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Carl Zimmer Octopuses, squid and cuttlefish — a group of mollusks known as cephalopods — are the ocean’s champions of camouflage. Octopuses can mimic the color and texture of a rock or a piece of coral. Squid can give their skin a glittering sheen to match the water they are swimming in. Cuttlefish will even cloak themselves in black and white squares should a devious scientist put a checkerboard in their aquarium. Cephalopods can perform these spectacles thanks to a dense fabric of specialized cells in their skin. But before a cephalopod can take on a new disguise, it needs to perceive the background that it is going to blend into. Cephalopods have large, powerful eyes to take in their surroundings. But two new studies in The Journal Experimental Biology suggest that they have another way to perceive light: their skin. It’s possible that these animals have, in effect, evolved a body-wide eye. When light enters the eye of a cephalopod, it strikes molecules in the retina called opsins. The collision starts a biochemical reaction that sends an electric signal from the cephalopod’s eye to its brain. (We produce a related form of opsins in our eyes as well.) In 2010, Roger T. Hanlon, a biologist at the Marine Biological Laboratory in Woods Hole, Mass., and his colleagues reported that cuttlefish make opsins in their skin, as well. This discovery raised the tantalizing possibility that the animals could use their skin to sense light much as their eyes do. Dr. Hanlon teamed up with Thomas W. Cronin, a visual ecologist at the University of Maryland Baltimore County, and his colleagues to take a closer look. © 2015 The New York Times Company

Keyword: Vision; Evolution
Link ID: 20966 - Posted: 05.21.2015

Athletes who lose consciousness after concussions may be at greater risk for memory loss later in life, a small study of retired National Football League players suggests. Researchers compared memory tests and brain scans for former NFL players and a control group of people who didn't play college or pro football. After concussions that resulted in lost consciousness, the football players were more likely to have mild cognitive impairment and brain atrophy years later. "Our results do suggest that players with a history of concussion with a loss of consciousness may be at greater risk for cognitive problems later in life," senior study author Munro Cullum, chief of neuropsychology at the University of Texas Southwestern Medical Center in Dallas, said by email. "We are at the early stages of understanding who is actually at risk at the individual level." Cullum and colleagues recruited 28 retired NFL players living in Texas: eight who were diagnosed with mild cognitive impairment and 20 who didn't appear to have any memory problems. They ranged in age from 36 to 79, and were an average of about 58 years old. All but three former athletes experienced at least one concussion, and they typically had more than three. Researchers compared these men to 27 people who didn't play football but were similar in age, education, and mental capacity to the retired athletes, including six with cognitive impairment. These men were 41 to 77 years old, and about 59 on average. ©2015 CBC/Radio-Canada

Keyword: Brain Injury/Concussion; Learning & Memory
Link ID: 20965 - Posted: 05.21.2015

Scientists at Mayo Clinic, Jacksonville, Florida created a novel mouse that exhibits the symptoms and neurodegeneration associated with the most common genetic forms of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS, Lou Gehrig’s disease), both of which are caused by a mutation in the a gene called C9ORF72. The study was partially funded by the National Institutes of Health and published in the journal Science. More than 30,000 Americans live with ALS, which destroys nerves that control essential movements, including speaking, walking, breathing and swallowing. After Alzheimer’s disease, FTD is the most common form of early onset dementia. It is characterized by changes in personality, behavior and language due to loss of neurons in the brain’s frontal and temporal lobes. Patients with mutations in the chromosome 9 open reading frame 72 (C9ORF72) gene have all or some symptoms associated with both disorders. “Our mouse model exhibits the pathologies and symptoms of ALS and FTD seen in patients with theC9ORF72 mutation,” said the study’s lead author, Leonard Petrucelli, Ph.D., chair and Ralph and Ruth Abrams Professor of the Department of Neuroscience at Mayo Clinic, and a senior author of the study. “These mice could greatly improve our understanding of ALS and FTD and hasten the development of effective treatments.” To create the model, Ms. Jeannie Chew, a Mayo Graduate School student and member of Dr. Petrucelli’s team, injected the brains of newborn mice with a disease-causing version of the C9ORF72 gene. As the mice aged, they became hyperactive, anxious, and antisocial, in addition to having problems with movement that mirrored patient symptoms.

