By Carl Yapp John and Sue Day jokingly refer to themselves as the "shakers". It is the physical sign that is one of the most recognisable symptoms of Parkinson's disease. But they can now add "incredibly rare" to their nickname, because according to experts they are one of only a handful of married couples who both have the condition. Parkinson's attacks the part of the brain that controls our movements, and affects activities we take for granted, such as talking, walking, swallowing and writing. Repetitive shaking, known to sufferers as tremors, slowness of movement, muscle stiffness, insomnia and lethargy are just some of the symptoms. In recent years awareness has increased about Parkinson's as a result of the likes of boxing legend Muhammad Ali and Hollywood actor Michael J Fox both acquiring the condition. Mr and Mrs Day, who have three grown-up children, and are from the Powys village of Bwlch y Fridd, near Newtown, have lived with Parkinson's for the past few years. They have learned to cope with it, and they say humour is one way of dealing with the debilitating effects. But it hasn't been easy and humour was the last thing on Mr Day's mind when he was diagnosed in 2005, three years after his wife. Unlike most people confronted with a disease, Mr Day, 59, knew some of the symptoms as not only his wife had the illness, but his brother, and his father before his death. "We've heard of brothers and sisters, but not husband and wife. It's very unusual for husband and wife to have it," he said. "I think people think shaking is the only symptom really and don't realise the fatigue that comes with it and the other things - stiffness of joints and things like that." Mrs Day, 63, said: "There's also your facial expressions. You don't express emotions - smiling, anger, things like that because the muscles don't respond." (C)BBC

Keyword: Parkinsons
Link ID: 12392 - Posted: 12.29.2008

By Nicole Branan, Melinda Wenner, Rachel Mahan and David Dobbs In the sci-fi movie Minority Report “Precrime” police units stop murders before they happen by relying on the visions of people who can see the future. Clairvoyants who possess precognition will likely remain fiction. But the idea of preventing individuals from committing crimes may be on the threshold of becoming reality, according to Northeastern University criminologist Nicole Rafter. Recent scientific advances, such as the decoding of the human genome and, growing out of that, studies that examine gene-environment interactions, have opened new avenues to explore the biological bases of character traits, including the propensity to commit crimes. As a result, Rafter says, criminologists are now shifting their attention toward biological reasons for delinquent behavior after decades of trying to define crime mainly on the basis of sociological factors. In The Criminal Brain, Rafter warns of the potentially dangerous consequences of this trend: “We already have genetically modified crops; maybe gene policing and genetically modified criminals are not far behind.” Whether we will head toward such a brave new world scenario, however, depends on how specialists and the general public evaluate research and policy in the booming field of biocriminology, she explains. Rafter provides the tools to do just that. The book takes readers on a fascinating journey through the history of criminology and details where the field stands today. Even though we still do not know what exactly a “criminal brain” is, current research suggests that some people are more genetically predisposed to offend than others, Rafter says. Still, “no one is destined to commit crime,” because environmental factors also play a role, even for those who are most at risk. © 1996-2008 Scientific American Inc.

Keyword: Aggression; Genes & Behavior
Link ID: 12391 - Posted: 06.24.2010

The facial expressions we make to show or hide our emotions are hardwired into our brains rather than learned during life, a study has concluded. Blind and sighted athletes made the same expressions when they won and lost, US researchers found. This, the study reported in the Journal of Personality and Social Psychology study suggests, meant the expressions were not picked up by watching others. The researchers believe they could be remnants of evolutionary history. The idea that facial expressions are in-built is not new - scientists have suggested it since the 1960s. However, the study at San Francisco State University provides some of the strongest evidence yet to support it. Professor David Matsumoto and his team compared 4,800 photographs, capturing the expressions of sighted and blind judo athletes at medal ceremonies at the 2004 Olympic and Paralympic Games. In each case, the faces of gold and silver medal winning athletes were scrutinised. While the winners frequently showed genuine joy at their victory, those in the lesser medal positions often produced "social smiles" - smiles involving only mouth movement, indicating that they may be artificial rather than spontaneous. The researchers concluded that sighted and blind competitors showed or controlled their expressions in exactly the same way. Professor Matsumoto said: "The statistical correlation between the facial expressions of sighted and blind individuals was almost perfect. A sighted athlete shows a very similar expression after losing "This suggests something genetically resident within us is the source of facial expressions of emotion. "Losers pushed their lower lip up as if to control the emotion on their face and many produced social smiles - individuals blind from birth could not have learned to control their emotions in this way through visual learning, so there must be another mechanism. (C)BBC

