Chapter 16. None

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By ANDREW POLLACK Driving to a meeting in 2008, Jay Lichter, a venture capitalist, suddenly became so dizzy he had to pull over and call a friend to take him to the emergency room. The diagnosis: Ménière’s disease, a disorder of the inner ear characterized by debilitating vertigo, hearing loss and tinnitus, or ringing in the ears. But from adversity can spring opportunity. When Mr. Lichter learned there were no drugs approved to treat Ménière’s, tinnitus or hearing loss, he started a company, Otonomy. It is one of a growing cadre of start-ups pursuing drugs for the ear, an organ once largely neglected by the pharmaceutical industry. Two such companies, Otonomy and Auris Medical, went public in 2014. Big pharmaceutical companies like Pfizer and Roche are also exploring the new frontier. A clinical trial recently began of a gene therapy being developed by Novartis that is aimed at restoring lost hearing. The sudden flurry of activity has not yet produced a drug that improves hearing or silences ringing in the ears, but some companies are reporting hints of promise in early clinical trials. There is a huge need, some experts say. About 48 million Americans have a meaningful hearing loss in at least one ear; 30 million of them have it in both ears, said Dr. Frank R. Lin, an associate professor of otolaryngology and geriatric medicine at Johns Hopkins University. That figure is expected to increase as baby boomers grow older. © 2015 The New York Times Company

Keyword: Hearing
Link ID: 20466 - Posted: 01.10.2015

By James Gallagher Health editor, BBC News website An elastic implant that moves with the spinal cord can restore the ability to walk in paralysed rats, say scientists. Implants are an exciting field of research in spinal cord injury, but rigid designs damage surrounding tissue and ultimately fail. A team at Ecole Polytechnique Federale de Lausanne (EPFL) has developed flexible implants that work for months. It was described by experts as a "groundbreaking achievement of technology". The spinal cord is like a motorway with electrical signals rushing up and down it instead of cars. Injury to the spinal cord leads to paralysis when the electrical signals are stuck in a jam and can no longer get from the brain to the legs. The same group of researchers showed that chemically and electrically stimulating the spinal cord after injury meant rats could "sprint over ground, climb stairs and even pass obstacles". Rat walks up stairs Previous work by the same researchers But that required wired electrodes going directly to the spinal cord and was not a long-term option. Implants are the next step, but if they are inflexible they will rub, causing inflammation, and will not work properly. The latest innovation, described in the journal Science, is an implant that moves with the body and provides both chemical and electrical stimulation. When it was tested on paralysed rats, they moved again. One of the scientists, Prof Stephanie Lacour, told the BBC: "The implant is soft but also fully elastic to accommodate the movement of the nervous system. "The brain pulsates with blood so it moves a lot, the spinal cord expands and retracts many times a day, think about bending over to tie your shoelaces. "In terms of using the implant in people, it's not going to be tomorrow, we've developed dedicated materials which need approval, which will take time. © 2015 BBC.

Keyword: Regeneration
Link ID: 20465 - Posted: 01.10.2015

Ewen Callaway Microscopes make living cells and tissues appear bigger. But what if we could actually make the things bigger? It might sound like the fantasy of a scientist who has read Alice’s Adventures in Wonderland too many times, but the concept is the basis for a new method that could enable biologists to image an entire brain in exquisite molecular detail using an ordinary microscope, and to resolve features that would normally be beyond the limits of optics. The technique, called expansion microscopy, involves physically inflating biological tissues using a material more commonly found in baby nappies (diapers). Edward Boyden, a neuroengineer at the Massachusetts Institute of Technology (MIT) in Cambridge, discussed the technique, which he developed with his MIT colleagues Fei Chen and Paul Tillberg, at a conference last month. Prizewinning roots Expansion microscopy is a twist on super-resolution microscopy, which earned three scientists the 2014 Nobel Prize in Chemistry. Both techniques attempt to circumvent a limitation posed by the laws of physics. In 1873, German physicist Ernst Abbe deduced that conventional optical microscopes cannot distinguish objects that are closer together than about 200 nanometres — roughly half the shortest wavelength of visible light. Anything closer than this 'diffraction limit' appears as a blur. © 2015 Nature Publishing Group

