooled by a fan or air-conditioning, I wear wraparound glasses even when I don’t need them to see clearly. Watertight goggles are de rigueur when swimming, even in fresh water. And I refresh my eyes with drops when I watch a movie, work long hours at the computer, or do any activity that depresses the frequency of blinking, which moistens the eyes. Dry eye is sometimes referred to as “a nuisance complaint — it’s not the sexiest of eye problems,” Dr. Rachel Bishop, chief consulting ophthalmologist at the National Eye Institute, told me. Nonetheless, she said, “Dry eye disease deserves serious professional — and personal — attention. It can be very debilitating and seriously diminish a person’s quality of life.” Tears serve a variety of functions, which accounts for the kinds of complications their deficiency can cause. They lubricate the eye, supply it with nutrients and oxygen, and help to focus images and clear the eye of debris. © 2017 The New York Times Company

Related chapters from BN8e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 23900 - Posted: 08.01.2017

Cells within an injured mouse eye can be coaxed into regenerating neurons and those new neurons appear to integrate themselves into the eye’s circuitry, new research shows. The findings potentially open the door to new treatments for eye trauma and retinal disease. The study appears in the July 26 issue of Nature, and was funded in part by the National Eye Institute (NEI), part of the National Institutes of Health. “The findings are significant because they suggest the feasibility of a novel approach for encouraging regeneration in the mammalian retina, the light sensitive tissue at the back of the eye that dies in many blinding diseases,” said Tom Greenwell, Ph.D., program director at NEI. “Importantly, the investigation also demonstrates that newly generated cells in the mouse retina not only look and behave like neurons, they also wire correctly to the existing neural circuitry at the back of the eye.” The study’s lead investigator, Tom Reh, Ph.D., and his team at UW Medicine in Seattle, looked to the zebrafish for clues about how to encourage regeneration in the mouse eye. When a zebrafish injures its eye, cells within the eye naturally regenerate, allowing the fish to maintain vision. Mammals lack this regenerative ability. In studying zebrafish the research team homed in on Müller glia, a type of retinal cell that supports the health and functioning of neighboring neurons, and that also exhibits an innate regenerative ability. Sometimes referred to as the stem cells of the zebrafish eye, Müller glia are the cells from which all other types of retinal cells are regenerated in the fish.

Related chapters from BN8e: 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: 23882 - Posted: 07.27.2017

By Erin Blakemore What do you see? That question is so complex it may be impossible to answer. But when Vanessa Potter lost her sight because of a rare condition, she became obsessed with describing the experience of both literal and inner vision. Patient H69: The Story of My Second Sight Book by Vanessa Potter Her new book, “Patient H69,” tracks Potter’s progression from advertising producer to patient. But her memoir shows how a medical ordeal also turned her into a scientific detective, advocate and artist. In 2012, Potter suddenly lost her sight. The first half of her book tracks her terrifying loss of vision and illustrates the psychological toll that accompanies the transition from healthy person to patient. Potter’s ailment turned out to be neuromyelitis optica, a disorder also known as Devic’s disease. People with the autoimmune disorder experience inflammation of the optic nerve, temporary blindness and spinal cord inflammation that can cause pain and sensory loss. Determined to regain her sight and understand her illness, Potter collaborated with scientists as her optical nerve healed.Along the way, she documented her experience. Her descriptive powers serve her well as she illustrates what it’s like to experience the development of sight in real time — a progression that, for Potter, included synesthesia (a blending of the senses in which a word may be seen as a certain color, for example), self-hypnosis and plenty of emotion. © 1996-2017 The Washington Post

Related chapters from BN8e: Chapter 10: Vision: From Eye to Brain; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 7: Vision: From Eye to Brain; Chapter 11: Emotions, Aggression, and Stress
Link ID: 23867 - Posted: 07.24.2017

