Chapter 19. Language and Lateralization

Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.


Links 1 - 20 of 2439

By Karen Weintraub A widely criticized experiment last year saw a researcher in China delete a gene in twin girls at the embryonic stage in an attempt to protect them from HIV. A new study suggests that using a drug to delete the same gene in people with stroke or traumatic brain injuries could help improve their recovery. The new work shows the benefits of turning off the gene in stroke-induced mice by using the drug, already approved as an HIV treatment. It also focuses on a sample of people who were naturally born without the gene. People without the gene recover faster and more completely from stroke than the general population does, the researchers found. The combined results suggest the drug might boost recovery in humans after a stroke or traumatic brain injury, says S. Thomas Carmichael, the study’s senior researcher and a neurologist at the University of California, Los Angeles, David Geffen School of Medicine. His team has started a follow-up human study to test the drug’s efficacy. The combination of mouse research and leveraging of people’s genetic data to confirm the relevance of drug targets makes the new research a “landmark paper,” says Jin-Moo Lee, co-director of the Barnes–Jewish Hospital and Washington University Stroke and Cerebrovascular Center in Saint Louis who was not involved with the work. © 2019 Scientific American

Keyword: Stroke
Link ID: 25981 - Posted: 02.22.2019

Jules Howard It’s a bit garbled but you can definitely hear it in the mobile phone footage. As the chimpanzees arrange their branches into a makeshift ladder and one of them makes its daring escape from its Belfast zoo enclosure, some words ring out loud and clear: “Don’t escape, you bad little gorilla!” a child onlooker shouts from the crowd. And … POP … with that a tiny explosion goes off inside my head. Something knocks me back about this sentence. It’s a “kids-say-the-funniest things” kind of sentence, and in any other situation I’d offer a warm smile and a chuckle of approval. But not this time. This statement has brought out the pedant in me. At this point, you may wonder if I’m capable of fleshing out a 700-word article chastising a toddler for mistakenly referring to a chimpanzee as a gorilla. The good news is that, though I am more than capable of such a callous feat, I don’t intend to write about this child’s naive zoological error. In fact, this piece isn’t really about the (gorgeous, I’m sure) child. It’s about us. You and me, and the words we use. So let’s repeat it. That sentence, I mean. “Don’t escape, you bad little gorilla!” the child shouted. The words I’d like to focus on in this sentence are the words “you” and “bad”. The words “you” and “bad” are nice examples of a simple law of nearly all human languages. They are examples of Zipf’s law of abbreviation, where more commonly used words in a language tend to be shorter. It’s thought that this form of information-shortening allows the transmission of more complex information in a shorter amount of time, and it’s why one in four words you and I write or say is likely to be something of the “you, me, us, the, to” variety. © 2019 Guardian News & Media Limited

Keyword: Language; Evolution
Link ID: 25971 - Posted: 02.18.2019

By Virginia Morell It’s hard to imagine a teen asking their mother for approval on anything. But a new study shows that male zebra finches—colorful songbirds with complex songs—learn their father’s tune better when mom “fluffs up” to signal her approval. This is the first time the songbirds, thought to be mere memorization machines, have been shown to use social cues for learning—putting them in an elite club that includes cowbirds, marmosets, and humans. The finding suggests other songbirds might also learn their tunes this way, and that zebra finches are better models for studying language development than thought. “Female zebra finches play an important role in male learning, in some ways even rivaling that of the male tutors,” says Karl Berg, an avian ecologist at the University of Texas in Brownsville, who was not involved in the new study. Previously, scientists knew only that the nonsinging females played some role in song acquisition, because males raised with deaf females develop incorrect songs. Researchers have long known that female brown-headed cowbirds make quick, lateral wing strokes to approve the songs of juvenile males (as in finches, only male cowbirds learn to sing). Most scientists discounted the cowbirds’ social cues as an isolated oddity, because the birds are brood parasites. But cowbirds’ similarities to zebra finches—both are highly social and use their songs to attract mates rather than claim territories—led Cornell University developmental psychobiologists Samantha Carouso-Peck and Michael Goldstein to wonder whether female finches also use social cues to help young males learn the best, mate-attracting songs. © 2018 American Association for the Advancement of Science.

