By Katharine Gammon Picture this: You’re sitting down, engrossed in a meal, when an unfamiliar person walks by. There’s something about them—Hair? Smile? Vibes?—that instantly draws you in and makes you want to strike up a friendship. A new study suggests that it could be the scent they exude that attracts you to them. Not just the way their skin or hair smells, but the deodorant and shampoo they use, the foods they consume, even their laundry detergent. Our sense of smell tends to operate below the level of conscious awareness, says Jessica Gaby, a psychology researcher at Middle Tennessee State University and an author of the study, so our responses to it are often hidden from us. “But at the same time, it’s inescapable,” she says. “You can’t fake it.” Gaby and her colleagues, who were at Cornell University when the study was conducted, brought 40 women aged 18-30 together in a Cornell dining hall, a large, refurbished barn with café tables that doubles as a beer hall at night. The scent of popcorn, beer, and leftover dinner wafted over the room: The idea was to have a complex olfactory environment. The women all identified as heterosexual, so the researchers could focus on the type of attraction that might lead to friendship. In the first phase of the study, the participants received cotton T-shirts and were instructed to wear them for 12 hours straight without altering their daily routines, and to keep notes about their activities. One participant used spray paint in an art project, another had sex, another said she spilled a small amount of black beans on her shirt. In the second phase of the study, the participants were instructed to view photographs of different individual women, some of whom they would later meet. They then each sniffed the worn T-shirts, then had four-minute meetings, speed-dating style, with the other individual women, then sniffed their T-shirts again. After each step, they judged their friendship potential with the other women on a scale of 1 to 7. © 2025 NautilusNext Inc.,

Keyword: Chemical Senses (Smell & Taste); Emotions
Link ID: 29783 - Posted: 05.11.2025

By Susan Milius Here’s a great case of real life turning out to be stranger than fiction. From baby’s first storybook to sly adult graphic novels, the story we’re told is the same: Male frogs croak with the bottom of their mouths ballooning out in one fat, rounded bubble. Yet “that’s actually only half the species of frogs,” says herpetologist Agustín Elías-Costa of the Bernardino Rivadavia Natural Science Museum in Buenos Aires. The diversity of body parts for ribbitting is astounding. Some males serenade with a pair of separate puff-out disks like padded headphones that slipped down the frog’s neck, throbbing in brilliant blue. Some have sacs that look like balloon Mickey Mouse ears in khaki. Others ribbit with a single upright like a fat horn stub on some inflatable swimming pool toy rhino. All together, 20 basic forms for vocal sacs have evolved among frogs and toads, Elías-Costa and herpetologist Julián Faivovich report in March in the Bulletin of the American Museum of Natural History. Still, about 18 percent of the 4,358 species examined didn’t have vocal sacs at all. The team studied 777 specimens over 10 years of visiting museums around the world, including the Smithsonian’s National Museum of Natural History in Washington, D.C. “Libraries of nature,” Faivovich calls them. Just drawing a picture of something doesn’t authenticate details the way a preserved specimen does. These collections for biodiversity studies are “what makes them a science,” he says. The survey showed that vocal sacs disappeared between 146 and 196 times across the very twiggy evolutionary branchings of the frog and toad family tree. That’s “an astounding number considering their biological importance,” Elías-Costa says. Even without sacs, the animals still emit sounds because, like human speech, frog and toad ribbits originate from the larynx. Vocal sacs amplify the sound and could convey nuances of male quality and sexiness, but can also tip off eavesdropping predators. Females in a few species vocalize too, but it’s mostly a male endeavor. © Society for Science & the Public 2000–2025.