Keyword: ALS-Lou Gehrig's Disease ; Alzheimers
Link ID: 20964 - Posted: 05.21.2015

By SINDYA N. BHANOO Male Java sparrows are songbirds — and, scientists reported on Wednesday, natural percussionists. The sparrows click their bills against a hard surface while singing. That clicking is done in coordination with the song, much as a percussion instrument accompanies a melody. Researchers at Hokkaido University in Japan observed the birds producing clicks frequently toward the beginning of their songs and around specific notes. Birds that were related produced similar percussive patterns, but whether this behavior is learned or innate is unclear. Next the scientists, who described their findings on Wednesday in the journal PLOS One, would like to know whether male sparrows use bill clicks during courtship communication. © 2015 The New York Times Company

Keyword: Sexual Behavior; Hearing
Link ID: 20963 - Posted: 05.21.2015

by Karl Gruber "As clever as a guppy" is not a huge compliment. But intelligence does matter to these tropical fish: big-brained guppies are more likely to outwit predators and live longer than their dim-witted peers. Alexander Kotrschal at Stockholm University, Sweden, and his colleagues bred guppies (Poecilia reticulata) to have brains that were bigger or smaller than average. His team previously showed that bigger brains meant smarter fish. When put in an experimental stream with predators, big-brained females were eaten about 13 per cent less often than small-brained ones. There was no such link in males, and the researchers suspect that their bright colours may counter any benefits of higher intelligence. They did find, Kotrschal says , that large-brained males were faster swimmers and better at learning and remembering the location of a female. "This is exciting because it confirms a critical mechanism for brain size evolution," says Kotrschal. It shows, he adds, that interactions between predator and prey can affect brain size. It might seem obvious that bigger brains would help survival. Yet previous research simply found a correlation between the two, leaving the possibility open that some third factor may have been driving the effect. Now, direct brain size manipulation allowed Kotrschal's team to pin it down as a cause of better survival. "This is the first time anyone has tested whether a larger brain confers a survival benefit," says Kotrschal. "The fact that large-brained females survived better in a naturalistic setting is the first experimental proof that a larger brain is beneficial for the fitness of its bearer. This is like watching evolution happen and shows how brain size evolves." © Copyright Reed Business Information Ltd.

Keyword: Intelligence; Evolution
Link ID: 20962 - Posted: 05.21.2015

Stacey Vanek Smith I'm in a booth with a computer program called Ellie. She's on a screen in front of me. Ellie was designed to diagnose post-traumatic stress disorder and depression, and when I get into the booth she starts asking me questions — about my family, my feelings, my biggest regrets. Emotions seem really messy and hard for a machine to understand. But Skip Rizzo, a psychologist who helped design Ellie, thought otherwise. When I answer Ellie's questions, she listens. But she doesn't process the words I'm saying. She analyzes my tone. A camera tracks every detail of my facial expressions. The doctor may see you now "Contrary to popular belief, depressed people smile as many times as non-depressed people," Rizzo says. "But their smiles are less robust and of less duration. It's almost like polite smiles rather than real, robust, coming from your inner-soul type of a smile." Ellie compares my smile to a database of soldiers who have returned from combat. Is my smile genuine? Is it forced? Ellie also listens for pauses. She watches to see whether I look off to the side or down. If I lean forward, she notices. All this analysis seems to work: In studies, Ellie could detect signs of PTSD and depression about as well as a large pool of psychologists. Jody Mitic served with the Canadian forces in Afghanistan. He lost both of his feet to a bomb. And Mitic remembers that Ellie's robot-ness helped him open up. "Ellie seemed to just be listening," Mitic says. "A lot of therapists, you can see it in their eyes, when you start talking about some of the grislier details of stuff that you might have seen or done, they are having a reaction." © 2015 NPR

