Chapter 9. Hearing, Vestibular Perception, Taste, and Smell

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Laura Sanders Sometimes a really good meal can make an evening unforgettable. A new study of rats, published online February 18 in the Journal of Neuroscience, may help explain why. A select group of nerve cells in rats’ brains holds information about both flavors and places, becoming active when the right taste hits the tongue when the rat is in a certain location. These double-duty cells could help animals overlay food locations onto their mental maps. Researchers implanted electrodes into the hippocampus, an area of the brain that is heavily involved in both memory formation and mapping. The rats then wandered around an enclosure, allowing researchers to identify “place cells” that become active only when the rat wandered into a certain spot. At the same time, researchers occasionally delivered one of four flavors (sweet, salty, bitter and plain water) via an implanted tube directly onto the wandering rats’ tongues. Some of the active place cells also responded to one or more flavors, but only when the rat was in the right spot within its enclosure. When the rat moved away from a place cell’s preferred spot, that cell no longer responded to the flavor, the researchers found. A mental map of the best spots for tasting something good would come in handy for an animal that needs to find its next meal. Citations L.E. Herzog et al. Interaction of taste and place coding in the hippocampus. Journal of Neuroscience. Published online February 18, 2019. doi: 10.1523/JNEUROSCI.2478-18.2019. |© Society for Science & the Public 2000 - 2019

Keyword: Chemical Senses (Smell & Taste)
Link ID: 25973 - Posted: 02.19.2019

Shawna Williams Watch a bacterium chase down the source of an enticing molecular trail using chemo-taxis, and it’s clear that its sensory and navigation abilities are tightly linked. But could the same be true for humans? In 2014, Louisa Dahmani, then a graduate student at McGill University in Montreal, set out to answer that question. After having reviewed the literature on studies of spatial memory and olfaction in people, “I realized that the two functions seemed to rely on similar brain regions,” she explains. “But no one had actually looked at it directly and tested the same sample of participants on an olfaction and on a spatial memory task.” Dahmani, her advisor Véronique Bohbot, and their colleagues set out to rectify that. The group recruited 60 volunteers and tested their ability to identify 40 odors, from menthol to cucumber to lavender. The researchers also had the subjects do a computer-based task in which they moved through a virtual town. After their exploration, the subjects navigated through the virtual town from one of its eight landmarks to a different destination via the shortest route possible. “People who are better at finding their way are also better at identifying smells,” Dahmani says, summing up the study’s biggest takeaway. The scientists also imaged participants’ brains using MRI and found that a larger medial orbitofrontal cortex—a brain region known to be associated, along with the hippocampus, with spatial navigation—correlated with both better smell identification and fewer errors on the navigation task (Nat Comm, 9:4162, 2018). © 1986 - 2019 The Scientist.

Keyword: Chemical Senses (Smell & Taste); Learning & Memory
Link ID: 25963 - Posted: 02.14.2019

Emily Conover Lasers can send sounds straight to a listener’s ear, like whispering a secret from afar. Using a laser tuned to interact with water vapor in the air, scientists created sounds in a localized spot that were loud enough to be picked up by human hearing if aimed near a listener’s ear. It’s the first time such a technique can be used safely around humans, scientists from MIT Lincoln Laboratory in Lexington, Mass., report in the Feb. 1 Optics Letters. At the wavelengths and intensities used, the laser won’t cause burns if it grazes eyes or skin. The scientists tested out the setup on themselves in the laboratory, putting their ears near the beam to pick up the sound. “You move your head around, and there’s a couple-inch zone where you go ‘Oh, there it is!’… It’s pretty cool,” says physicist Charles Wynn. The researchers also used microphones to capture and analyze the sounds. The work relies on a phenomenon called the photoacoustic effect, in which pulses of light are converted into sound when absorbed by a material, in this case, water vapor. Based on this effect, the researchers used two different techniques to make the sounds. The first technique, which involves rapidly ramping the intensity of the laser beam up and down, can transmit voices and songs. “You can hear the music really well; you can understand what people are saying,” says physicist Ryan Sullenberger, who coauthored the study along with Wynn and physicist Sumanth Kaushik. |© Society for Science & the Public 2000 - 2019.