Keyword: Brain imaging
Link ID: 20464 - Posted: 01.10.2015

By Nicholas Weiler A friend can make even the shiest creature bold. Rats usually fear strange open spaces, but having a companion by their side makes the rodents more intrepid, scientists report in the current issue of Animal Cognition. Researchers tracked rats’ exploration of a large, unfamiliar room, first alone, then again 2 days later either alone or paired with a familiar cagemate. On their own, rats made short, hesitant forays into the open space before darting back to huddle by the door. Solitary rats’ anxiety in the room didn’t improve on their second visit. But adding a friend, even one who’d never seen the room before, gave the pair the confidence to actively explore, covering 50% more ground and running significantly faster than the control rats. And exploring with company seemed to boost the rats’ sense of security permanently. Placed in the room a third time, once more alone, the socialized rats boldly explored more new places than ever, while solo rats continued to cower. This illustrates that for communal animals like rats—and perhaps humans—friendship can be the best antidote to fear. © 2015 American Association for the Advancement of Scienc

Keyword: Emotions
Link ID: 20462 - Posted: 01.10.2015

|William Mullen, Tribune reporter Researchers at Northwestern University say they have discovered a common cause behind the mysterious and deadly affliction of amyotrophic lateral sclerosis, or Lou Gehrig's disease, that could open the door to an effective treatment. Dr. Teepu Siddique, a neuroscientist with Northwestern's Feinberg School of Medicine whose pioneering work on ALS over more than a quarter-century fueled the research team's work, said the key to the breakthrough is the discovery of an underlying disease process for all types of ALS. The discovery provides an opening to finding treatments for ALS and could also pay dividends by showing the way to treatments for other, more common neurodegenerative diseases such as Alzheimer's, dementia and Parkinson's, Siddique said. The Northwestern team identified the breakdown of cellular recycling systems in the neurons of the spinal cord and brain of ALS patients that results in the nervous system slowly losing its ability to carry brain signals to the body's muscular system. Without those signals, patients gradually are deprived of the ability to move, talk, swallow and breathe. "This is the first time we could connect (ALS) to a clear-cut biomedical mechanism," Siddique said. "It has really made the direction we have to take very clear and sharp. We can now test for drugs that would regulate this protein pathway or optimize it, so it functions as it should in a normal state."

Keyword: ALS-Lou Gehrig's Disease
Link ID: 20459 - Posted: 01.08.2015

|By Karen Hopkin Sometimes it’s hard to see the light. Especially if it lies outside the visible spectrum, like x-rays or ultraviolet radiation. But if you long to see the unseeable, you might be interested to hear that under certain conditions people can catch a glimpse of usually invisible infrared light. That’s according to a study in the Proceedings of the National Academy of Sciences. [Grazyna Palczewska et al, Human infrared vision is triggered by two-photon chromophore isomerization] Our eyes are sensitive to elementary particles called photons that have sufficient energy to excite light-sensitive receptor proteins in our retinas. But the photons in infrared radiation don’t have enough oomph. We can detect these lower energy photons using what are sometimes called night-vision goggles or cameras. But the naked eye is usually blind to infrared radiation. But recently researchers in a laser lab noticed that they sometimes saw flashes of light while working with devices that emitted brief infrared pulses. So they filled a test tube with retinal cells and zapped it with their lasers. When the light pulses rapidly enough, the receptors can get hit with two photons at the same time—which supplies enough energy to excite the receptor. This double dose makes the infrared visible. One application of the finding is that it could give doctors a new tool to diagnose diseases of the retina. So they could eyeball trouble before it might otherwise be seen.

