Biological Psychology Links

By Susan Milius In a long-running war between bats and moths, at least one bat has gotten the upper wing. Western barbastelle bats in Europe typically ping out their echolocation calls softly enough to locate a moth for dinner before the moth hears them coming, says Holger Goerlitz of the University of Bristol in England. It’s the first documented case of a bat species outwitting its prey by quiet stealth, he and his colleagues say online in a Current Biology paper released August 19. The battle between bats and moths has become a classic system for studying the evolution of predators and their prey. In searching for moths, barbastelles echolocate at about the 94 decibel level, roughly the equivalent of a busy highway, Goerlitz reports. This bat version of whispering is 10 to 100 times lower in amplitude than other aerial-hunting bats’ echolocation calls. Those rank more in the range of jet engines and the vuvuzelas blaring at the latest World Cup, Goerlitz says. People can’t hear frequencies high enough to detect any of this bat racket — “quite lucky for us,” Goerlitz says. To measure the loudness of the barbastelle calls, researchers needed to know how far away from a microphone a flying bat was when it pinged. So they set up a microphone array where bats swooped through at night. The slight differences in times that the calls took to reach different microphones let researchers figure out the bat’s position for each of more than 100 calls. © Society for Science & the Public 2000 - 2010

By Nathan Seppa The prevalence of hearing loss in teenagers rose by nearly one-third in recent years compared with the rate in the 1980s and 1990s, a new study shows. The findings come as a surprise to the study’s authors, who had expected overall hearing to improve thanks to publicity about the risks of exposure to loud music and the advent of childhood vaccines against meningitis and pneumonia that can prevent many ear infections. But in the August 18 Journal of the American Medical Association, the scientists report that the portion of U.S. adolescents aged 12 to 19 with any hearing loss rose from 14.9 percent during the 1988 to 1995 period to 19.5 percent in 2005 and 2006. Researchers based the analysis on information gathered from nearly 3,000 kids in the earlier time frame and more than 1,700 in the later sampling. The findings suggest that as many as 6.5 million teens in the United States now have some hearing loss. The surveys used largely similar questionnaires and standard hearing tests in which “any hearing loss” was defined as a loss of 15 decibels in at least one ear. That is, a person was determined to have some hearing loss if a tone had to be increased by 15 dB or more beyond the standard detection level to be heard at least half the time. Hearing loss of 25 dB or greater is less common, particularly in children. But it also rose, from 3.5 to 5.3 percent, between the study time frames. The rate of hearing loss increased in high — but not low — frequencies, the researchers found. © Society for Science & the Public 2000 - 2010

by Bijal Trivedi CLAIRE CHESKIN used to live in a murky world of grey, her damaged eyes only seeing large objects if they were right next to her. She could detect the outlines of people but not their expressions, and could just about make out the silhouettes of buildings, but no details. Looking into the distance? Forget it. Nowadays things are looking distinctly brighter for Cheskin. Using a device called vOICe, which translates visual images into "soundscapes", she has trained her brain to "see through her ears". When travelling, the device helps her identify points of interest; at home she uses it to find things she has put down, like coffee cups. "I've sailed across the English Channel and across the North Sea, sometimes using the vOICe to spot landmarks," she says. "The lights on the land were faint but the vOICe could pick them up." As if the signposting of objects wasn't impressive and useful enough, some long-term users of the device like Cheskin eventually report complete images somewhat akin to normal sight, thanks to a long-term rewiring of their brains. Sometimes these changes are so profound that it alters their perceptions even when they aren't using the device. As such, the vOICe (the "OIC" standing for "Oh, I See") is now proving invaluable as a research tool, providing insights into the brain's mind-boggling capacity for adaptation. The idea of hijacking another sense to replace lost vision has a long history. One of the first "sensory substitution" devices was developed in 1969 by neuroscientist Paul Bach-y-Rita. He rigged up a television camera to a dentist's chair, on which was a 20-by-20 array of stimulators that translated images into tactile signals by vibrating against the participant's back. Despite the crudeness of the set-up, it allowed blind participants to detect the presence of horizontal, vertical and diagonal lines, while skilled users could even associate the physical sensations with faces and common objects. © Copyright Reed Business Information Ltd.

