By Hannah Docter-Loeb At the otolaryngology department at the Ohio State University, Kai Zhao is on a quest to solve smell loss. While cochlear implants or hearing aids can be used to treat auditory impairments and lenses or surgery can tackle vision loss, there is no equivalent go-to treatment for a weakened sense of smell. Among all the senses, smell is perhaps the least well understood. Scientists are only just beginning to get to grips with how smell is organized in the brain and body. And exactly why and how some people lose their sense of smell is unclear at best. “Smell loss is a really underrecognized problem and medical condition, and currently there [is] no treatment at all,” Zhao says. Some researchers have experimented with bionic noses and implants that pulse electrical signals into the olfactory system to try and restore smell. But Zhao is trying a different method: wearable devices that help redirect airflow in the nose to the olfactory region. Only a fraction of the air we breathe in through our noses reaches the olfactory cleft—that’s the place inside our noses where the olfactory bulb, a structure in the forebrain that processes smell signals, resides. Zhao theorized that perhaps it would be possible to increase the airflow to the olfactory system. He likens the idea to hearing aids, which amplify sound signals in the ears. “You’re amplifying the smell signal instead of the sound,” he says. In March 2025 Zhao and his colleagues published the results of their first prototypes in BMC Medicine. They developed a nasal foam plug and a clip similar to those used by synchronized swimmers. Both work to enhance the odor delivery to the olfactory region. The plug helps open the odor flow to the nose. Meanwhile, according to Zhao, the clip is a bit more counterintuitive: it pinches the nasal valve to enhance narrowing, which can improve function. © 2026 SCIENTIFIC AMERICAN INC.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 30340 - Posted: 07.25.2026

Ushika Kidd Long-term exposure to road traffic noise is associated with a higher risk of Parkinson’s disease, the biggest study of its kind has found. Parkinson’s disease is a progressive disorder in which parts of the brain become damaged over time, affecting movement and balance. Existing research has found potential biological pathways that link noise exposure to Parkinson’s disease, largely due to stress responses and disrupted sleep. The researchers modelled noise exposure at the most and least exposed exterior of the residence of each participant and calculated the difference in noise levels. The magnitude of the effect was modest but consistent; at the most exposed facade, for every 11.5dB rise in noise level, the risk of Parkinson’s disease rose by 3% over the study period. Having a quiet part of the home may mitigate the association between exposure to road traffic noise and higher risk of Parkinson’s disease, according to the findings. The study, published in Jama Neurology, included 3.1 million Danish participants aged 40 and over, and followed them for 18 years. It was established using nationwide health register data, making it the largest study on road traffic noise and Parkinson’s disease. Previous research linked the rise in neurological disorders, including Parkinson’s disease, with exposure to environmental toxins. Environmental risk factors such as air pollution, microplastics and pesticides have become the main focus of prevention strategies. © 2026 Guardian News & Media Limited

Keyword: Parkinsons; Hearing
Link ID: 30339 - Posted: 07.25.2026

By Victoria Clayton About 14 years ago, Chrissi Kelly lost her sense of smell. She had traveled to the Czech Republic to visit family and caught some virus. Months later, when she still couldn’t smell, she made the rounds to doctors, including her general practitioner and an ear, nose and throat specialist, trying to find answers. She was diagnosed with anosmia (smell loss), and like many patients with her condition, was told she’d have to learn to live with it. But for her, the loss was catastrophic. “After about six months of complete loss, I was just climbing the walls, and I did not feel like myself anymore,” she says. Researchers estimate that up to 22 percent of the population lives with smell impairments, like hyposmia (partial smell loss) or anosmia (complete smell loss). And many others live with smell disorders like phantosmia, in which a person picks up phantom smells, or parosmia, where typically pleasant scents like coffee or shampoo begin to register as highly unpleasant (think feces or vomit). Yet the conditions have been poorly understood, underdiagnosed and often minimized by clinicians. Photos of shampoo, coffee, trees and logs. A world without scents or with warped ones can feel deeply unfamiliar. When our sense of smell goes awry, normally pleasant scents such as shampoo or coffee may be perceived as disgusting, or strong, unmistakable odors such as pine trees in a forest or fresh-cut lumber may fail to be registered at all. The pandemic changed that. Covid brought unprecedented attention — and research interest — to the sense of smell. There have been 780 million reported cases of Covid-19 since December 2019 (and many more unreported), according to the World Health Organization, and smell loss is a well-known symptom. In one 2023 survey published in the journal Laryngoscope, 60 percent of individuals with Covid experienced smell loss, most temporarily, but some over the longer term.