Keyword: Hearing
Link ID: 25925 - Posted: 02.02.2019

By James Gorman Carpenter ants follow trails. Just watch them wandering about on your wooden porch until they strike a trail of pheromones (chemicals ants use for communication) that another ant has laid down. Ants don’t have noses, so they wave their antennas around to pick up the trail, then off they go on the road to ruin. (Carpenter ants destroy houses.) Scientists know plenty about ants, including their ability to follow scent trails, but researchers at Harvard wanted to get a more detailed understanding of how exactly ants sniff, or taste, the pheromone-marked path. First, some basics: Ants use their antennas to pick up chemical cues left by other ants. And the chemical sense of ants, call it smell or taste or chemo-reception, enables them to follow straight trails, curved trails, even zigzags. To see how ants do it, the scientists mixed ink and ant pheromones and used the result to paint trails on paper. They set ants out on trails and recorded dozens of hours of ant movement. They analyzed the video and tried out different computer models of the ants’ behavior. What Ryan W. Dash and his adviser, Venkatesh N. Murthy, and other researchers found was that the ants had several strategies for path-following. The scientists published their results in the Journal of Experimental Biology. All the ants used their antennas to sweep the trail side to side. One strategy they used was probing. A probing ant moved slowly, keeping its antennas close together. The researchers termed another strategy exploratory: Ants still moved slowly, but they took winding paths moving away from and back to a trail. When they were locked into a pheromone trail, they moved along more quickly, keeping their antennas on either side of the path. They kept one antenna closer to the path, but which antenna varied from ant to ant. In other words, some were lefties and others were righties. © 2019 The New York Times Company

Keyword: Chemical Senses (Smell & Taste)
Link ID: 25891 - Posted: 01.22.2019

By Elizabeth Pennisi TAMPA, FLORIDA—The pinnacle of beauty to most people is a symmetrical face, one without any major left-right differences. But for blind Mexican cavefish (Astyanax mexicanus), asymmetry may be a lifesaver. That’s because their lopsided skulls may help them feel their way along dark cave walls—similar to a person navigating by touch in the dark. That behavior, presented here this week at the annual meeting of the Society for Integrative and Comparative Biology, suggests being a little “off” can have evolutionary benefits. Lots of cave dwellers are a bit unbalanced. Cave fish tend to have one eye that is larger than the other, for example, and cave crickets have different size antennae. Some researchers wondered whether left-right differences might help these creatures get around. They scanned the skulls of A. mexicanus fish from three caves in Mexico. Their computerized tomography scans revealed most fish skulls bent slightly to the left, giving the right side of their faces slightly more exposure. Other tests showed these fish tended to drift along the right-hand side of cave walls, presumably using the larger side of their faces to feel their way in the dark. Amanda Powers and Josh Gross Next, the researchers counted mechanical sensors known as neuromasts in the heads of embryonic fish. These sensors, or “nerve buttons,” detect water flow and sometimes vibrations. Blind fish had more—and larger—neuromasts than fish of the same species that lived on the surface, they reported. © 2018 American Association for the Advancement of Science.

Keyword: Laterality; Pain & Touch
Link ID: 25838 - Posted: 01.05.2019

By Jane E. Brody The earsplitting sound of ambulance sirens in New York City is surely hastening the day when I and many others repeatedly subjected to such noise will be forced to get hearing aids. I just hope this doesn’t happen before 2021 or so when these devices become available over-the-counter and are far less expensive and perhaps more effective than they are now. Currently, hearing aids and accompanying services are not covered by medical insurance, Medicare included. Such coverage was specifically excluded when the Medicare law was passed in 1965, a time when hearing loss was not generally recognized as a medical issue and hearing aids were not very effective, said Dr. Frank R. Lin, who heads the Cochlear Center for Hearing and Public Health at the Johns Hopkins Bloomberg School of Public Health. Now a growing body of research by his colleagues and others is linking untreated hearing loss to several costly ills, and the time has come for hearing protection and treatment of hearing loss to be taken much more seriously. Not only is poor hearing annoying and inconvenient for millions of people, especially the elderly. It is also an unmistakable health hazard, threatening mind, life and limb, that could cost Medicare much more than it would to provide hearing aids and services for every older American with hearing loss. Currently, 38.2 million Americans aged 12 or older have hearing loss, a problem that becomes increasingly common and more severe with age. More than half of people in their 70s and more than 80 percent in their 80s have mild to moderate hearing loss or worse, according to tests done by the National Health and Nutrition Examination Survey between 2001 and 2010. Two huge new studies have demonstrated a clear association between untreated hearing loss and an increased risk of dementia, depression, falls and even cardiovascular diseases. In a significant number of people, the studies indicate, uncorrected hearing loss itself appears to be the cause of the associated health problem. © 2018 The New York Times Company