By Jane C. Hu In English the sky is blue, and the grass is green. But in Vietnamese there is just one color category for both sky and grass: xanh. For decades cognitive scientists have pointed to such examples as evidence that language largely determines how we see color. But new research with four- to six-month-old infants indicates that long before we learn language, we see up to five basic categories of hue—a finding that suggests a stronger biological component to color perception than previously thought. The study, published recently in the Proceedings of the National Academy of Sciences USA, tested the color-discrimination abilities of more than 170 British infants. Researchers at the University of Sussex in England measured how long babies spent gazing at color swatches, a metric known as looking time. First the team showed infants one swatch repeatedly until their looking time decreased—a sign they had grown bored with it. Then the researchers showed them a different swatch and noted their reaction. Longer looking times were interpreted to mean the babies considered the second swatch to be a new hue. Their cumulative responses showed that they distinguished among five colors: red, green, blue, purple and yellow. The finding “suggests we’re all working from the same template,” explains lead author Alice Skelton, a doctoral student at Sussex. “You come prepackaged to make [color] distinctions, but given your culture and language, certain distinctions may or may not be used.” For instance, infants learning Vietnamese most likely see green and blue, even if their native language does not use distinct words for the two colors. © 2017 Scientific American

Related chapters from BN8e: 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: 23830 - Posted: 07.13.2017

by Laura Sanders Lots of newborn decorations come in black and white, so that young babies can better see the shapes. But just because it’s easier for babies to see bold blacks and whites doesn’t mean they can’t see color. Very few studies of color vision in newborns exist, says Anna Franklin, a color researcher at the University of Sussex in England. “But those that have been conducted suggest that newborns can see some color, even if their color vision is limited,” she says. Newborns may not be great at distinguishing maroon from scarlet, but they can certainly see a vivid red. But as babies get a little older, they get remarkably adept at discerning the world’s palette, new research shows. Babies ages 4 months to 6 months old are able to sort colors into five categories, researchers report in the May 23 Proceedings of the National Academy of Sciences. These preverbal color capabilities offer insight into something scientists have long wondered: Without words for individual colors, how do babies divvy up the hues across the color wheel, telling when blue turns to green, for instance? Along with Franklin and colleagues, psychologist Alice Skelton, also of the University of Sussex, bravely approached this question. The team coaxed 179 4- to 6-month-old babies to calmly and repeatedly look at two squares, each 1 of 14 various colors. |© Society for Science & the Public 2000 - 2017. All rights reserved.

Related chapters from BN8e: 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: 23702 - Posted: 06.03.2017

By Clare Wilson Seeing shouldn’t always be believing. We all have blind spots in our vision, but we don’t notice them because our brains fill the gaps with made-up information. Now subtle tests show that we trust this “fake vision” more than the real thing. If the brain works like this in other ways, it suggests we should be less trusting of the evidence from our senses, says Christoph Teufel of Cardiff University, who wasn’t involved in the study. “Perception is not providing us with a [true] representation of the world,” he says. “It is contaminated by what we already know.” The blind spot is caused by a patch at the back of each eye where there are no light-sensitive cells, just a gap where neurons exit the eye on their way to the brain. We normally don’t notice blind spots because our two eyes can fill in for each other. When vision is obscured in one eye, the brain makes up what’s in the missing area by assuming that whatever is in the regions around the spot continues inwards. But do we subconsciously know that this filled-in vision is less trustworthy than real visual information? Benedikt Ehinger of the University of Osnabrück in Germany and his colleagues set out to answer this question by asking 100 people to look at a picture of a circle of vertical stripes, which contained a small patch of horizontal stripes. The circle was positioned so that with one eye obscured, the patch of horizontal stripes fell within the other eye’s blind spot. As a result, the circle appeared as though there was no patch and the vertical stripes were continuous. © Copyright New Scientist Ltd.

Related chapters from BN8e: 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: 23640 - Posted: 05.20.2017

By Susana Martinez-Conde There is something deeply disconcerting about mirrors. The myriad reflecting surfaces that surround us in our everyday lives help us conduct many necessary tasks, such as applying makeup, shaving, or driving a car. But despite our constant use of mirrors, our nervous systems remain surprisingly ill-equipped to grasp the mechanics of refraction and reflection. Some magic tricks take advantage of such perceptual limitations, and are the origin of phrases such as “it’s all smoke and mirrors,” or “it’s all done with mirrors.” Kokichi Sugihara, a mathematical engineer at Meiji University in Japan, has exploited our poor understanding of mirrors to create new and spectacular varieties of perceptual magic. Our May/June Illusions column features mirror-based illusions by Sugihara and others. How can you use a mirror to vanish half an object? To make your own half-disappearing hexagon, follow the diagram above (you can print it from this template). Part A is the upper half of the object, which you will need to fold along the two edges, forming 120-degree angles. Part B, or the lower half of the object, is a flat structure and should not be folded. Glue both parts together matching the “a” and “b” letters. For the strongest effect, tilt the mirror slightly downward. © 2017 Scientific American

