Chapter 6. Hearing, Balance, Taste, and Smell

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By Eva Frederick They’re the undertakers of the bee world: a class of workers that scours hives for dead comrades, finding them in the dark in as little as 30 minutes, despite the fact that the deceased haven’t begun to give off the typical odors of decay. A new study may reveal how they do it. “The task of undertaking is fascinating” and the new work is “pretty cool,” says Jenny Jandt, a behavioral ecologist at the University of Otago, Dunedin, who was not involved with the study. Wen Ping, an ecologist at the Chinese Academy of Sciences’s Xishuangbanna Tropical Botanical Garden, wondered whether a specific type of scent molecule might help undertaker bees find their fallen hive mates. Ants, bees, and other insects are covered in compounds called cuticular hydrocarbons (CHCs), which compose part of the waxy coating on their cuticles (the shiny parts of their exoskeletons) and help prevent them from drying out. While the insects are alive, these molecules are continually released into the air and are used to recognize fellow hive members. Wen speculated that less of the pheromones were being released into the air after a bee died and its body temperature decreased. When he used chemical methods of detecting gases to test this hypothesis, he confirmed that cooled dead bees were indeed emitting fewer volatile CHCs than living bees. © 2020 American Association for the Advancement of Science.

Keyword: Chemical Senses (Smell & Taste); Animal Communication
Link ID: 27138 - Posted: 03.24.2020

By Roni Caryn Rabin A mother who was infected with the coronavirus couldn’t smell her baby’s full diaper. Cooks who can usually name every spice in a restaurant dish can’t smell curry or garlic, and food tastes bland. Others say they can’t pick up the sweet scent of shampoo or the foul odor of kitty litter. Anosmia, the loss of sense of smell, and ageusia, an accompanying diminished sense of taste, have emerged as peculiar telltale signs of Covid-19, the disease caused by the coronavirus, and possible markers of infection. On Friday, British ear, nose and throat doctors, citing reports from colleagues around the world, called on adults who lose their senses of smell to isolate themselves for seven days, even if they have no other symptoms, to slow the disease’s spread. The published data is limited, but doctors are concerned enough to raise warnings. “We really want to raise awareness that this is a sign of infection and that anyone who develops loss of sense of smell should self-isolate,” Prof. Claire Hopkins, president of the British Rhinological Society, wrote in an email. “It could contribute to slowing transmission and save lives.” She and Nirmal Kumar, president of ENT UK, a group representing ear, nose and throat doctors in Britain, issued a joint statement urging health care workers to use personal protective equipment when treating any patients who have lost their senses of smell, and advised against performing nonessential sinus endoscopy procedures on anyone, because the virus replicates in the nose and the throat and an exam can prompt coughs or sneezes that expose the doctor to a high level of virus. Two ear, nose and throat specialists in Britain who have been infected with the coronavirus are in critical condition, Dr. Hopkins said. Earlier reports from Wuhan, China, where the coronavirus first emerged, had warned that ear, nose and throat specialists as well as eye doctors were infected and dying in large numbers, Dr. Hopkins said. © 2020 The New York Times Company

