Chapter 15. Brain Asymmetry, Spatial Cognition, and Language
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By Catherine Matacic Twenty-three years ago, a bonobo named Kanzi (above) aced a test in understanding human language. But a new study reveals he may not be as brainy as scientists thought—at least when it comes to grammar. The original test consisted of 660 verbal commands, in English, that asked Kanzi to do things like "show me the hot water" and "pour cold water in the potty." Overall, the ape did well, responding correctly 71.5% of the time (compared with 66.6% for an infant human). But when the researchers asked him to perform an action on more than one item, his performance plummeted to just 22.2%, according to the new analysis. When he was asked to "give the lighter and the shoe to Rose," for example, he gave Rose the lighter, but no shoe. When asked to "give the water and the doggie to Rose," he gave her the toy dog, but no water. The cause? Animals like bonobos may have a harder time than humans in processing complex noun phrases like “water and doggie,” linguist Robert Truswell of the University of Edinburgh reported in New Orleans, Louisiana, this week at the Evolution of Language conference. This feature of grammar—which effectively “nests” one unit within the bigger construct of a sentence—is easily picked up by humans, allowing us to communicate—and understand—more complex ideas. But Truswell cautions that humans probably aren’t born with the ability to interpret this kind of nesting structure. Instead, we must be taught how to use it. © 2016 American Association for the Advancement of Science
By Jordana Cepelewicz Last week a senior National Football League official acknowledged for the first time the link between head injuries in professional football and a degenerative brain disease called chronic traumatic encephalopathy. The admission—which has been compared with Big Tobacco’s 1997 disclosure that smoking causes cancer—comes at a time when the dangers of less severe traumatic brain injuries (TBIs), including concussions, have also been making headlines. Scientists do not yet understand the biological mechanisms underlying the detrimental effects of TBI—and as a result, effective treatments remain elusive. In fact, how to deal with even a mild concussion is the subject of debate: Some doctors prescribe rest for several weeks whereas others claim this may have negative consequences and urge patients to stay active. Now it turns out that the type of rest patients get may be key. In a study on rats published this week in The Journal of Neuroscience a team of researchers at University Hospital Zurich (UHZ) found that enhancing the slow-wave cycle of sleep after a traumatic head injury preserves brain function and minimizes damage to axons, the long projections from neurons that send signals to other cells in the brain. Previous research has shown that TBIs cause axonal damage as well as the buildup of neurotoxic molecular waste products that result from injury. In the new study the researchers examined two different methods of inducing a slow-wave sleep state—the deepest sleep stage characterized by low-frequency, high-amplitude waves. During this stage, the brain clears out protein buildup, leading the researchers to question whether it could help treat rats that had suffered a brain injury. © 2016 Scientific American
Nicola Davis Electrical brain stimulation could benefit stroke patients by boosting the effects of rehabilitation therapy, new research suggests. Writing in the journal Science Translational Medicine, the authors reveal that patients who were given electrical brain stimulation during a rehabilitation programme performed better on a range of tasks than those taking part in the rehabilitation programme. “It is an exciting message because there is so much frustration about people not reaching their true recovery potential,” said Professor Heidi Johansen-Berg, an author of the study from the University of Oxford, highlighting the fact that the cost of programmes and limited availability of therapists often restricts the amount of rehabilitation offered to patients. To probe the effects of brain stimulation, the researchers chose 24 patients who had experienced a stroke at least six months before, and who had difficulties with moving one hand. The participants were then split into two groups. The first group underwent nine consecutive days of rehabilitation training, with each session lasting an hour. For the first 20 minutes, the patients had two electrodes placed on their heads and a direct current applied, a process known as anodal transcranial direct current stimulation (tDCS). This is stimulation is thought to prime the brain for learning. © 2016 Guardian News and Media Limited
Link ID: 22000 - Posted: 03.17.2016
