By Claudia López Lloreda In what seems like something out of a sci-fi movie, scientists have plucked the famous Pink Floyd song “Another Brick in the Wall” from individuals’ brains. Using electrodes, computer models and brain scans, researchers previously have been able to decode and reconstruct individual words and entire thoughts from people’s brain activity (SN: 11/15/22; SN: 5/1/23). The new study, published August 15 in PLOS Biology, adds music into the mix, showing that songs can also be decoded from brain activity and revealing how different brain areas pick up an array of acoustical elements. The finding could eventually help improve devices that allow communication from people with paralysis or other conditions that limit one’s ability to speak. People listened to Pink Floyd’s “Another Brick in the Wall” song while having their brain activity monitored. Using that data and a computer model, researchers were able to reconstruct sounds that resemble the song. To decode the song, neuroscientist Ludovic Bellier of the University of California, Berkeley and colleagues analyzed the brain activity recorded by electrodes implanted in the brains of 29 individuals with epilepsy. While in the hospital undergoing monitoring for the disorder, the individuals listened to the 1979 rock song. People’s nerve cells, particularly those in auditory areas, responded to hearing the song, and the electrodes detected not only neural signals associated with words but also rhythm, harmony and other musical aspects, the team found. With that information, the researchers developed a computer model to reconstruct sounds from the brain activity data, and found that they could produce sounds that resemble the song. © Society for Science & the Public 2000–2023.

Related chapters from BN: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System; Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 2: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals; Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 28876 - Posted: 08.19.2023

By Elizabeth Preston Some things need no translation. No matter what language you speak, you can probably recognize a fellow human who is cheering in triumph or swearing in anger. If you are a crocodile, you may recognize the sound of a young animal crying in distress, even if that animal is a totally different species — like, say, a human baby. That sound means you are close to a meal. In a study published Wednesday in Proceedings of the Royal Society B, researchers put speakers near crocodiles and played recordings of human, bonobo and chimpanzee infants. The crocodiles were attracted to the cries, especially shrieks that sounded more distressed. “That means that distress is something that is shared by species that are really, really distant,” said Nicolas Grimault, a bioacoustic research director at the French National Centre for Scientific Research and one of the paper’s authors. “You have some kind of emotional communication between crocodiles and humans.” These infant wails most likely drew crocodiles because they signaled an easy meal nearby, the authors say. But in some cases, the opposite may have been true: The crocs were trying to help. The animals in the study were Nile crocodiles, African predators that can reach up to 18 feet long. Understandably, the researchers kept their distance. They visited the reptiles at a Moroccan zoo and placed remote-controlled loudspeakers on the banks of outdoor ponds. The researchers played recordings of cries from those speakers while groups of up to 25 crocodiles were nearby. Some cries came from infant chimpanzees or bonobos calling to their mothers. Others were human babies, recorded either at bath time or in the doctor’s office during a vaccination. Nearly all of the recordings prompted some crocodiles to look or to move toward the speaker. When they heard the sounds of human babies getting shots, for example, almost half the crocodiles in a group responded. Dr. Grimault said the reptiles seemed most tempted by cries with a harsh quality that other studies have linked to distress in mammals. © 2023 The New York Times Company

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 28871 - Posted: 08.09.2023

By Freda Kreier Pregnancy can do weird things to the body. For some bats, it can hamper their ability to “see” the world around them. Kuhl’s pipistrelle bats (Pipistrellus kuhlii) echolocate less frequently while pregnant, researchers report March 28 in BMC Biology. The change may make it harder for the tiny bats to detect prey and potential obstacles in the environment. The study is among the first to show that pregnancy can shape how nonhuman mammals sense their surroundings, says Yossi Yovel, a neuroecologist at Tel Aviv University in Israel. Nocturnal bats like Kuhl’s pipistrelles famously use sound to navigate and hunt prey in the dark (SN: 9/20/17). Their calls bounce off whatever is nearby and bats use the echoes to reconstruct what’s around them, a process aptly named echolocation. The faster a bat makes calls, the better it can make out its surroundings. But rapid-fire calling requires breathing deeply, which is something that pregnancy can get in the way of. “Although I’ve never been pregnant, I know that when I eat a lot, it’s more difficult to breathe,” Yovel says. So pregnancy — which can add a full gram to a 7-gram Kuhl’s pipistrelle and may push up on the lungs — might hamper echolocation. Yovel and colleagues tested their hypothesis by capturing 10 Kuhl’s pipistrelles, five of whom were pregnant, and training the bats to find and land on a platform. Recordings of the animals’ calls revealed that bats that weren’t pregnant made around 130 calls on average while searching for the platform. But bats that were pregnant made only around 110 calls, or 15 percent fewer. © Society for Science & the Public 2000–2023.