By Bruce Bower At scientific meetings, psycho-biologist Colwyn Trevarthen often plays a video of a 5-month-old Swedish girl giving her mother a musical surprise. Blind from birth, the girl reaches for a bottle and laughs appreciatively as her mother launches into a familiar song about feeding blueberries to a bear. As in baby songs everywhere, Trevarthen says, each line of the Swedish tune runs about four seconds and each stanza lasts about 20. In a flash, the girl raises her left arm — an arm she has never seen — and begins conducting her mother’s performance. The baby, named Maria, moves her arm just before many of the song’s lines begin, leading her mother by about one-third of a second. In some cases, Maria synchronizes her hand movements with the rise and fall of her mother’s voice. Mom’s face glows in response to Maria’s playful directions. “Babies are born with a musical readiness that includes a basic sense of timing and rhythm,” declares Trevarthen, of the University of Edinburgh. Scientists have been finding that these chubby-cheeked cherubs heed a musical sense that moves them and grooves them long before they utter a word. Within a day or two after birth, babies recognize the first beat in a sound sequence; neural signs of surprise appear when that initial “downbeat” goes missing. Classical music lights up specific hearing areas in newborns’ right brains. Even more intriguingly, babies enter the world crying in melodic patterns that the little ones have heard in their mothers’ conversations for at least two months while in the womb (SN: 12/5/09, p. 14). © Society for Science & the Public 2000 - 2010

By Susan Gaidos Anyone who has felt the sting of tears while listening to a bugler play “Taps,” swooned to a love song or cringed with irritation as a neighbor cranked the heavy metal knows that music can exert a powerful emotive effect. And you don’t need a neuroscientist to tell you that manipulating a melody’s pace, tone and intensity can stir the emotions. Composers of symphonies, pop tunes, movie sound tracks and TV ads all know how to tune an audience’s mood along a dial ranging from sad and glum to cheerful and chipper. But neuroscientists might have something to say about how music orchestrates such profound emotional effects on the brain. And understanding the how may offer a hint as to why music affects humans so powerfully. Over the past decade or so, studies have shown that music stimulates numerous regions of the brain all at once, including those responsible for emotion, memory, motor control, timing and language. While the lyrics of a song activate language centers, such as Broca’s area, other parts of the brain may connect the tune to a long-ago association — a first kiss or a road trip down the coast, perhaps. “It’s like the brain is on fire when you’re listening to music,” says Istvan Molnar-Szakacs, a neuroscientist at the University of California, Los Angeles. “In terms of brain imaging, studies have shown listening to music lights up, or activates, more of the brain than any other stimulus we know.” © Society for Science & the Public 2000 - 2010

By Rachel Ehrenberg Not so long ago, Mozart mania swept the nation. A small study found that students who listened to 10 minutes of a Mozart sonata performed better on a paper-folding task than their peers, and suddenly a flourishing industry sprouted. Mozart’s music sang from CDs and videos marketed for children, babies and moms-to-be. The craze reached a crescendo when Georgia’s governor Zell Miller included $105,000 in his state budget to send every child born in a Georgia hospital home with a classical music tape or CD. “No one questions that listening to music at a very early age affects the spatial, temporal reasoning that underlies math and engineering and even chess,” Miller said. Actually, a lot of researchers questioned the link between listening to music and smarts. In the original study, the “Mozart effect” was minor and lasted only minutes. Follow-up studies found the effect specific neither to the composer nor to music. Students listening to Mozart were just more stimulated than those listening to a relaxation tape or silence. And while arousal can improve learning, research suggests, the effects can be fleeting and aren’t limited to music. Assessments of the original report now tend to be dirges: In the May-June issue of Intelligence, researchers from the University of Vienna published a paper titled “Mozart effect–Shmozart effect.” “It’s a short-lived effect and it spawned a huge industry of baby Einstein, baby Mozart CDs, all sorts of stuff,” says Aniruddh Patel of the Neurosciences Institute in San Diego. “But the science behind it is pretty thin.” © Society for Science & the Public 2000 - 2010