Keyword: Animal Communication; Sexual Behavior
Link ID: 25922 - Posted: 02.01.2019

Hannah Devlin Science correspondent People who stutter are being given electrical brain stimulation in a clinical trial aimed at improving fluency without the need for gruelling speech training. If shown to be effective, the technique – which involves passing an almost imperceptible current through the brain – could be routinely offered by speech therapists. “Stuttering can have serious effects on individuals in terms of their choice of career, what they can get out of education, their earning potential and personal life,” said Prof Kate Watkins, the trial’s principal investigator and a neuroscientist at the University of Oxford. About one in 20 young children go through a phase of stuttering, but most grow out of it. It is estimated that stuttering affects about one in 100 adults, with men about four times more likely to stutter than women. Advertisement In the film The King’s Speech, a speech therapist uses a barrage of techniques to help King George VI, played by Colin Firth, to overcome his stutter, including breathing exercises and speaking without hearing his own voice. The royal client also learns that he can sing without stuttering, a common occurrence in people with the impediment. Speech therapy has advanced since the 1930s, but some of the most effective programmes for improving fluency still require intensive training and involve lengthy periods of using unnatural-sounding speech. © 2019 Guardian News and Media Limited

Keyword: Language
Link ID: 25901 - Posted: 01.26.2019

Susan Milius After some 20 years of theorizing, a scientist is publicly renouncing the “beautiful hypothesis” that male birds’ sexy songs could indicate the quality of their brains. Behavioral ecologist Steve Nowicki of Duke University called birdsong “unreliable” as a clue for choosy females seeking a smart mate, in a paper published in the March 2018 Animal Behaviour. He will also soon publish another critique based on male songbirds that failed to score consistently on learning tests. And in what he calls a “public service announcement,” Nowicki summarized the negative results of those tests on January 4 at the annual meeting of the Society for Integrative and Comparative Biology in Tampa, Fla. “This was a beautiful hypothesis that got beaten up by data,” he says. Knowing that something about male singing matters to a female songbird, Nowicki and other researchers once proposed that the quality of singing might indicate a bird’s brainpower. The idea was that, because songbirds need to learn their songs, females could select males with the best brain development by selecting those singing the most precisely copied songs. A brainier male might be better at hunting baby food or spotting predators, thus helping more chicks to survive. Or braininess might signal an indirect benefit, such as contributing good genes to chicks. The first evidence for the notion that birdsong indicates bird smarts came from Neeltje Boogert at the University of Exeter in England, whose research suggested female zebra finches preferred smarter males with more complex songs. But subsequent studies have found evidence both supporting and contradicting the theory. To try to settle the matter, Nowicki and collaborators hand-raised 19 male song sparrows in the lab, controlling which songs the little birds heard as examples to copy so that it was clear how well each youngster learned each song. |© Society for Science & the Public 2000 - 2019

Keyword: Animal Communication; Sexual Behavior
Link ID: 25900 - Posted: 01.26.2019

By Abdul-Kareem Ahmed, M.D. “He wouldn’t want to live like this.” The cardiology team consulted us that Sunday evening. A patient was getting sleepy, and weak on one side. The man was 68 years old, not a healthy man, but a strong man. He had suffered a heart attack, again, and had been transferred from another hospital. Because he’d been far from a major medical center, where a wire might have been used to clear the blockage in his coronary arteries, he was treated with the next best method, a blood-thinner, and then sent to us. The drug, tenecteplase, is an enzyme that works by digesting clots. It effectively reverses the problem and is lifesaving for a majority of patients. But in a small minority of patients, it can also cause bleeding. Titrating the thickness of blood is precarious. If your blood is too thick you can clot. If it’s too thin you can bleed. The team had performed a rapid head CT. “He’s not going to make it,” my senior whispered as I scrolled through the fresh images. Our patient was bleeding into his brain, suffering a hemorrhagic stroke. Tenecteplase thinned his blood to save his heart, but it most likely had resulted in injury to his brain. I ran downstairs to examine him. He was big, and bald, and lying peacefully in his bed. With some encouragement, he gave me a grin, though lopsided. His pupils were different sizes, and half his body was paralyzed. But he was completely “there.” I was only one month into residency. Though I knew he was critical, and I knew our next decision would be difficult, I remained optimistic. © 2019 The New York Times Company