Related chapters from BN: Chapter 9: Hearing, Balance, 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: 28774 - Posted: 05.10.2023

By Neelam Bohra Ayla Wing’s middle school students don’t always know what to make of their 26-year-old teacher’s hearing aids. The most common response she hears: “Oh, my grandma has them, too.” But grandma’s hearing aids were never like this: Bluetooth-enabled and connected to her phone, they allow Ms. Wing to toggle with one touch between custom settings. She can shut out the world during a screeching subway ride, hear her friends in noisy bars during a night out and even understand her students better by switching to “mumbly kids.” A raft of new hearing aids have hit the market in recent years, offering greater appeal to a generation of young adults that some experts say is both developing hearing problems earlier in life and — perhaps paradoxically — becoming more comfortable with an expensive piece of technology pumping sound into their ears. Some of the new models, including Ms. Wing’s, are made by traditional prescription brands, which usually require a visit to a specialist. But the Food and Drug Administration opened up the market last year when it allowed the sale of hearing aids over the counter. In response, brand names like Sony and Jabra began releasing their own products, adding to the new wave of designs and features that appeal to young consumers. “These new hearing aids are sexy,” said Pete Bilzerian, a 25-year-old in Richmond, Va., who has worn the devices since he was 7. He describes his early models as distinctly unsexy: “big, funky, tan-colored hearing aids with the molding that goes all around the ear.” But increasingly, those have given way to sleeker, smaller models with more technological capabilities. Nowadays, he said, no one seems to notice the electronics in his ear. “If it ever does come up as a topic, I just brush it off and say, ‘Hey, I got these very expensive AirPods.’” More people in Mr. Bilzerian’s age group might need the equivalent of expensive AirPods, experts say. By the time they turn 30, about a fifth of Americans today have had their hearing damaged by noise, the Centers for Disease Control and Prevention recently estimated. This number adds to the already substantial population of young people with hearing loss tied to genetics or medical conditions. © 2023 The New York Times Company

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 28770 - Posted: 05.06.2023

Nicola Davis Science Correspondent If the sound of someone chewing gum or slurping their tea gets on your nerves, you are not alone. Researchers say almost one in five people in the UK has strong negative reactions to such noises. Misophonia is a disorder in which people feel strong emotional responses to certain sounds, feeling angry, distressed or even unable to function in social or work settings as a result. But just how common the condition is has been a matter of debate. Now researchers say they have found 18.4% of the UK population have significant symptoms of misophonia. “This is the very first study where we have a representative sample of the UK population,” said Dr Silia Vitoratou, first author of the study at King’s College London. “Most people with misophonia think they are alone, but they are not. This is something we need to know [about] and make adjustments if we can.” Writing in the journal Plos One, the team report how they gathered responses from 768 people using metrics including the selective sound sensitivity syndrome scale. This included one questionnaire probing the sounds that individuals found triggering, such as chewing or snoring, and another exploring the impact of such sounds – including whether they affected participants’ social life and whether the participant blamed the noise-maker – as well as the type of emotional response participants felt to the sounds and the intensity of their emotions. As a result, each participant was given an overall score. The results reveal more than 80% of participants had no particular feelings towards sounds such as “normal breathing” or “yawning” but this plummeted to less than 25% when it came to sounds including “slurping”, “chewing gum” and “sniffing”. © 2023 Guardian News & Media Limited

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 14: Attention and Higher Cognition
Link ID: 28712 - Posted: 03.23.2023