By Sandra G. Boodman As he picked up the phone to make the call, Wayne Curtis worried that his doctor might think he was a hypochondriac. Three weeks earlier, Curtis, then 48, had consulted Baltimore internist Charles Locke about a pulled muscle. Now the real estate agent had a new and seemingly trivial complaint: He couldn't hear anything out of his left ear, which seemed blocked. Curtis assumed that his problem was related to the thick coating of tree pollen that blanketed his downtown Baltimore neighborhood. Normally Curtis, who has long battled spring allergies, would have toughed it out and waited several weeks to see if his hearing returned as the pollen counts dropped. But a newly formed choral quartet of which Curtis was a member was about to have its first concert, and the tenor, who has performed with the Boston Symphony Orchestra, was concerned that his impaired hearing was affecting his singing. "I expected him to put me on a stronger decongestant, not to tell me to come in the very next day," said Curtis, who was taken aback by Locke's emphatic response. "It's probably a classic case of 'It's better to be lucky than good,' " Locke quipped. His sense of urgency was fueled by a memorable patient he had seen more than a decade earlier. Curtis's season of misery was as perennial as the pollen, and he was accustomed to loading up on antihistamines and decongestants every spring to get through it. © 2010 The Washington Post Company

The undersea world isn't as quiet as we thought, according to a New Zealand researcher who found fish can "talk" to each other. Fish communicate with noises including grunts, chirps and pops, University of Auckland marine scientist Shahriman Ghazali has discovered according to newspaper reports Wednesday. "All fish can hear, but not all can make sound -- pops and other sounds made by vibrating their swim bladder, a muscle they can contract," Ghazali told the New Zealand Herald. Fish are believed to communicate with each other for different reasons, including attracting mates, scaring off predators or orienting themselves. The gurnard species has a wide vocal repertoire and keeps up a constant chatter, Ghazali found after studying different species of fish placed into tanks. On the other hand, cod usually kept silent, except when they were spawning. "The hypothesis is that they are using sound as a synchronization so that the male and female release their eggs at the same time for fertilization," he said. Some reef fish, such as the damselfish, made sounds to attempt to scare off threatening fish and even divers, he said. But anyone hoping to strike up a conversation with their pet goldfish is out of luck. © 2010 Discovery Communications, LLC.

by Laurie Rich, Jane Bosveld, Andrew Grant, Amy Barth The brain is a castle on a hill. Encased in bone and protected by a special layer of cells, it is shielded from infections and injuries—but also from many pharmaceuticals and even from the body’s own immune defenses. As a result, brain problems are tough to diagnose and to treat. To meet this challenge, researchers are exploring unconventional therapies, from electrodes to laser-light stimulation to mind-bending drugs. Some of these radical experiments may never pan out. But, as frequently happens in medicine, a few of today’s improbable approaches may evolve into tomorrow’s miraculous cures. 1. Man Meets Machine In a sense, cyborgs already walk among us: Nearly 200,000 deaf or near-deaf people have cochlear implants, electronic sound-processing machines that stimulate the auditory nerve and link into the brain. But even by the fanciful science fiction definition, the age of cyborgs is just around the corner. In the last decade, researchers have become increasingly skilled at detecting and interpreting brain signals. Technologies that allow people to use their thoughts to control machines—computers, speaking devices, or prosthetic limbs—are already being tested and could soon be available for widespread applications.

COLUMBUS, Ohio -- Musicians who hear the music they are performing while learning a new piece have a better memory for the music later, a new study suggests. But after they learn a song, actually hearing the music as they play does not improve the accuracy of their performance. These results shed new light on how memory works and on theories about how people learn, said Caroline Palmer, co-author of the study and professor of psychology at Ohio State University. Specifically, Palmer said the findings cast doubt on the universality of matching theories – theories that state memory works best when conditions are similar during learning and during recall of the information.