Keyword: Brain Injury/Concussion
Link ID: 25897 - Posted: 01.24.2019

By Catherine L. Caldwell-Harris, Ph.D. Does the language you speak influence how you think? This is the question behind the famous linguistic relativity hypothesis, that the grammar or vocabulary of a language imposes on its speakers a particular way of thinking about the world. The strongest form of the hypothesis is that language determines thought. This version has been rejected by most scholars. A weak form is now thought to be obviously true, which is that if one language has a specific vocabulary item for a concept but another language does not, then speaking about the concept may happen more frequently or more easily. For example, if someone explained to you, an English speaker, the meaning for the German term Schadenfreude, you could recognize the concept, but you may not have used the concept as regularly as a comparable German speaker. Scholars are now interested in whether having a vocabulary item for a concept influences thought in domains far from language, such as visual perception. Consider the case of the "Russian blues." While English has a single word for blue, Russian has two words, goluboy for light blue and siniy for dark blue. These are considered "basic level" terms, like green and purple, since no adjective is needed to distinguish them. Lera Boroditsky and her colleagues displayed two shades of blue on a computer screen and asked Russian speakers to determine, as quickly as possible, whether the two blue colors were different from each other or the same as each other. The fastest discriminations were when the displayed colors were goluboy and siniy, rather than two shades of goluboy or two shades of siniy. The reaction time advantage for lexically distinct blue colors was strongest when the blue hues were perceptually similar.

Keyword: Language; Vision
Link ID: 25869 - Posted: 01.16.2019

By Karen Weintraub Sometimes a whale just wants to change its tune. That’s one of the things researchers have learned recently by eavesdropping on whales in several parts of the world and listening for changes in their pattern and pitch. Together, the new studies suggest that whales are not just whistling in the water, but constantly evolving a form of communication that we are only beginning to understand. Most whales and dolphins vocalize, but dolphins and toothed whales mostly make clicking and whistling sounds. Humpbacks, and possibly bowheads, sing complex songs with repeated patterns, said Michael Noad, an associate professor in the Cetacean Ecology and Acoustics Laboratory at the University of Queensland in Australia. Birds may broadcast their social hierarchy among song-sharing populations by allowing the dominant bird to pick the playlist and patterns. But how and why whales pass song fragments across hundreds of miles, and to thousands of animals, is far more mysterious. The biggest question is why whales sing at all. “The thing that always gets me out of bed in the morning is the function of the song,” Dr. Noad said. “I find humpback song fascinating from the point of view of how it’s evolved.” The leading hypothesis is that male humpbacks — only the males sing — are trying to attract females. But they may also switch tunes when another male is nearby, apparently to assess a rival’s size and fitness, said Dr. Noad, who was the senior author of one of four new papers on whale songs. © 2019 The New York Times Company

Keyword: Animal Communication; Sexual Behavior
Link ID: 25850 - Posted: 01.09.2019

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 Kelly Servick For many people who are paralyzed and unable to speak, signals of what they'd like to say hide in their brains. No one has been able to decipher those signals directly. But three research teams recently made progress in turning data from electrodes surgically placed on the brain into computer-generated speech. Using computational models known as neural networks, they reconstructed words and sentences that were, in some cases, intelligible to human listeners. None of the efforts, described in papers in recent months on the preprint server bioRxiv, managed to re-create speech that people had merely imagined. Instead, the researchers monitored parts of the brain as people either read aloud, silently mouthed speech, or listened to recordings. But showing the reconstructed speech is understandable is "definitely exciting," says Stephanie Martin, a neural engineer at the University of Geneva in Switzerland who was not involved in the new projects. People who have lost the ability to speak after a stroke or disease can use their eyes or make other small movements to control a cursor or select on-screen letters. (Cosmologist Stephen Hawking tensed his cheek to trigger a switch mounted on his glasses.) But if a brain-computer interface could re-create their speech directly, they might regain much more: control over tone and inflection, for example, or the ability to interject in a fast-moving conversation. The hurdles are high. "We are trying to work out the pattern of … neurons that turn on and off at different time points, and infer the speech sound," says Nima Mesgarani, a computer scientist at Columbia University. "The mapping from one to the other is not very straightforward." How these signals translate to speech sounds varies from person to person, so computer models must be "trained" on each individual. And the models do best with extremely precise data, which requires opening the skull. © 2018 American Association for the Advancement of Science