Keyword: Depression; Robotics
Link ID: 20961 - Posted: 05.21.2015

Dan Sung A 10-year study has revealed a startling link between high levels of anxiety and an increased risk of death from liver disease. The research, carried out by scientists at the University of Edinburgh, took account for obvious sociological and physiological factors such as alcohol consumption, obesity, diabetes and class, but still the data pointed to a clear relationship between the psychological conditions of stress and depression and the physical health of the hepatic system. There were over 165,000 participants surveyed for mental distress. They were each tracked for over a decade during which time the causes of death for those who passed on were recorded and categorised. What was found was that those who’d scored highly for signs of depression and stress were far more likely to suffer fatal liver disease. “This study provides further evidence for the important links between mind and body, and of the damaging effects psychological distress can have on physical wellbeing,” said Dr Tom Russ of the Centre for Clinical Brain Sciences. The work did not uncover any reasons for direct cause and effect but is the first to identify such a link between mental states and liver damage. Previous research has described how psychological conditions can lead to increased risk of cardiovascular disease which, in turn, may develop into obesity, raised blood pressure and then eventually to liver failure but, with this methodology controlling for such factors, it appears that the link is more direct than was previously thought.

Keyword: Depression; Stress
Link ID: 20960 - Posted: 05.20.2015

by Bas den Hond Watch your language. Words mean different things to different people – so the brainwaves they provoke could be a way to identify you. Blair Armstrong of the Basque Center on Cognition, Brain, and Language in Spain and his team recorded the brain signals of 45 volunteers as they read a list of 75 acronyms – such as FBI or DVD – then used computer programs to spot differences between individuals. The participants' responses varied enough that the programs could identify the volunteers with about 94 per cent accuracy when the experiment was repeated. The results hint that such brainwaves could be a way for security systems to verify individuals' identity. While the 94 per cent accuracy seen in this experiment would not be secure enough to guard, for example, a room or computer full of secrets, Armstrong says it's a promising start. Techniques for identifying people based on the electrical signals in their brain have been developed before. A desirable advantage of such techniques is that they could be used to verify someone's identity continuously, whereas passwords or fingerprints only provide a tool for one-off identification. Continuous verification – by face or ear recognition, or perhaps by monitoring brain activity – could in theory allow someone to interact with many computer systems simultaneously, or even with a variety of intelligent objects, without having to repeatedly enter passwords for each device. © Copyright Reed Business Information Ltd

Keyword: Language; Brain imaging
Link ID: 20959 - Posted: 05.20.2015

By Susan Cosier Once a memory is lost, is it gone forever? Most research points to yes. Yet a study published in the online journal eLife now suggests that traces of a lost memory might remain in a cell's nucleus, perhaps enabling future recall or at least the easy formation of a new, related memory. The current theory accepted by neurobiologists is that long-term memories live at synapses, which are the spaces where impulses pass from one nerve cell to another. Lasting memories are dependent on a strong network of such neural connections; memories weaken or fade if the synapses degrade. In the new study, researchers at the University of California, Los Angeles, studied sea slugs' neurons in a cell culture dish. Over several days the neurons spontaneously formed a number of synapses. The scientists then administered the neurotransmitter serotonin to the neurons, causing them to create many more synapses—the same process by which a living creature would form a long-term memory. When they inhibited a memory-forming enzyme and checked the neurons after 48 hours, the number of synapses had returned to the initial number—but they were not the same individual synapses as before. Some of the original and some of the new synapses retracted to create the exact number the cells started with. The finding is surprising because it suggests that a nerve cell body “knows” how many synapses it is supposed to form, meaning it is encoding a crucial part of memory. The researchers also ran a similar experiment on live sea slugs, in which they found that a long-term memory could be totally erased (as gauged by its synapses being destroyed) and then re-formed with only a small reminder stimulus—again suggesting that some information was being stored in a neuron's body. © 2015 Scientific American