Keyword: Chemical Senses (Smell & Taste); Emotions
Link ID: 30289 - Posted: 06.20.2026

Chris Simms Olfactory receptors in the mouse nose have been mapped out in unprecedented detail — overturning researchers’ understanding of how noses build a sense of smell. The research, published today in Cell1, shows how around 1,100 olfactory receptors expressed on sensory neurons are organized in tightly regulated spatial locations in the epithelial tissue that lines the nasal cavity. A second study2 provides a complementary atlas of olfactory receptor expression in the olfactory epithelium and their neural connections to the olfactory bulb in the brain. “For 30 years, we’ve taught students that the mouse olfactory epithelium is divided into a handful of broad zones, within which receptor choice is essentially random,” says Johan Lundström, a psychologist and experimental neuroscientist at the Karolinska Institute in Stockholm. In the study, researchers examined about five million neurons from hundreds of individual mice. They first used single-cell sequencing to identify which smell receptors were expressed by neurons in the nose, and then used spatial transcriptomics to map out where key genes were being expressed. This allowed them to pinpoint where the receptors are and show that they are always arranged in horizontal stripes running from the top of the nose to the bottom. “Each receptor adopts a particular position in the nose. Since there are a thousand positions in the nose, each receptor is expressed basically in a stripe that overlaps with other receptor stripes, in a thousand overlapping stripes,” says study co-author Sandeep Robert Datta, a neurobiologist at Harvard Medical School in Boston, Massachusetts. Datta and his colleagues propose that this spatial mapping is organized during development and is controlled by sets of genes. The authors found that a molecule called retinoic acid had a key role in this process. They discovered a gradient in the amount of retinoic acid present at different points in the nose. By tweaking how much this molecule was expressed, they showed that it helps to control gene activity, guiding each neuron to express the correct type of smell receptor for its location. © 2026 Springer Nature Limited

Keyword: Chemical Senses (Smell & Taste)
Link ID: 30224 - Posted: 04.29.2026

By Gina Kolata The Food and Drug Administration on Thursday approved a gene therapy that can cure a rare, inherited form of deafness. The treatment is the first to restore normal hearing in children who were born deaf. The maker of the therapy, Regeneron, plans to provide it free to any child who needs it. “We wanted to make a statement,” Dr. George Yancopoulos, Regeneron’s chief scientific officer said on Thursday morning. He explained that the company wants to be sure its treatment “would be able to reach its full potential and help as many people as possible.” Some gene therapies for other diseases, priced in the millions of dollars, have had dismal sales. The therapy called Otarmeni, is intended for children with otoferlin deafness, a rare form of hearing loss caused by a mutation in a single gene. The mutation destroys a protein in the inner ear that is needed to transmit sound to the brain. Although otoferlin deafness accounts for just 2 percent to 8 percent of congenital hearing loss, the new treatment “is groundbreaking,” Dr. Dylan Chan, a pediatric otolaryngologist at the University of California, San Francisco, said. He added, “This is the first time in history that there has been a medical therapy that has enabled deaf children to hear.” Dr. Chan has been a paid adviser to Regeneron and to Eli Lilly, which is also developing a gene therapy for otoferlin deafness. He is also a principal investigator for Lilly’s clinical trial of the treatment. © 2026 The New York Times Company

Keyword: Hearing; Genes & Behavior
Link ID: 30216 - Posted: 04.26.2026

By Corinna da Fonseca-Wollheim The placid chords of a Debussy prelude splashed through a darkened auditorium during a recital by the pianist Nicolas Namoradze at the University of California, San Francisco, on a November evening. A translucent image of Namoradze’s brain appeared above him on a screen: Electrical currents of different wavelengths, associated with varying levels of alertness, registered as colorful activity coursing through the model like storm fronts on a weather map. With each chord, clouds of green and blue bloomed, then faded as the sound receded. As the recital progressed with works by Bach, Beethoven and Scriabin, the image of the gently rotating brain showed a complex choreography of signals that sometimes ping-ponged between different areas or flickered simultaneously across the organ’s hemispheres. As a visual spectacle accompanying Namoradze’s pellucid playing, it was mesmerizing: an X-ray, seemingly, of virtuosity at work. But to the scientists in the audience, attendees at a conference on the neuroscience of music and dance, it was more than entertainment. It was evidence of a breakthrough in experiment design — one that opens up possibilities in an area that has long eluded scientific study: how music activates the brain, not in listeners, but in performers. It was also a reminder of the value artists can bring to scientific inquiry as active participants shaping studies of their craft. The neuroscientist Theodore Zanto, a member of the Neuroscape lab at U.C.S.F. that created the “Glass Brain” animations, said in an interview the next day that he was surprised — and moved — by the result. “It’s probably the cleanest real-time representation of what’s happening inside the brain during a piano performance,” he said. © 2026 The New York Times Company

