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By Gary Stix A decline in hearing acuity is not only an occurrence that happens in the aged. An article in the August Scientific American by M. Charles Liberman, a professor of otology and laryngology at Harvard Medical School and director of the Eaton-Peabody Laboratories at Massachusetts Eye and Ear, focuses on relatively recent discoveries that show the din of a concert or high-decibel machine noise is enough to cause some level of hearing damage. After reading the article check out this video by medical illustrator Brandon Pletsch and its narrated animation explaining how the sensory system that detects sound functions. © 2015 Scientific American

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 21250 - Posted: 08.02.2015

Chris Woolston A study that did not find cognitive benefits of musical training for young children triggered a “media firestorm”. Researchers often complain about inaccurate science stories in the popular press, but few air their grievances in a journal. Samuel Mehr, a PhD student at Harvard University in Cambridge, Massachusetts, discussed in a Frontiers in Psychology article1 some examples of media missteps from his own field — the effects of music on cognition. The opinion piece gained widespread attention online. Arseny Khakhalin, a neuroscientist at Bard College in Annandale-on-Hudson, New York, tweeted: Mehr gained first-hand experience of the media as the first author of a 2013 study in PLoS ONE2. The study involved two randomized, controlled trials of a total of 74 four-year-olds. For children who did six weeks of music classes, there was no sign that musical activities improved scores on specific cognitive tests compared to children who did six weeks of art projects or took part in no organized activities. The authors cautioned, however, that the lack of effect of the music classes could have been a result of how they did the studies. The intervention in the trials was brief and not especially intensive — the children mainly sang songs and played with rhythm instruments — and older children might have had a different response than the four-year-olds. There are many possible benefits of musical training, Mehr said in an interview, but finding them was beyond the scope of the study. © 2015 Nature Publishing Group

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 13: Memory, Learning, and Development
Link ID: 21216 - Posted: 07.25.2015

By Hanae Armitage Playing an instrument is good for your brain. Compared to nonmusicians, young children who strum a guitar or blow a trombone become better readers with better vocabularies. A new study shows that the benefits extend to teenagers as well. Neuroscientists compared two groups of high school students over 3 years: One began learning their first instrument in band class, whereas the other focused on physical fitness in Junior Reserve Officers’ Training Corps (JROTC). At the end of 3 years, those students who had played instruments were better at detecting speech sounds, like syllables and words that rhyme, than their JROTC peers, the team reports online today in the Proceedings of the National Academy of Sciences. Researchers know that as children grow up, their ability to soak up new information, especially language, starts to diminish. These findings suggest that musical training could keep that window open longer. But the benefits of music aren’t just for musicians; taking up piano could be the difference between an A and a B in Spanish class. © 2015 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 13: Memory, Learning, and Development
Link ID: 21194 - Posted: 07.21.2015

By C. CLAIBORNE RAY Q. Can you hear without an intact eardrum? A. “When the eardrum is not intact, there is usually some degree of hearing loss until it heals,” said Dr. Ashutosh Kacker, an ear, nose and throat specialist at NewYork-Presbyterian Hospital and a professor at Weill Cornell Medical College, “but depending on the size of the hole, you may still be able to hear almost normally.” Typically, Dr. Kacker said, the larger an eardrum perforation is, the more severe the hearing loss it will cause. The eardrum, or tympanic membrane, is a thin, cone-shaped, pearly gray tissue separating the outer and middle ear canals, he explained. Soundwaves hit the eardrum, which in turn vibrates the bones of the middle ear. The bones pass the vibration to the cochlea, which leads to a signal cascade culminating in the sound being processed by the brain and being heard. There are several ways an eardrum can be ruptured, Dr. Kacker said, including trauma, exposure to sudden or very loud noises, foreign objects inserted deeply into the ear canal, and middle-ear infection. “Usually, the hole will heal by itself and hearing will improve within about two weeks to a few months, especially in cases where the hole is small,” he said. Sometimes, when the hole is larger or does not heal well, surgery will be required to repair the eardrum. Most such operations are done by placing a patch over the hole to allow it to heal, and the surgery is usually very successful in restoring hearing, Dr. Kacker said. © 2015 The New York Times Company