Keyword: Learning & Memory
Link ID: 20958 - Posted: 05.20.2015

by Clare Wilson Does this qualify as irony? Our bodies need iron to be healthy – but too much could harm our brains by bringing on Alzheimer's disease. If that's the case, measuring people's brain iron levels could help identify those at risk of developing the disease. And since we already have drugs that lower iron, we may be able to put the brakes on. Despite intense efforts, the mechanisms behind this form of dementia are still poorly understood. For a long time the main suspect has been a protein called beta-amyloid, which forms distinctive plaques in the brain, but drugs that dissolve it don't result in people improving. Not so good ferrous Studies have suggested that people with Alzheimer's also have higher iron levels in their brains. Now it seems that high iron may hasten the disease's onset. Researchers at the University of Melbourne in Australia followed 144 older people who had mild cognitive impairment for seven years. To gauge how much iron was in their brains, they measured ferritin, a protein that binds to the metal, in their cerebrospinal fluid. For every nanogram per millilitre people had at the start of the study, they were diagnosed with Alzheimer's on average three months earlier. The team also found that the biggest risk gene for Alzheimer's, ApoE4, was strongly linked with higher iron, suggesting this is why carrying the gene makes you more vulnerable. Iron is highly reactive, so it probably subjects neurons to chemical stress, says team member Scott Ayton. © Copyright Reed Business Information Ltd

Keyword: Alzheimers
Link ID: 20957 - Posted: 05.20.2015

By PAM BELLUCKM The largest analysis to date of amyloid plaques in people’s brains confirms that the presence of the substance can help predict who will develop Alzheimer’s and determine who has the disease. Two linked studies, published Tuesday in JAMA, also support the central early role in Alzheimer’s of beta amyloid, the protein that creates plaques. Data from nearly 9,500 people on five continents shows that amyloid can appear 20 to 30 years before symptoms of dementia, that the vast majority of Alzheimer’s patients have amyloid and that the ApoE4 gene, known to increase Alzheimer’s risk, greatly accelerates amyloid accumulation. The findings also confirm that amyloid screening, by PET scan or cerebral spinal fluid test, can help identify people for clinical trials of drugs to prevent Alzheimer’s. Such screening is increasingly used in research. Experts say previous trials of anti-amyloid drugs on people with dementia failed because their brains were already too damaged or because some patients, not screened for amyloid, may not have had Alzheimer’s. “The papers indicate that amyloid imaging is important to be sure that the drugs are being tested on people who have amyloid,” said Dr. Roger Rosenberg, the director of the Alzheimer’s Disease Center at the University of Texas Southwestern Medical Center at Dallas, who wrote an editorial about the studies. Dr. Samuel Gandy, an Alzheimer’s researcher at Mount Sinai Hospital, who was not involved in the research, said doctors “can feel fairly confident that amyloid is due to Alzheimer’s.” But he and others cautioned against screening most people without dementia because there is not yet a drug that prevents or treats Alzheimer’s, and amyloid scans are expensive and typically not covered by insurance. © 2015 The New York Times Company