Keyword: Hearing; Brain imaging
Link ID: 30115 - Posted: 02.11.2026

By Nora Bradford For more than a century, psychologists thought that the infant experience was, as the psychologist and philosopher William James famously put it, a “blooming, buzzing confusion.” But new research suggests babies are born with a surprisingly sophisticated neurological toolkit that can organize the visual world into categories and pick out the beat in a song. In the first of two new studies, neuroscientists managed a rare feat: performing functional MRI (fMRI) scans on more than 100 awake 2-month-old infants to see how their brains categorize visual objects. fMRI requires near-stillness, which makes scanning babies notoriously difficult. While the infants lay in the machines, images of animals, food, household objects and other familiar items appeared above their heads like “an IMAX for babies,” says Cliona O’Doherty, a developmental neuroscientist at Stanford University who conducted the work at Trinity College Dublin. “MRI is difficult even under ‘ideal’ circumstances when research participants can follow instructions to hold still,” says Scott Johnson, a developmental psychologist at UCLA who was not involved in the study. “Babies can’t take instruction, so these researchers must have the patience of saints.” The imaging showed that a brain region called the ventral visual cortex, responsible for recognizing what we see, already responded similarly to that of adults, O’Doherty and colleagues report February 2 in Nature Neuroscience. In both adults and 2-month olds, the ventral visual cortex’s activity is distinct for different categories of objects, pushing back against the traditional view that the brain gradually learns to distinguish between categories throughout development. © Society for Science & the Public 2000–2026

Keyword: Hearing; Development of the Brain
Link ID: 30111 - Posted: 02.07.2026

By Catherine Offord Researchers have tested a proof-of-concept device that enabled people who had lost their normal sense of smell to detect the presence of certain odors. Rather than exploiting the smell pathway, in which nasal cells send signals along olfactory nerves to the brain, the technology makes use of a less known nerve highway in the nose that transmits other sensations, including the kick of wasabi and the coolness of mint. “It’s an interesting study,” says Zara Patel, a rhinologist at Stanford Medicine who was not involved in the work, published today in Science Advances. “This is not recovering a sense of smell, this is activating a different system.” But she and others caution it remains to be seen how beneficial this kind of technology could be for people with smell loss, or anosmia. Humans have about 400 different olfactory receptors that are thought to enable the nose to detect billions of odors. But people can lose some or all of their sense of smell for a variety of reasons, including head trauma and viral infections such as COVID-19. People with long-term anosmia describe a significantly reduced quality of life and are at higher risk of mental health disorders, notes Halina Stanley, a research scientist at CNRS, the French national research agency, and co-author on the new paper. “The idea that if you lose your sense of smell, this isn’t as bad as losing another sense, I think is actually quite wrong.” Research by another team in 2018 found that electrodes placed in the sinuses near the olfactory bulb, the brain region that processes odor signals, could stimulate perception of smell, with people reporting onion or fruity scents, for example. Scientists are now working to develop implants that could more directly and specifically stimulate the olfactory bulb—akin to cochlear implants, which replace lost hearing by detecting sounds and stimulating the auditory nerve. However, such technology would be complex and invasive, and, at present, is a long way from becoming a therapy. © 2025 American Association for the Advancement of Science.

Keyword: Chemical Senses (Smell & Taste); Robotics
Link ID: 30032 - Posted: 11.29.2025

Davide Castelvecchi Pigeons can sense Earth’s magnetic field by detecting tiny electrical currents in their inner ears, researchers suggest. Such an inner compass could help to explain how certain animals can achieve astonishing feats of long-distance navigation. The team performed advanced brain mapping as well single-cell RNA sequencing of pigeon inner-ear cells. Both lines of evidence point to the inner ear as the birds’ ‘magnetoreception’ organ. The results appeared in the Science on 20 November 1. “This is probably the clearest demonstration of the neural pathways responsible for magnetic processing in any animal,” says Eric Warrant, a sensory biology researcher at the University of Lund in Sweden. Studies have suggested that various animals, including turtles, trout and robins, can sense the direction and strength of magnetic fields, although the evidence has sometimes been contested — and the mechanisms have remained controversial. Bird-brained navigation Two leading hypotheses have led the research into how birds sense magnetic fields. One is a quantum-physics effect in retina cells where birds ‘see’ magnetic fields. Another is that microscopic iron oxide particles in the beak could act as tiny compass needles. However, it’s largely unknown where magnetic information is sensed in animals’ brains and how sensory neurons confer sensitivity to electromagnetic changes. In 2011, researchers found hints that magnetic fields triggered pigeons’ vestibular system, the organ that enables vertebrates to sense accelerations (including gravity) and helps them to stay balanced2. The structure is made of three fluid-filled loops which are mutually perpendicular, so they can communicate to the brain the direction of an acceleration by breaking it down into three ‘x, y, z’ components. © 2025 Springer Nature Limited

