Nicola Davis Science correspondent The human sense of smell is nothing to turn one’s nose up at, research suggests, with scientists revealing we are far more sensitive to the order of odours captured by a sniff than previously thought. Charles Darwin is among those who have cast aspersions on our sense of smell, suggesting it to be “of extremely slight service” to humans, while scientists have long thought our olfactory abilities rather sluggish. “Intuitively, each sniff feels like taking a long-exposure shot of the chemical environment,” said Dr Wen Zhou, co-author of the research from the Chinese Academy of Sciences, adding that when a smell is detected it can seem like one scent, rather than a discernible mixture of odours that arrived at different times. “Sniffs are also separated in time, occurring seconds apart from one another,” she said. But now researchers have revealed our sense of smell operates much faster than previously thought, suggesting we are as sensitive to rapid changes in odours as we are to rapid changes in colour. A key challenge to probing our sense of smell, said Zhou, is that it has been difficult to create a setup that enables different smelly substances to be presented in a precise sequence in time within a single sniff. However, writing in the journal Nature Human Behaviour, Zhou and colleagues report how they did just that by creating an apparatus in which two bottles containing different scents were hooked up to a nosepiece using tubes of different lengths. These tubes were fitted with miniature check valves that were opened by the act of taking a sniff. © 2024 Guardian News & Media Limited

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29518 - Posted: 10.16.2024

By Angie Voyles Askham Unlike the primary sensory brain areas that process sights and sounds, the one that decodes scents also responds to other stimuli, such as images and words associated with an odor, according to a study published today in Nature. The extent to which neurons in the primary olfactory cortex, which includes the piriform cortex, respond to non-odor stimuli was surprising, says Marc Spehr, head of the Chemosensation Laboratory at RWTH Aachen University, who co-led the study. One neuron, for example, which activated in response to the scent of black licorice, also responded to the word “licorice,” images of the candy and the odor of anise seed, which is unrelated but has a similar scent. Cells in the amygdala also showed multimodal responses; one neuron, for example, responded to a banana scent as well as the word “banana.” “These aren’t odor signals that these cells are encoding; these cells are encoding concepts,” says Kevin Franks, associate professor of neurobiology at Duke University, who was not involved in the work but wrote a News and Views article on it. “So in this part of the brain, traditionally being considered this primary sensory area, you have sensory invariant conceptual representations of specific types of objects. And that’s really, really cool.” Smell-detecting neurons in the nose project into the brain’s olfactory bulb, which then passes information directly to the piriform cortex and other parts of the primary olfactory cortex. That means the piriform cortex lies only two synapses away from the stimuli it decodes, Franks says. In the visual system, on the other hand, a cell two synapses away from a photon is still in the retina, he says. Despite the limited odor processing that happens before the signal reaches the piriform cortex, there have been earlier hints that the area acts more like an association cortex than like other primary sensory areas, says Thorsten Kahnt, investigator at the U.S. National Institute on Drug Abuse, who was not involved in the work. © 2024 Simons Foundation

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29514 - Posted: 10.12.2024

By Shaena Montanari Sea robins skitter across the sea floor with six tiny fins-turned-legs. And at least one species of these bottom feeders is exceptionally skilled at digging up food—so good that other fishes follow these sea robins to snatch up leftover snacks. The sea robins owe this talent to their legs, according to a pair of studies published today in Current Biology. The new work shows that the appendages evolved a specialized sensory system to feel and taste hidden prey. The legs of one common species, for example, are innervated by touch-sensitive neurons and dotted with tiny papillae that express taste receptors. “It’s just really neat to see the molecular components that nature is using to spin out not only new structures, but also new behaviors,” says David Kingsley, professor of developmental biology at Stanford University and an investigator on both studies. The results formalize work from the 1960s and ’70s that first indicated the special chemosensory abilities of sea robins, says Tom Finger, professor of cell and developmental biology at the University of Colorado Anschutz Medical Campus, who was not involved in the new studies. This is “a major, important contribution to show that taste receptors have become expressed in the specialized sensory organ.” This finding “demonstrates, I think, an evolutionary principle, which is that evolution uses the tool kit that’s in place and then just slightly changes it,” says Nicholas Bellono, professor of molecular and cellular biology at Harvard University, who is an investigator on both new studies and also researches unique senses in cephalopods. Last year, he and his colleagues described a similar adaptation in octopuses: “They took this receptor that was for neurotransmission and then just repurposed it with a slight tinkering to now be a sensory receptor. So it’s sort of a theme we keep seeing repeat across the diversity of life.” © 2024 Simons Foundation