Keyword: Alzheimers
Link ID: 20956 - Posted: 05.20.2015

by Ashley Yeager This guest post is by SN's web producer Ashley Yeager, who can't remember ever not knowing how to swim. Sometimes my brother-in-law will scoop up my 2-year-old niece and fly her around like Superwoman. She’ll start kicking her legs and swinging her arms like she’s swimming — especially when we say, “paddle, paddle, paddle.” My niece, Baby D, loves the water. She often looks like one of the kids captured in famed photographer Seth Casteel’s new book, Underwater Babies. But she probably won’t remember her first trips to the pool — she was only a few months old when her mom first took her swimming. Part of my sister’s reasoning for such an early start was standard water safety. Every day in the United States, accidental drowning claims the lives of two children under the age of 14 years. Our family spends a lot of time at the pool and the beach, so making sure Baby D is protected is a priority. But there’s another reason my sister was keen to get Baby D to the pool. Loosely based on something our mother told us, it’s that learning to swim early in life may give kids a head start in developing balance, body awareness and maybe even language and math skills. Mom may have been right. A multi-year study released in 2012 suggests that kids who take swim lessons early in life appear to hit certain developmental milestones well before their nonswimming peers. In the study, Australian researchers surveyed about 7,000 parents about their children’s development and gave 177 kids aged 3 to 5 years standard motor, language, memory and attention tests. Compared with kids who didn’t spend much time in the water, kids who had taken swim lessons seemed to be more advanced at tasks like running and climbing stairs and standing on their tiptoes or on one leg, along with drawing, handling scissors and building towers out of blocks. © Society for Science & the Public 2000 - 2015.

Keyword: Development of the Brain; Learning & Memory
Link ID: 20955 - Posted: 05.20.2015

An octopus filmed off the coast of Kalaoa in Hawaii has shown that even cephalopods can get into a game of peekaboo. In the footage, shot last month by the GoPro camera of diver Timothy Ewing, the octopus bobs up and down behind a rock as a Ewing does the same in an effort to take the animal's picture. It's clear from the video that the octopus is wary of Ewing and his big, light-equipped camera — but the animal is also very curious. “Octopus are one of the more intelligent creatures in the ocean. Sometimes they are too curious for their own good. If you hide from them they will come out and look for you," the diver wrote in his online posting of the video. Ewing explained to CaliforniaDiver.com that the encounter wasn't limited to the time captured on his GoPro. "I was interacting with that octopus for about 10 minutes before I took the video," Ewing told CaliforniaDiver.com. "I normally mount my GoPro to my big camera housing, however I always carry a small tripod with me to use with the GoPro for stationary shots like this or selfie videos." The octopus, found worldwide in tropical, subtropical and temperate areas, is known for its smarts and striking ability to camouflage itself. When it feels threatened, pigment cells in its skin allow it to change color instantly to blend in with its surroundings. The animals can also adapt their skin texture and body posture to further match their background. © 2015 Discovery Communications, LLC.

Keyword: Learning & Memory; Intelligence
Link ID: 20954 - Posted: 05.20.2015

by Ashley Yeager New Caledonian crows are protective of their tools. The birds safeguard the sticks they use to find food and become even more careful with the tools as the cost of losing them goes up. Researchers videotaped captive and wild Corvus moneduloides crows and tracked what the birds did with their sticks. In between eating, the birds tucked the tools under their toes or left them in the holes they were probing. When higher up in the trees, the birds dropped the tools less often and were more likely to leave them in the holes they were probing than when they were on the ground. The finding, published May 20 in the Proceedings of the Royal Society B, shows how tool-protection tactics can prevent costly losses that could keep the crows from chowing down. © Society for Science & the Public 2000 - 2015

Keyword: Intelligence; Evolution
Link ID: 20953 - Posted: 05.20.2015

By James Gorman and Robin Lindsay Before human ancestors started making stone tools by chipping off flakes to fashion hand axes and other implements, their ancestors may have used plain old stones, as animals do now. And even that simple step required the intelligence to see that a rock could be used to smash open a nut or an oyster and the muscle control to do it effectively. Researchers have been rigorous in documenting every use of tools they have found find in animals, like crows, chimpanzees and dolphins. And they are now beginning to look at how tools are used by modern primates — part of the scientists’ search for clues about the evolution of the kind of delicate control required to make and use even the simplest hand axes. Monkeys do not exhibit human dexterity with tools, according to Madhur Mangalam of the University of Georgia, one of the authors of a recent study of how capuchin monkeys in Brazil crack open palm nuts. “Monkeys are working as blacksmiths,” he said, “They’re not working as goldsmiths.” But they are not just banging away haphazardly, either. Mr. Mangalam, a graduate student who is interested in “the evolution of precise movement,” reported in a recent issue of Current Biology on how capuchins handle stones. His adviser and co-author was Dorothy M. Fragaszy, the director of the Primate Behavior Laboratory at the university. Using video of the capuchins’ lifting rocks with both hands to slam them down on the hard palm nuts, he analyzed how high a monkey lifted a stone and how fast it brought it down. He found that the capuchins adjusted the force of a strike according to the condition of the nut after the previous strike. © 2015 The New York Times Company