Keyword: Chemical Senses (Smell & Taste)
Link ID: 27135 - Posted: 03.23.2020

Amy Schleunes Preti was a leading expert on human odors who sought to understand the chemistry of odor in the underarm and the behavior aspects of human scents, and an ambassador to patients suffering from rare metabolic diseases who provided communities worldwide with knowledge about their condition and how to cope with it. Preti was also dedicated to using odor biomarkers to detect cancer in its early stages, contributing both research and money to the cause, according to a Monell Center press release. Born on October 7, 1944 in Brooklyn, New York, Preti received a bachelor’s degree in chemistry from the Polytechnic Institute of Brooklyn in 1966. He then went on to MIT, where he earned a PhD in chemistry in 1971. His thesis was titled, “A Study of the Organic Compounds in the Lunar Crust and in Terrestrial Model Systems,” according to the Monell Center’s statement. Preti coauthored a paper published in Science on the same topic, and reportedly saved a vial of “moon dust” that he sometimes showed off to visitors to his lab. Upon completing his doctorate in 1971, he immediately accepted a postdoc at Monell and later become a member of the Monell Chemical Senses Center and an adjunct professor at the University of Pennsylvania School of Medicine. While Preti and his colleagues investigated a range of odors in different species—anal sac emissions from dogs, scent marks by marmoset monkeys, urine from guinea pigs and mice—Preti’s main focus was on the meaning of human odors. He studied the scents of human underarms and melanoma cells as well as the odors associated with generalized stress. Along with his collaborator, Charles Wysocki, Preti published papers on how human physiology and behavior are affected by body odor. Preti was skeptical of human pheromones and their associated hype, telling The Scientist in 2018, “I am not compelled by any studies that are out there that say there is an active steroid component from the underarm that causes [sexual attraction].” © 1986–2020 The Scientist

Keyword: Chemical Senses (Smell & Taste)
Link ID: 27133 - Posted: 03.23.2020

By Maria Temming When it comes to identifying scents, a “neuromorphic” artificial intelligence beats other AI by more than a nose. The new AI learns to recognize smells more efficiently and reliably than other algorithms. And unlike other AI, this system can keep learning new aromas without forgetting others, researchers report online March 16 in Nature Machine Intelligence. The key to the program’s success is its neuromorphic structure, which resembles the neural circuitry in mammalian brains more than other AI designs. This kind of algorithm, which excels at detecting faint signals amidst background noise and continually learning on the job, could someday be used for air quality monitoring, toxic waste detection or medical diagnoses. The new AI is an artificial neural network, composed of many computing elements that mimic nerve cells to process scent information (SN: 5/2/19). The AI “sniffs” by taking in electrical voltage readouts from chemical sensors in a wind tunnel that were exposed to plumes of different scents, such as methane or ammonia. When the AI whiffs a new smell, that triggers a cascade of electrical activity among its nerve cells, or neurons, which the system remembers and can recognize in the future. Like the olfactory system in the mammal brain, some of the AI’s neurons are designed to react to chemical sensor inputs by emitting differently timed pulses. Other neurons learn to recognize patterns in those blips that make up the odor’s electrical signature. © Society for Science & the Public 2000–2020

Keyword: Chemical Senses (Smell & Taste); Robotics
Link ID: 27126 - Posted: 03.17.2020

Laura Reiley A study published in the journal Cell Metabolism by a group of Yale researchers found that the consumption of the common artificial sweetener sucralose (which is found in Splenda, Zerocal, Sukrana, SucraPlus and other brands) in combination with carbohydrates can swiftly turn a healthy person into one with high blood sugar. From whole grain English muffins to reduced-sugar ketchup, sucralose is found in thousands of baked goods, condiments, syrups and other consumer packaged goods — almost all of them containing carbs. The finding, which researchers noted has yet to be replicated in other studies, raises new questions about the use of artificial sweeteners and their effects on weight gain and overall health. In the Yale study, researchers took 60 healthy-weight individuals and separated them into three groups: A group that consumed a regular-size beverage containing the equivalent of two packets of sucralose sweetener, a second group that consumed a beverage sweetened with table sugar at the equivalent sweetness, and a third control group that had a beverage with the artificial sweetener as well as a carbohydrate called maltodextrin. The molecules of maltodextrin don’t bind to taste receptors in the mouth and are impossible to detect. While the sensation of the third group’s beverage was identical to the Splenda-only group, only this group exhibited significant adverse health effects. The artificial sweetener by itself seemed to be fine, the researchers discovered, but that changed when combined with a carbohydrate. Seven beverages over two weeks and the previously healthy people in this group became glucose intolerant, a metabolic condition that results in elevated blood glucose levels and puts people at an increased risk for diabetes.