By Erin Blakemore Tinnitus — a ringing or whistling sound in the ears — plagues millions worldwide. Though the estimates of those bothered by the condition vary, a new study suggests they may have something in common: exposure to road traffic noise at home. The paper, published in Environmental Health Perspectives, looked to Denmark to find a potential link between road noise and tinnitus levels. The nationwide study included data on 3.5 million Danish residents who were 30 and older between 2000 and 2017. Over that time, 40,692 were diagnosed with tinnitus. When the researchers calculated likely traffic and noise levels at the quietest facade of their residences in that period, they found those living with louder road noise were more likely to be diagnosed with tinnitus than those who lived in quieter areas. People’s risk rose 6 percent with every 10-decibel increase in road traffic noise compared with controls. Levels rose the longer a person had been exposed to higher road traffic noise. Women, people without a previous history of hearing loss, and people with higher education and income were at increased risk. The study did not find an association between railway noise and tinnitus diagnoses. Though the paper shows an association between tinnitus and traffic noise, it does not prove that one causes the other. The researchers say it’s important to learn more about the potential effects of residential noise exposure — and posit that if traffic noise does cause tinnitus, it might do so by disrupting people’s sleep. “We know that traffic noise can make us stressed and affect our sleep. And that tinnitus can get worse when we live under stressful situations and we do not sleep well,” said Jesper Hvass Schmidt, an associate professor at the University of Southern Denmark and the paper’s co-author, in a news release.

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 28661 - Posted: 02.11.2023

Niyazi Arslan Cochlear implants are among the most successful neural prostheses on the market. These artificial ears have allowed nearly 1 million people globally with severe to profound hearing loss to either regain access to the sounds around them or experience the sense of hearing for the first time. However, the effectiveness of cochlear implants varies greatly across users because of a range of factors, such as hearing loss duration and age at implantation. Children who receive implants at a younger age may may be able to acquire auditory skills similar to their peers with natural hearing. I am a researcher studying pitch perception with cochlear implants. Understanding the mechanics of this technology and its limitations can help lead to potential new developments and improvements in the future. In fully-functional hearing, sound waves enter the ear canal and are converted into neural impulses as they move through hairlike sensory cells in the cochlea, or inner ear. These neural signals then travel through the auditory nerve behind the cochlea to the central auditory areas of the brain, resulting in a perception of sound. Analysis of the world, from experts People with severe to profound hearing loss often have damaged or missing sensory cells and are unable to convert sound waves into electrical signals. Cochlear implants bypass these hairlike cells by directly stimulating the auditory nerve with electrical pulses. Cochlear implants consist of an external part wrapped behind the ear and an internal part implanted under the skin. © 2010–2023, The Conversation US, Inc.

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 28639 - Posted: 01.25.2023

Miryam Naddaf Stimulating neurons that are linked to alertness helps rats with cochlear implants learn to quickly recognize tunes, researchers have found. The results suggest that activity in a brain region called the locus coeruleus (LC) improves hearing perception in deaf rodents. Researchers say the insights are important for understanding how the brain processes sound, but caution that the approach is a long way from helping people. “It’s like we gave them a cup of coffee,” says Robert Froemke, an otolaryngologist at New York University School of Medicine and a co-author of the study, published in Nature on 21 December1. Cochlear implants use electrodes in the inner-ear region called the cochlea, which is damaged in people who have severe or total hearing loss. The device converts acoustic sounds into electrical signals that stimulate the auditory nerve, and the brain learns to process these signals to make sense of the auditory world. Some people with cochlear implants learn to recognize speech within hours of the device being implanted, whereas others can take months or years. “This problem has been around since the dawn of cochlear implants, and it shows no signs of being resolved,” says Gerald Loeb at the University of Southern California in Los Angeles, who helped to develop one of the first cochlear implants. Researchers say that a person’s age, the duration of their hearing loss and the type of processor and electrodes in the implant don’t account for this variation, but suggest that the brain could be the source of the differences. “It’s sort of the black box,” says Daniel Polley, an auditory neuroscientist at Harvard Medical School in Boston, Massachusetts. Most previous research has focused on improving the cochlear device and the implantation procedure. Attempts to improve the brain’s ability to use the device open up a way to improve communication between the ear and the brain, says Polley. © 2022 Springer Nature Limited