Cassowaries’ low-frequency sounds may give insight into dinosaur communications NEW YORK -- A family of huge forest birds living in the dense jungles of Papua New Guinea emit low-frequency calls deeper than virtually all other bird species, possibly to communicate through thick forest foliage, according to a study published by the New York-based Wildlife Conservation Society. Published in the recent issue of the scientific journal The Auk, the study says that three species of cassowaries – flightless birds that can weigh as much as 125 pounds – produce a "booming" call so low that humans may not be able to detect much of the sound. The researchers draw similarities between the birds' calls and the rumbling elephants make to communicate. "When close to the bird, these calls can be heard or felt as an unsettling sensation, similar to how observers describe elephant vocalizations," said WCS researcher Dr. Andrew Mack, the lead author of the study.

A protein associated with a disorder that causes deafness and blindness in people may be a key to unraveling one of the foremost mysteries of how we hear, says a study in the June 28 issue of the Journal of Neuroscience. Scientists with the National Institute on Deafness and Other Communication Disorders (NIDCD), one of the National Institutes of Health (NIH), and the University of Sussex, Brighton, United Kingdom, have identified protocadherin-15 as a likely player in the moment-of-truth reaction in which sound is converted into electrical signals. (Protocadherin-15 is a protein made by a gene that causes one form of type 1 Usher syndrome, the most common cause of deaf-blindness in humans.) The findings will not only provide insight into how hearing takes place at the molecular level, but also may help us figure out why some people temporarily lose their hearing after being exposed to loud noise, only to regain it a day or two later. “These findings offer a more precise picture of the complicated processes involved with our sense of hearing,” says Elias A. Zerhouni, M.D., director of the NIH. “With roughly 15 percent of American adults reporting some degree of hearing loss, it is increasingly vital that we continue making inroads into our understanding of these processes, helping us seek new and better treatments, and opening the doors to better hearing health for Americans.” Researchers have long known that hair cells, small sensory cells in the inner ear, convert sound energy into electrical signals that travel to the brain, a process called mechanotransduction. However, the closer one zooms in on the structures involved, the murkier our understanding becomes. When fluid in the inner ear is set into motion by vibrations emanating from the bones of the middle ear, the rippling effect causes bristly structures atop the hair cells to bump up against an overlying membrane and to deflect.

By JANE E. BRODY Josh Swiller was 22 and profoundly deaf when he applied to the Peace Corps in search of adventure. And indeed, adventure he found. His experiences in Zambia are eloquently recounted in his hard-to-put-down memoir of deafness and Africa, “The Unheard” (Holt, 2007). But how could someone so hard of hearing get into the Peace Corps, let alone learn a foreign language and communicate in it? Mr. Swiller told me he had no problem with the interview, which was conducted one-on-one in a quiet room, enabling him to hear and to read lips. Through the devoted efforts of an audiologist and his mother, he could speak nearly as well as a normal-hearing person. And he did not have a problem learning the language of Zambia. “I was so used to paying close attention when other people spoke,” Mr. Swiller recalled in an interview. “I was used to asking people to repeat themselves.” He added: “Being deaf and having three brothers, one of whom is also deaf, I learned how to communicate without language. I could conduct conversations when I understood only a few words in each sentence.” That was remarkable in itself. But far more remarkable is that the interview with me was conducted over the telephone, something Mr. Swiller, 37, could not have done three years ago. In 2005, he and his brother underwent life-changing surgery, substituting a cochlear implant for the hearing aids that were no longer working for them. Copyright 2008 The New York Times Company