Keyword: Sexual Behavior; Hearing
Link ID: 29774 - Posted: 05.07.2025

Logan S. James It is late at night, and we are silently watching a bat in a roost through a night-vision camera. From a nearby speaker comes a long, rattling trill. The bat briefly perks up and wiggles its ears as it listens to the sound before dropping its head back down, uninterested. Next from the speaker comes a higher-pitched “whine” followed by a “chuck.” The bat vigorously shakes its ears and then spreads its wings as it launches from the roost and dives down to attack the speaker. Bats show tremendous variation in the foods they eat to survive. Some species specialize on fruits, others on insects, others on flower nectar. There are even species that catch fish with their feet. At the Smithsonian Tropical Research Institute in Panama, we’ve been studying one species, the fringe-lipped bat (Trachops cirrhosus), for decades. This bat is a carnivore that specializes in feeding on frogs. Male frogs from many species call to attract female frogs. Frog-eating bats eavesdrop on those calls to find their next meal. But how do the bats come to associate sounds and prey? We were interested in understanding how predators that eavesdrop on their prey acquire the ability to discriminate between tasty and dangerous meals. We combined our expertise on animal behavior, bat cognition and frog communication to investigate. © 2010–2025, The Conversation US, Inc.

Keyword: Hearing; Development of the Brain
Link ID: 29768 - Posted: 05.03.2025

By Gina Kolata Do we really have free will when it comes to eating? It’s a vexing question that is at the heart of why so many people find it so difficult to stick to a diet. To get answers, one neuroscientist, Harvey J. Grill of the University of Pennsylvania, turned to rats and asked what would happen if he removed all of their brains except their brainstems. The brainstem controls basic functions like heart rate and breathing. But the animals could not smell, could not see, could not remember. Would they know when they had consumed enough calories? To find out, Dr. Grill dripped liquid food into their mouths. “When they reached a stopping point, they allowed the food to drain out of their mouths,” he said. Those studies, initiated decades ago, were a starting point for a body of research that has continually surprised scientists and driven home that how full animals feel has nothing to do with consciousness. The work has gained more relevance as scientists puzzle out how exactly the new drugs that cause weight loss, commonly called GLP-1s and including Ozempic, affect the brain’s eating-control systems. The story that is emerging does not explain why some people get obese and others do not. Instead, it offers clues about what makes us start eating, and when we stop. While most of the studies were in rodents, it defies belief to think that humans are somehow different, said Dr. Jeffrey Friedman, an obesity researcher at Rockefeller University in New York. Humans, he said, are subject to billions of years of evolution leading to elaborate neural pathways that control when to eat and when to stop eating. © 2025 The New York Times Company

Keyword: Obesity; Chemical Senses (Smell & Taste)
Link ID: 29762 - Posted: 04.26.2025

Andrew Gregory Health editor Doctors in London have successfully restored a sense of smell and taste in patients who lost it due to long Covid with pioneering surgery that expands their nasal airways to kickstart their recovery. Most patients diagnosed with Covid-19 recover fully. But the infectious disease can lead to serious long-term effects. About six in every 100 people who get Covid develop long Covid, with millions of people affected globally, according to the World Health Organization. Losing a sense of smell and taste are among more than 200 different symptoms reported by people with long Covid. Now surgeons at University College London Hospitals NHS Foundation Trust (UCLH) have cured a dozen patients, each of whom had suffered a profound loss of smell after a Covid infection. All had experienced the problem for more than two years and other treatments, such as smell training and corticosteroids, had failed. In a study aiming to find new ways to resolve the issue, surgeons tried a technique called functional septorhinoplasty (fSRP), which is typically used to correct any deviation of the nasal septum, increasing the size of nasal passageways. This boosts airflow into the olfactory region, at the roof of the nasal cavity, which controls smell. Doctors said the surgery enabled an increased amount of odorants – chemical compounds that have a smell – to reach the roof of the nose, where sense of smell is located. They believe that increasing the delivery of odorants to this area “kickstarts” smell recovery in patients who have lost their sense of smell to long Covid. © 2025 Guardian News & Media Limited