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 29500 - Posted: 10.02.2024

By Daniela Hirschfeld Peter Mombaerts is a man of strong preferences. He likes Belgian beer — partly, but not entirely, for patriotic reasons. He likes classical music and observing the Earth from above while flying small planes with his amateur pilot’s license. He loves the feel of alpaca clothing during winter. But Mombaerts, who leads the Max Planck Research Unit for Neurogenetics in Frankfurt, Germany, says he has no favorite odor — even though he has been studying smells for more than 30 years. Mombaerts’s research has focused on how the brain processes odors, and on the impressive group of genes encoding odorant receptors in mammals. Humans have about 400 of these genes, which means that 2 percent of our roughly 20,000 genes help us to smell — the largest gene family known to date, as Mombaerts noted back in 2001 in the Annual Review of Genomics and Human Genetics. More than two decades later, it remains the record holder, and Mombaerts continues to delve into the genetics and neuroscience of how we smell the world around us. He spoke with Knowable Magazine about what’s been learned about the genes, receptors and neurons involved in sensing odors — and the mysteries that remain. This interview has been edited for length and clarity. Why did you start working on smell? When studying medicine in my native Belgium in the 1980s, I learned that I don’t really like to work so much with patients. But research interested me. I wanted to do neurobiology. I did my PhD in immunology with mice and genetics, and then moved to neuroscience. It was what I always wanted to do, but I had to find the right topic, the right lab and the right mentor — and all that came together when Linda Buck and Richard Axel published their paper about their discovery of the genes for odorant receptors. This paper came out in the journal Cell on April 5, 1991, and when I read the first few sentences I thought, “That’s what I want to work on.” Axel became my postdoc mentor. When Buck and Axel won the Nobel Prize in Physiology or Medicine in 2004, I wrote a Perspective piece for the New England Journal of Medicine  that I titled “Love at First Smell.” © 2024 Annual Reviews

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29469 - Posted: 09.07.2024

By Kerri Smith The smell in the laboratory was new. It was, in the language of the business, tenacious: for more than a week, the odour clung to the paper on which it had been blotted. To researcher Alex Wiltschko, it was the smell of summertime in Texas: watermelon, but more precisely, the boundary where the red flesh transitions into white rind. “It was a molecule that nobody had ever seen before,” says Wiltschko, who runs a company called Osmo, based in Cambridge, Massachusetts. His team created the compound, called 533, as part of its mission to understand and digitize smell. His goal — to develop a system that can detect, predict or create odours — is a tall order, as molecule 533 shows. “If you looked at the structure, you would never have guessed that it smelled this way.” That’s one of the problems with understanding smell: the chemical structure of a molecule tells you almost nothing about its odour. Two chemicals with very similar structures can smell wildly different; and two wildly different chemical structures can produce an almost identical odour. And most smells — coffee, Camembert, ripe tomatoes — are mixtures of many tens or hundreds of aroma molecules, intensifying the challenge of understanding how chemistry gives rise to olfactory experience. Another problem is working out how smells relate to each other. With vision, the spectrum is a simple colour palette: red, green, blue and all their swirling intermediates. Sounds have a frequency and a volume, but for smell there are no obvious parameters. Where does an odour identifiable as ‘frost’ sit in relation to ‘sauna’? It’s a real challenge to make predictions about smell, says Joel Mainland, a neuroscientist at the Monell Chemical Senses Center, an independent research institute in Philadelphia, Pennsylvania. © 2024 Springer Nature Limited