Keyword: Emotions; Evolution
Link ID: 12390 - Posted: 12.29.2008

By Rob Stein Teenagers who pledge to remain virgins until marriage are just as likely to have premarital sex as those who do not promise abstinence and are significantly less likely to use condoms and other forms of birth control when they do, according to a study released today. The new analysis of data from a large federal survey found that more than half of youths became sexually active before marriage regardless of whether they had taken a "virginity pledge," but that the percentage who took precautions against pregnancy or sexually transmitted diseases was 10 points lower for pledgers than for non-pledgers. "Taking a pledge doesn't seem to make any difference at all in any sexual behavior," said Janet E. Rosenbaum of the Johns Hopkins Bloomberg School of Public Health, whose report appears in the January issue of the journal Pediatrics. "But it does seem to make a difference in condom use and other forms of birth control that is quite striking." The study is the latest in a series that have raised questions about programs that focus on encouraging abstinence until marriage, including those that specifically ask students to publicly declare their intention to remain virgins. The new analysis, however, goes beyond earlier analyses by focusing on teens who had similar values about sex and other issues before they took a virginity pledge. © 2008 The Washington Post Company

Keyword: Sexual Behavior
Link ID: 12389 - Posted: 06.24.2010

Rogue immune cells entering the brain may contribute to the development of Parkinson's disease, say scientists. A French study in diseased mice revealed the cells accumulating in brain tissue, and mice bred to lack them did not fall ill as quickly. The researchers suggested that the cells could be targeted using drugs. A UK charity said the findings, published in the Journal of Clinical Investigation, did not yet prove that this approach would work. About 120,000 people in the UK have Parkinson's disease, a progressive brain condition which causes symptoms such as tremor and difficulty moving. This is caused by the death of nerve cells which produce the chemical dopamine, which helps coordinate movements. Previous research had suggested a link between inflammation in the brain and the condition, pointing the finger at one of the body's own immune responses. The researchers from the INSERM institute in Paris looked for the presence of a particular type of immune cell called a "T-cell" in the brain tissues directly affected by Parkinson's. They found the cells gathering both in human brain samples taken from Parkinson's patients after death, and at an earlier stage in mice bred to develop the disease. When mice lacking these immune cells were studied, the rate of nerve cell death was significantly slower. The researchers said that this was enough evidence to start considering the possibility of using drugs to reduce this kind of immune response in patients with Parkinson's, in the hope that this might slow the progress of the disease. (C)BBC

Keyword: Parkinsons; Neuroimmunology
Link ID: 12388 - Posted: 12.29.2008

A strong cup of coffee has a greater effect on men than women, research shows. In a study on 668 healthy volunteers, an espresso pepped up men after just 10 minutes. Women also became more alert after the beverage, but less so. The University of Barcelona researchers say some of this effect might be psychological because decaffeinated coffee also worked to some extent. Progress in Neuro-Psychopharmacology & Biological Psychiatry reports the work. The volunteers were asked to drink either a classic espresso containing 100mg of caffeine or a decaffeinated espresso containing 5mg of caffeine. Then the researchers looked for changes in alertness over the following minutes and hours. Both men and women saw an improvement in their activity levels after drinking the classic espresso and these effects began after as little as 10 minutes. According to the investigators, 45 minutes is the time needed for maximum caffeine concentration to be reached in the blood, but levels reach half this concentration after just a few minutes. And the effect appeared to be greater in the men. The decaf coffee had a similar, but weaker effect and tended to be more potent in the women rather than in the men. Lead researcher Ana Adan said: "Numerous studies have demonstrated the stimulant effects of caffeine, but none of these have looked at their effects in terms of the consumer's gender." Anna Denny of the British Nutrition Foundation said: "This study provides an interesting insight into how the effects of specific foods and nutrients may differ between men and women. Research into 'gene-nutrient' interactions is moving forward quickly and we are finding out more about how our genetic make-up affects our requirements for certain foods and nutrients, and how our bodies react to these." (C)BBC