Keyword: Obesity; Chemical Senses (Smell & Taste)
Link ID: 27113 - Posted: 03.12.2020

By Jonathan Lambert To a sea turtle, plastic debris might smell like dinner. As the plastic detritus of modern human life washes into oceans, marine creatures of all kinds interact with and sometimes eat it (SN: 11/13/19). Recent research suggests that this is no accident. Plastic that’s been stewing in the ocean emits a chemical that, to some seabirds and fish, smells a lot like food (SN: 11/9/16). That chemical gas, dimethyl sulfide, is also produced by phytoplankton, a key food source for many marine animals. Now, scientists have determined that loggerhead sea turtles may also confuse the smell of plastic with food, according to a study published March 9 in Current Biology. Over two weeks in January 2019, 15 captive loggerheads in tanks were exposed at the water surface to a slew of scents, including the largely neutral scent of water as a control, of food such as shrimp and of new and ocean-soaked plastic. The turtles (Caretta caretta) largely ignored smells of water and clean plastic. But when the scientists puffed air containing scents of either food or ocean-stewed plastic, the reptiles increased their sniffing above water — a typical foraging behavior. In fact, those responses to food and ocean-soaked plastic were indistinguishable to the researchers, suggesting that the plastic can induce foraging behavior in sea turtles, the team says. That might explain why sea turtles get entangled in or eat plastic, which can be harmful. Along with previous research, this study expands the breadth of marine life that may confuse plastic with food. © Society for Science & the Public 2000–2020

Keyword: Chemical Senses (Smell & Taste)
Link ID: 27111 - Posted: 03.12.2020

Jon Hamilton A song fuses words and music. Yet the human brain can instantly separate a song's lyrics from its melody. And now scientists think they know how this happens. A team led by researchers at McGill University reported in Science Thursday that song sounds are processed simultaneously by two separate brain areas – one in the left hemisphere and one in the right. "On the left side you can decode the speech content but not the melodic content, and on the right side you can decode the melodic content but not the speech content," says Robert Zatorre, a professor at McGill University's Montreal Neurological Institute. The finding explains something doctors have observed in stroke patients for decades, says Daniela Sammler, a researcher at the Max Planck Institute for Cognition and Neurosciences in Leipzig, Germany, who was not involved in the study. "If you have a stroke in the left hemisphere you are much more likely to have a language impairment than if you have a stroke in the right hemisphere," Sammler says. Moreover, brain damage to certain areas of the right hemisphere can affect a person's ability to perceive music. By subscribing, you agree to NPR's terms of use and privacy policy. NPR may share your name and email address with your NPR station. See Details. This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. The study was inspired by songbirds, Zatorre says. Studies show that their brains decode sounds using two separate measures. One assesses how quickly a sound fluctuates over time. The other detects the frequencies in a sound. © 2020 npr

Keyword: Hearing; Language
Link ID: 27082 - Posted: 02.28.2020

By Virginia Morell Dogs’ noses just got a bit more amazing. Not only are they up to 100 million times more sensitive than ours, they can sense weak thermal radiation—the body heat of mammalian prey, a new study reveals. The find helps explain how canines with impaired sight, hearing, or smell can still hunt successfully. “It’s a fascinating discovery,” says Marc Bekoff, an ethologist, expert on canine sniffing, and professor emeritus at the University of Colorado, Boulder, who was not involved in the study. “[It] provides yet another window into the sensory worlds of dogs' highly evolved cold noses.” The ability to sense weak, radiating heat is known in only a handful of animals: Black fire beetles, certain snakes, and one species of mammal, the common vampire bat, all of which use it to hunt prey. Most mammals have naked, smooth skin on the tip of their noses around the nostrils, an area called the rhinarium. But dogs’ rhinaria are moist, colder than the ambient temperature, and richly endowed with nerves—all of which suggests an ability to detect not just smell, but heat. To test the idea, researchers at Lund University in Sweden and Eotvos Lorand University in Hungary trained three pet dogs to choose between a warm (31 C degrees) and an ambient-temperature object, each placed 1.6 meters away. The dogs weren’t able to see or smell the difference between these objects. (Scientists could only detect the difference by touching the surfaces.) After training, the dogs were tested on their skill in double-blind experiments; all three successfully detected the objects emitting weak thermal radiation, the scientists reveal today in Scientific Reports. © 2020 American Association for the Advancement of Science