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 21187 - Posted: 07.20.2015

Jon Hamilton It's almost impossible to ignore a screaming baby. (Click here if you doubt that.) And now scientists think they know why. "Screams occupy their own little patch of the soundscape that doesn't seem to be used for other things," says David Poeppel, a professor of psychology and neuroscience at New York University and director of the Department of Neuroscience at the Max Planck Institute in Frankfurt. And when people hear the unique sound characteristics of a scream — from a baby or anyone else — it triggers fear circuits in the brain, Poeppel and a team of researchers report in Cell Biology. The team also found that certain artificial sounds, like alarms, trigger the same circuits. "That's why you want to throw your alarm clock on the floor," Poeppel says. The researchers in Poeppel's lab decided to study screams in part because they are a primal form of communication found in every culture. And there was another reason. "Many of the postdocs in my lab are in the middle of having kids and, of course, screams are very much on their mind," Poeppel says. "So it made perfect sense for them to be obsessed with this topic." The team started by trying to figure out "what makes a scream a scream," Poeppel says. Answering that question required creating a large database of recorded screams — from movies, from the Internet and from volunteers who agreed to step into a sound booth. A careful analysis of these screams found that they're not like any other sound that people make, including other loud, high-pitched vocalizations. The difference is something called the amplitude modulation rate, which is how often the loudness of a sound changes. © 2015 NPR

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition; Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 14: Attention and Consciousness; Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 21183 - Posted: 07.18.2015

By Sarah Schwartz In a possible step toward treating genetic human deafness, scientists have used gene therapy to partially restore hearing in deaf mice. Some mice with genetic hearing loss could sense and respond to noises after receiving working copies of their faulty genes, researchers report July 8 in Science Translational Medicine. Because the mice’s mutated genes closely correspond to those responsible for some hereditary human deafness, the scientists hope the results will inform future human therapies. “I would call this a really exciting big step,” says otolaryngologist Lawrence Lustig of Columbia University Medical Center. The ear’s sound-sensing hair cells convert noises into information the brain can process. Hair cells need specific proteins to work properly, and alterations in the genetic blueprints for these proteins can cause deafness. To combat the effects of two such mutations, the scientists injected viruses containing healthy genes into the ears of deaf baby mice. The virus infected some hair cells, giving them working genes. The scientists tried this therapy on two different deafness-causing mutations. Within a month, around half the mice with one mutation showed brainwave activity consistent with hearing and jumped when exposed to loud noises. Treated mice with the other mutation didn’t respond to noises, but the gene therapy helped their hair cells — which normally die off quickly due to the mutation — survive. All of the untreated mice remained deaf. © Society for Science & the Public 2000 - 2015

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 21152 - Posted: 07.09.2015

By Sarah Lewin Evolutionary biologists have long wondered why the eardrum—the membrane that relays sound waves to the inner ear—looks in humans and other mammals remarkably like the one in reptiles and birds. Did the membrane and therefore the ability to hear in these groups evolve from a common ancestor? Or did the auditory systems evolve independently to perform the same function, a phenomenon called convergent evolution? A recent set of experiments performed at the University of Tokyo and the RIKEN Evolutionary Morphology Laboratory in Japan resolves the issue. When the scientists genetically inhibited lower jaw development in both fetal mice and chickens, the mice formed neither eardrums nor ear canals. In contrast, the birds grew two upper jaws, from which two sets of eardrums and ear canals sprouted. The results, published in Nature Communications, confirm that the middle ear grows out of the lower jaw in mammals but emerges from the upper jaw in birds—all supporting the hypothesis that the similar anatomy evolved independently in mammals and in reptiles and birds. (Scientific American is part of Springer Nature.) Fossils of auditory bones had supported this conclusion as well, but eardrums do not fossilize and so could not be examined directly. © 2015 Scientific American