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 28615 - Posted: 12.28.2022

Hannah Devlin Science correspondent Music makes you lose control, Missy Elliott once sang on a hit that is almost impossible to hear without bopping along. Now scientists have discovered that rats also find rhythmic beats irresistible, showing how they instinctively move in time to music. This ability was previously thought to be uniquely human and scientists say the discovery provides insights into the animal mind and the origins of music and dance. “Rats displayed innate – that is, without any training or prior exposure to music – beat synchronisation,” said Dr Hirokazu Takahashi of the University of Tokyo. “Music exerts a strong appeal to the brain and has profound effects on emotion and cognition,” he added. While there have been previous demonstrations of animals dancing along to music – TikTok has a wealth of examples – the study is one of the first scientific investigations of the phenomenon. In the study, published in the journal Science Advances, 10 rats were fitted with wireless, miniature accelerometers to measure the slightest head movements. They were then played one-minute excerpts from Mozart’s Sonata for Two Pianos in D Major, at four different tempos: 75%, 100%, 200% and 400% of the original speed. Twenty human volunteers also participated. The scientists thought it possible that rats would prefer faster music as their bodies, including heartbeat, work at a faster pace. By contrast, the time constant of the brain is surprisingly similar across species. © 2022 Guardian News & Media Limited

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 28547 - Posted: 11.13.2022

Elizabeth Pennisi Think of the chattiest creatures in the animal kingdom and songbirds, dolphins, and—yes—humans probably come to mind. Turtles probably don’t register. But these charismatic reptiles also communicate using a large repertoire of clicks, snorts, and chortles. Now, by recording the “voices” of turtles and other supposedly quiet animals, scientists have concluded that all land vertebrate vocalizations—from the canary’s song to the lion’s roar—have a common root that dates back more than 400 million years. The findings imply animals began to vocalize very early in their evolutionary history—even before they possessed well-developed ears, says W. Tecumseh Fitch, a bioacoustician at the University of Vienna who was not involved with the work. “It suggests our ears evolved to hear these vocalizations.” Several years ago, University of Arizona evolutionary ecologist John Wiens and his graduate student Zhuo Chen started looking into the evolutionary roots of acoustic communication—basically defined as the sounds animals make with their mouths using their lungs. Combing the scientific literature, the duo compiled a family tree of all the acoustic animals known at the time, eventually concluding such soundmaking abilities arose multiple times in vertebrates between 100 million and 200 million years ago. But Gabriel Jorgewich-Cohen, an evolutionary biologist at the University of Zürich, noticed an oversight: turtles. Though Wiens and Chen had found that only two of 14 families of turtles made sounds, he was finding a lot more. He spent 2 years recording 50 turtle species in the act of “speaking.”

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 28530 - Posted: 10.28.2022

By Paula Span The world of hearing health will change on Oct. 17, when the Food and Drug Administration’s new regulations, announced in August, will make quality hearing aids an over-the-counter product. It just won’t transform as quickly or as dramatically, at least at first, as advocates, technology and consumer electronics companies and people with mild to moderate hearing loss have been hoping. “It finally, actually happened after all these years,” said Dr. Frank Lin, the director of the Johns Hopkins Cochlear Center for Hearing and Public Health and a longtime supporter of the regulations, which Congress authorized five years ago. “Ninety-plus percent of adults with hearing loss have needs that can be served by over-the-counter hearing aids,” he said. For decades, the sale of hearing aids was restricted to licensed audiologists and other professionals; that has kept prices high — prescription hearing aids can cost $4,000 to $5,000 — and access limited. In contrast, the regulations provide “a clear glide path for new companies to enter this field,” Dr. Lin said. But, he quickly added, “it may be the Wild West for the next few years.” Barbara Kelley, the executive director of the Hearing Loss Association of America, concurred: “It’s a new frontier, and it is confusing. We need time to see how the market settles out.” In an ideal scenario, a person would be able to walk into almost any pharmacy or big-box store and buy a sophisticated pair of hearing aids for a few hundred dollars, no prescription required. But the shift won’t materialize right away, experts say. In 2017, Congress granted the F.D.A. three years to develop standards for safe and effective over-the-counter hearing aids. The agency took five years instead, and the long delay and continued industry opposition made manufacturers skittish about investing, Dr. Lin said. © 2022 The New York Times Company