Keyword: Chemical Senses (Smell & Taste)
Link ID: 27081 - Posted: 02.28.2020

By Jillian Kramer Scientists often test auditory processing in artificial, silent settings, but real life usually comes with a background of sounds like clacking keyboards, chattering voices and car horns. Recently researchers set out to study such processing in the presence of ambient sound—specifically the even, staticlike hiss of white noise. Their result is counterintuitive, says Tania Rinaldi Barkat, a neuroscientist at the University of Basel: instead of impairing hearing, a background of white noise made it easier for mice to differentiate between similar tones. Barkat is senior author of the new study, published last November in Cell Reports. It is easy to distinguish notes on opposite ends of a piano keyboard. But play two side by side, and even the sharpest ears might have trouble telling them apart. This is because of how the auditory pathway processes the simplest sounds, called pure frequency tones: neurons close together respond to similar tones, but each neuron responds better to one particular frequency. The degree to which a neuron responds to a certain frequency is called its tuning curve. The researchers found that playing white noise narrowed neurons’ frequency tuning curves in mouse brains. “In a simplified way, white noise background—played continuously and at a certain sound level—decreases the response of neurons to a tone played on top of that white noise,” Barkat says. And by reducing the number of neurons responding to the same frequency at the same time, the brain can better distinguish between similar sounds. © 2020 Scientific American,

Keyword: Hearing
Link ID: 27074 - Posted: 02.26.2020

By Kim Tingley Hearing loss has long been considered a normal, and thus acceptable, part of aging. It is common: Estimates suggest that it affects two out of three adults age 70 and older. It is also rarely treated. In the U.S., only about 14 percent of adults who have hearing loss wear hearing aids. An emerging body of research, however, suggests that diminished hearing may be a significant risk factor for Alzheimer’s disease and other forms of dementia — and that the association between hearing loss and cognitive decline potentially begins at very low levels of impairment. In November, a study published in the journal JAMA Otolaryngology — Head and Neck Surgery examined data on hearing and cognitive performance from more than 6,400 people 50 and older. Traditionally, doctors diagnose impairment when someone experiences a loss in hearing of at least 25 decibels, a somewhat arbitrary threshold. But for the JAMA study, researchers included hearing loss down to around zero decibels in their analysis and found that they still predicted correspondingly lower scores on cognitive tests. “It seemed like the relationship starts the moment you have imperfect hearing,” says Justin Golub, the study’s lead author and an ear, nose and throat doctor at the Columbia University Medical Center and NewYork-Presbyterian. Now, he says, the question is: Does hearing loss actually cause the cognitive problems it has been associated with and if so, how? Preliminary evidence linking dementia and hearing loss was published in 1989 by doctors at the University of Washington, Seattle, who compared 100 patients with Alzheimer’s-like dementia with 100 demographically similar people without it and found that those who had dementia were more likely to have hearing loss, and that the extent of that loss seemed to correspond with the degree of cognitive impairment. But that possible connection wasn’t rigorously investigated until 2011, when Frank Lin, an ear, nose and throat doctor at Johns Hopkins School of Medicine, and colleagues published the results of a longitudinal study that tested the hearing of 639 older adults who were dementia-free and then tracked them for an average of nearly 12 years, during which time 58 had developed Alzheimer’s or another cognitive impairment. They discovered that a subject’s likelihood of developing dementia increased in direct proportion to the severity of his or her hearing loss at the time of the initial test. The relationship seems to be “very, very linear,” Lin says, meaning that the greater the hearing deficit, the greater the risk a person will develop the condition. © 2020 The New York Times Company