By TARA PARKER-POPE Few products are hated as much as hearing aids. The devices can squeal with feedback and overamplify background noises like the click of a turn signal or whir of a ceiling fan. They must be removed for showering or sleeping, and their batteries die frequently. Many users, out of exasperation, decide they’d rather live with hearing loss. But now scientists have come up with a different kind of hearing aid. While the device, called the Lyric, is being used in only 500 patients, it appears to have overcome many of the problems associated with traditional hearing aids — without the expense and uncertainty of surgery and anesthesia. The Lyric, made by InSound Medical of Newark, Calif., is hidden deep inside the ear canal, just four millimeters (about one-sixth of an inch) from the ear drum. While doctors for years have been implanting hearing devices in the middle ear, the Lyric is not an implant: it can be removed with a small magnet. It is worn 24 hours a day, and its batteries last one to four months. Typically, anything that clogs the ear canal would trap moisture and pose an infection risk, but the Lyric is surrounded by a spongy material that allows moisture to escape. Because it sits so close to the ear drum, doctors say that it works more efficiently and that sounds are more natural because they don’t have to be amplified as much. Copyright 2008 The New York Times Company

By BINA VENKATARAMAN The song of the blue whale, one of the eeriest sounds in the ocean, has mysteriously grown deeper. The calls have been steadily dropping in frequency for seven populations of blue whales around the world over the past 40 years, say researchers at the Scripps Institution of Oceanography, the National Oceanic and Atmospheric Administration and WhaleAcoustics, a private research company. The scientists analyzed data collected with hydrophones and other tools and found that the songs, which they believe are by males advertising for mates, had lowered by as much as 30 percent in certain populations. Much of the song lies at frequencies too low to be detected by the human ear. The study, though not yet published, has been reviewed by several experts in the field who, in interviews, called the global decline “dramatic,” “significant,” “convincing” and “unequivocal.” Scientists cannot explain why blue whales from places as disparate as the northern Pacific and the Southern Ocean, which surrounds Antarctica, would drop the pitch of their songs. Each blue whale population has a distinct tempo and tone set to its vocals. John Hildebrand, professor of oceanography at Scripps and an author of the study, said the drop might signal a rebound in the population of blue whales since commercial whaling bans began to take effect in the 1970s. Copyright 2008 The New York Times Company

By JANE E. BRODY Michael became hooked on headphones in his early teens. He walked the streets of Brooklyn day after day with his favorite music blasting directly into his ears. By his early 20s, the sensory hair cells in his inner ears had been permanently damaged and Michael had lost much of his upper-range hearing. The Children’s Hearing Institute reports that hearing loss among children and young adults is rising in the United States, and that one-third of the damage is caused by noise. According to the American Academy of Audiology, about one child in eight has noise-induced hearing loss. That means some five million children have an entirely preventable disability that will stay with them for life. The academy has begun a “turn it to the left” (the volume dial, that is) awareness campaign in hopes of protecting current and future generations of youngsters from unwittingly damaging their hearing. Often, the problem is not detected until children develop persistent ringing in the ears or begin to have learning or behavior problems in school because of trouble understanding speech. Copyright 2008 The New York Times Company

By Victoria Gill As if flying around in the dark swooping and diving to catch insects was not tricky enough, bats also listen for their fellow hunters. A study has revealed how these winged mammals recognise other bats' voices. They are able to differentiate the ultrasonic "echolocation" calls that other bats make as they navigate. In the journal PLoS Computational Biology, the scientists report that the bats have an internal "reference" call to which they compare others. Yossi Yovel from the Weizmann Institute of Science, Israel, and his colleagues in Germany recorded the echolocation calls of five greater mouse-eared bats The bats use these brief bursts of sound in sonar navigation - bouncing sound waves off their surroundings to find their way and locate prey. Dr Yovel's team tested the bats' ability to identify the others by playing the recorded sounds to them. "Each bat was assigned two others it had to distinguish between," Dr Yovel explained. "So we trained bat A on a platform, playing a sound from bat B on one side and from bat C on the other. He had crawl to where the 'correct' sound was coming from." Each of the subjects was taught that a call from just one of the other bats was correct. So during this training exercise, if the bat A made the right choice, and crawled towards the sound from bat B, it was rewarded with its favourite food - a mealworm. "Then, in the next stage - the test - we rewarded them no matter what choice they made, and they still chose correctly more than 80% of the time," said Dr Yovel. (C)BBC