Keyword: Drug Abuse; Sexual Behavior
Link ID: 12387 - Posted: 12.25.2008

Scientists have found that when the brain is slowly starved of glucose over time, some forms of Alzheimer's disease may result. Researchers used human and mice brains to study how a reduction in blood flow deprives the brain of energy. The chronic starvation eventually leads to sticky clumps of a protein linked to Alzheimer's, the leading cause of dementia in the elderly, they found. "This finding is significant because it suggests that improving blood flow to the brain might be an effective therapeutic approach to prevent or treat Alzheimer's," said the study's lead author, Robert Vassar, a professor of cell and molecular biology at Northwestern University in Chicago. It's possible that preventive strategies such as getting exercise, reducing cholesterol and managing blood pressure could help prevent Alzheimer's by improving blood flow to the brain. "If people start early enough, maybe they can dodge the bullet," Vassar added in a release. In the Dec. 26 issue of the journal Neuron, Vassar and his colleagues said they discovered a protein called elF2alpha that is changed when the brain fails to get enough energy in the form of glucose. © CBC 2008

Keyword: Alzheimers
Link ID: 12386 - Posted: 06.24.2010

By Paul Patton We were talking about politics. My housemate, an English professor, opined that certain politicians were thinking with their reptilian brains when they threatened military action against Iran. Many people believe that a component of the human brain inherited from reptilian ancestors is responsible for our species’ aggression, ritual behaviors and territoriality. One of the most common misconceptions about brain evolution is that it represents a linear process culminating in the amazing cognitive powers of humans, with the brains of other modern species representing previous stages. Such ideas have even influenced the thinking of neuroscientists and psychologists who compare the brains of different species used in biomedical research. Over the past 30 years, however, research in comparative neuroanatomy clearly has shown that complex brains—and sophisticated cognition—have evolved from simpler brains multiple times independently in separate lineages, or evolutionarily related groups: in mollusks such as octopuses, squid and cuttlefish; in bony fishes such as goldfish and, separately again, in cartilaginous fishes such as sharks and manta rays; and in reptiles and birds. Nonmammals have demonstrated advanced abilities such as learning by copying the behavior of others, finding their way in complicated spatial environments, manufacturing and using tools, and even conducting mental time travel (remembering specific past episodes or anticipating unique future events). Collectively, these findings are helping scientists to understand how intelligence can arise—and to appreciate the many forms it can take. © 1996-2008 Scientific American Inc.

Keyword: Evolution; Intelligence
Link ID: 12385 - Posted: 06.24.2010

by Andy Coghlan Are gay people hard-wired that way? Rooting around in the brain is an obvious way to tackle this provocative question, but it has been fraught with difficulty. A 1990s study seemed to show that the brains of gay men were more like those of women than men, but the science was questioned in the ensuing furore. This June, controversial brain scans gave us probably the best evidence yet that our brains are hard-wired before birth to be gay or straight, suggesting that nature not nurture governs sexual orientation. The startling study by Ivanka Savic and Per Lindström of the Karolinska Institute in Stockholm, Sweden, showed that lesbians have asymmetric brains like straight men, while gay men have symmetric brains like straight women. So far, so clinical. But sexuality is as much about emotions as it is about biology. Enter the amygdala, the area of the brain that governs our every emotion, especially fear and anxiety. The amygdala of straight women and gay men connects mainly to areas of the brain that manifest fear as anxiety. In straight men and gay women though, the amygdala connects more to areas that trigger a fight-or-flight response. So if we are hard-wired to be gay or straight, how could that arise? Perhaps our brains get too much or too little of a crucial hormone in the womb. Or maybe the answer lies in our genes. Gay and bisexual men, for example, often have unusually fertile female relatives - this could be how "gay genes" get passed on, even though few gay men have babies themselves. © Copyright Reed Business Information Ltd

Keyword: Sexual Behavior
Link ID: 12384 - Posted: 06.24.2010

Just one extra hour of sleep a day appears to lower the risk of developing calcium deposits in the arteries, a precursor to heart disease, US researchers said on Tuesday. The finding adds to a growing list of health consequences - including weight gain, diabetes and high blood pressure - linked to getting too little sleep. "We found that people who on average slept longer were at reduced risk of developing new coronary artery calcifications over five years," said Diane Lauderdale of the University of Chicago Medical Center, whose study appears in the Journal of the American Medical Association. "It was surprisingly strong," Lauderdale said. Calcium deposits in the coronary arteries are considered a precursor of future heart disease. "It's a very early marker of future risk," she said. Unlike other studies looking at the risks of getting too little sleep, which use people's own estimates of their sleep patterns, Lauderdale's team set out to measure actual sleep patterns. They fitted 495 people aged 35 to 47 with sophisticated wrist bands that tracked subtle body movements. Information from these recorders was fed into a computer program that was able to detect actual sleep patterns. The team used special computed tomography, or CT, scans to assess the buildup of calcium inside heart arteries, performing one scan at the start of the study and one five years later. © Copyright Reed Business Information Ltd