Related chapters from BN8e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 23612 - Posted: 05.15.2017

By Michael Price Unless you’re colorblind, you probably have a pretty good idea of what red, green, and blue are. Yet those labels are arbitrary divisions of the color spectrum; there’s no definitive point where the wavelengths of light we call orange turn into red. So cognitive scientists have long wondered whether we learn our labels from our culture or inherit them from our biology. Now, a study finds that infants see red, yellow, green, blue, and purple as different color categories, suggesting that at least some distinctions may be hardwired. “I find it really compelling,” says Michael Webster, a psychologist who studies visual perception at the University of Nevada in Reno, who wasn’t involved in the study. “This isn’t going to immediately change anyone’s mind. But it’s another piece in the puzzle, and it’s a very nice piece.” Scientists can’t just ask a newborn what it knows, so they use a trick known as “infant looking time” to figure out what’s in babies’ brains. The idea is that an infant’s gaze will linger on something unfamiliar for longer than something familiar, giving researchers a window into what babies expect—and what surprises them. Applying this to color research, scientists led by Anna Franklin, a perception and cognition researcher at the University of Sussex in the United Kingdom, showed 179 infants aged 46 months 14 different swaths of color, each from a different part of the color wheel. Researchers showed one swath several times before displaying a hue from the next range over. If the infants looked at the new hue longer than the previous one, experimenters concluded that the babies considered it a different color. © 2017 American Association for the Advancement of Science

Related chapters from BN8e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 7: Vision: From Eye to Brain
Link ID: 23596 - Posted: 05.09.2017

By C. CLAIBORNE RAY Q. What are cataracts made of and what causes them to form in the eyes? A. Cataracts are made of the same soluble proteins and water that are found in the normal lenses of the eyes, but arranged differently so that they interfere with the path of light, clouding vision and scattering light. The lens forms in the uterus and its protein strands are not equipped with cellular mechanisms for cleanup and repair. With age, the proteins may become misfolded and clump together, according to a 2012 review article in the journal Trends in Molecular Medicine. Chaperone proteins that keep the strands in order may fail, and the strands are also subject to chemical processes, including oxidation, that can change their color. Researchers have found several possible causes for the deterioration and jumbling of the proteins, with much recent work focusing on the effects of both ultraviolet A and B radiation. A 2014 study in The Journal of Biological Chemistry outlined the chemical changes suspected to take place upon prolonged exposure to such rays. Other risk factors for cataracts include some diseases, like diabetes; smoking; and excessive use of alcohol.question@nytimes.com © 2017 The New York Times Company

Related chapters from BN8e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 23590 - Posted: 05.09.2017

Beau Lotto When you open your eyes, do you see the world as it really is? Do we see reality? Humans have been asking themselves this question for thousands of years. From the shadows on the wall of Plato’s cave in “The Republic” to Morpheus offering Neo the red pill or the blue bill in “The Matrix,” the notion that what we see might not be what is truly there has troubled and tantalized us. In the eighteenth century, the philosopher Immanuel Kant argued that we can never have access to the Ding an sich, the unfiltered “thing-in-itself ” of objective reality. Great minds of history have taken up this perplexing question again and again. They all had theories, but now neuroscience has an answer. The answer is that we don’t see reality. The world exists. It’s just that we don’t see it. We do not experience the world as it is because our brain didn’t evolve to do so. It’s a paradox of sorts: Your brain gives you the impression that your perceptions are objectively real, yet the sensory processes that make perception possible actually separate you from ever accessing that reality directly. Our five senses are like a keyboard to a computer — they provide the means for information from the world to get in, but they have very little to do with what is then experienced in perception. They are in essence just mechanical media, and so play only a limited role in what we perceive. In fact, in terms of the sheer number of neural connections, just 10 percent of the information our brains use to see comes from our eyes. The rest comes from other parts of our brains, and this other 90 percent is in large part what this book is about. Perception derives not just from our five senses but from our brain’s seemingly infinitely sophisticated network that makes sense of all the incoming information. © 2017 The Associated Press.