Keyword: Hearing; Alzheimers
Link ID: 25834 - Posted: 01.01.2019

By: Robert Zatorre, Ph.D. Human beings seem to have innate musicality. That is, the capacity to understand and derive pleasure from complex musical patterns appears to be culturally universal.1 Musicality is expressed very early in development.2 In this sense, music may be compared to speech—the other cognitively interesting way that we use sound. But whereas speech is most obviously important for communicating propositions or concepts, obtaining such knowledge, this is not the primary function of music. Rather, it is music’s power to communicate emotions, moods, or affective mental states that seems beneficial to our quality of life. Which brings us to the question that forms the title of this article: why do we love music? On its face, there is no apparent reason why a sequence or pattern of sounds that has no specific propositional meaning should elicit any kind of pleasurable response. Yet music is widely considered amongst our greatest joys.3 Where does this phenomenon come from? There are several approaches to this question. A musicologist might have a very different answer than a social scientist. Since I’m a neuroscientist, I would like to address it from that perspective—recognizing that other perspectives may also offer valuable insights. An advantage of neuroscience is that we can relate our answer to established empirical findings and draw from two especially relevant domains: the neuroscience of auditory perception and of the reward system. To give away the punch line of my article, I believe that music derives its power from an interaction between these two systems, the first of which allows us to analyze sound patterns and make predictions about them, and the second of which evaluates the outcomes of these predictions and generates positive (or negative) emotions depending on whether the expectation was met, not met, or exceeded. © 2018 The Dana Foundation

Keyword: Hearing; Emotions
Link ID: 25832 - Posted: 01.01.2019

By Penelope Green On winter nights, the white-noise app on my phone is tuned to Air Conditioner: a raspy, metallic whir that sounds like the mechanical noise that might echo deep inside the ductwork of a huge commercial building. (Among the app’s other offerings are Dishwasher Rinsing, Crowded Room and Vacuum Cleaner.) It lulls me to sleep nonetheless, because it blankets the din in my apartment (the ragged snore of a roommate; the clanking of the steam radiator; the cat’s skidding pursuit of something only he can see). It may also soothe because it replicates an early sound environment, probably that of a Manhattan childhood, though perhaps it suggests something much, much older. Some sleep experts note that babies, their ears accustomed to the whisper of the maternal circulatory system and the slosh of the womb, sleep better accompanied by a device that mimics those familiar whooshings. My app is but one note in the mighty chorus of white-noise generators, an exploding industry of mechanical and digital devices; apps and websites, and Sonos and Spotify playlists that grows ever more refined, as if to block out the increased rate of speeding, the wrecks, on the information superhighway. Car Interior? Oil Tanker? Laundromat? These ballads are in the vast soundscape library created by Stephane Pigeon, a Belgian electrical engineer, and ready to play on Mynoise.net, a sound generator he put online in 2013 that now has one million page views each month. It’s a nearly philanthropic enterprise, as it runs on donations. “I have enough stress,” Dr. Pigeon said. Reddit, among other message boards, offers D.I.Y. white-noise hacks for light sleepers, shift workers and tinnitus sufferers. Rough up the blades of a box fan with a box cutter, suggested Christopher Suarez, a field service technician from Riverside, Calif., whose wife is an insomniac, on one captivating thread there. © 2018 The New York Times Company