Keyword: Animal Migration; Hearing
Link ID: 30024 - Posted: 11.22.2025

By Siddhant Pusdekar Taste and smell are so intimately connected that a whiff of well-loved foods evokes their taste without any conscious effort. Now, brain scans and machine learning have for the first time pinpointed the region responsible for this sensory overlap in humans, a region called the insula, researchers report September 12 in Nature Communications. The findings could explain why people crave certain foods or are turned away from them, says Ivan de Araujo, a neuroscientist at Max Planck Institute for Biological Cybernetics in Tübingen, Germany. Smell and taste become associated from the moment we bite into something, says Putu Agus Khorisantono, a neuroscientist at Karolinska Institutet in Stockholm. Some food chemicals activate sweet, salty, sour, bitter or umami taste receptors on the tongue. Others travel through the roof of the mouth, activating odor receptors in the back of the nose. These “retronasal odors” are what distinguish mangoes from peaches, for example. Both taste mostly sour, Khorisantono says, “but it’s really the aroma that differentiates them.” The brain combines these signals to create our sense of flavor, but scientists have struggled to identify where this happens in the brain. In the new study, Khorisantono and colleagues gave 25 people drops of beverages designed to activate only their taste or retronasal receptors, while scanning brain activity over multiple sessions. Previously, the participants had learned to associate the combination of smells and tastes with particular flavors. © Society for Science & the Public 2000–2025.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29967 - Posted: 10.11.2025

By Jeré Longman Dr. A. James Hudspeth, a neuroscientist at the Rockefeller University in Manhattan who was pivotal in discovering how sound waves are converted in the inner ear to electrical signals that the brain can perceive as a whisper, a symphony or a thunderclap, died on Aug. 16 at his home in Manhattan. He was 79. His wife, Dr. Ann Maurine Packard, said the cause was glioblastoma, a brain cancer. Scientists have long understood how sound waves enter the ear canal and cause the eardrum to vibrate. They have also understood how the vibrations travel through the three small bones of the middle ear, then to the cochlea in the inner ear, a tiny organ about the size of a chickpea that is filled with fluid and is shaped like a snail’s shell. And they have long known that microscopic receptor cells in the cochlea play a role in the process of hearing. But by the time Dr. Hudspeth began his research in the 1970s, it was still unclear how these cells — known as hair cells (the name derives from tufts of cylindrical, hairlike rods known as stereocilia) — transformed the mechanical vibrations of sound waves into nerve impulses that the brain could interpret as, say, a child crying or a dog barking. Dr. Hudspeth “provided the major framework” for this understanding, the committee that awarded him and two other scientists (Robert Fettiplace and Christine Petit) the Kavli Prize in Neuroscience for their pioneering work on the processes of hearing wrote in its citation in 2018. Each cochlea contains about 16,000 hair cells. Atop each cell, 20 to 300 of these rods are gathered in a bundle — the shortest to the tallest — in rows that resemble a staircase or a pipe organ. Hair cells line the cochlea, with each tuned to a narrow frequency range that collectively decodes the broad spectrum of tones in every sound. © 2025 The New York Times Compan

Keyword: Hearing
Link ID: 29915 - Posted: 09.06.2025

By K. R. Callaway Ever bite into something so bitter that you had to spit it out? An ages-old genetic mutation helps you and other animals perceive bitterness and thus avoid toxins associated with it. But while most creatures instinctively spit first and ask questions later, molecular biologists have been trying to get a taste of what bitterness can tell us about sensory evolution and human physiology. A new study, published in the Journal of Agricultural and Food Chemistry, is the first analysis of how taste receptors respond to a mushroom’s bitter compounds—which include some of the most potently bitter flavors currently known to science. The bitter bracket mushroom is nontoxic but considered inedible because of its taste. Researchers extracted its bitter compounds, finding two familiar ones—and three that were previously unknown. Instead of tasting these substances themselves, the scientists introduced them to an “artificial tongue” that they made by inserting human taste receptors into fast-growing embryonic kidney cells. One of the newfound bitter substances activated the taste receptors even at the lowest concentration measured, 63.3 micrograms per liter. That’s like sensing three quarters of a cup of sugar in an Olympic-sized swimming pool. Humans have about 25 kinds of bitter taste receptors lining our mouths and throats, but these same receptors also grow throughout the body—in the lungs, digestive tract and even brain. Despite their ubiquity, they have been only partially explored. Four of our bitter receptors have no known natural activator. Finding activating compounds could illuminate the interactions that might have shaped those taste receptors’ evolution, says study lead author Maik Behrens, a molecular biologist at the Leibniz Institute for Food Systems Biology. © 2025 SCIENTIFIC AMERICAN,