Keyword: Hearing; Alzheimers
Link ID: 27057 - Posted: 02.20.2020

By Katherine Kornei Imagine a frog call, but with a metallic twang—and the intensity of a chainsaw. That’s the “boing” of a minke whale. And it’s a form of animal communication in danger of being drowned out by ocean noise, new research shows. By analyzing more than 42,000 minke whale boings, scientists have found that, as background noise intensifies, the whales are losing their ability to communicate over long distances. This could limit their ability to find mates and engage in important social contact with other whales. Tyler Helble, a marine acoustician at the Naval Information Warfare Center Pacific, and colleagues recorded minke whale boings over a 1200-square-kilometer swathe of the U.S. Navy’s Pacific Missile Range Facility near the Hawaiian island of Kauai from 2012 to 2017. By measuring when a single boing arrived at various underwater microphones, the team pinpointed whale locations to within 10 to 20 meters. The researchers then used these positions, along with models of how sound propagates underwater, to calculate the intensity of each boing when it was emitted. The team compared these measurements with natural ambient noise, including waves, wind, and undersea earthquakes (no military exercises were conducted nearby during the study period). They found that minke whale boings grew louder in louder conditions. That’s not surprising—creatures across the animal kingdom up their volume when there’s background noise. (This phenomenon, dubbed the Lombard effect, holds true for humans, too—think of holding a conversation at a loud concert.) © 2019 American Association for the Advancement of Science.

Keyword: Animal Communication; Hearing
Link ID: 27051 - Posted: 02.19.2020

By Brian Platzer Three years ago I wrote an essay for Well about the chronic dizziness that had devastated my life. In response, I received thousands of letters, calls, tweets, emails and messages from Times readers who were grateful to see a version of their own story made public. Their symptoms varied. While some experienced a constant disequilibrium and brain fog that were similar to mine, others had become accustomed to a pattern of short periods of relative health alternating with longer periods of vertigo. Most of them, like me, felt that family and friends often didn’t understand how dizziness could be so debilitating. They told me that the combination of the loneliness and feelings of uselessness that come from an inability to work or spend time with family led to despair and depression. And, most commonly, they felt that the medical system made them feel responsible for their own suffering. “Doctors began to suggest that anxiety or depression were the cause of my symptoms,” a young woman from Connecticut wrote. “I eventually gave up on the quest for answers, as their attitudes added stress to an already stressful reality.” “Have been to so many doctors that keep saying, ‘It’s all in your head. There’s nothing wrong with you,’” wrote an older woman from Ohio. “Mostly been told there is nothing they can find,” wrote a middle-aged woman from Illinois. Her doctor told her it was probably just depression and anxiety. Dizziness is among the most common reasons people visit their doctor in the United States. When patients first experience prolonged dizziness, they may go to an emergency room or to see their primary care physician. That’s what I did. And I heard what most patients hear: “People get dizzy for all sorts of reasons, and it should resolve itself soon.” It’s true that dizziness often is a temporary symptom. The most common causes of dizziness are benign paroxysmal positional vertigo (caused by displaced pieces of small bone-like calcium in the inner ear), and vestibular neuritis (dizziness attributed to a viral infection or tiny stroke of the vestibular nerve), both of which typically last only weeks or months. © 2020 The New York Times Company