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29463 - Posted: 09.04.2024

By Sneha Khedkar About 10 years ago, when Michael Yartsev set up the NeuroBat Lab, he built a new windowless cave of sorts: a fully automated bat flight room. Equipped with cameras and other recording devices, the remote-controlled space has enabled his team to study the neuronal basis of navigation, acoustic and social behavior in Egyptian fruit bats without having any direct interaction with the animals. “In our lab, there’s never a human involved in the experiments,” says Yartsev, associate professor of bioengineering at the University of California, Berkeley. The impetus to create the space was clear. The setup, paired with wireless electrodes inserted in the bats’ hippocampus, has helped the team demonstrate, for example, that place cells encode a flying bat’s current, past and future locations. Also, a mountain of evidence suggests that the identity, sex and stress levels of human experimenters can influence the behavior of and brain circuit activity in other lab animals, such as mice and rats. Now Yartsev and his team have proved that “experimenter effects” hold true for bats, too, according to a new study published last month in Nature Neuroscience. The presence of human experimenters changed hippocampal neuronal activity in bats both at rest and during flight—and exerted an even stronger influence than another fruit bat, the study shows. The team expected that humans would influence neural activity, Yartsev says, “but we did not expect it to be so profound.” © 2024 Simons Foundation

Keyword: Attention; Hearing
Link ID: 29430 - Posted: 08.13.2024

Ari Daniel On a dark night in northern Belize in early May, Gliselle Marin stands in the middle of a patchy forest in the Lamanai Archaeological Reserve, about a two-hour drive from where she grew up. Every few minutes, she and her fellow researchers sweep their headlamps over the nets they’ve strung up to see if they’ve caught anything. Before long, a chirping leaf-nosed bat the color of hot cocoa is entangled. He’s small — about the size of a lemon. Marin works carefully and quickly to free him. “We’re trying to get the net off of him,” she says. “It’s kind of like a puzzle. I like to take the feet out first. And then I do one wing, then the head.” Within a minute, the tiny bat is out. Marin jots down some basic information about the bat and then places him inside a cloth bag for further study that night. All the tools Marin needs for this kind of delicate extraction — including an ordinary crochet hook, for the worst tangles — fit into a fanny pack that’s adorned with little printed bats. The scientist also sports bat earrings, as well as a tattoo of small bats flying up the nape of her neck. Marin is a biology PhD student at York University in Toronto, and she’s here with the “Bat-a-thon,” a group of 80-some bat researchers who converge on this part of Belize each year to study these winged mammals. Growing up, Marin’s family had bats roosting under their house. “But when I actually started working with them and realizing we have close to 80 species of bats,” she says, “I was like, ‘Okay, it’s kind of crazy that I’ve been in science my whole life and was never taught that we have this diversity of bats in Belize.’” Over time, she’s come to admire not just the cornucopia of species, but the spectacular array of abilities and behaviors of these adaptable little animals. Scientists, she says, have only scratched the surface when it comes to understanding these furry, flying mammals. © 2024 npr

Keyword: Hearing
Link ID: 29429 - Posted: 08.13.2024

By Elena Kazamia It was a profound moment of connection. Carlos Casas could feel the elephant probing him, touching him with sound. The grunts emanating from the large male were of a frequency too low to hear, but Casas felt an agitation on his skin and deep inside his chest. “I was being scanned,” he says. At the time of the encounter, Casas was filming a project in Sri Lanka, and was holding a camera. But his interactions with the elephant gave the Catalonian filmmaker and installation artist an idea: What if instead of relying on images alone, he could use sound to create a physical connection between an audience of people and the subjects that fascinate him most, the animals with which we share life on this planet? Bestiari, his audio-visual project, now on display inside a former shipping warehouse at the Venice Biennale, weaves an immersive landscape for visitors. (You can explore some of the project, which was curated by Filipa Ramos, at the Instagram page for the installation.) Audio of the sounds the animals make is accompanied by video collected from remote camera traps set across national parks of Catalonia and Kenya, together with abstract film meant to capture the world as the animals see it, based on a combination of scientific research and artistic license. A series of texts serve as field guides to each animal featured in the installation. Entering the dark warehouse where Bestiari is housed, you are invited to lie on the floor, as if to fall asleep, before communing with seven different species: bees, donkeys, parakeets, snakes, bats, dolphins, and elephants. Each of the chosen species is represented by a speaker, customized to deliver the desired acoustics. Casas calls the speakers, “Trojan horses of meaning and communication.” The pitches and volumes were curated to be authentic to the original animal but perceptible by humans. For example, the echolocation chirps of bats have been slowed down to showcase the tonal progression of the sound. © 2024 NautilusNext Inc.,