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29882 - Posted: 08.09.2025

By Nazeefa Ahmed Humans prefer fruit at its sweetest, whereas many birds happily snack on the sourest of the bunch, from zesty lemons to unripe honey mangoes. Researchers may now know why. A study published today in Science suggests birds have evolved a specialized taste receptor that’s suppressed by high acidity, which effectively dulls the sharp, sour taste of fruits they eat. The finding reveals the evolutionary history of the pucker-inducing diets of many fruit-eating birds around the world—and may also help explain birds’ knack for survival, by broadening their potential food sources. The study is a “robust” addition to our understanding of how birds taste sour foods, which is still a research area in its infancy, says Leanne Grieves, an ornithologist at Cornell University’s Lab of Ornithology. Scientists identified a sour taste receptor in vertebrates—known as OTOP1—only 7 years ago, and few studies focus on why birds eat what they eat, rather than simply what they eat. Grieves, who studies birds’ sense of smell but who was not involved with the current work, adds that the new study “provides a really nice starting point.” To examine how birds approach sour-tasting foods, scientists exposed OTOP1 receptors from mice, domestic pigeons, and canaries to various acidic solutions. The activity of the mouse version of the receptor increased with greater acidity—meaning more acidic foods register to mice, and other mammals like us, as increasingly sour. However, the pigeon and canary versions of OTOP1 became less active in solutions about as acidic as a lemon. As a result, the birds wouldn’t perceive as much of a sour taste, allowing them to take advantage of the fruits mammals can’t stomach. Determining why bird OTOP1 reacted differently was a challenge, according to study author Hao Zhang, an evolutionary biologist at the Chinese Academy of Sciences (CAS). So, the researchers mutated sections of the gene that encodes the OTOP1 receptor, which let them identify four candidate amino acids within the protein that are responsible for sour tolerance. One of them, known as G378, is found almost exclusively in songbirds such as the canary—a species that showed greater sour tolerance than the pigeon, which lacks this variance. “A single amino acid in the bird OTOP1 can increase sour tolerance,” says study author Lei Luo, a biologist at CAS. © 2025 American Association for the Advancement of Science.

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 29840 - Posted: 06.21.2025

By Sofia Quaglia When octopuses extend their eight arms into hidden nooks and crannies in search of a meal, they are not just feeling around in the dark for their food. They are tasting their prey, and with even more sensory sophistication than scientists had already imagined. Researchers reported on Tuesday in the journal Cell that octopus arms are fine-tuned to “eavesdrop into the microbial world,” detecting microbiomes on the surfaces around them and deriving information from them, said Rebecka Sepela, a molecular biologist at Harvard and an author of the new study. Where octopus eyes cannot see, their arms can go to identify prey and make sense of their surroundings. Scientists knew that those eight arms (not tentacles) sense whether their eggs are healthy or need to be pruned. And the hundreds of suckers on each arm have over 10,000 chemotactile sensory receptors each, working with 500 million neurons to pick up that information and relay it throughout the nervous system. Yet, what exactly the octopus is tasting by probing and prodding — and how its arms can distinguish, say, a rock from an egg, a healthy egg in its clutch from a sick one or a crab that’s safe to eat from a rotting, toxic one — has long baffled scientists. What about the surfaces are they perceiving? For Dr. Sepela, this question was heightened when her team discovered 26 receptors along the octopuses’ arms that didn’t have a known function. She supposed those receptors were tuned only to molecules found on surfaces, rather than those diffused in water. So she and her colleagues collected swaths of molecules coating healthy and unhealthy crabs and octopus eggs. They grew and cultured the microbes from those surfaces in the lab, then tested 300 microbial strains, one by one, on two of those 26 receptors. During the screening, only particular microbes could switch open the receptors, and these microbes were more abundant on the decaying crabs and dying eggs than on their healthy counterparts. © 2025 The New York Times Company

Keyword: Chemical Senses (Smell & Taste); Neuroimmunology
Link ID: 29831 - Posted: 06.18.2025

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