Keyword: Sleep; Hearing
Link ID: 25828 - Posted: 12.28.2018

Shawna Williams The sensation of perceiving a smell can be induced in people by using electrodes to stimulate the brain’s olfactory bulb, researchers report today (November 27) in the International Forum of Allergy & Rhinology. The results, they suggest, are a proof of concept that it would be possible to develop an “olfactory implant system” to aid people with an impaired sense of smell, known as anosmia. “Our work shows that smell restoration technology is an idea worth studying further,” says coauthor Eric Holbrook of Massachusetts Eye and Ear Infirmary in a press release. “The development of cochlear implants, for example, didn’t really accelerate until someone placed an electrode in the cochlea of a patient and found that the patient heard a frequency of some type.” Holbrook and colleagues enrolled five subjects in the study who were able to smell. Three of them reported perceiving odors not actually present when the researchers stimulated different parts of their olfactory bulbs with electrodes inserted through the nose, a procedure the study authors say caused “minimal discomfort.” Subjects described the smells as “onion-like,” “antiseptic-like,” “sour,” “fruity,” or simply “bad.” The finding follows a report earlier this year that electrically stimulating structures high up in the nasal cavity produced smell sensations. The scientists who conducted that study at Malaysia’s Imagineering Institute aim to one day transmit smells electronically, reportes IEEE Spectrum—for example, to give restaurant-goers a whiff of dishes on the menu as they decide what to order. © 1986 - 2018 The Scientist

Keyword: Chemical Senses (Smell & Taste)
Link ID: 25726 - Posted: 11.29.2018

Tina Hesman Saey Whether people prefer coffee or tea may boil down to a matter of taste genetics. People with a version of a gene that increases sensitivity to the bitter flavor of caffeine tend to be coffee drinkers, researchers report online November 15 in Scientific Reports. Tea drinkers tended to be less sensitive to caffeine’s bitter taste, but have versions of genes that increase sensitivity to the bitterness of other chemicals, the researchers found. It’s long been thought that people avoid eating bitter foods because bitterness is an indicator of poison, says John Hayes, a taste researcher at Penn State who was not involved in the study. The coffee and tea findings help challenge that “overly simplistic ‘bitter is always bad, let’s avoid it’” view, he says. In the new study, researchers examined DNA variants of genes involved in detecting the bitter taste of the chemicals, caffeine, quinine — that bitter taste in tonic water — and propylthiouracil (PROP), a synthetic chemical not naturally found in food or drink. Other bitter components naturally in coffee and tea may trigger the same taste responses as quinine and PROP do, Hayes says. Researchers in Australia, the United States and England examined DNA from more than 400,000 participants in the UK Biobank, a repository of genetic data for medical research. Participants also reported other information about their health and lifestyle, including how much tea or coffee they drink each day. |© Society for Science & the Public 2000 - 2018

Keyword: Chemical Senses (Smell & Taste); Genes & Behavior
Link ID: 25693 - Posted: 11.16.2018

Jennifer Leman Some moths aren’t so easy for bats to detect. The cabbage tree emperor moth has wings with tiny scales that absorb sound waves sent out by bats searching for food. That absorption reduces the echoes that bounce back to bats, allowing Bunaea alcinoe to avoid being so noticeable to the nocturnal predators, researchers report online November 12 in the Proceedings of the National Academy of Sciences. “They have this stealth coating on their body surfaces which absorbs the sound,” says study coauthor Marc Holderied, a bioacoustician at the University of Bristol in England. “We now understand the mechanism behind it.” Bats sense their surroundings using echolocation, sending out sound waves that bounce off objects and return as echoes picked up by the bats’ supersensitive ears (SN: 9/30/17, p. 22). These moths, without ears that might alert them to an approaching predator, have instead developed scales of a size, shape and thickness suited to absorbing ultrasonic sound frequencies used by bats, the researchers found. The team shot ultrasonic sound waves at a single, microscopic scale and observed it transferring sound wave energy into movement. The scientists then simulated the process with a 3-D computer model that showed the scale absorbing up to 50 percent of the energy from sound waves. What’s more, it isn’t just wings that help such earless moths evade bats. Other moths in the same family as B. alcinoe also have sound-absorbing fur, the same researchers report online October 18 in the Journal of the Acoustical Society of America. |© Society for Science & the Public 2000 - 2018