Keyword: Vision
Link ID: 20458 - Posted: 01.08.2015

By Virginia Morell Animals that live in larger societies tend to have larger brains. But why? Is it because a larger group size requires members to divide up the labor on tasks, thus causing some individuals to develop specialized brains and neural anatomy? (Compared with most humans, for instance, taxicab drivers have brains that have larger areas that are involved with spatial memory.) Or is it because the challenges of group living—needing to know all the foibles of your neighbors—cause the brains of all members to grow larger? Scientists tested the two hypotheses with wild colonies of acacia ants (Pseudomyrmex spinicola), which make their nests in the hollow spines of acacia trees in Panama. Ant workers at the base of the tree wait to attack intruders, while workers foraging on the leaves (as in the photo above), aren’t as aggressive but are faster at managing the colony’s brood. This division of labor is most marked in larger colonies (those found on larger trees), while workers in smaller colonies do both jobs. The scientists studied 17 colonies of ants and measured the brain volumes of 29 of the leaf ants and 34 of the trunk ants. As the colony size increased, the leaf ants showed a marked increase in the regions of the brain concerned with learning and memory, the scientists report today in the Proceedings of the Royal Society B. But the same neural areas decreased in the trunk ants. Thus, larger societies’ need for specialized workers, some strictly for defense, others for foraging and brood tending—rather than for social masters—seems to be the key to the expanding brain, at least in ants.

Keyword: Evolution
Link ID: 20457 - Posted: 01.08.2015

Haroon Siddique Research that aims to map the activity of serotonin in the brain could revolutionise the use of antidepressants and behavioural therapy for people with mental illnesses. The neurotransmitter serotonin has long been associated with mood, with drugs that boost the chemical in the brain helping to alleviate the symptoms of common illnesses such as depression and anxiety, but scientists lack a deep understanding of how it mediates different mood disorders. By understanding the biology of serotonin, the hope is that drugs can be created that only target cells relevant to a particular disorder and behavioural therapies can be made more effective, reducing the need for antidepressants. Dr Jeremiah Cohen, an assistant professor at the Johns Hopkins Brain Science Institute in Baltimore, said: “The ultimate aim is to understand the biology of mood and how groups of cells in the brain connect to produce our emotional behaviour. Most antidepressants operate broadly in the entire serotonin system. What we hope to do with this map is use drugs that are available or design new drugs that will target only the components of that system relevant to a particular disorder.” The use of antidepressants in England has soared since the late 1990s, raising concerns in some quarters about over-prescription. Researchers from the Nuffield Trust and the Health Foundation found that 40m prescriptions for antidepressants were made in 2012, compared to 15m in 1998. Doctors write prescriptions for more than one in 10 adults in developed countries, with Iceland, Australia, Canada and European Nordic countries leading the way, according to 2013 data from the Organisation for Economic Co-operation and Development. More than 10% of American adults have used antidepressants.

Keyword: Depression
Link ID: 20455 - Posted: 01.06.2015

ARE you spending enough time in the sun? As well as keeping our bones strong, vitamin D – the hormone our skin makes when exposed to ultraviolet rays – may also help regulate our body clocks. We all have a small group of "clock genes" which switch on and off during the day. As a result, the levels of the proteins they code for rise and fall over a 24-hour period. Enforced routines such as night shift work can play havoc with our health – increasing our risk of a stroke, for example. To find out whether a lack of vitamin D might be responsible, Sean-Patrick Scott and his colleagues at the Monterrey Institute of Technology and Higher Education in Mexico looked at the behaviour of two clock genes in human fat cells. When the cells were immersed in blood serum, they acted as they would in the body: the clock genes' activity oscillated over a 24-hour period. Dosing the cells with vitamin D instead produced the same effect. No such effect was seen in cells placed inside a nutrient broth. "Vitamin D synchronises the cells," says Scott. "Our results explain some of the benefits of sunlight," he says. "Vitamin D is one of the ways we might be able to maintain circadian rhythms in the body." Julia Pakpoor of the University of Oxford says clinical trials are needed to confirm the effect in people, but she adds, "We should all make sure we are vitamin D replete regardless." The work was presented at the World Stem Cell Summit in San Antonio, Texas, last month. © Copyright Reed Business Information Ltd.