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 21098 - Posted: 06.27.2015

By Rachel Feltman Here's why you hate the sound of your own voice(1:07) If you've ever listened to your voice recorded, chances are you probably didn't like what you heard. So, why do most people hate the sound of their own voice? The answer: It's all in how sound travel to your ears. (Pamela Kirkland/The Washington Post) Whether you've heard yourself talking on the radio or just gabbing in a friend's Instagram video, you probably know the sound of your own voice -- and chances are pretty good that you hate it. As the video above explains, your voice as you hear it when you speak out loud is very different from the voice the rest of the world perceives. That's because it comes to you via a different channel than everyone else. When sound waves from the outside world -- someone else's voice, for example -- hit the outer ear, they're siphoned straight through the ear canal to hit the ear drum, creating vibrations that the brain will translate into sound. When we talk, our ear drums and inner ears vibrate from the sound waves we're putting out into the air. But they also have a another source of vibration -- the movements caused by the production of the sound. Our vocal cords and airways are trembling, too, and those vibrations make their way over to auditory processing as well. Your body is better at carrying low, rich tones than the air is. So when those two sources of sound get combined into one perception of your own voice, it sounds lower and richer. That's why hearing the way your voice sounds without all the body vibes can be off-putting -- it's unfamiliar -- or even unpleasant, because of the relative tinniness.

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 21062 - Posted: 06.17.2015

How echolocation really works By Dwayne Godwin and Jorge Cham © 2015 Scientific American

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 21017 - Posted: 06.06.2015

Lauren Silverman Jiya Bavishi was born deaf. For five years, she couldn't hear and she couldn't speak at all. But when I first meet her, all she wants to do is say hello. The 6-year-old is bouncing around the room at her speech therapy session in Dallas. She's wearing a bright pink top; her tiny gold earrings flash as she waves her arms. "Hi," she says, and then uses sign language to ask who I am and talk about the ice cream her father bought for her. Jiya is taking part in a clinical trial testing a new hearing technology. At 12 months, she was given a cochlear implant. These surgically implanted devices send signals directly to the nerves used to hear. But cochlear implants don't work for everyone, and they didn't work for Jiya. A schoolboy with a cochlear implant listens to his teacher during lessons at a school for the hearing impaired in Germany. The implants have dramatically changed the way deaf children learn and transition out of schools for the deaf and into classrooms with non-disabled students. "The physician was able to get all of the electrodes into her cochlea," says Linda Daniel, a certified auditory-verbal therapist and rehabilitative audiologist with HEAR, a rehabilitation clinic in Dallas. Daniel has been working with Jiya since she was a baby. "However, you have to have a sufficient or healthy auditory nerve to connect the cochlea and the electrodes up to the brainstem." But Jiya's connection between the cochlea and the brainstem was too thin. There was no way for sounds to make that final leg of the journey and reach her brain. © 2015 NPR

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 21005 - Posted: 06.01.2015

By Meeri Kim The dangers of concussions, caused by traumatic stretching and damage to nerve cells in the brain that lead to dizziness, nausea and headache, has been well documented. But ear damage that is sometimes caused by a head injury has symptoms so similar to the signs of a concussion that doctors may misdiagnose it and administer the wrong treatment. A perilymph fistula is a tear or defect in the small, thin membranes that normally separate the air-filled middle ear from the inner ear, which is filled with a fluid called perilymph. When a fistula forms, tiny amounts of this fluid leak out of the inner ear, an organ crucial not only for hearing but also for balance. Losing even a few small drops of perilymph leaves people disoriented, nauseous and often with a splitting headache, vertigo and memory loss. While most people with a concussion recover within a few days, a perilymph fistula can leave a person disabled for months. There is some controversy around perilymph fistula due to its difficulty of diagnosis — the leak is not directly observable, but rather identified by its symptoms. However, it is generally accepted as a real condition by otolaryngologists and sports physicians, and typically known to follow a traumatic event. But concussions — as well as post-concussion syndrome, which is marked by dizziness, headache and other symptoms that can last even a year after the initial blow — also occur as the result of such an injury.