Keyword: Miscellaneous
Link ID: 27036 - Posted: 02.13.2020

John Henning Schumann As the owner of a yellow lab named Gus, author Maria Goodavage has had many occasions to bathe her pooch when he rolls around in smelly muck at the park. Nevertheless, her appreciation for his keen sense of smell has inspired her write best-selling books about dogs with special assignments in the military and the U.S. Secret Service. Her latest, Doctor Dogs: How Our Best Friends Are Becoming Our Best Medicine, highlights a vast array of special medical tasks that dogs can perform — from the laboratory to the bedside, and everywhere else a dog can tag along and sniff. Canines' incredible olfactory capacity — they can sniff in parts per trillion — primes them to detect disease, and their genius for observing our behavior helps them guide us physically and emotionally. Goodavage spoke with NPR contributor John Henning Schumann, a doctor and host of Public Radio Tulsa's #MedicalMonday about what she has learned about dogs in medicine What led you to look into dogs in medicine? I've been reading and writing about military dogs and Secret Service dogs for many years now, and it was sort of a natural next step. These are dogs on the cutting edge of medicine. They're either working in research or right beside someone to save their life every day. And really, doctor dogs are, for the most part, using their incredible sense of smell to detect diseases. And if they're paired with a person, they bond with that person to tell them something that will save their life. © 2020 npr

Keyword: Chemical Senses (Smell & Taste)
Link ID: 26992 - Posted: 01.25.2020

By Bradley Berman The day is approaching when commuters stuck in soul-crushing traffic will be freed from the drudgery of driving. Companies are investing billions to devise sensors and algorithms so motorists can turn our attention to where we like it these days: our phones. But before the great promise of multitasking on the road can be realized, we need to overcome an age-old problem: motion sickness. “The autonomous-vehicle community understands this is a real problem it has to deal with,” said Monica Jones, a transportation researcher at the University of Michigan. “That motivates me to be very systematic.” So starting in 2017, Ms. Jones led a series of studies in which more than 150 people were strapped into the front seat of a 2007 Honda Accord. They were wired with sensors and set on a ride that included roughly 50 left-hand turns and other maneuvers. Each subject was tossed along the same twisty route for a second time but also asked to complete a set of 13 simple cognitive and visual tasks on an iPad Mini. About 11 percent of the riders got nauseated or, for other reasons, asked that the car be stopped. Four percent vomited. Ms. Jones takes no joy in documenting her subjects’ getting dizzy, hyperventilating or losing their lunch. She feels their pain. Ms. Jones, a chronic sufferer of motion sickness, has experienced those discomforts in car back seats all her life. “I don’t remember not experiencing it,” she said. “As I’m getting older, it’s getting worse.” It’s also getting worse for the legions of commuters hailing Ubers or taxis and hopping in, barely lifting their gaze from a screen in the process. © 2020 The New York Times Company

Keyword: Miscellaneous
Link ID: 26976 - Posted: 01.21.2020

By Tina Hesman Saey Some hairy cells in the nose may trigger sneezing and allergies to dust mites, mold and other substances, new work with mice suggests. When exposed to allergens, these “brush cells” make chemicals that lead to inflammation, researchers report January 17 in Science Immunology. Only immune cells previously were thought to make such inflammatory chemicals — fatty compounds known as lipids. The findings may provide new clues about how people develop allergies. Brush cells are shaped like teardrops topped by tufts of hairlike projections. In people, mice and other animals, these cells are also found in the linings of the trachea and the intestines, where they are known as tuft cells (SN: 4/13/18). However, brush cells are far more common in the nose than in other tissues, and may help the body identify when pathogens or noxious chemicals have been inhaled, says Lora Bankova, an allergist and immunologist at Brigham and Women’s Hospital in Boston. Bankova and her colleagues discovered that, when exposed to certain molds or dust mite proteins, brush cells in mice’s noses churn out inflammation-producing lipids, called cysteinyl leukotrienes. The cells also made the lipids when encountering ATP, a chemical used by cells for energy that also signals when nearby cells are damaged, as in an infection. Mice exposed to allergens or ATP developed swelling of their nasal tissues. But mice that lacked brush cells suffered much less inflammation. Such inflammation may lead to allergies in some cases. The researchers haven’t yet confirmed that brush cells in human noses respond to allergens in the same way as these cells do in mice. © Society for Science & the Public 2000–2020

Keyword: Chemical Senses (Smell & Taste); Neuroimmunology
Link ID: 26974 - Posted: 01.21.2020