Keyword: Biological Rhythms
Link ID: 20454 - Posted: 01.06.2015

By Susan Milius Whole scientific careers have gone into understanding why a harmless handful of fluff like a California ground squirrel taunts rattlesnakes. Now Rulon Clark and his team at San Diego State University are exploring the puzzle of why the squirrels also seem to taunt rocks, sticks and the occasional shrub. On spotting a snake, a California ground squirrel (Otospermophilus beecheyi) stares and sniffs, or if the snake is uncoiled, may even kick sand at it. And in bursts, the squirrel flags its tail left and right “like a windshield wiper,” Clark says. A rattler can strike a target 30 centimeters away in less than 70 milliseconds. But ground squirrels twist and dodge fast enough to have a decent chance of escape. Also, adult squirrels from snake country have evolved some resistance to venom. So taunting is worth the risks as a signal to neighboring squirrels and to the snake that its ambush attempt has been discovered. After getting publicly and lengthily squirreled, snakes often just slip away. Yet the squirrels also nyah-nyah tail flag at places where snakes might be but aren’t. To see if flagging indicates wariness, Clark and his colleagues built a squirrel startler that shoots out a cork using the classic spring that launches gag snakes out of cans (see video below). At spots with no sign of real snakes, squirrels mostly nibbled seeds in apparent tranquility with only a rare tail flag. The pop of a cork typically sent these squirrels scampering off on four speed-blurred paws. © Society for Science & the Public 2000 - 2014.

Keyword: Aggression; Animal Communication
Link ID: 20453 - Posted: 01.06.2015

Carl Zimmer Among scientists who study how our DNA affects our weight, a gene called FTO stands out. “It’s the poster child for the genetics of obesity,” said Struan F. Grant, an associate professor of pediatrics at the University of Pennsylvania School of Medicine. In 2007, researchers discovered that people with a common variant of FTO tend to be heavier than those without it. Since then, studies have repeatedly confirmed the link. On average, one copy of the risky variant adds up to 3.5 extra pounds of weight. Two copies of the gene bring 7 extra pounds — and increase a person’s risk of becoming obese by 50 percent. But the gene doesn’t seem to have always been a problem. If scientists had studied FTO just a few decades ago, they would have found no link to weight whatsoever. A new study shows that FTO became a risk only in people born after World War II. The research, published this week in the Proceedings of the National Academy of Sciences, raises questions that extend far beyond obesity. Genes clearly influence our health in many ways, but so does our environment; often, it is the interplay between them that makes the difference in whether we develop obesity or cancer or another ailment. But the relative importance of certain genes may shift over the years, the new study suggests, as our environment changes. James Niels Rosenquist of Massachusetts General Hospital and his colleagues were inspired to conduct the study by recent research documenting how people’s experiences alter the effects of their genes. A variant of a gene called AKT1, for example, can raise the risk of psychosis — but only if the carrier smokes a lot of marijuana. If he avoids smoking, the AKT1 variant doesn’t cause a problem. © 2015 The New York Times Company

Keyword: Obesity; Genes & Behavior
Link ID: 20451 - Posted: 01.01.2015

By Stephanie M. Lee Decorating the house has always been challenging for Sheila Carter. Like other color-blind people, she limits her wardrobe to a few bold hues that can be easily mixed and matched, like blue and black. But a new pair of glasses she recently started wearing, she said, has changed her worldview. Carter owns high-tech eyewear made by EnChroma, a Berkeley startup that wants to help people with color deficiency see the full spectrum of the rainbow. Carter is among an estimated 32 million Americans who are color-blind, either from birth or as a result of some condition, like head trauma. The condition is most prevalent among people of Northern European descent, affecting 8 percent of men and 0.5 percent of women. EnChroma makes color-enhancing sunglasses for the vast majority of such people, who have trouble seeing red or green due to a genetic defect. The company has sold more than 1,000 pairs in two years. Last month, it introduced glasses with polycarbonate lenses for children, athletes and prescription- and nonprescription-wearers at prices ranging from $325 to $450. The proprietary lens contains a filter that blocks a portion of the spectrum where the overlap between the two cones occurs and restores the separation between them. “It’s essentially taking out that stuff that’s confusing the signal,” said Andy Schmeder, vice president of technology.