Keyword: Hearing; Evolution
Link ID: 29421 - Posted: 08.03.2024

By Hannah Richter Humans aren’t the only animals that lose hearing as they grow older. Almost every mammal studied struggles to pick up some sounds as they age. Some veterinarians even fit dogs for tiny hearing aids. But at least one species of bat appears to be an exception. Reporting this month on the preprint server bioRxiv, scientists have discovered that big brown bats (Eptesicus fuscus) don’t hear any worse as they grow older, possibly because their ability to echolocate is so critical to their survival. “Hearing is kind of their superpower,” says Mirjam Knörnschild, a behavioral ecologist at the Museum of Natural History Berlin who was not involved with the work. The research, she and others say, could lead to new ways to understand—and possibly treat—hearing loss in humans. Bats actually have two superpowers. Not only can most of them echolocate—bouncing sound off objects to hunt and navigate—they also tend to be remarkably long-lived for their size. Most small mammals are short-lived, but compared with mice of similar stature, the big brown bat lives up to five times as long, sometimes topping out at 19 years old. That makes the species a fascinating target for studies of aging, says Grace Capshaw, a postdoctoral researcher at Johns Hopkins University. The bat auditory system is fundamentally the same as that of every other mammal, she says, so “bats can be a really powerful model for comparing how hearing works.” To test whether big brown bats lose their hearing over time, Capshaw and colleagues divided 23 wild-caught bats into groups of young and old, making 6 years—the mean age of the species—the dividing line. The researchers determined the bats’ ages using a precise genetic method that involves comparing each animal’s DNA with the DNA of bats with known ages. They then sedated the animals to conduct a hearing examination similar to those done on human infants.

Keyword: Hearing
Link ID: 29411 - Posted: 07.31.2024

By Meghan Rosen Float like a butterfly, sniff out cancer like a bee? Honeybees can detect the subtle scents of lung cancer in the lab — and even the faint aroma of disease that can waft from a patient’s breath. Inspired by the insects’ exquisite olfactory abilities, scientists hooked the brains of living bees up to electrodes, passed different scents under the insects’ antennae and then recorded their brain signals. “It’s very clear — like day and night — whether [a bee] is responding to a chemical or not,” says Debajit Saha, a neural engineer at Michigan State University in East Lansing. Different odors sparked recognizable brain activity patterns, a kind of neural fingerprint for scent, Saha and colleagues report June 4 in Biosensors and Bioelectronics. One day, he says, doctors might be able to use honeybees in cancer clinics as living sensors for early disease detection. Electronic noses, or e-noses, and other types of mechanical odor-sensing equipment exist, but they’re not exactly the bee’s knees. When it comes to scent, Saha says, “biology has this ability to differentiate between very, very similar mixtures, which no other engineered sensors can do.” Scent is an important part of how many insect species communicate, says chemical ecologist Flora Gouzerh of the French National Research Institute for Sustainable Development in Montpellier. For them, “it’s a language,” she says. The idea that animal senses can get a whiff of disease is nothing new; doctors reported a case of a border collie and a Doberman sniffing out their owner’s melanoma in 1989. More recently, scientists have shown that dogs can detect COVID-19 cases by smelling people’s sweat (SN: 6/1/22). A lot of insects probably have disease-detecting abilities, too, Gouzerh says. Ants, for instance, can be trained to pick out the smell of cancer cells grown in a lab dish. But until now, bees’ abilities haven’t been quite so clear, she says. © Society for Science & the Public 2000–2024.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29372 - Posted: 06.26.2024