Keyword: Sleep
Link ID: 12383 - Posted: 06.24.2010

By Rachel Zelkowitz Talk about Dr. Jekyll and Mr. Hyde. Misfolded proteins known as prions cause mad cow disease and other fatal neurodegenerative illnesses. But in their properly folded form, the proteins may be important to survival, helping mice and other animals keep their sniffing skills sharp, new research shows. Prions get the bad reputation--and the lion's share of research attention--but interest in the normal form of prion proteins is increasing. Brain tissue is particularly high in these proteins, and a growing body of research has shown that they help neurons conduct copper and may even protect them from destruction by rogue chemicals in the body. But no one had pegged prion proteins to a particular neurological function such as sight or smell. That's changed, thanks to an intriguing finding by electrophysiologist Stuart Firestein of Columbia University. Firestein and colleagues were studying the sense of smell in mice when they noticed high levels of normal prion protein (PrPc) in the cells that make up the animals' olfactory systems. Wondering whether the protein might play a role in this sense, the researchers hid bits of peanut butter cookies in the shredded bedding of a cage. They then timed how long it took both normal mice and rodents genetically engineered to not make PrPc to sniff out the snack. Normal mice spent an average of 73 seconds searching for the treat before they found it, three times faster than their PrPc-free counterparts. Six of the 20 PrPc-free mice never found the cookie at all, the team reports this week in Nature Neuroscience. © 2008 American Association for the Advancement of Science.

Keyword: Prions; Chemical Senses (Smell & Taste)
Link ID: 12382 - Posted: 06.24.2010

by Jessica Griggs The deep sea is full of surprises, and the four-eyed spookfish is up there with the best of them. It is the first vertebrate found with eyes that use mirrors, rather than a lens, to focus light. In clear water, sunlight can penetrate to a depth of 1000 metres, so some deep-sea fish have developed tubular, upward-looking eyes. "It is like having a telescope on your head that points towards the surface," says Ron Douglas from City University London. However, sunlight is only part of the story. The most important source of light at that depth is other creatures, as 80% emit their own light, called bioluminescence. The unusual spookfish was caught in the deep waters between Samoa and New Zealand, but no one on the research boat knew what it was. "It caught my attention because it looked like it had four eyes, and vertebrates with four eyes don't exist," says Douglas. It turns out that the spookfish (Dolichopteryx longipes) actually has just two eyes, but each eye has two parts, one looking upwards and the other down. The team found that the part looking down uses thousands of tiny reflective crystals – acting like mirrors – that are angled in slightly different directions to focus light onto the retina. This is completely different to a typical fish eye, which uses a single lens to bend light onto a focal point, similar to the way the human eye works. © Copyright Reed Business Information Ltd

Keyword: Vision; Evolution
Link ID: 12381 - Posted: 06.24.2010

By Nathan Seppa People who kick and lash out while fast asleep in bed face a high risk of developing Parkinson’s disease and certain forms of dementia, scientists report online December 24 in Neurology. The condition, called rapid-eye-movement sleep behavior disorder, results when a person’s muscles fail to relax during sleep. “During REM sleep, with the most vivid dreaming, mostly we’re paralyzed,” says neurologist Ronald Postuma of McGill University in Montreal. “The brain shuts off muscle tone. We want to run but we can’t.” But in people with REM sleep behavior disorder, muscle tone isn’t shut down. “As a consequence, you act out your dreams,” he says. People with the condition have been known to break a hand on a wall, hurt a spouse or fall out of bed, he says. Postuma and his colleagues have monitored the progress of 93 people who were diagnosed with REM sleep behavior disorder between 1989 and 2006 at Sacré Coeur Hospital, also in Montreal. The team followed some patients for 15 years or more. Roughly 80 percent are men, and most were enrolled while in their 60s. Of the 93 participants, 26 have developed a neurodegenerative disease during the study years. Of these, 14 developed Parkinson’s disease, and seven developed Lewy body dementia, which is marked by the appearance of Lewy bodies — abnormal protein deposits — in the brain. Four other study participants were diagnosed with Alzheimer’s disease, but the researchers suspect that these patients might actually have Lewy body dementia. One person developed a less common neurodegenerative condition called multiple system atrophy. © Society for Science & the Public 2000 - 2008