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 28509 - Posted: 10.13.2022

By Carolyn Gramling Hot or not? Peeking inside an animal’s ear — even a fossilized one — may tell you whether it was warm- or cold-blooded. Using a novel method that analyzes the size and shape of the inner ear canals, researchers suggest that mammal ancestors abruptly became warm-blooded about 233 million years ago, the team reports in Nature July 20. Warm-bloodedness, or endothermy, isn’t unique to mammals — birds, the only living dinosaurs, are warm-blooded, too. But endothermy is one of mammals’ key features, allowing the animals to regulate their internal body temperatures by controlling their metabolic rates. This feature allowed mammals to occupy environmental niches from pole to equator, and to weather the instability of ancient climates (SN: 6/7/22). When endothermy evolved, however, has been a mystery. Based on fossil analyses of growth rates and oxygen isotopes in bones, researchers have proposed dates for its emergence as far back as 300 million years ago. The inner ear structures of mammals and their ancestors hold the key to solving that mystery, says Ricardo Araújo, a vertebrate paleontologist at the University of Lisbon. In all vertebrates, the labyrinth of semicircular canals in the inner ear contains a fluid that responds to head movements, brushing against tiny hair cells in the ear and helping to maintain a sense of balance. That fluid can become thicker or thinner depending on body temperature. “Mammals have very unique inner ears,” Araújo says. Compared with cold-blooded vertebrates of similar size, the dimensions of mammals’ semicircular canals — such as thickness, length and radius of curvature — is particularly small, he says. “The ducts are very thin and tend to be very circular compared with other animals.” By contrast, fish have the largest for their body size. © Society for Science & the Public 2000–2022.

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell; Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 28408 - Posted: 07.23.2022

Freda Kreier Some bats can imitate the sound of buzzing hornets to scare off owls, researchers say. The discovery is the first documented case of a mammal mimicking an insect to deter predators. Many animals copy other creatures in a bid to make themselves seem less palatable to predators. Most of these imitations are visual. North America’s non-venomous scarlet kingsnake (Lampropeltis elapsoides), for instance, has evolved to have similar colour-coding to the decidedly more dangerous eastern coral snake (Micrurus fulvius). Now, a study comparing the behaviour of owls exposed to insect and bat noises suggests that greater mouse-eared bats (Myotis myotis) might be among the few animals to have weaponized another species’ sound, says co-author Danilo Russo, an animal ecologist at the University of Naples Federico II in Italy. “When we think of mimicry, the first thing that comes to mind is colour, but in this case, it is sound that plays a crucial role,” he adds. The research was published on 9 May in Current Biology1. Because they are nocturnal and have poor eyesight, most bats rely on echolocation to find their way around, and communicate using a wide array of other noises. Russo first noticed that the distress call of the greater mouse-eared bat sounded like the buzzing of bees or hornets while he was catching the bats for a different research project. To investigate whether other animals might make the same connection, Russo and his colleagues compared the sound structure of buzzing by the European hornet (Vespa crabro) to that of the bat’s distress call. At most frequencies, the two sounds were not dramatically similar, but they were when the bat’s call was stripped down to include only frequencies that owls — one of the animal’s main predators — are able to hear. This suggests that the distress call as heard by owls strongly resembles the buzzing of a hornet, Russo says, so it could fool predators. © 2022 Springer Nature Limited

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 28324 - Posted: 05.11.2022

Neuroscience researchers have found a master gene that controls the development of special sensory cells in the ears – potentially opening the door to reversing hearing loss. A team led by Jaime García-Añoveros of Northwestern University, US, established that a gene called Tbx2 controls the development of ear hair cells in mice. The findings of their study are published today in Nature. What are hair cells? Hair cells are the sensory cells in our ears that detect sound and then transmit a message to our brains. They are so named because they have tiny hairlike structures called stereocilia. “The ear is a beautiful organ,” says García-Añoveros. “There is no other organ in a mammal where the cells are so precisely positioned.” Hair cells are found in a structure called the organ of Corti, in the cochlea in the inner ear. The organ of Corti sits on top of the basilar membrane. Sound waves are funnelled through our ear canal and cause the eardrum (also known as the tympanic membrane) and ossicles (tiny bones called the malleus, incus and stapes) to vibrate. The vibrations, or waves, are transmitted through fluid in the cochlea, causing the basilar membrane to move as well. When the basilar membrane moves, the stereocilia tilt, causing ion channels in the hair cell membrane to open. This stimulates the hair cell to release neurotransmitter chemicals, which will transmit the sound signal to the brain via the auditory nerve.