By Scott Sayare As a boy, Les Milne carried an air of triumph about him, and an air of sorrow. Les was a particularly promising and energetic young man, an all-Scottish swim champion, head boy at his academy in Dundee, a top student bound for medical school. But when he was young, his father died; his mother was institutionalized with a diagnosis of manic depression, and he and his younger brother were effectively left to fend for themselves. His high school girlfriend, Joy, was drawn to him as much by his sadness as his talents, by his yearning for her care. “We were very, very much in love,” Joy, now a flaxen-haired 72-year-old grandmother, told me recently. In a somewhat less conventional way, she also adored the way Les smelled, and this aroma of salt and musk, accented with a suggestion of leather from the carbolic soap he used at the pool, formed for her a lasting sense of who he was. “It was just him,” Joy said, a steadfast marker of his identity, no less distinctive than his face, his voice, his particular quality of mind. Listen to this article, read by Robert Petkoff Joy’s had always been an unusually sensitive nose, the inheritance, she believes, of her maternal line. Her grandmother was a “hyperosmic,” and she encouraged Joy, as a child, to make the most of her abilities, quizzing her on different varieties of rose, teaching her to distinguish the scent of the petals from the scent of the leaves from the scent of the pistils and stamens. Still, her grandmother did not think odor of any kind to be a polite topic of conversation, and however rich and enjoyable and dense with information the olfactory world might be, she urged her granddaughter to keep her experience of it to herself. Les only learned of Joy’s peculiar nose well after their relationship began, on a trip to the Scandinavian far north. Joy would not stop going on about the creamy odor of the tundra, or what she insisted was the aroma of the cold itself. Joy planned to go off to university in Paris or Rome. Faced with the prospect of tending to his mother alone, however, Les begged her to stay in Scotland. He trained as a doctor, she as a nurse; they married during his residency. He was soon the sort of capable young physician one might hope to meet, a practitioner of uncommon enthusiasm, and shortly after his 30th birthday, he was appointed consultant anesthesiologist at Macclesfield District General Hospital, outside Manchester, in England, the first in his graduating class to make consultant. © 2024 The New York Times Company

Keyword: Parkinsons; Chemical Senses (Smell & Taste)
Link ID: 29363 - Posted: 06.15.2024

Ian Sample Science editor Five children who were born deaf now have hearing in both ears after taking part in an “astounding” gene therapy trial that raises hopes for further treatments. The children were unable to hear because of inherited genetic mutations that disrupt the body’s ability to make a protein needed to ensure auditory signals pass seamlessly from the ear to the brain. Doctors at Fudan University in Shanghai treated the children, aged between one and 11, in both ears in the hope they would gain sufficient 3D hearing to take part in conversations and work out which direction sounds were coming from. Within weeks of receiving the therapy, the children had gained hearing, could locate the sources of sounds, and recognised speech in noisy environments. Two of the children were recorded dancing to music, the researchers reported in Nature Medicine. A child facing away from the camera towards a panel of auditory testing equipment with script in the top left corner Dr Zheng-Yi Chen, a scientist at Massachusetts Eye and Ear, a Harvard teaching hospital in Boston that co-led the trial, said the results were “astounding”, adding that researchers continued to see the children’s hearing ability “dramatically progress”. The therapy uses an inactive virus to smuggle working copies of the affected gene, Otof, into the inner ear. Once inside, cells in the ear use the new genetic material as a template to churn out working copies of the crucial protein, otoferlin. Video footage of the patients shows a two-year-old boy responding to his name three weeks after the treatment and dancing to music after 13 weeks, having shown no response to either before receiving the injections. © 2024 Guardian News & Media Limited