Keyword: Hearing; Evolution
Link ID: 25679 - Posted: 11.14.2018

By JoAnna Klein Lavender bath bombs; lavender candles; deodorizing lavender sachets for your shoes, car or underwear drawer; lavender diffusers; lavender essential oils; even lavender chill pills for humans and dogs. And from Pinterest: 370 recipes for lavender desserts. Take a deep breath. Release. People like lavender. We’ve been using this violet-capped herb since at least medieval times. It smells nice. But Google “lavender” and results hint at perhaps the real fuel for our obsession: “tranquillity,” “calm,” “relaxation,” “soothing,” and “serenity.” Lavender has purported healing powers for reducing stress and anxiety. But are these effects more than just folk medicine? Yes, said Hideki Kashiwadani, a physiologist and neuroscientist at Kagoshima University in Japan — at least in mice. “Many people take the effects of ‘odor’ with a grain of salt,” he said in an email. “But among the stories, some are true based on science.” In a study published Tuesday in the journal Frontiers in Behavioral Neuroscience, he and his colleagues found that sniffing linalool, an alcohol component of lavender odor, was kind of like popping a Valium. It worked on the same parts of a mouse’s brain, but without all the dizzying side effects. And it didn’t target parts of the brain directly from the bloodstream, as was thought. Relief from anxiety could be triggered just by inhaling through a healthy nose. Their findings add to a growing body of research demonstrating anxiety-reducing qualities of lavender odors and suggest a new mechanism for how they work in the body. Dr. Kashiwadani believes this new insight is a key step in developing lavender-derived compounds like linalool for clinical use in humans. Dr. Kashiwadani and his colleagues became interested in learning how linalool might work for anti-anxiety while testing its effects on pain relief in mice. In this earlier study, they noticed that the presence of linalool seemed to calm mice. © 2018 The New York Times Company

Keyword: Emotions; Chemical Senses (Smell & Taste)
Link ID: 25610 - Posted: 10.24.2018

Allison Aubrey By age 40, about one in 10 adults will experience some hearing loss. It happens so slowly and gradually, says audiologist Dina Rollins, "you don't realize what you're missing." And even as it worsens, many people are in denial. By the time someone is convinced they have a hearing problem, age-related memory loss may have already set in. But, here's the good news: Restoring hearing with hearing aids can help slow down cognitive decline. Consider these findings: Researchers tracked about 2,000 older adults in the U.S. both before and after they started using hearing aids. The adults were participants in a big, national study, the Health and Retirement Study. "We found the rate of cognitive decline was slowed by 75 percent following the adoption of hearing aids," says Asri Maharani, a researcher at the University of Manchester in the division of neuroscience and experimental psychology and an author of the paper. "It is a surprising result," Maharani says. The study was published this spring in the Journal of the American Geriatrics Society. To assess cognition over time, researchers performed a battery of tests face-to-face with participants. This was done every two years from 1996 to 2014. One test to assess memory required participants to recall a list of 10 words, both immediately after the words were read aloud, and then again after the participants had been distracted by other tasks. © 2018 npr

Keyword: Alzheimers; Development of the Brain
Link ID: 25599 - Posted: 10.22.2018

Gina Mantica Have you ever seen a picture of a mother dog caring for an unusual baby, like a kitten? This sort of animal adoption story is an example of a phenomenon known as alloparenting: care provided to offspring that are not genetically related. We humans may toss around the phrase “It takes a village to raise a child,” but there are cases in the animal world where this is more literally true. Naked mole-rats, wrinkly mammals of the East African desert, offer an example of the whole “village” cooperating to raise offspring. Each individual naked mole-rat has a specific job. Like in a honeybee hive, a naked mole-rat colony has one queen, whose job it is to reproduce. There are just a few sexually reproductive males, who mate with the queen. All the others, both male and female, are either soldiers that protect the colony or workers that forage for food, dig tunnels and care for the queen’s offspring, known as pups. Until now, no one had a physiological explanation for why naked mole-rat workers care for pups that aren’t their own. Normally when a mom gives birth, estrogen levels are high and progesterone levels drop, resulting in maternal behaviors such as feeding or grooming. In many unusual adoption stories, like that of the mother dog caring for a kitten, the adoptive mom will have recently given birth to her own offspring – meaning her hormone levels have left her primed and ready to care for offspring, even those that aren’t her own. © 2010–2018, The Conversation US, Inc.