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 15: Language and Our Divided Brain
Link ID: 20968 - Posted: 05.23.2015

Jon Hamilton When Sam Swiller used hearing aids, his musical tastes ran to AC/DC and Nirvana – loud bands with lots of drums and bass. But after Swiller got a cochlear implant in 2005, he found that sort of music less appealing. "I was getting pushed away from sounds I used to love," he says, "but also being more attracted to sounds that I never appreciated before." So he began listening to folk and alternative music, including the Icelandic singer Bjork. There are lots of stories like this among people who get cochlear implants. And there's a good reason. A cochlear implant isn't just a fancy hearing aid. When his cochlear implant was first switched on, the world sounded different. "A hearing aid is really just an amplifier," says Jessica Phillips-Silver, a neuroscience researcher at Georgetown University. "The cochlear implant is actually bypassing the damaged part of the ear and delivering electrical impulses directly to the auditory nerve." As a result, the experience of listening to music or any other sound through the ear, with or without a hearing aid, can be completely unlike the experience of listening through a cochlear implant. "You're basically remapping the audio world," Swiller says. Swiller is 39 years old and lives in Washington, D.C. He was born with an inherited disorder that caused him to lose much of his hearing by his first birthday. That was in the 1970s, and cochlear implants were still considered experimental devices. So Swiller got hearing aids. They helped, but Swiller still wasn't hearing what other people were. © 2015 NPR

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20945 - Posted: 05.18.2015

By Chris Cesare For bats, too many echoes can be like blurry vision. That’s because the nocturnal creatures navigate by bouncing ultrasonic sound off of their surroundings, a technique known as echolocation. In cramped spots, these sounds can reverberate, creating a noisy background that clouds the mammals’ sonic sight. Now, new research published online before print in the Proceedings of the National Academy of Sciences has discovered one way that bats might overcome this auditory ambush. Scientists found that the animals modify the width of their navigation pulses on the fly by adjusting the size of their mouth gape. The researchers used an array of cameras, flashes, and ultrasonic recorders to take snapshots of bats while they swooped down to take a sip at a desert pond in Israel. As the bats descended toward the confined banks of the pond, they opened their mouths wider to more tightly focus their sound pulses. As the bats left, they narrowed their mouths, projecting an ultrasonic beam up to four times wider than on the descending leg. These counterintuitive effects were due to diffraction, which causes sound waves traveling through a smaller hole to spread out more. The researchers repeated the experiment with captive bats and found the same effect, controlling for the possibility that they had observed a behavior tied to drinking. The team writes that these changes in gape allow the animals to “zoom in” on their view of an area, potentially reducing the amount of distracting echoes in a tight space. © 2015 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20901 - Posted: 05.09.2015

by Clare Wilson WHAT is it like to be a bat? It's a question philosophers interested in consciousness like to ponder. Yet a few people already have something of a bat's world view. Brian Borowski, a 59-year-old Canadian who was born blind, began teaching himself to echolocate aged 3. He clicks with his tongue or snaps his fingers as he moves about, unconsciously decoding the echoes. Although many blind people get information from sounds around them, few turn this into a supersense by making sounds to help themselves get around. "When I'm walking down a sidewalk and I pass trees, I can hear the tree: the vertical trunk of the tree and maybe the branches above me," says Borowski. "I can hear a person in front of me and go around them." Borowski, who works as a programmer at Western University in London, Ontario, suspects he experiences "images" in a similar way to people who can see, just with less detail. "I store maps of information in my head and I compare what I have in my memory with what I'm hearing around me," he says. "I am matching images of some sort." This probably isn't too far from the truth – we know from brain scans of Borowski and another echolocator that the strategy co-opts the same parts of the brain that usually deal with visual information. For his latest scientific collaboration, he helped a team of researchers to explore how well echolocators can determine the relative sizes and distances of objects. © Copyright Reed Business Information Ltd