By PERRI KLASS, M.D. The 8-year-old boy already had hearing aids when I met him, back in the 1990s. He had been born before newborns were routinely screened for hearing problems, so the diagnosis had not taken place until he was a slow-to-talk toddler. An extensive trail of subspecialists had evaluated him after that first test showed severe hearing loss in both ears. A geneticist, a developmentalist, a kidney specialist — no one could find anything wrong. He was a healthy, cheerful child who couldn’t hear very well. Nowadays, 97 percent of babies born in this country have their hearing screened in the newborn nursery. (More in a minute about the clever technologies that make this possible.) That means essential follow-up testing and treatment can begin very early indeed. But the key term is “follow-up.” As many as 46 percent of children who failed the newborn screening test in 2007 did not have documented repeat testing and treatment, said Marcus Gaffney, a health scientist with the Early Hearing Detection and Intervention program at the Centers for Disease Control and Prevention. “Screening a child doesn’t do a lot of good,” Mr. Gaffney told me, “if you don’t take the appropriate follow-up.” Before newborn screening changed the picture in the late 1990s, the average age for diagnosing hearing loss was about 2 �. And the testing was usually done only because the child’s speech was slow to develop. In children with relatively mild hearing loss, or loss in only one ear, it sometimes took even longer. Copyright 2010 The New York Times Company

By Cristen Conger A debate is brewing in the bat research community over one of the winged mammal’s senses. No, it has nothing to do with vision. Despite the tiny eyes and nocturnal lifestyle, none of the roughly 1,100 bat species is blind. “All bats can see and all bats are sensitive to changing light levels because this is the main cue that they use to sense when it is (night time) and time to become active,” said Paul Faure, of McMaster University’s Bat Lab. Instead, researchers can’t agree on a certain aspect of the mammal’s sonar sight, called echolocation. To track down prey, avoid predators and find their way home in the dark, most bats depend on echolocation. They broadcast high-pitched sonar signals and listen for the echoes of sound waves bouncing off objects they’re looking for or obstacles in their path. Bats’ brains then process the auditory information within those echoes as visual maps. Scientists know a lot about the finer points of how echolocation works, but they differ on whether that sense evolved before or after bat’s ability to fly. “Some question whether echolocation 60 million years ago would’ve been too sophisticated,” said Brock Fenton, of the University of Western Ontario. The scientists who discovered Onychonycteris finneyi, the oldest known bat fossil (above), concluded that the prehistoric species could fly but that the sonar sense didn't evolve until later. © 2010 Discovery Channel

By CLAUDIA DREIFUS Three years ago, when Oxford University Press published “Music, Language, and the Brain,” Oliver Sacks described it as “a major synthesis that will be indispensable to neuroscientists.” The author of that volume, Aniruddh D. Patel, a 44-year-old senior fellow at the Neurosciences Institute in San Diego, was in New York City in May. We spoke over coffee for more than an hour and later by telephone. An edited and condensed version of the conversations follows. Q. YOU DESCRIBE YOURSELF AS A NEUROSCIENTIST OF MUSIC. THIS HAS TO BE A NEW PROFESSION. HOW DID YOU COME TO IT? A. I’ve been passionate about two things since childhood — science and music. At graduate school, Harvard, I hoped to combine the two. But studying with E.O. Wilson, I quite naturally got caught up with ants. In 1990, I found myself in Australia doing fieldwork on ants for a Ph.D. thesis. And there, I had this epiphany: the only thing I really wanted to do was study the biology of how humans make and process music. I wondered if the drive to make it was innate, a product of our evolution, as Darwin had speculated. Did we have a special neurobiological capacity for music, as we do for language and grammar? So from Australia, I wrote Wilson that there was no way I could continue with ants. Amazingly, he wrote: “You must follow your passion. Come back to Harvard, and we’ll give it a shot.” Copyright 2010 The New York Times Company

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