Related chapters from BN8e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 23529 - Posted: 04.25.2017

Jonathan Rée Beau Lotto is a gung-ho neuroscientist. “[The] great minds of history,” he says, “had theories, but now neuroscience has an answer.” The latest research has, it seems, established that everything you experience “takes place in the brain” and that “you never, ever see reality!” (Lotto loves his italics and exclamation marks.) Your brain may be beautiful, but “what makes it beautiful is that it is delusional” and you should therefore get shot of your inhibitions and summon the courage to “deviate!” Perhaps we should back up a little. Early in the book, Lotto mentions a French scientist called Michel Chevreul who started working at the Gobelins textile factory in Paris in the 1820s. Chevreul had to deal with complaints about coloured yarns that seemed to fade after being woven into tapestries, and his patient chemical analyses did not get him anywhere. But then he shifted his attention from the science of dyestuffs to the psychology of perception, and he was on the way to a solution: colours, he discovered, change their appearance when looked at side by side. I needed respite from Lotto’s exclamation marks so I spent an afternoon in the British Library looking through a gorgeous old volume in which Chevreul expounded his “law of the simultaneous contrast of colours”. Chevreul began by showing how a black line has drastic effects on the appearance of adjacent colours, and how a red patch makes its surroundings look green. He then discussed the difference between colours in an object and colours in a painting, and offered suggestions about the design of picture frames and the use of colour in theatre; and he finished with wonderful planting plans for beds of multicoloured crocuses and dahlias. The book is itself an exuberant work of art, with tinted pages and fold-out arrays of coloured dots looking like prototypes of the spot paintings of Damien Hirst.

Related chapters from BN8e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 23526 - Posted: 04.24.2017

By Pascal Wallisch One of psychologist Robert Zajonc’s lasting contributions to science is the “mere exposure effect,” or the observation that people tend to like things if they are exposed to them more often. Much of advertising is based on this notion. But it was sorely tested in late February 2015, when “the dress” broke the internet. Within days, most people were utterly sick of seeing or talking about it. I can only assume that now, two years later, you have very limited interest in being here. (Thank you for being here.) But the phenomenon continues to be utterly fascinating to vision scientists like me, and for good reason. The very existence of “the dress” challenged our entire understanding of color vision. Up until early 2015, a close reading of the literature could suggest that the entire field had gone somewhat stale—we thought we basically knew how color vision worked, more or less. The dress upended that idea. No one had any idea why some people see “the dress” differently than others—we arguably still don’t fully understand it. It was like discovering a new continent. Plus, the stimulus first arose in the wild (in England, no less), making it all the more impressive. (Most other stimuli used by vision science are generally created in labs.) Even outside of vision scientists, most people just assume everyone sees the world in the same way. Which is why it’s awkward when disagreements arise—it suggests one party either is ignorant, is malicious, has an agenda, or is crazy. We believe what we see with our own eyes more than almost anything else, which may explain the feuds that occurred when “the dress” first struck and science lacked a clear explanation for what was happening.

Related chapters from BN8e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 23489 - Posted: 04.14.2017

By Erin Blakemore It’s scientific canard so old it’s practically cliché: When people lose their sight, other senses heighten to compensate. But are there really differences between the senses of blind and sighted people? It’s been hard to prove, until now. As George Dvorsky reports for Gizmodo, new research shows that blind people’s brains are structurally different than those of sighted people. In a new study published in the journal PLOS One, researchers reveal that the brains of people who are born blind or went blind in early childhood are wired differently than people born with their sight. The study is the first to look at both structural and functional differences between blind and sighted people. Researchers used MRI scanners to peer at the brains of 12 people born with “early profound blindness”—that is, people who were either born without sight or lost it by age three, reports Dvorsky. Then they compared the MRI images to images of the brains of 16 people who were born with sight and who had normal vision (either alone or with corrective help from glasses). The comparisons showed marked differences between the brains of those born with sight and those born without. Essentially, the brains of blind people appeared to be wired differently when it came to things like structure and connectivity. The researchers noticed enhanced connections between some areas of the brain, too—particularly the occipital and frontal cortex areas, which control working memory. There was decreased connectivity between some areas of the brain, as well.