Keyword: Vision
Link ID: 20450 - Posted: 01.01.2015

By Abby Phillip Your smartphone addiction is doing more than giving your thumbs a workout, it is also changing your brain. A new study suggests that using a smartphone -- touching the fingertips against the smooth surface of a screen -- can make the brain more sensitive to the thumb, index and middle finger tips being touched. The study, which was published in the journal Current Biology this week, found that the differences between people when it comes to how the brain responds to thumb stimulation is partly explained by how often they use their smartphones. "I was really surprised by the scale of the changes introduced by the use of smartphones," said Arko Ghosh, of the Institute of Neuroinformatics of the University of Zurich and one of the study's authors, in a news release. Other research has shown that musicians and expert video gamers show the same type of brain adaptations. Smartphone use isn't something most people would consider an "expertise," but frequent use of the devices might similarly lead to brain adaptations. Researchers used an electroencephalography (EEG) device to record the activity that occurred in the brain when people touched their thumbs, index and middle fingers to a mechanical object. They compared the brain recordings of smartphone users and regular cellphone users.

Keyword: Pain & Touch
Link ID: 20446 - Posted: 01.01.2015

By KEVIN RANDALL MILWAUKEE — When two financiers purchased the Milwaukee Bucks for $550 million last April, they promised to pour not only money and new management into the moribund franchise, but also the same kind of creative and critical thinking that had helped make them hedge fund billionaires. It was not enough to increase the franchise’s sales force or beef up the team’s analytics department — the Bucks were looking for a more elusive edge. So in May, the team hired Dan Hill, a facial coding expert who reads the faces of college prospects and N.B.A. players to determine if they have the right emotional attributes to help the Bucks. The approach may sound like palm reading to some, but the Bucks were so impressed with Hill’s work before the 2014 draft that they retained him to analyze their players and team chemistry throughout this season. With the tenets of “Moneyball” now employed in the front offices of every major sport, perhaps it was inevitable that professional teams would turn to emotion metrics and neuroscience tools to try to gain an edge in evaluating players. Many sports teams have adopted advanced data analytics to help determine a player’s athletic abilities and value. And now, some are taking it a step further — trying to analyze the psychological aspects of the players as well. “We spend quite a bit of time evaluating the players as basketball players and analytically,” said David Morway, Milwaukee’s assistant general manager, who works for the owners Wesley Edens and Marc Lasry. “But the difficult piece of the puzzle is the psychological side of it, and not only psychological, character and personality issues, but also team chemistry issues.” © 2014 The New York Times Company

Keyword: Emotions
Link ID: 20445 - Posted: 12.27.2014

ByDavid Malakoff This bird might look like a holiday ornament, but it is actually a rare half-female, half-male northern cardinal (Cardinalis cardinalis, pictured with female plumage on the left and male plumage on the right) spotted a few years ago in Rock Island, Illinois. Researchers have long known such split-sex “gynandromorphs” exist in insects, crustaceans, and birds. But scientists rarely get to extensively study a gynandromorph in the wild; most published observations cover just a day or so. Observers got to follow this bird, however, for more than 40 days between December 2008 and March 2010. They documented how it interacted with other birds and even how it responded to recorded calls. The results suggest being half-and-half carries consequences: The cardinal didn’t appear to have a mate, and observers never heard it sing, the researchers report this month in The Wilson Journal of Ornithology. On the other hand, it wasn’t “subjected to any unusual agonistic behaviors from other cardinals,” according to the paper. Intriguingly, another gynandromorph cardinal sighted briefly in 1969 had the opposite plumage, they note: the male’s bright red plumes on the right, the drabber female feathers on the left. © 2014 American Association for the Advancement of Science