Related chapters from BN: Chapter 9: Hearing, Balance, 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 and Learning
Link ID: 28319 - Posted: 05.07.2022

By Sharon Oosthoek Despite their excellent vision, one city-dwelling colony of fruit bats echolocates during broad daylight — completely contrary to what experts expected. A group of Egyptian fruit bats (Rousettus aegyptiacus) in downtown Tel Aviv uses sound to navigate in the middle of the day, researchers report in the April 11 Current Biology. The finding greatly extends the hours during which bats from this colony echolocate. A few years ago, some team members had noticed bats clicking while they flew under low-light conditions. The midday sound-off seems to help the bats forage and navigate, even though they can see just fine. Bats that are active during the day are unusual. Out of the more than 1,400 species, roughly 10 are diurnal. What’s more, most diurnal bats don’t use echolocation during the day, relying instead on their vision to forage and avoid obstacles. They save echolocation for dim light or dark conditions. So that’s why, two years ago, a group of Tel Aviv researchers were surprised when they noticed a bat smiling during the day. They were looking over photos from their latest study of Egyptian fruit bats when they noticed one with its mouth slightly parted and upturned. “When an Egyptian fruit bat is smiling, he’s echolocating — he’s producing clicks with his tongue and his mouth is open,” says Ofri Eitan, a bat researcher at Tel Aviv University. “But this was during the day, and these bats see really well.” When Eitan and his colleagues looked through other photos — thousands of them — many showed smiling bats in broad daylight. The team showed in 2015 that the diurnal Egyptian fruit bats do use echolocation outdoors under various low light conditions, at least occasionally. But the researchers hadn’t looked at whether the bats were echolocating during midday hours when light levels are highest. © Society for Science & the Public 2000–2022.

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 28286 - Posted: 04.16.2022

Nicola Davis Science correspondent It may not yet feature in a West End musical but scientists say they have found an unexpected response to singin’ in the brain. Researchers say they have found particular groups of neurons that appear to respond selectively to the sound of singing. Writing in the journal Current Biology, a team of scientists in the US report how they made their discovery by recording electrical activity in the brains of 15 participants, each of whom had electrodes inserted inside their skulls to monitor epileptic seizures before undergoing surgery. The team recorded electrical activity in response to 165 different sounds, from pieces of instrumental music to speech and sounds such as dogs barking, and then processed them using an algorithm. They combined the results with data from fMRI brain scans previously collected from 30 different individuals to map the location of the patterns in the brain. Dr Samuel Norman-Haignere, a co-author of the study based at the University of Rochester, said the team decided to combine the data from the different approaches to overcome their respective weaknesses and combine their strengths. “fMRI is one of the workhorses of human cognitive neuroscience, but it is very coarse. Intracranial data is much more precise but has very poor spatial coverage,” he said. The results confirmed previous findings from fMRI scans that some neurons respond only to speech or respond more strongly to music. However, they also revealed populations of neurons that appear to respond selectively to the sound of singing, showing only very weak responses to other types of music or speech alone. © 2022 Guardian News & Media Limited

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 14: Attention and Higher Cognition
Link ID: 28217 - Posted: 02.23.2022

By Hallie Levine If you have ever had a ringing or buzzing in one or both ears after a live concert, you have experienced tinnitus — defined as the perception of noise where no external noise is present, according to the American Tinnitus Association. Aside from loud sound, a variety of issues, like excess ear wax, infections and nasal congestion, can cause short-term tinnitus. After a loud event like a concert, the intrusive sounds usually fade within hours to days. But chronic tinnitus — where noise persistently waxes and wanes, or never disappears — affects about 11 percent of adults. In some cases, this can lead to trouble sleeping or concentrating, isolation, anxiety, depression and stress. A 2019 research letter published in JAMA Otolaryngology Head & Neck Surgery found that women with undiagnosed tinnitus were even at increased risk of suicide. Is there a covid-19 connection? During the pandemic, reports of tinnitus rose, especially in people with covid-19. A study published online last March in the International Journal of Audiology estimated that almost 15 percent of those with covid-19 said they had tinnitus, often early in the course of the virus. This typically lasted only a few days. But “there have been anecdotal reports from patients that they have experienced changes in hearing and tinnitus post-covid,” says Cleveland Clinic audiologist Sarah Sydlowski, president of the American Academy of Audiology. One theory is that the virus that causes covid-19 damages the auditory nerve at least temporarily, says Douglas Hildrew, an ear, nose, and throat (ENT) specialist at Yale Medicine.