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20898 - Posted: 05.08.2015

by Helen Thomson Tinnitus is the debilitating sensation of a high-pitched noise without any apparent source. It can be permanent or fleeting, and affects at least 25 million people in the US alone. To understand more about the condition, William Sedley at the University of Newcastle, UK, and his colleagues took advantage of a rare opportunity to study brain activity in a man with tinnitus who was undergoing surgery for epilepsy. Surgeons placed recording electrodes in several areas of his brain to identify the source of his seizures. The man – who they knew as Bob (not his real name) – was awake during the procedure, which allowed Sedley's team to manipulate his tinnitus while recording from his brain. First they played him 30 seconds of white noise, which suppressed his tinnitus for about 10 seconds before it gradually returned. Bob was asked to rate the loudness of his tinnitus before the experiment started, as well as immediately after the white noise finished and 10 seconds later. This protocol was then repeated many times over two days. "Normally, studies compare brain activity of people with and without tinnitus using non-invasive techniques," says Sedley. "Not only are these measurements less precise, but the people with tinnitus might be concentrating on the sound, while the ones without tinnitus might be thinking about their lunch." This, he says, can make the results hard to interpret. © Copyright Reed Business Information Ltd

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20847 - Posted: 04.25.2015

Hannah Devlin, science correspondent They may stop short of singing The Bells of Saint Mary’s, as demonstrated by the mouse organ in Monty Python, but scientists have discovered that male mice woo females with ultrasonic songs. The study shows for the first time that mouse song varies depending on the context and that male mice have a specific style of vocalisation reserved for when they smell a female in the vicinity. In turn, females appear to be more interested in this specific style of serenade than other types of squeak that male mice produce. “It was surprising to me how much change occurs to these songs in different social contexts, when the songs are thought to be innate,” said Erich Jarvis, who led the work at Duke University in North Carolina. “It is clear that the mouse’s ability to vocalise is a lot more limited than a songbird’s or human’s, and yet it’s remarkable that we can find these differences in song complexity.” The findings place mice in an elite group of animal vocalisers, that was once thought to be limited to birds, whales, and some primates. Mouse song is too high-pitched for the human ear to detect, but when listened to at a lower frequency, it sounds somewhere between birdsong and the noise of clean glass being scrubbed. The Duke University team recorded the male mice when they were roaming around their cages, when they were exposed to the smell of female urine and when they were placed in the presence of a female mouse. They found that males sing louder and more complex songs when they smell a female but don’t see her. By comparison, the songs were longer and simpler when they were directly addressing their potential mate, according to the findings published in Frontiers of Behavioural Neuroscience. © 2015 Guardian News and Media Limited

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 8: Hormones and Sex
Link ID: 20751 - Posted: 04.02.2015

by Bethany Brookshire Music displays all the harmony and discord the auditory world has to offer. The perfect pair of notes at the end of the Kyrie in Mozart’s Requiem fills churches and concert halls with a single chord of ringing, echoing consonance. Composers such as Arnold Schönberg explored the depths of dissonance — groups of notes that, played together, exist in unstable antagonism, their frequencies crashing and banging against each other. Dissonant chords are difficult to sing and often painful to hear. But they may get less painful with age. As we age, our brains may lose the clear-cut representations of these consonant and dissonant chords, a new study shows. The loss may affect how older people engage with music and shows that age-related hearing loss is more complex than just having to reach for the volume controls. The main mechanism behind age-related hearing loss is the deterioration of the outer hair cells in the cochlea, a coiled structure within our inner ear. When sound waves enter the ear, a membrane vibrates, pulling the hair cells to and fro and kicking off a series of events that produce electrical signals that will be sent onward to the brain. As we age, we lose some of these outer hair cells, and with them goes our ability to hear extremely high frequencies. In a new study, researchers tested how people perceive consonant pairs of musical notes, which are harmonious and generally pleasing, or dissonant ones, which can be harsh and tense. © Society for Science & the Public 2000 - 2015

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 13: Memory, Learning, and Development
Link ID: 20737 - Posted: 03.31.2015