Related chapters from BN8e: Chapter 10: Vision: From Eye to Brain; Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 7: Vision: From Eye to Brain; Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 23410 - Posted: 03.27.2017

Austin Frakt By middle age, the lenses in your eyes harden, becoming less flexible. Your eye muscles increasingly struggle to bend them to focus on this print. But a new form of training — brain retraining, really — may delay the inevitable age-related loss of close-range visual focus so that you won’t need reading glasses. Various studies say it works, though no treatment of any kind works for everybody. The increasing difficulty of reading small print that begins in middle age is called presbyopia, from the Greek words for “old man” and “eye.” It’s exceedingly common, and despite the Greek etymology, women experience it, too. Every five years, the average adult over 30 loses the ability to see another line on the eye reading charts used in eye doctors’ offices. By 45, presbyopia affects an estimated 83 percent of adults in North America. Over age 50, it’s nearly universal. It’s why my middle-aged friends are getting fitted for bifocals or graduated lenses. There are holdouts, of course, who view their cellphones and newspapers at arm’s length to make out the words. The decline in vision is inconvenient, but it’s also dangerous, causing falls and auto accidents. Bifocals or graduated lenses can help those with presbyopia read, but they also contribute to falls and accidents because they can impair contrast sensitivity (the ability to distinguish between shades of gray) and depth perception. I’m 45. I don’t need to correct my vision for presbyopia yet, but I can tell it’s coming. I can still read the The New York Times print edition with ease, but to read text in somewhat smaller fonts, I have to strain. Any year now, I figured my eye doctor would tell me it was time to talk about bifocals. Or so I thought. Then I undertook a monthslong, strenuous regimen designed to train my brain to correct for what my eye muscles no longer can manage. © 2017 The New York Times Company

Related chapters from BN8e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 23407 - Posted: 03.27.2017

By Chris Baraniuk It’s sometimes practically impossible to tell similar colours apart. Even side by side, they look the same. A special pair of spectacles gives us new power to see more distinct colours, and could one day help to spot counterfeit banknotes or counteract camouflage. The glasses, devised by a team at the University of Wisconsin-Madison, basically enhance the user’s colour vision, allowing them to see metamers – colours that look the same but give off different wavelengths of light – as recognisably distinct hues. Human colour vision relies on three types of cone cells that react to short (blue), medium (green) and long (red) wavelengths. While brushing up on his knowledge of the eye before teaching a photonics class, physicist Mikhail Kats had a brainwave. Could the eye be tricked into effectively having another type of cone cell? In theory, this could take our vision from being trichromatic, which uses three colour channels, to tetrachromatic. Some animals see in four (or more) channels. Goldfish, for example, have cells for red, blue, green and ultraviolet light. Some researchers suggest that a very small number of humans may be tetrachromats too. Read more: Human eye proteins detect red beyond red To make their glasses, Kats and his colleagues designed two colour filters, one for each eye that strip out specific parts of the blue light spectrum. With each eye receiving slightly different spectral information about blue things, the team hypothesised that any subtle differences in colour would be more pronounced. And they were right. © Copyright Reed Business Information Ltd

Related chapters from BN8e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 23381 - Posted: 03.21.2017

By DENISE GRADY Three women suffered severe, permanent eye damage after stem cells were injected into their eyes, in an unproven treatment at a loosely regulated clinic in Florida, doctors reported in an article published Wednesday in The New England Journal of Medicine. One, 72, went completely blind from the injections, and the others, 78 and 88, lost much of their eyesight. Before the procedure, all had some visual impairment but could see well enough to drive. The cases expose gaps in the ability of government health agencies to protect consumers from unproven treatments offered by entrepreneurs who promote the supposed healing power of stem cells. The women had macular degeneration, an eye disease that causes vision loss, and they paid $5,000 each to receive stem-cell injections in 2015 at a private clinic in Sunrise, Fla. The clinic was part of a company then called Bioheart, now called U.S. Stem Cell. Staff members there used liposuction to suck fat out of the women’s bellies, and then extracted stem cells from the fat to inject into the women’s eyes. The disastrous results were described in detail in the journal article, by doctors who were not connected to U.S. Stem Cell and treated the patients within days of the injections. An accompanying article by scientists from the Food and Drug Administration warned that stem cells from fat “are being used in practice on the basis of minimal clinical evidence of safety or efficacy, sometimes with the claims that they constitute revolutionary treatments for various conditions.” © 2017 The New York Times Company

Related chapters from BN8e: 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: 23365 - Posted: 03.16.2017