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 28190 - Posted: 02.09.2022

ByWarren Cornwall Bats use sound to hunt a dizzying array of prey. Some zero in on flowers to sip nectar, whereas others find cattle and suck their blood. Many nab insects midflight. One species of bat senses small fish beneath the water and snatches them as osprey do. Now, scientists have discovered an anatomical quirk in the ears of some bats that could help explain how they evolved so many hunting specialties. “For me this is a huge revelation,” says Zhe-Xi Luo, a University of Chicago evolutionary biologist who has studied the origins of mammalian hearing and supervised the new research. “This is totally distinct and unique from all other hearing mammals.” Most bats use their ears to “see” the world around them: After a bat chirps, its ears sense shapes and movement as sound waves bounce off objects, much as ships use sonar. Bats’ ears were long thought to be just a finely tuned version of the ears of nearly all mammals. Then, in 2015, Benjamin Sulser, a University of Chicago biology student on the hunt for a thesis project, took detailed 3D images of the inner ear of a bat skull. But he couldn’t find a feature common in virtually all mammals—a bony tube that encases the nerve cells and connects the ear to the brain. Thinking he’d made a mistake, he and Luo imaged the skulls of two more related species using a computed tomography scanner, with similar results. The researchers realized they might have stumbled across an answer to a mystery that had bedeviled bat biologists for 2 decades—and an explanation for why some families of bats had such a diverse echolocation arsenal. © 2022 American Association for the Advancement of Science.

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 28175 - Posted: 01.29.2022

By Elizabeth Landau In a narrow medical school hallway, Matt Stewart opened a large cabinet to reveal dozens of shelves stacked with wooden boxes and trays, some at least 100 years old. Stewart, tall and silver-haired, pulled out one of the trays and showed off its contents: Thin slices of human skull bones and the organs of hearing and balance they contain, stained shades of pink. Affixed to microscope slides, the anatomical bits resembled abstract rubber stamp art, no bigger than thumbprints. “Our Johns Hopkins history,” he said, referring to the university’s collection of specimens from more than 5,000 patients. Stewart’s research team at Johns Hopkins University in Baltimore had a long, complicated journey to make slides like these in 2021. The researchers need these specimens, sliced from the portion of skull that houses the inner ear, to ask a fundamental question about the novel coronavirus, SARS-CoV-2: Does it directly invade the cells of tissues that enable hearing and balance? Ear surgeon Matt Stewart leads a research team at Johns Hopkins University that is investigating how SARS-CoV-2 might infect ear cells that enable hearing and balance. Data on ear problems as they relate to Covid-19, the disease caused by SARS-CoV-2, is spotty. To date, case reports and small studies have found that some Covid-19 patients experience significant and rapid hearing loss, ringing in the ears called tinnitus, or balance issues. Estimates vary on the prevalence of these symptoms, but because the coronavirus has infected hundreds of millions of people, even a few percent of Covid patients experiencing hearing loss would add up to a large increase globally. Yet no causal link has been drawn between the novel coronavirus and auditory symptoms. Hearing problems aren’t even on lists of Covid-19 symptoms, short or long-term, published by the Centers for Disease Control and Prevention.

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 28139 - Posted: 01.05.2022

Bill Chappell People with mild or moderate hearing loss could soon be able to buy hearing aids without a medical exam or special fitting, under a new rule being proposed by the Food and Drug Administration. The agency says 37.5 million American adults have difficulty hearing. "Today's move by FDA takes us one step closer to the goal of making hearing aids more accessible and affordable for the tens of millions of people who experience mild to moderate hearing loss," Health and Human Services Secretary Xavier Becerra said as he announced the proposed rule on Tuesday. There is no timeline yet for when consumers might be able to buy an FDA-regulated over-the-counter (OTC) hearing aid. The proposed rule is now up for 90 days of public comment. The Hearing Loss Association of America, a consumer advocacy group, welcomed the proposal. "This is one step closer to seeing OTC hearing devices on the market," Barbara Kelley, the group's executive director, said in an email to NPR. "We hope adults will be encouraged to take that important first step toward good hearing health." Advocates and lawmakers have been calling for OTC hearing aids for years, including in a big push in 2017, when Sen. Elizabeth Warren, D-Mass., and co-sponsor Sen. Chuck Grassley, R-Iowa, introduced the bipartisan Over-the-Counter Hearing Aid Act. The legislators are now praising the FDA's move. © 2021 npr

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 28042 - Posted: 10.20.2021