Keyword: Sexual Behavior; Chemical Senses (Smell & Taste)
Link ID: 25577 - Posted: 10.16.2018

By Jane E. Brody Jane R. Madell, a pediatric audiology consultant and speech-language pathologist in Brooklyn, N.Y., wants every parent with a child who is born hearing-impaired to know that it is now possible for nearly all children with severe hearing loss to learn to listen and speak as if their hearing were completely normal. “Children identified with hearing loss at birth and fitted with technology in the first weeks of life blend in so well with everyone else that people don’t realize there are so many deaf children,” she told me. With the appropriate hearing device and auditory training for children and their caregivers during the preschool years, even those born deaf “will have the ability to learn with their peers when they start school,” Dr. Madell said. “Eighty-five percent of such children are successfully mainstreamed. Parents need to know that listening and spoken language is a possibility for their children.” Determined to get this message out to all who learn their children lack normal hearing, Dr. Madell and Irene Taylor Brodsky produced a documentary, “The Listening Project,” to demonstrate the enormous help available through modern hearing assists and auditory training. Among the “stars” in the film, all of whom grew up deaf or severely hearing-impaired, are Dr. Elizabeth Bonagura, an obstetrician-gynecologist and surgeon; Jake Spinowitz, a musician; Joanna Lippert, a medical social worker, and Amy Pollick, a psychologist. All started out with hearing aids that helped them learn to speak and understand spoken language. But now all have cochlear implants that, as Ms. Lippert put it, “really revolutionized my world” when, at age 11, she became the first preteen to get a cochlear implant at New York University Medical Center. © 2018 The New York Times Company

Keyword: Hearing
Link ID: 25541 - Posted: 10.08.2018

Susan Milius It’s a lovely notion, but tricky to prove. Still, lemurs sniffing around wild fruits in Madagascar are bolstering the idea that animal noses contributed to the evolution of aromas of fruity ripeness. The idea sounds simple, says evolutionary ecologist Omer Nevo of the University of Ulm in Germany. Plants can use mouth-watering scents to lure animals to eat fruits, and thus spread around the seeds. But are those odors really advertising, or are they just the way fruits happen to smell as they ripen? For some wild figs and a range of other fruits in eastern Madagascar, a strong scent of ripeness does seem to have evolved in aid of allure, Nevo and his colleagues argue October 3 in Science Advances. A lot of fruit collecting and odor chemistry suggest that fruits dispersed by lemurs, with their sensitive noses, change more in scent than fruits that rely more on birds with acute color vision. Earlier studies had sniffed around several species, such as figs. But for a broader look, Nevo and his colleagues analyzed scents from 25 other kinds of fruits as well as five kinds of figs. All grew wild in a “really magnificent” mountainous rainforest preserved as a park in eastern Madagascar, Nevo says. The researchers classified 19 of the plants as depending largely on red-bellied and other local lemurs to spread seeds. Most of these lemurs are red-green color-blind, not great for spotting the ripe fruits among foliage. But the researchers following some lemurs foraging in daylight noticed that sniffing at fruits was a big deal for the primates. |© Society for Science & the Public 2000 - 2018

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 25528 - Posted: 10.04.2018

Craig Richard Have you ever stumbled upon an hourlong online video of someone folding napkins? Or maybe crinkling paper, sorting a thimble collection or pretending to give the viewer an ear exam? They’re called ASMR videos and millions of people love them and consider watching them a fantastic way to relax. Other viewers count them among the strangest things on the internet. So are they relaxing or strange? I think they are both, which is why I have been fascinated with trying to understand ASMR for the past five years. In researching my new book “Brain Tingles,” I explored the many mysteries about ASMR as well as best practices for incorporating ASMR into various aspects of life, like parenting, spas and health studios. ASMR is short for Autonomous Sensory Meridian Response. Enthusiast Jennifer Allen coined the term in 2010. You may also hear this phenomenon called “head orgasms” or “brain tingles.” It’s distinct from the “aesthetic chills” or frisson some people experience when listening to music, for instance. People watch ASMR videos in hopes of eliciting the response, usually experienced as a deeply relaxing sensation with pleasurable tingles in the head. It can feel like the best massage in the world – but without anyone touching you. Imagine watching an online video while your brain turns into a puddle of bliss. The actions and sounds in ASMR videos mostly recreate moments in real life that people have discovered spark the feeling. These stimuli are called ASMR triggers. They usually involve receiving personal attention from a caring person. Associated sounds are typically gentle and non-threatening. © 2010–2018, The Conversation US, Inc.