By Victoria Gill Science reporter, BBC News Researchers in Denmark have revealed how porpoises finely adjust the beams of sound they use to hunt. The animals hunt with clicks and buzzes - detecting the echoes from their prey. This study showed them switching from a narrow to a wide beam of sound - "like adjusting a flashlight" - as they homed in on a fish. Researchers think that other whales and dolphins may use the same technique to trap a fish in their beam of sound in the final phase of an attack. This could help prevent porpoises, whales and dolphins' prey from evading their capture. By revealing these acoustic secrets in detail, researchers are hoping to develop ways to prevent porpoises, and other toothed whales, from becoming trapped in fishing nets. The study, published in the journal eLife, was led by Danuta Wisniewska of Aarhus University. She and her colleagues worked with harbour porpoises in a semi-natural enclosure on the coast of Denmark. "The facility is quite exceptional, " explained Dr Wisniewska. "The animals still have access to the seafloor and are only separated from the harbour by a net. Fish are able to come in, so they're still hunting." In this unique environment, the researchers were able to fit the porpoises with sound-detecting tags, and to place an array of microphones to pick up sound around their enclosure. The team carried out a series of these experiments to work out where the sound energy the porpoises produced was being directed In one experiment, researchers dropped fish into the water to tempt the porpoises to hunt. As echolocating porpoises, whales and dolphins hunt, they switch from an exploratory clicking to a more intense, high frequency buzz - to elicit a continuous echo from the fish they are pursuing. Their beam can be envisaged a cone of sound, said Dr Wisniewska, comparing it to the cone-shaped beam of light from a torch. © 2015 BBC.

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20731 - Posted: 03.30.2015

By Virginia Morell Children and parrot and songbird chicks share a rare talent: They can mimic the sounds that adults of their species make. Now, researchers have discovered this vocal learning skill in baby Egyptian fruit bats (Rousettus aegyptiacus, pictured), a highly social species found from Africa to Pakistan. Only a handful of other mammals, including cetaceans and certain insectivorous bats, are vocal learners. The adult fruit bats have a rich vocal repertoire of mouselike squeaks and chatter (listen to a recording here), and the scientists suspected the bat pups had to learn these sounds. To find out, they placed baby bats with their mothers in isolation chambers for 5 months and made video and audio recordings of each pair. Lacking any other adults to vocalize to, the mothers were silent, and their babies made only isolation calls and babbling sounds, the researchers report today in Science Advances. As a control, the team raised another group of bat pups with their mothers and fathers, who chattered to each other. Soon, the control pups’ babbling gave way to specific sounds that matched those of their mothers. But the isolated pups quickly overcame the vocal gap after the scientists united both sets of bats—suggesting that unlike many songbird species (and more like humans), the fruit bats don’t have a limited period for vocal learning. Although the bats’ vocal learning is simple compared with that of humans, it could provide a useful model for understanding the evolution of language, the scientists say. © 2015 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 13: Memory, Learning, and Development
Link ID: 20726 - Posted: 03.28.2015

Lights, sound, action: we are constantly learning how to incorporate outside sensations into our reactions in specific situations. In a new study, brain scientists have mapped changes in communication between nerve cells as rats learned to make specific decisions in response to particular sounds. The team then used this map to accurately predict the rats’ reactions. These results add to our understanding of how the brain processes sensations and forms memories to inform behavior. “We’re reading the memories in the brain,” said Anthony Zador, M.D., Ph.D., professor at Cold Spring Harbor Laboratory, New York, and senior author of the study, published in Nature. The work was funded by the National Institutes of Health and led by Qiaojie Xiong, Ph.D., a former postdoctoral researcher in Dr. Zador’s laboratory. “For decades scientists have been trying to map memories in the brain,” said James Gnadt, Ph.D., a program director at the National Institute of Neurological Disorders and Stroke (NINDS), one of the NIH institutes that funded the study. “This study shows that scientists can begin to pinpoint the precise synapses where certain memories form and learning occurs.” The communication points, or synapses, that Dr. Zador’s lab studied were in the striatum, an integrating center located deep inside the brain that is known to play an important role in coordinating the translation of thoughts and sensations into actions. Problems with striatal function are associated with certain neurological disorders such as Huntington’s disease in which affected individuals have severely impaired skill learning.

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 13: Memory, Learning, and Development
Link ID: 20649 - Posted: 03.04.2015