Keyword: Hearing; Genes & Behavior
Link ID: 29347 - Posted: 06.06.2024

By Joanne Silberner Think for a minute about the little bumps on your tongue. You probably saw a diagram of those taste bud arrangements once in a biology textbook — sweet sensors at the tip, salty on either side, sour behind them, bitter in the back. But the idea that specific tastes are confined to certain areas of the tongue is a myth that “persists in the collective consciousness despite decades of research debunking it,” according to a review published this month in The New England Journal of Medicine. Also wrong: the notion that taste is limited to the mouth. The old diagram, which has been used in many textbooks over the years, originated in a study published by David Hanig, a German scientist, in 1901. But the scientist was not suggesting that various tastes are segregated on the tongue. He was actually measuring the sensitivity of different areas, said Paul Breslin, a researcher at Monell Chemical Senses Center in Philadelphia. “What he found was that you could detect things at a lower concentration in one part relative to another,” Dr. Breslin said. The tip of the tongue, for example, is dense with sweet sensors but contains the others as well. The map’s mistakes are easy to confirm. If you place a lemon wedge at the tip of your tongue, it will taste sour, and if you put a bit of honey toward the side, it will be sweet. The perception of taste is a remarkably complex process, starting from that first encounter with the tongue. Taste cells have a variety of sensors that signal the brain when they encounter nutrients or toxins. For some tastes, tiny pores in cell membranes let taste chemicals in. Such taste receptors aren’t limited to the tongue; they are also found in the gastrointestinal tract, liver, pancreas, fat cells, brain, muscle cells, thyroid and lungs. We don’t generally think of these organs as tasting anything, but they use the receptors to pick up the presence of various molecules and metabolize them, said Diego Bohórquez, a self-described gut-brain neuroscientist at Duke University. For example, when the gut notices sugar in food, it tells the brain to alert other organs to get ready for digestion. © 2024 The New York Times Company

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29336 - Posted: 06.02.2024

By Jordan Pearson Engineers and scientists have an enduring fascination with spider silk. Similar to typical worm silk that makes for comfy bedsheets, but much tougher, the material has inspired the invention of lighter and more breathable body armor and materials that could make airplane components stronger without adding weight. Researchers are even using examples drawn from spider webs to design sensitive microphones that can one day be used to treat hearing loss and deafness and to improve other listening devices. Spiders use their webs like enormous external eardrums. A team of scientists from Binghamton University and Cornell University reported in 2022 that webs allow arachnids to detect sound from 10 feet away. When you hear a sound through your ear, what you’re really experiencing are changes in air pressure that cause your eardrum to vibrate. This is how microphones work: by mimicking the human ear and vibrating in response to pressure. Instead of vibrating when hit by a wave of pressure like a stick hitting a drumhead, they move with the flow of the air being displaced. Air is a fluid medium “like honey,” said Ronald Miles, a professor of mechanical engineering at Binghamton. Humans navigate this environment without noticing much resistance, but silk fibers are buffeted about by the velocity of the viscous forces in air. Dr. Miles couldn’t help but wonder if this principle could lead to a new kind of microphone. “Humans are kind of arrogant animals,” he said. “They make devices that work like they do.” But he wondered about building a device to be more like a spider and sense “sound with the motion of the air.” © 2024 The New York Times Company

Keyword: Hearing
Link ID: 29310 - Posted: 05.18.2024

By Jake Buehler Sounding like a toxic moth might keep some beetles safe from hungry bats. When certain tiger beetles hear an echolocating bat draw near, they respond with extremely high-pitched clicks. This acoustic countermeasure is a dead ringer for the noises toxic moths make to signal their nasty taste to bats, researchers report May 15 in Biology Letters. Such sound-based mimicry may be widespread among groups of night-flying insects, the scientists say. At night, bats and bugs are locked in sonic warfare. At least seven major insect groups have ears sensitive to bat echolocation pitches, and many often flee in response. Some moths have sound-absorbent wings and fuzz that impart stealth against bat sonar (SN: 11/14/18). Others use their genitals to make ultrasonic trills — above the range of human hearing — that may startle bats or jam their sonar (SN: 7/3/13). Previous research suggested some tiger beetles — a family of fast-running, often strikingly colored predatory beetles with strong jaws — also make high-pitched clicks as a response to human-made imitations of bat ultrasound. So Harlan Gough, a conservation entomologist now at the U.S. Fish and Wildlife Service in Burbank, Wash., and his colleagues set out to answer why. The researchers collected 19 tiger beetle species from southern Arizona and brought them into the lab. They tethered the insects to a metal rod and prompted them to fly. The team then filmed and recorded audio to see how the beetles responded to playback of a bat clicking sequence that immediately precedes an attack. Right away, seven of these species — all nocturnal fliers — pulled their hard, case-like forewings into the path of their beating hindwings. The resulting collisions made high-pitched clicking noises. © Society for Science & the Public 2000–2024.