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29697 - Posted: 03.08.2025

By Laura Sanders Ancient ear-wiggling muscles kick on when people strain to hear. That auricular activity, described January 30 in Frontiers in Neuroscience, probably doesn’t do much, if anything. But these small muscles are at least present, and more active than anyone knew. You’ve probably seen a cat or dog swing their ears toward a sound, like satellite dishes orienting to a signal. We can’t move our relatively rigid human ears this dramatically. And yet, humans still possess ear-moving muscles, as those of us who can wiggle our ears on demand know. Neuroscientist Andreas Schröer and colleagues asked 20 people with normal hearing to listen to a recorded voice while distracting podcasts played in the background. All the while, electrodes around the ears recorded muscle activity. An ear muscle called the superior auricular muscle, which sits just above the ear and lifts it up, fired up when the listening conditions were difficult, the researchers found. Millions of years ago, these muscles may have helped human ancestors collect sounds. Today, it’s doubtful that this tiny wisp of muscle activity helps a person hear better, though scientists haven’t tested that. “It does its best, but it probably doesn’t work,” says Schröer, of Saarland University in Saarbrücken, Germany. These vestigial muscles may not help us hear, but their activity could provide a measurement of a person’s hearing efforts. That information may be useful to hearing aid technology, telling the device to change its behavior when a person is struggling, for instance. © Society for Science & the Public 2000–2025.

Keyword: Hearing; Evolution
Link ID: 29665 - Posted: 02.12.2025

By Jackson Ryan Fruit fly larvae can sense the texture of rotting fruit.Credit: Scott Bauer/USDA/SPL For maggots, the experience of eating a succulent meal isn’t just about how their food tastes, but also how it feels. Researchers used genetic tools to reveal that certain neurons in the brain control food choice and can sense both taste and texture1 . The conventional view of taste sensing holds that specific neurons carry single signals to the brain, says study co-author Simon Sprecher, a neurobiologist at the University of Fribourg in Switzerland. For instance, sweet taste neurons carry sweet signals and bitter taste neurons carry bitter signals. But those assumptions have been challenged over the past two decades by studies in fruit flies and mice that suggest neurons might have the capacity to respond to both chemical signals, such as bitter or sweet, as well as mechanical signals, such as texture. In the current study, published in PLoS Biology on 30 January, Sprecher and his colleagues set out to see whether individual neurons in taste organs have this ‘multimodal’ capacity. They fed fruit-fly larvae — maggots — different preparations of agarose, a sugary gel. The maggots showed a propensity for a ‘Goldilocks’ preparation, one that was neither too hard nor too soft. The preferred hardness for larvae is “similar to [that] of decaying fruit”, says Sprecher. The researchers then used genetic engineering tools to disable a subset of taste-sensing neurons in the larval taste-sensing organs. Disabling the neurons prevented the maggots from tasting the sweetness of the agarose, as expected, but it also changed which preparations they ate — the maggots no longer preferred Goldilocks preparations, suggesting that they had also lost their ability to feel their food. By studying individual neurons, the researchers determined that C6 neurons can both taste sugar and sense mechanical simulation. © 2025 Springer Nature Limited

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29650 - Posted: 02.01.2025

Nicola Davis Science correspondent Wiggling your ears might be more of a pub party piece than a survival skill, but humans still try to prick up their ears when listening hard, researchers have found. Ear movement is crucial in many animals, not least in helping them focus their attention on particular noises and work out which direction they are coming from. But while the human ear is far more static, traces of our ancestors’ ear-orienting system remain in what has been called a “neural fossil”. “It is believed that our ancestors lost their ability to move their ears about 25m years ago. Why, exactly, is difficult to say,” said Andreas Schröer, the lead author of the research from Saarland University in Germany. “However, we have been able to demonstrate that the neural circuits still seem to be present in some state, [that is] our brain retained some of the structures to move the ears, even though they apparently are not useful any more.” The team previously found the movement of these muscles in humans is related to the direction of the sounds they are paying attention to. Now, they have found that some of these muscles become activated when humans listen hard to a sound. Writing in the journal Frontiers in Neuroscience, the team reported how they asked 20 adults without hearing problems to listen to an audiobook played through a speaker at the same time as a podcast was played from the same location. The team created three different scenarios: in the “easiest” scenario the podcast was quieter than the audiobook, with a large difference in pitch between the voices. In the “hardest” scenario, two podcasts were played which, taken together, were louder than the audiobook, with one of the podcasts spoken at a similar pitch to the audiobook. © 2025 Guardian News & Media Limited

Keyword: Hearing; Evolution
Link ID: 29649 - Posted: 02.01.2025

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