Keyword: Parkinsons; Sleep
Link ID: 12380 - Posted: 06.24.2010

Experiments in rats may have revealed why some painkilling drugs are less effective in women compared with men. US researchers found brain differences affecting the potency of opioids such as morphine. The Journal of Neuroscience study also found drug effectiveness varied during the rats' menstrual cycles. Another expert said it showed the growing importance of tailoring pain relief to match the individual needs of the patient. Morphine remains one of the most widely used drugs to alleviate severe persistent pain and doctors have noticed that it frequently does not work as well in women. However, the study from Georgia State University claims to be the first to pinpoint the reason why. It looked closely at a tiny area of the brain called the periaqueductal grey area (PAG), which is important in the way that pain signals are interpreted. Many neurons in this region have, on their surface, "receptors" designed to receive and lock onto the molecules found in opioid drugs. These "mu-opioid receptors", when locked onto an opioid drug, send a message telling the brain to stop responding to pain signals, reducing the sensation of pain. The Georgia State team found that, in the rat brain, females had a lower level of mu-opioid receptors in this part of the brain, suggesting that the potential potency of morphine is much reduced. Additional tests suggested that the response to morphine varied depending on which part of the menstrual cycle the female rat was in. Professor Anne Murphy, who led the research, said: "It is increasingly clear that morphine is significantly less potent in women compared with men - until now, the mechanism driving the phenomenon was unknown. "Additional research with the inclusion of female subjects needs to be devoted to determining a more potent treatment for persistent pain in women." (C)BBC

Keyword: Pain & Touch; Sexual Behavior
Link ID: 12379 - Posted: 12.25.2008

CHICAGO - U.S. scientists have created the first human model for studying a devastating nerve disease, which allows them to watch how the disease develops and could help researchers find a way to treat it. Using skin cells from a child with spinal muscular atrophy, a genetic disease that attacks motor neurons in the spinal cord, researchers grew batches of nerve cells with the same genetic defects. The finding allowed scientists to watch the nerve cells die off. "Now we can start from the beginning of development and replay the disease process in the lab dish," Clive Svendsen of the University of Wisconsin-Madison said in a telephone interview. The finding, reported on Sunday in the journal Nature, marks the latest advance in research that reprograms ordinary cells to look and act like embryonic stem cells — the master cells of the body that can produce any type of tissue or blood cell. Spinal muscular atrophy is the most common cause of childhood death caused by a genetic mutation, Svendsen said. It is caused by a deficiency of a protein called SMN, for survival of motor neurons. "That SMN protein is important for motor neuron survival. They are the cells that make muscles move," Svendsen said. Copyright 2008 Reuters.

Keyword: Movement Disorders; Genes & Behavior
Link ID: 12378 - Posted: 06.24.2010

By Amelia Tomas Spiders are bizarre sex freaks. But it’s all harmless fun ... no wait, actually it’s very harmful. Girl kills guy or guy kills girl — there’s shrill crying, plugged orifices, torn-off genitals, eaten body parts, and psychedelic rituals. And you thought humans had crazy sex lives? Mounting evidence in recent years shows just how crazy spider sex is. For example, in the case of redback spiders (Latrodectus hasselti), courtship tends to last an average of 50 minutes when males are competing head-to-head for mating rights and 4.5 hours for single, non-competing males. It seems as if the larger male redbacks would always be favored, but scientists recently discovered that the smaller ones actually get more action than their bigger counterparts because they mature faster and are quicker on their feet. Meanwhile, mature jumping spiders sport crucial glowing patches on their bodies to lure in mates, as if dressed for a rave. The males exhibit UV-reflecting scales that glow in bright white and green, and the females’ have front appendages that similarly glow in a bright green hue. Turns out, females and males will ignore each other if not seen under full-spectrum light, suggesting that both partners must show their glowing bodies to prove their health before courtship can proceed. © 2008 LiveScience.com.