Keyword: Hearing; Evolution
Link ID: 29308 - Posted: 05.16.2024

Andrew Gregory Health editor A British toddler has had her hearing restored after becoming the first person in the world to take part in a pioneering gene therapy trial, in a development that doctors say marks a new era in treating deafness. Opal Sandy was born unable to hear anything due to auditory neuropathy, a condition that disrupts nerve impulses travelling from the inner ear to the brain and can be caused by a faulty gene. But after receiving an infusion containing a working copy of the gene during groundbreaking surgery that took just 16 minutes, the 18-month-old can hear almost perfectly and enjoys playing with toy drums. Her parents were left “gobsmacked” when they realised she could hear for the first time after the treatment. “I couldn’t really believe it,” Opal’s mother, Jo Sandy, said. “It was … bonkers.” The girl, from Oxfordshire, was treated at Addenbrooke’s hospital, part of Cambridge university hospitals NHS foundation trust, which is running the Chord trial. More deaf children from the UK, Spain and the US are being recruited to the trial and will all be followed up for five years. Prof Manohar Bance, an ear surgeon at the trust and chief investigator for the trial, said the initial results were “better than I hoped or expected” and could cure patients with this type of deafness. “We have results from [Opal] which are very spectacular – so close to normal hearing restoration. So we do hope it could be a potential cure.” He added: “There’s been so much work, decades of work … to finally see something that actually worked in humans …. It was quite spectacular and a bit awe-inspiring really. It felt very special.” Auditory neuropathy can be caused by a fault in the OTOF gene, which makes a protein called otoferlin. This enables cells in the ear to communicate with the hearing nerve. To overcome the fault, the new therapy from biotech firm Regeneron sends a working copy of the gene to the ear. © 2024 Guardian News & Media Limited

Keyword: Hearing; Genes & Behavior
Link ID: 29300 - Posted: 05.09.2024

By Gina Kolata At 7 p.m. on May 7, 1824, Ludwig van Beethoven, then 53, strode onto the stage of the magnificent Theater am Kärntnertor in Vienna to help conduct the world premiere of his Ninth Symphony, the last he would ever complete. That performance, whose 200th anniversary is on Tuesday, was unforgettable in many ways. But it was marked by an incident at the start of the second movement that revealed to the audience of about 1,800 people how deaf the revered composer had become. Ted Albrecht, a professor emeritus of musicology at Kent State University in Ohio and author of a recent book on the Ninth Symphony, described the scene. The movement began with loud kettledrums, and the crowd cheered wildly. But Beethoven was oblivious to the applause and his music. He stood with his back to the audience, beating time. At that moment, a soloist grasped his sleeve and turned him around to see the raucous adulation he could not hear. It was one more humiliation for a composer who had been mortified by his deafness since he had begun to lose his hearing in his twenties. But why had he gone deaf? And why was he plagued by unrelenting abdominal cramps, flatulence and diarrhea? A cottage industry of fans and experts has debated various theories. Was it Paget’s disease of bone, which in the skull can affect hearing? Did irritable bowel syndrome cause his gastrointestinal problems? Or might he have had syphilis, pancreatitis, diabetes or renal papillary necrosis, a kidney disease? After 200 years, a discovery of toxic substances in locks of the composer’s hair may finally solve the mystery. © 2024 The New York Times Company