Keyword: Language; Brain imaging
Link ID: 25837 - Posted: 01.03.2019

Emily Hanford Jack Silva didn't know anything about how children learn to read. What he did know is that a lot of students in his district were struggling. Silva is the chief academic officer for Bethlehem, Pa., public schools. In 2015, only 56 percent of third-graders were scoring proficient on the state reading test. That year, he set out to do something about that. "It was really looking yourself in the mirror and saying, 'Which 4 in 10 students don't deserve to learn to read?' " he recalls. Bethlehem is not an outlier. Across the country, millions of kids are struggling. According to the National Assessment of Educational Progress, 32 percent of fourth-graders and 24 percent of eighth-graders aren't reading at a basic level. Fewer than 40 percent are proficient or advanced. One excuse that educators have long offered to explain poor reading performance is poverty. In Bethlehem, a small city in Eastern Pennsylvania that was once a booming steel town, there are plenty of poor families. But there are fancy homes in Bethlehem, too, and when Silva examined the reading scores he saw that many students at the wealthier schools weren't reading very well either. Silva didn't know what to do. To begin with, he didn't know how students in his district were being taught to read. So, he assigned his new director of literacy, Kim Harper, to find out. Harper attended a professional-development day at one of the district's lowest-performing elementary schools. The teachers were talking about how students should attack words in a story. When a child came to a word she didn't know, the teacher would tell her to look at the picture and guess. © 2019 npr

Keyword: Language; Development of the Brain
Link ID: 25835 - Posted: 01.03.2019

Katie Brown When polite people talk, they take turns speaking and adjust the timing of their responses on the fly. So do wild macaques, a team of Japanese ethologists reports. Analysis of 20-minute vocal exchanges involving 15 adult female Japanese macaques (Macaca fuscata) revealed that the monkeys altered their conversational pauses depending on how quickly others answered, the researchers report in a study in an upcoming issue of Current Zoology. It’s unclear whether the monkeys were actually talking in any way analogous to how humans converse. While macaques have the vocal equipment to form humanlike words, their brains are unable to transform that vocal potential into human talk (SN Online: 12/19/16). The primates instead communicate in grunts, coos and other similar sounds. But the length of pauses between those grunts and coos closely match the length of pauses in human chats, says coauthor Noriko Katsu of the University of Tokyo. The researchers analyzed 64 vocal exchanges, called bouts, between at least two monkeys that were recorded between April and October 2012 at the Iwatayama Monkey Park in Kyoto, Japan. The team found that the median length of time between the end of one monkey’s calls and the beginning of another’s was 250 milliseconds — similar to the average 200 milliseconds in conversational pause time between humans. That makes the macaques’ gaps between turns in chattering one of the shortest call-and-response pauses yet measured in nonhuman primates. |© Society for Science & the Public 2000 - 2018.

Keyword: Animal Communication; Language
Link ID: 25829 - Posted: 01.01.2019

Jon Hamilton It was a question about soccer that got Philip Bayly interested in brain injuries. Bayly, a mechanical engineer at Washington University in St. Louis, was approached by several doctors who wanted advice about some young soccer players they were treating. "They said, 'Well, we've got some kids who have concussions and they want to know if they can go back to play. And we don't know what's happening to their head when they're heading a soccer ball,' " Bayly recalls. Does a header have a big effect or a small one? The doctors thought Bayly might have the answer. "I said, 'That's really interesting. I play soccer and my kids play soccer, and I don't know what's happening when you head a soccer ball either,' " Bayly told them. "But I know how we can find out." So in the early 2000s, Bayly brought soccer players into his lab to figure out precisely how much acceleration their heads experienced when they headed balls hurled at them by a machine. The answer was 15 to 20 times the force of gravity, a relatively minor impact. "Jump up and down you're feeling maybe 4 or 5 G's when you hit the ground," Bayly says. "When you play football, you have a hard collision with someone else, it's maybe 50 to 100 G's." © 2018 npr

Keyword: Brain Injury/Concussion
Link ID: 25824 - Posted: 12.26.2018

By Leslie Nemo If you came across California mice in the wild, you wouldn’t hear a thing. Their jabber is ultrasonic—humans hear it only when it's slowed to five percent its original speed. But that’s when the imperceptible squeaks morph into a vocal range that’d put Mariah Carey to shame. Mice, you see, regularly vocalize to communicate in many different situations—which researchers did not know until recently. “It’s an under-appreciated part of biology of one of most diverse groups of mammals,” says Matina Kalcounis-Rueppell, a professor of biology at University of North Carolina, Greensboro who discovered about a decade ago that these mice vocalize. These sounds range from coos to startling barks. New research published in Frontiers in Ecology and Evolution shows that when these monogamous mice are separated from their mate and then reunited, the animals sometimes don’t handle it well—revealing a new side to their social lives and behavior. Here are some of the mouse calls recorded by Josh Pultorak, who recently earned his PhD with principal investigator Catherine Marler at the University of Wisconsin-Madison in the course of this research. The first sounds, short tweets, are considered friendly, and the most common. The second, slightly longer calls appear when the mice are getting “lovey-dovey”, says Pultorak. The third whale-like yelps are also friendly and connote a strengthening relationship.