Keyword: Hearing; Emotions
Link ID: 25498 - Posted: 09.27.2018

By William J. Broad During the Cold War, Washington feared that Moscow was seeking to turn microwave radiation into covert weapons of mind control. More recently, the American military itself sought to develop microwave arms that could invisibly beam painfully loud booms and even spoken words into people’s heads. The aims were to disable attackers and wage psychological warfare. Now, doctors and scientists say such unconventional weapons may have caused the baffling symptoms and ailments that, starting in late 2016, hit more than three dozen American diplomats and family members in Cuba and China. The Cuban incidents resulted in a diplomatic rupture between Havana and Washington. The medical team that examined 21 affected diplomats from Cuba made no mention of microwaves in its detailed report published in JAMA in March. But Douglas H. Smith, the study’s lead author and director of the Center for Brain Injury and Repair at the University of Pennsylvania, said in a recent interview that microwaves were now considered a main suspect and that the team was increasingly sure the diplomats had suffered brain injury. “Everybody was relatively skeptical at first,” he said, “and everyone now agrees there’s something there.” Dr. Smith remarked that the diplomats and doctors jokingly refer to the trauma as the immaculate concussion. Strikes with microwaves, some experts now argue, more plausibly explain reports of painful sounds, ills and traumas than do other possible culprits — sonic attacks, viral infections and contagious anxiety. In particular, a growing number of analysts cite an eerie phenomenon known as the Frey effect, named after Allan H. Frey, an American scientist. Long ago, he found that microwaves can trick the brain into perceiving what seem to be ordinary sounds. The false sensations, the experts say, may account for a defining symptom of the diplomatic incidents — the perception of loud noises, including ringing, buzzing and grinding. Initially, experts cited those symptoms as evidence of stealthy attacks with sonic weapons. © 2018 The New York Times Company

Keyword: Brain Injury/Concussion; Hearing
Link ID: 25410 - Posted: 09.01.2018

By James Gorman It’s not easy to help ducks. Ask Kate McGrew, a masters student in wildlife ecology at the University of Delaware. Over two seasons, 2016 and 2017, she spent months raising and working with more than two dozen hatchlings from three different species, all to determine what they hear underwater. This was no frivolous inquiry. Sea ducks, like the ones she trained, dive to catch their prey in oceans around the world and are often caught unintentionally in fish nets and killed. Christopher Williams, a professor at the university who is Ms. McGrew’s adviser, said one estimate puts the number of ducks killed at sea at 400,000 a year, although he said the numbers are hard to pin down. A similar problem plagues marine mammals, like whales, and acoustic devices have been developed to send out pings that warn them away from danger. A similar tactic might work with diving ducks, but first, as Dr. Williams said, it would make sense to answer a question that science hasn’t even asked about diving ducks: “What do they hear?” “There actually is little to no research done on duck hearing in general,” Ms. McGrew said, “and on the underwater aspect of it, there’s even less.” That’s the recipe for a perfect, although demanding research project. Her goal was to use three common species of sea ducks to study a good range of underwater hearing ability. But while you can lead a duck to water and it will paddle around naturally, teaching it to take a hearing test is another matter entirely. © 2018 The New York Times Company

Keyword: Hearing
Link ID: 25389 - Posted: 08.28.2018

Laurel Hamers Dealing with poop is an unavoidable hazard of raising children, regardless of species. But for naked mole rats, that wisdom is especially salient. During pregnancy, the scat of a naked mole rat queen — the only female in the colony that reproduces, giving birth to a few dozen pups each year — contains high levels of the sex hormone estradiol. When subordinate female naked mole rats eat that poop, the estradiol they pick up cues them to snap into parenting mode and care for the queen’s offspring, researchers report the week of August 27 in the Proceedings of the National Academy of Sciences. In colonies of naked mole rats (Heterocephalus glaber), lower-ranking females don’t have developed ovaries and don’t reproduce. They also don’t experience the pregnancy-induced hormonal shifts that usually cue parenting behaviors, yet they still care for the queen’s babies. Researchers gave poop pellets from nonpregnant queens to subordinates for nine days. One group got pellets with added estradiol, to mimic pregnancy poop. Levels of estradiol increased in the dung of subordinate females that ate the hormone-packed pellets, suggesting that scat snacks could induce measurable hormonal changes. And those mole rats were more responsive to the cries of pups than those that didn’t get the hormone boost, the team found. |© Society for Science & the Public 2000 - 2018.

Keyword: Sexual Behavior; Chemical Senses (Smell & Taste)
Link ID: 25383 - Posted: 08.28.2018