By Jane E. Brody Every now and then I write a column as much to push myself to act as to inform and motivate my readers. What follows is a prime example. Last year in a column entitled “Hearing Loss Threatens Mind, Life and Limb,” I summarized the current state of knowledge about the myriad health-damaging effects linked to untreated hearing loss, a problem that afflicts nearly 38 million Americans and, according to two huge recent studies, increases the risk of dementia, depression, falls and even cardiovascular diseases. Knowing that my own hearing leaves something to be desired, the research I did for that column motivated me to get a proper audiology exam. The results indicated that a well-fitted hearing aid could help me hear significantly better in the movies, theater, restaurants, social gatherings, lecture halls, even in the locker room where the noise of hair dryers, hand dryers and swimsuit wringers often challenges my ability to converse with my soft-spoken friends. That was six months ago, and I’ve yet to go back to get that recommended hearing aid. Now, though, I have a new source of motivation. A large study has documented that even among people with so-called normal hearing, those with only slightly poorer hearing than perfect can experience cognitive deficits. That means a diminished ability to get top scores on standardized tests of brain function, like matching numbers with symbols within a specified time period. But while you may never need or want to do that, you most likely do want to maximize and maintain cognitive function: your ability to think clearly, plan rationally and remember accurately, especially as you get older. While under normal circumstances, cognitive losses occur gradually as people age, the wisest course may well be to minimize and delay them as long as possible and in doing so, reduce the risk of dementia. Hearing loss is now known to be the largest modifiable risk factor for developing dementia, exceeding that of smoking, high blood pressure, lack of exercise and social isolation, according to an international analysis published in The Lancet in 2017. © 2019 The New York Times Company

Keyword: Hearing
Link ID: 26923 - Posted: 12.30.2019

By Carolyn Gramling Exceptionally preserved skulls of a mammal that lived alongside the dinosaurs may be offering scientists a glimpse into the evolution of the middle ear. The separation of the three tiny middle ear bones — known popularly as the hammer, anvil and stirrup — from the jaw is a defining characteristic of mammals. The evolutionary shift of those tiny bones, which started out as joints in ancient reptilian jaws and ultimately split from the jaw completely, gave mammals greater sensitivity to sound, particularly at higher frequencies (SN: 3/20/07). But finding well-preserved skulls from ancient mammals that can help reveal the timing of this separation is a challenge. Now, scientists have six specimens — four nearly complete skeletons and two fragmented specimens — of a newly described, shrew-sized critter dubbed Origolestes lii that lived about 123 million years ago. O. lii was part of the Jehol Biota, an ecosystem of ancient wetlands-dwellers that thrived between 133 million and 120 million years ago in what’s now northeastern China. The skulls on the nearly complete skeletons were so well-preserved that they were able to be examined in 3-D, say paleontologist Fangyuan Mao of the Chinese Academy of Sciences in Beijing and colleagues. That analysis suggests that O. lii’s middle ear bones were fully separated from its jaw, the team reports online December 5 in Science. Fossils from an older, extinct line of mammals have shown separated middle ear bones, but this newfound species would be the first of a more recent lineage to exhibit this evolutionary advance. © Society for Science & the Public 2000–2019