Keyword: Sexual Behavior
Link ID: 20442 - Posted: 12.27.2014

George Johnson Training a dog to salivate at the sound of a bell would have seemed pretty stupid to Ivan Pavlov. He was after much bigger things. Using instruments like metronomes and harmoniums, he demonstrated that a dog could make astonishingly fine discriminations — distinguishing between a rhythm of 96 and 104 beats a minute or an ascending and a descending musical scale. But what he really wanted to know was what his animals were thinking. His dream was a grand theory of the mind. He couldn’t put his subjects on a couch like his colleague Freud and ask them to free-associate, so he gauged their reactions to a variety of stimuli, meticulously counting their “psychic secretions,” those droplets of drool. He knew he was pricking at the skin of something deeper. “It would be stupid,” he said, “to reject the subjective world.” This is not the Pavlov most people think they know. In an excellent new biography, “Ivan Pavlov: A Russian Life in Science,” Daniel P. Todes, a medical historian, describes a man whose laboratory in pre-Soviet Russia was like an early-20th-century version of the White House Brain Initiative, with its aim “to revolutionize our understanding of the human mind.” That was also Pavlov’s goal: to build a science that would “brightly illuminate our mysterious nature” and “our consciousness and its torments.” He spoke those words 111 years ago and spent his life pursuing his goal. Yet when we hear his name, we reflexively think of a drooling dog and a clanging bell. Our brains have been conditioned with the myth. © 2014 The New York Times Company

Keyword: Learning & Memory
Link ID: 20439 - Posted: 12.23.2014

Richard Stephens ‘The curve that sets everything straight” was how comedian Phyllis Diller once described the smile. And it’s true that there’s something charming, trustworthy and disarming about a smile – but this can be misleading. Dig a little deeper and you will understand a much less wholesome side. Because, ladies and gentleman, the smile is one of the biggest fakes going. I know what you’re thinking: we all pull a false smile now and again to appease our fellows and avoid unnecessary conflict. On the other hand, a genuine smile of true enjoyment is something different. Psychologists have named such a smile after the French neurologist Guillaume-Benjamin-Amand Duchenne de Boulogne. The Duchenne smile, utilising the muscles around the eyes that lift the cheeks to produce crow’s feet, has long been held as an inimitable sign of true human emotion. Or at least it was until 2013, when a team of researchers from Northeastern University, Boston, broke that hoodoo. Sarah Gunnery and her colleagues asked one group of volunteers to imitate smiles on photographs, and another group of volunteers to rate them. Some of the photographs depicted mouth-only smiles but others were Duchenne smiles, using mouth and eye muscles together. Surprisingly, a high proportion of individuals – two-thirds – could fake a Duchenne smile – and those that could do this were better able to put on false expressions in their everyday lives. This straightforward study indicates that even the sacrosanct Duchenne smile can be convincingly simulated. So much for smiling being an inimitable sign of true human emotion. So why are we so good at faking smiles? The answer isn’t necessarily sinister – some research shows you can actually smile yourself into a better mood. © 2014 Guardian News and Media Limited