Keyword: Sexual Behavior; Animal Communication
Link ID: 25791 - Posted: 12.17.2018

By Elizabeth Pennisi Anyone who has tried to whisper sweet nothings into their lover’s ear while standing on a noisy street corner can understand the plight of the túngara frog. A tiny amphibian about the size of a U.S. quarter, the male Physalaemus pustulosus has had to make its call more complex to woo mates when they move from the forest to the city. Now, researchers have found that female túngara frogs from both the country and the city prefer these mouthy city slickers. Biologists have long studied túngara frog courtship, demonstrating that visual signals and calls by themselves are unattractive to females but together are a winning combination, and that a female’s decision to mate depends on the context. Now, researchers have recorded the calls of male frogs living in cities, small towns, and forests across Panama. As they played the calls back, they counted the females, frog-eating bats, and frog-biting insects lured in by each call. Then they transplanted forest-dwelling frogs to the city and city dwellers to the forest to see how females there reacted to their calls. Finally, in the lab, they tested female preference for each call. Males living in cities and towns called more frequently and had more complex calls—with louder “chucks” interspersed in the whine—than forest frogs, the team reports today in Nature Ecology & Evolution. When they were moved into the country, they simplified their calls; but when their country cousins were brought to the big city, they couldn’t make the switch, and kept singing simply. When the researchers played back the calls to females, the females preferred more complex calls, even if the female herself was from the country, they reported. © 2018 American Association for the Advancement of Science

Keyword: Animal Communication; Sexual Behavior
Link ID: 25769 - Posted: 12.11.2018

By Ramin Skibba Even when you’re fluent in two languages, it can be a challenge to switch back and forth smoothly between them. It’s common to mangle a split verb in Spanish, use the wrong preposition in English or lose sight of the connection between the beginning and end of a long German sentence. So, does mastering a second language hone our multitasking skills or merely muddle us up? This debate has been pitting linguists and psychologists against one another since the 1920s, when many experts thought that bilingual children were fated to suffer cognitive impairments later in life. But the science has marched on. Psycholinguist Mark Antoniou of Western Sydney University in Australia argues that bilingualism — as he defines it, using at least two languages in your daily life — may benefit our brains, especially as we age. In a recent article, he addressed how best to teach languages to children and laid out evidence that multiple-language use on a regular basis may help delay the onset of Alzheimer’s disease. This conversation has been edited for length and clarity. Q: What are the benefits of bilingualism? A: The first main advantage involves what’s loosely referred to as executive function. This describes skills that allow you to control, direct and manage your attention, as well as your ability to plan. It also helps you ignore irrelevant information and focus on what’s important. Because a bilingual person has mastery of two languages, and the languages are activated automatically and subconsciously, the person is constantly managing the interference of the languages so that she or he doesn’t say the wrong word in the wrong language at the wrong time. The brain areas responsible for that are also used when you’re trying to complete a task while there are distractions. The task could have nothing to do with language; it could be trying to listen to something in a noisy environment or doing some visual task. The muscle memory developed from using two languages also can apply to different skills. © 1996-2018 The Washington Post

Keyword: Language; Alzheimers
Link ID: 25767 - Posted: 12.10.2018

By Stephen L. Macknik Sensory information flowing into our brains is inherently ambiguous. We perceive 3D despite having only 2D images on our retinas. It’s an illusion. A sunburn on our face can feel weirdly cool. Illusion. A little perfume smells good but too much is obnoxious. Also an illusion. The brain expends a great deal of effort to disambiguate the meaning of each incoming signal—often using context as a clue—but the neural mechanisms of these abilities remain mysterious. Neuroscientists are a little closer to understanding how to study these mechanisms, thanks to a new study by Kevin Ortego, Michael Pitts, & Enriqueta Canseco-Gonzalez from Pitts's lab at Reed College, presented at the 2018 Society for Neuroscience meeting, on the brain's responses to both visual and language illusions. Illusions are experiences in which the physical reality is different from our perception or expectation. Ambiguous stimuli are important tools to science because the physical reality can legitimately be interpreted in more than one way. Take the classic rabbit-duck illusion, published by the Fliegende Blätter magazine, in Münich, at the end of the 19th century, in which the image can be seen as either a duck or a rabbit. Bistable illusions like these can flip back and forth between competing interpretations, but one cannot see both percepts at the same time. Recent examples of ambiguous illusions show that numerous interpretations are possible. The first place winner of this year's Best Illusion of the Year Contest, created by from Kokichi Sugihara, shows three different ways of perceiving the same object, depending on your specific vantage point. © 2018 Scientific American,