Keyword: Hearing; Evolution
Link ID: 26880 - Posted: 12.07.2019

By Jade Wu What do the sounds of whispering, crinkling paper, and tapping fingernails have in common? What about the sight of soft paint brushes on skin, soap being gently cut to pieces, and hand movements like turning the pages of a book? Well, if you are someone who experiences the autonomous sensory meridian response—or ASMR, for short—you may recognize these seemingly ordinary sounds and sights as “triggers” for the ASMR experience. No idea what I’m talking about? Don’t worry, you’re actually in the majority. Most people, myself included, aren’t affected by these triggers. But what happens to those who are? What is the ASMR experience? It’s described as a pleasantly warm and tingling sensation that starts on the scalp and moves down the neck and spine. ASMR burst onto the Internet scene in 2007, according to Wikipedia, when a woman with the username “okaywhatever” described her experience of ASMR sensations in an online health discussion forum. At the time, there was no name for this weird phenomenon. But by 2010, someone called Jennifer Allen had named the experience, and from there, ASMR became an Internet sensation. Today, there are hundreds of ASMR YouTubers who collectively post over 200 videos of ASMR triggers per day, as reported by a New York Times article in April, 2019. Some ASMR YouTubers have become bona fide celebrities with ballooning bank accounts, millions of fans, and enough fame to be stopped on the street for selfies. There’s been some controversy. Some people doubt whether this ASMR experience is “real,” or just the result of recreational drugs or imagined sensations. Some have chalked the phenomenon up to a symptom of loneliness among Generation Z, who get their dose of intimacy from watching strangers pretend to do their makeup without having to interact with real people. Some people are even actively put off by ASMR triggers. One of my listeners, Katie, said that most ASMR videos just make her feel agitated. But another listener, Candace, shared that she has been unknowingly chasing ASMR since she was a child watching BBC. © 2019 Scientific American

Keyword: Hearing; Emotions
Link ID: 26873 - Posted: 12.05.2019

Jon Hamilton When we hear a sentence, or a line of poetry, our brains automatically transform the stream of sound into a sequence of syllables. But scientists haven't been sure exactly how the brain does this. Now, researchers from the University of California, San Francisco, think they've figured it out. The key is detecting a rapid increase in volume that occurs at the beginning of a vowel sound, they report Wednesday in Science Advances. "Our brain is basically listening for these time points and responding whenever they occur," says Yulia Oganian, a postdoctoral scholar at UCSF. The finding challenges a popular idea that the brain monitors speech volume continuously to detect syllables. Instead, it suggests that the brain periodically "samples" spoken language looking for specific changes in volume. The finding is "in line" with a computer model designed to simulate the way a human brain decodes speech, says Oded Ghitza, a research professor in the biomedical engineering department at Boston University who was not involved in the study. Detecting each rapid increase in volume associated with a syllable gives the brain, or a computer, an efficient way to deal with the "stream" of sound that is human speech, Ghitza says. And syllables, he adds, are "the basic Lego blocks of language." Oganian's study focused on a part of the brain called the superior temporal gyrus. "It's an area that has been known for about 150 years to be really important for speech comprehension," Oganian says. "So we knew if you can find syllables somewhere, it should be there." The team studied a dozen patients preparing for brain surgery to treat severe epilepsy. As part of the preparation, surgeons had placed electrodes over the area of the brain involved in speech. © 2019 npr

Keyword: Language; Hearing
Link ID: 26841 - Posted: 11.21.2019

By Neuroskeptic | Many people may be living life without a particular brain region – and not suffering any ill-effects. In a new paper in Neuron, neuroscientists Tali Weiss and colleagues discuss five women who appear to completely lack olfactory bulbs (OB). According to most neuroscience textbooks, no OB should mean no sense of smell, because the OB is believed to be a key relay point for olfactory signals. As Wikipedia puts it: The olfactory bulb transmits smell information from the nose to the brain, and is thus necessary for a proper sense of smell. Scent molecules activate olfactory receptors and signals travel up the olfactory nerves to the olfactory bulb, and then on to the rest of the brain via the olfactory tract. From Wikipedia. However, remarkably, Weiss et al.’s five women seem to have entirely normal sense of smell despite lacking any visible OBs on brain MRI scans. On both subjective and objective measures of olfactory function, these women showed no abnormalities. MRIs showing normal development of olfactory bulbs (A) compared to two women with no visible olfactory bulbs but normal sense of smell (B) & (D) and one woman with no sense of smell (C). From Weiss et al. Fig 1 Weiss et al. came across two of the women serendipitously while carrying out MRI scans for an unrelated project. The other 3 were found among healthy controls in the Human Connectome Project MRI dataset.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 26825 - Posted: 11.18.2019