Keyword: Evolution; Learning & Memory
Link ID: 20952 - Posted: 05.19.2015

by Michael Le Page Humble fungi and a home-brewing kit could soon do what the combined might of the West failed to – halt the thriving poppy industry in Afghanistan, the source of 80 per cent of the world's opium. Genetically engineered yeasts could make it easy to produce opiates such as morphine anywhere, cutting out the international drug smugglers and making such drugs cheap and more readily available. If home-brew drugs become widespread, it would make the Sisyphean nature of stopping the supply of illegal narcotics even more obvious than it is now. "It would be as disruptive to drug enforcement policy as it would be to crime syndicates," says Tanya Bubela, a public health researcher at the University of Alberta in Edmonton, Canada. "It may force the US to rethink its war on drugs." A growing number of drugs, scents and flavours once obtainable only from plants can now be made using genetically modified organisms. Researchers want to add opiates to that list because they are part of a family of molecules that may have useful medicinal properties (see box, below). Plant yields of many of these molecules are vanishingly small, and the chemicals are difficult and expensive to make in the lab. Getting yeast to pump them out would be far cheaper. Yeasts capable of doing this do not exist yet, but none of the researchers that New Scientist spoke to had any doubt that they soon will. "The field is moving much faster than we had previous realised," says John Dueber of the University of California, Berkeley, whose team has just created a yeast that produces the main precursor of opiates. Until recently, Dueber had thought the creation of, say, a morphine-making yeast was 10 years away. He now thinks a low-yielding strain could be made in two or three years.

Keyword: Drug Abuse
Link ID: 20951 - Posted: 05.19.2015

By Camille Bains, Imagine being able to see three times better than 20/20 vision without wearing glasses or contacts — even at age 100 or more — with the help of bionic lenses implanted in your eyes. Dr. Garth Webb, an optometrist in British Columbia who invented the Ocumetics Bionic Lens, says patients would have perfect vision and that driving glasses, progressive lenses and contact lenses would become a dim memory as the eye-care industry is transformed. Dr. Garth Webb says the bionic lens would allow people to see to infinity and replace the need for eyeglasses and contact lenses. (Darryl Dyck/Canadian Press) Webb says people who have the specialized lenses surgically inserted would never get cataracts because their natural lenses, which decay over time, would have been replaced. Perfect eyesight would result "no matter how crummy your eyes are," Webb says, adding the Bionic Lens would be an option for someone who depends on corrective lenses and is over about age 25, when the eye structures are fully developed. "This is vision enhancement that the world has never seen before," he says, showing a Bionic Lens, which looks like a tiny button. "If you can just barely see the clock at 10 feet, when you get the Bionic Lens you can see the clock at 30 feet away," says Webb, demonstrating how a custom-made lens that folded like a taco in a saline-filled syringe would be placed in an eye, where it would unravel itself within 10 seconds. He says the painless procedure, identical to cataract surgery, would take about eight minutes and a patient's sight would be immediately corrected. ©2015 CBC/Radio-Canada.