Keyword: Hearing; Neurotoxins
Link ID: 29293 - Posted: 05.07.2024

By Laura Sanders What does it feel like to be a rat? We will never know, but some very unusual mice may now have an inkling. In a series of new experiments, bits of rat brain grew inside the brains of mice. Donor stem cells from rats formed elaborate — and functional — neural structures in mice’s brains, despite being from a completely different species, researchers report in two papers published April 25 in Cell. The findings are “remarkable,” says Afsaneh Gaillard, a neuroscientist at INSERM and the University of Poitiers in France. “The ability to generate specific neuronal cells that can successfully integrate into the brain may provide a solution for treating a variety of brain diseases associated with neuronal loss.” These chimeric mice are helping to reveal just how flexible brain development can be (SN: 3/29/23). And while no one is suggesting that human brains could be grown in another animal, the results may help clarify biological details relevant to interspecies organ transplants, the researchers say. The success of these rat-mouse hybrids depended on timing: The rat and mouse cells had to grow into brains together from a very young stage. Stem cells from rats that had the potential to mature into several different cell types were injected into mouse embryos. From there, these rat cells developed alongside mice cells in the growing brain, though researchers couldn’t control exactly where the rat cells ended up. In one set of experiments, researchers first cleared the way for these rat cells to develop in the young mouse brains. Stem cell biologist Jun Wu and colleagues used a form of the genetic tool CRISPR to inactivate a mouse gene that instructs their brain cells to build a forebrain, a large region involved in learning, remembering and sensing the world. This left the mice without forebrains — normally, a lethal problem. © Society for Science & the Public 2000–2024.

Keyword: Development of the Brain; Neurogenesis
Link ID: 29274 - Posted: 04.26.2024

Sofia Quaglia Noise pollution from traffic stunts growth in baby birds, even while inside the egg, research has found. Unhatched birds and hatchlings that are exposed to noise from city traffic experience long-term negative effects on their health, growth and reproduction, the study found. “Sound has a much stronger and more direct impact on bird development than we knew before,” said Dr Mylene Mariette, a bird communication expert at Deakin University in Australia and a co-author of the study, published in the journal Science. “It would be wise to work more to reduce noise pollution.” A growing body of research has suggested that noise pollution causes stress to birds and makes communication harder for them. But whether birds are already distressed at a young age because they are affected by noise, or by how noise disrupts their environment and parental care, was still unclear. Mariette’s team routinely exposed zebra finch eggs for five days to either silence, soothing playbacks of zebra finch songs, or recordings of city traffic noises such as revving motors and cars driving past. They did the same with newborn chicks for about four hours a night for up to 13 nights, without exposing the birds’ parents to the sounds. They noticed that the bird eggs were almost 20% less likely to hatch if exposed to traffic noise. The chicks that did hatch were more than 10% smaller and almost 15% lighter than the other hatchlings. When the team ran analyses on their red blood cells and their telomeres – a piece of DNA that shortens with stress and age – they were more eroded and shorter than their counterparts’. The effects continued even after the chicks were no longer exposed to noise pollution, and carried over into their reproductive age four years later. The birds disturbed by noise during the early stages of their lives produced fewer than half as many offspring as their counterparts. © 2024 Guardian News & Media Limited

Keyword: Hearing; Development of the Brain
Link ID: 29273 - Posted: 04.26.2024

By Gillian Dohrn No one wants to eat when they have an upset stomach. To pinpoint exactly where in the brain this distaste for eating originates, scientists studied nauseated mice. The work, published in Cell Reports on 27 March1, describes a previously uncharacterized cluster of brain cells that fire when a mouse is made to feel nauseous, but don’t fire when the mouse is simply full. This suggests that responses to satiety and nausea are governed by separate brain circuits. “With artificial activation of this neuron, the mouse just doesn’t eat, even if it is super hungry,” says Wenyu Ding at the Max Planck Institute for Biological Intelligence in Martinsried, Germany, who led the study. Ding and colleagues suspected that this group of neurons was involved in processing negative experiences, such as feeling queasy, so they injected the mice with a chemical that induces nausea and then scanned the animals’ brains. This confirmed that the neurons are active when mice feel nauseous. Using a light-based technique called optogenetics, the team artificially activated the neurons of mice that had been deprived of food in the hours before the experiment. When the neurons were ‘off’, the mice ate. When the researchers turned them on, the mice walked away mid-chow. These brain cells could influence how fast you eat — and when you stop Researchers also blocked the activity of these neurons in nauseated mice that were hungry and found that the mice overcame their nausea to eat. © 2024 Springer Nature Limited

Keyword: Obesity; Chemical Senses (Smell & Taste)
Link ID: 29263 - Posted: 04.20.2024