Keyword: Emotions
Link ID: 20438 - Posted: 12.23.2014

Alison Abbott Activists calling for an end to research using non-human primates have stepped up activities in Germany and Italy. An estimated 800 animal-rights activists demonstrated in front of the Max Planck Institute for Biological Cybernetics in Tübingen, Germany, on 20 December, calling for an end to the research with monkeys that takes place there. A smaller group maintained an all-night vigil. Friedrich Mülln, head of the activist group SOKO Tierschutz, which organized the action, told Nature that the group would continue actions against the institute next year “until the department that does this research is closed down.” In September, SOKO Tierschutz, which is based in Augsburg, Germany, posted a video on its website that included material filmed secretly in the institute by a former animal carer. The footage was used in a television report that claimed malpractice in the laboratory, but a preliminary investigation commissioned in response by the Max Planck Society did not reveal systematic problems in animal welfare. The society says that the Tübingen scientists contribute importantly to global research efforts to understand the human brain. In a similar undercover operation, an anonymous person took smartphone footage of caged monkeys in a primate laboratory at the Sapienza University of Rome. The popular show Striscia la Notizia, which mixes exposé with entertainment, used the footage in an 18 December report which claimed that scientists at the university conducted their work in secret and without oversight. The TV report also said that its producers contacted the Italian ministry of health and the local health office, and that neither was able to explain what the lab's experiments are about. © 2014 Nature Publishing Group

Keyword: Animal Rights
Link ID: 20437 - Posted: 12.23.2014

By Nicholas Bakalar Planning to read in bed tonight? It may be better to read an actual book instead of an e-book reader. A small study has found that reading light-emitting electronic devices before bedtime is a recipe for poor sleep. Researchers randomly assigned 12 healthy young adults to one of two activities: reading a light-emitting e-book in a dimly lit room for about four hours before bedtime on five consecutive evenings, or reading a printed book for the same amount of time. All participants did both tasks. The researchers took blood samples to measure melatonin levels, and electronically tracked how long it took to fall asleep and how much time was spent in each sleep stage. The study, done at Brigham and Women’s Hospital in Boston, is online in the Proceedings of the National Academy of Sciences. Compared with a printed book, a light-emitting e-book decreased sleepiness, reduced REM sleep (often called dream sleep), and substantially suppressed the normal bedtime rise of melatonin, the hormone that regulates the sleep and wake cycle. The e-book users took longer to fall asleep and felt sleepier in the morning. “Much more has to be known about the kind of impact these devices have on our health and well-being,” said the lead author, Anne-Marie Chang, an assistant professor of biobehavioral health at Penn State. “The technology moves quickly, and the science lags.” © 2014 The New York Times Company

Keyword: Sleep; Vision
Link ID: 20436 - Posted: 12.23.2014

By Susan Milius In nighttime flying duels, Mexican free-tailed bats make short, wavering sirenlike waaoo-waaoo sounds that jam each other’s sonar. These “amazing aerial battles” mark the first examples of echolocating animals routinely sabotaging the sonar signals of their own kind, says Aaron Corcoran of Wake Forest University in Winston-Salem, N.C. Many bats, like dolphins, several cave-dwelling birds and some other animals, locate prey and landscape features by pinging out sounds and listening for echoes. Some prey, such as tiger moths, detect an incoming attack and make frenzied noises that can jam bat echolocation, Corcoran and his colleagues showed in 2009 (SN: 1/31/09, p. 10). And hawkmoths under attack make squeaks with their genitals in what also may be defensive jamming (SN Online: 7/3/13). But Corcoran didn’t expect bat-on-bat ultrasonic warfare. He was studying moths dodging bats in Arizona’s Chiricahua Mountains when his equipment picked up a feeding buzz high in the night sky. A free-tailed bat was sending faster and faster echolocation calls to refine the target position during the final second of an attack. (Bats, the only mammals known with superfast muscles, can emit more than 150 sounds a second.) Then another free-tailed bat gave a slip-sliding call. Corcoran, in a grad student frenzy of seeing his thesis topic as relevant to everything, thought the call would be a fine way to jam a buzz. “Then I totally told myself that’s impossible — that’s too good to be true.” Five years later he concluded he wasn’t just hearing things. He and William Conner, also of Wake Forest, report in the Nov. 7 Science that the up-and-down call can cut capture success by about 70 percent. Using multiple microphones, he found that one bat jams another, swoops toward the moth and gets jammed itself. © Society for Science & the Public 2000 - 201

Keyword: Hearing
Link ID: 20435 - Posted: 12.20.2014