Keyword: Vision
Link ID: 20950 - Posted: 05.19.2015

By Will Lippincott In January 2012, two weeks after my discharge from a psychiatric hospital in Connecticut, I made a plan to die. My week in an acute care unit that had me on a suicide watch had not diminished my pain. Back in New York, I stormed out of my therapist’s office and declared I wouldn’t return to the treatment I’d dutifully followed for three decades. Nothing was working, so what was the point? I fit the demographic profile of the American suicide — white, male and entering middle age with a history of depression. Suicide runs in families, research tells us, and it ran in mine. My father killed himself at age 49 in April 1990. A generation before, an aunt of his took her life; before her, there were others. Shame runs in families, too, and no one in mine talked much about mental illness. The first time I was hospitalized for wanting to kill myself, as a teenager, my dad visited me a few days in. I made an effort to greet him with a firm handshake; he shared a few jokes with me. Dad was visibly concerned and told me he loved me. Only after his suicide a few years later did I learn that he, too, had been hospitalized, for depression, when he was in his early 20s. Setting out to start my own life after college, I felt that suicide was a clear and present opportunity, one that glowed more brightly during my depressive episodes. But I had an ambitious plan to beat it. I’d be a performer: work hard, keep my goals in the line of sight at all times, and make as much money as I could. Professional success would be my first line of defense to keep hopelessness at bay. In parallel, I’d find excellent doctors and be a compliant patient, take my meds and show up for talk therapy. And for a long time, through my 20s and 30s, that plan worked. © 2015 The New York Times Company

Keyword: Depression
Link ID: 20949 - Posted: 05.19.2015

Monica Tan The age-old question of whether human traits are determined by nature or nurture has been answered, a team of researchers say. Their conclusion? It’s a draw. By collating almost every twin study across the world from the past 50 years, researchers determined that the average variation for human traits and disease is 49% due to genetic factors and 51% due to environmental factors. University of Queensland researcher Beben Benyamin from the Queensland Brain Institute collaborated with researchers at VU University of Amsterdam to collate 2,748 studies involving more than 14.5 million pairs of twins. “Twin studies have been conducted for more than 50 years but there is still some debate in terms of how much the variation is due to genetic or environmental factors,” Benyamin said. He said the study showed the conversation should move away from nature versus nature, instead looking at how the two work together. “Both are important sources of variation between individuals,” he said. While the studies averaged an almost even split between nature and nurture, there was wide variation within the 17,800 separate traits and diseases examined by the studies. For example, the risk for bipolar disorder was found to be 68% due to genetics and only 32% due to environmental factors. Weight maintenance was 63% due to genetics and 37% due to environmental factors. In contrast, risk for eating disorders was found to be 40% genetic and 60% environmental, whereas the risk for mental and behavioural disorders due to use of alcohol was 41% genetic and 59% environmental. © 2015 Guardian News and Media Limited

Keyword: Genes & Behavior
Link ID: 20948 - Posted: 05.19.2015

By Angus Chen Jumping spiders are the disco dancers of the arachnid world. The males thump and throb their brightly patterned legs and abdomens at the ladies like in the video above. Yet most of these bright colors should be impossible for the arachnids to see. That’s because their eyes have only two types of color-sensitive cone cells, which are designed to detect just ultraviolet and green light. Now, researchers report today in Current Biology that the North American genus of jumping spiders sees extra colors via a small, thin layer of red-pigmented cells partially covering the center of their retinas. The layer acts as a filter, allowing only red light to pass through and activate retinal cells just below the layer. This essentially converts a few of their green-sensitive cells into red-sensitive cells, allowing the spiders to build palates from three colors much the same way humans do—we have blue, green, and red cone cells. These jumping spiders have some limitations, though. Because their red filter is a small dot over the center of their retinas, they can see red only if they look directly at it. And because the filter blocks out any light that’s not red, anything that they look at has to be pretty bright before they can see any redness on it. Luckily for them, they like to spend time dancing in the sun. © 2015 American Association for the Advancement of Science

Keyword: Vision
Link ID: 20947 - Posted: 05.19.2015