Keyword: Sexual Behavior
Link ID: 12377 - Posted: 06.24.2010

By MARC E. AGRONIN, M.D. The forest still stands, but the people are gone. Only a stone memorial guards their place, surrounded by tall grasses that hide bits of ash and bone deep beneath their roots. On this spot on Feb. 4, 1942, more than 920 Jewish men, women and children from the town of Rakov in what is now Belarus were rounded up by the Nazis and herded into the synagogue. Several shrieking children were stabbed with bayonets and thrown over the heads of the weeping Jews just before the doors and windows were sealed and the building was doused with kerosene. An unspeakable scene of wailing ensued as the once vibrant Jewish community was annihilated in the fire. My patient, now 98, still weeps when he describes witnessing this horror from a hidden perch in a tree. He gasps audibly when he recalls watching his father being pummeled by a Nazi soldier before he was thrust into the doomed crowd. When this survivor first told me his story, I was speechless. He held tight to my arm, and I imagined myself as the branches of the tree that supported him during this trauma. I was now a witness. As his psychiatrist I am obliged to ease his suffering, but no medicine of mine can touch such a memory. I have tried hard to understand how he and others managed to mentally survive such traumatic experiences. These aging Holocaust survivors, in particular, have taught me what I have come to call “lessons from fire.” Copyright 2008 The New York Times Company

Keyword: Learning & Memory; Stress
Link ID: 12376 - Posted: 06.24.2010

By NATALIE ANGIER When considering the behavior of putative scam operators like Bernard “Ponzi scheme” Madoff or Rod “Potty Mouth” Blagojevich, feel free to express a sense of outrage, indignation, disgust, despair, amusement, schadenfreude. But surprise? Don’t make me laugh. Sure, Mr. Madoff may have bilked his clients of $50 billion, and Governor Blagojevich, of Illinois, stands accused of seeking personal gain through the illicit sale of public property — a United States Senate seat. Yet while the scale of their maneuvers may have been exceptional, their apparent willingness to lie, cheat, bluff and deceive most emphatically was not. Deceitful behavior has a long and storied history in the evolution of social life, and the more sophisticated the animal, it seems, the more commonplace the con games, the more cunning their contours. In a comparative survey of primate behavior, Richard Byrne and Nadia Corp of the University of St. Andrews in Scotland found a direct relationship between sneakiness and brain size. The larger the average volume of a primate species’ neocortex — the newest, “highest” region of the brain — the greater the chance that the monkey or ape would pull a stunt like this one described in The New Scientist: a young baboon being chased by an enraged mother intent on punishment suddenly stopped in midpursuit, stood up and began scanning the horizon intently, an act that conveniently distracted the entire baboon troop into preparing for nonexistent intruders. Copyright 2008 The New York Times Company

Keyword: Emotions; Evolution
Link ID: 12375 - Posted: 06.24.2010

By Moheb Costandi The body image is a mental representation of one's physical appearance, constructed by the brain from past experiences and present sensations. It is an essential component of self-identity, which, when altered, can have dramatic effects on how one perceives oneself. For example, a small proportion of migraine sufferers experience visual hallucinations just before the onset of a headache, in which the body parts appear larger or smaller than they actually are. Lewis Carroll, who is known to have suffered from migraines, documented such hallucinations in Alice in Wonderland.

 These body image distortions can have bizarre consequences. Otherwise healthy people report that they have always percived a part of their body as feeling "wrong," and opt to have it removed by amputation; some brain-damaged or psychiatric patients experience alien hand syndrome, in which they deny ownership of a limb, and insist that it is under the control of external forces. Our perception of our own body can, of course, be easily manipulated. As we walk through a house of mirrors at a fair, for example, we may view ourselves as being very short and fat one minute, and then very tall and thin the next. By looking through a pair of binoculars, a limb can be made to appear disproportionately large or small. © 1996-2008 Scientific American Inc.

Keyword: Pain & Touch
Link ID: 12374 - Posted: 06.24.2010

by Justin Mullins The number of people suffering seriously impaired vision due to damaged retinas is increasing in the developed world, as populations age and diabetes becomes more common. The search for a technological solution to the problem has led to growing interest in "bionic eyes". Devices developed so far have usually involved installing a silicon chip into the eye to electrically stimulate the retina's nerves in response to light. Some impressive results have been achieved in this way, but implanted chips do have drawbacks. Their relatively large size means they block light that would have fallen on healthy parts of the retina and they can also cause tissue damage, such as tearing. So Jeffrey Olsen at the University of Colorado Hospital has come up with another method entirely – amplifying the light that reaches the retina using the eye's still functioning light-sensitive cells. Light amplification could be achieved by implanting quantum dots – nanoscale specks of semiconductor – into the retina, he says. These fluoresce when hit by photons and would have the effect of making any received retinal image brighter. © Copyright Reed Business Information Ltd.

Keyword: Vision; Robotics
Link ID: 12373 - Posted: 06.24.2010