Keyword: Language; Attention
Link ID: 25744 - Posted: 12.03.2018

By Kara Manke A single season of high school football may be enough to cause microscopic changes in the structure of the brain, according to a new study by researchers at UC Berkeley, Duke University and the University of North Carolina at Chapel Hill. A 3D representation of a magnetic resonance imaging scan, showing areas in the front and rear of the brain lit up. Magnetic resonance imaging (MRI) brain scans have revealed that playing a single season of high school football can cause microscopic changes in the grey matter in young players’ brains. These changes are located in the front and rear of the brain, where impacts are most likely to occur, as well as deep inside the brain. The researchers used a new type of magnetic resonance imaging (MRI) to take brain scans of 16 high school players, ages 15 to 17, before and after a season of football. They found significant changes in the structure of the grey matter in the front and rear of the brain, where impacts are most likely to occur, as well as changes to structures deep inside the brain. All participants wore helmets, and none received head impacts severe enough to constitute a concussion. The study, which is the cover story of the November issue of Neurobiology of Disease, is one of the first to look at how impact sports affect the brains of children at this critical age. © 2018 UC Regents

Keyword: Brain Injury/Concussion; Development of the Brain
Link ID: 25740 - Posted: 12.01.2018

Ashley Westerman A single season playing football might be all it takes to change a young athlete's brain. Those are the preliminary findings of research presented this week in Chicago at the annual meeting of the Radiological Society of North America. Researchers used special MRI methods to look at nerve bundles in the brain in a study of the brains of 26 young male football players, average age 12, before and after one season. Twenty-six more young males who didn't play football also got MRI scans at the same time to be used as a control group. In the youths who played football, the researchers found that nerve fibers in their corpus callosum — the band that connects the two halves of brain — changed over the season, says lead study author Jeongchul Kim, a research associate in the Radiology Informatics and Imaging Laboratory at Wake Forest School of Medicine in Winston-Salem, N.C. "We applied here two different imaging approaches," he says. One analyzed the shape of the nerve fibers and the other focused on the integrity of the nerves. Kim says the researchers found some nerve bundles grew longer and other bundles became shorter, or contracted, after the players' initial MRI scans at the beginning of the season. He says they saw no changes in the integrity of the bundles. The team says these results suggest that repeated blows to the head could lead to changes in the shape of the corpus callosum, which is critical to integrating cognitive, motor and sensory functions between the two hemispheres of the brain, during a critical time for brain development in young people. © 2018 npr

Keyword: Brain Injury/Concussion; Development of the Brain
Link ID: 25739 - Posted: 12.01.2018

By Michael Allen When a peacock catches the attention of a female, he doesn’t just turn her head—he makes it vibrate. That’s the surprising conclusion of a new study, which finds that a male peafowl’s tail feathers create low-frequency sounds that cause feathers on the females’ heads to quiver. The finding is “fascinating,” says Richard Prum, an evolutionary ornithologist at Yale University who was not involved with the work. As far as he knows, it’s the first demonstration that feathers respond to acoustic communication signals from other birds. Scientists have long known that a bird’s feathers can sense vibrations. Much like a rodent’s whiskers, they are coupled to vibration-sensitive nerve cells, allowing them to sense their surroundings. Feathers can, for example, detect changes in airflow during flight, and some seabirds even use feathers on their heads to feel their way through dark, underground crevices. When peacocks are ready to mate, they fan out their iridescent tail feathers (known as trains), before rushing at females, shaking those feathers to catch their attention. But when researchers discovered low-frequency sounds—which are inaudible to humans—coming from this “train rattle” several years back, no one knew how they worked. All they knew was that peahens perked up and paid attention to recordings of these “infrasounds,” even though they couldn’t see the males. © 2018 American Association for the Advancement of Science

Keyword: Sexual Behavior; Animal Communication
Link ID: 25730 - Posted: 11.29.2018