By KEN BELSON and ALAN SCHWARZ Perhaps no one will remember the setting, a hearing room for the House Energy and Commerce Committee, or the person who asked the question, a member of the House of Representatives from Illinois. But seven words spoken in the Rayburn House Office Building in Washington on Monday could profoundly affect the country’s most popular sport. After years of the N.F.L.‘s disputing evidence that connected football to chronic traumatic encephalopathy, the degenerative brain disease found in nearly 100 former players, a top official for the league for the first time acknowledged the link. To many, it was an echo of big tobacco’s confession in 1997 that smoking causes cancer and heart disease. Representative Jan Schakowsky, Democrat of Illinois, asked during a round-table discussion about concussions whether “there is a link between football and degenerative brain disorders like C.T.E.” Jeff Miller, the N.F.L.’s senior vice president for health and safety policy, said, “The answer to that is certainly, yes.” His response signaled a stunning about-face for the league, which has been accused by former players and independent experts of hiding the dangers of head injuries for decades. His reply came moments after a leading C.T.E. researcher — Dr. Ann McKee — had presented her findings, showing that dozens of former players who had died were afflicted with the disease. “The comments made by Jeff Miller yesterday accurately reflect the view of the N.F.L.,” Brian McCarthy, a league spokesman, said Tuesday, confirming that Mr. Miller had not misspoken. © 2016 The New York Times Company
Keyword: Brain Injury/Concussion
Link ID: 21997 - Posted: 03.16.2016
A senior British doctor, who has been an expert defence witness for parents accused of killing their children, has been found guilty of multiple charges that include giving misleading evidence in court. The Medical Practitioners Tribunal Service said that Waney Squier, a consultant pathologist at John Radcliffe Hospital in Oxford, UK, had failed to work within the limits of her competence, failed to be objective and unbiased, and failed to heed the views of other experts. In many of the cases investigated, her actions were deliberately misleading and irresponsible. The MPTS had considered Squier’s work as an expert witness in six child abuse cases and one appeal in which parents faced charges of non-accidental head injury, formerly known as shaken-baby syndrome. Squier is prominent among several researchers worldwide who have challenged a long-standing belief that a trio of symptoms of head injury provide unequivocal evidence of abusive behaviour. Squier has argued in the scientific literature and in court that the symptoms in question – haemorrhages on the surface of the brain, haemorrhages in the retinas, and a swollen brain – can have innocent causes, such as choking or other difficulties in breathing. These symptoms, they say, can also arise from the birthing process itself. Michele Codd, chair of the tribunal, gave examples of where the panel felt Squier’s court evidence had strayed outside her field of expertise. These included offering opinions on biomechanics in relation to injuries from falling, pathology of the eyes, and paediatric medicine. © Copyright Reed Business Information Ltd.
By Bob Roehr Retired American soccer star Brandi Chastain recently agreed to donate her brain to concussion research after her death. Females are often an unseen part of the concussion story even though they suffer more concussions than males, have more severe symptoms and are slower to recover. Just why is not completely clear, but the deficit in knowledge is slowly beginning to change thanks to women’s advocates behind Pink Concussions. The group gathered last weekend at Georgetown University to review the science behind concussions, and also to develop recommendations on gender-specific prevention protocols and clinical practices on how best to treat females with concussions. In comparable sports “female rates of concussions are much higher than those of their male counterparts,” says Zachary Kerr, director of the National Collegiate Athletic Association (NCAA) Injury Surveillance Program. Over a five-year period the rates per 1000 athlete-exposures were 6.3 in females versus 3.4 in males in soccer, 6.0 in females versus 3.9 in males in basketball and 3.3 in females versus 0.9 in males in baseball and softball. Only in swimming and diving did male rates (0.3) exceed those of females (0.5). Headache, dizziness and difficulty concentrating were roughly similar among both sexes, Kerr says. But among injured high school athletes, “larger portions of females are reporting sensitivity to light, sensitivity to noise, nausea and drowsiness,” he says. They were also slower to return to normal activity. The difference between the incidence and severity of concussions between the sexes does not start at birth, because infants and young children of both sexes have similar rates and symptoms with concussions. Puberty, however, which marks a significant developmental fork in the road for males and females, also marks a divergence for concussions. © 2016 Scientific American
By Nala Rogers Treatments that zap the brain with magnets or electricity are rising in popularity, and some evidence suggests they can help lift depression. But scientists are starting to wonder whether they could be hitting the wrong place in left-handed patients. Now, two small studies suggest this could very well be the case. “This is the kind of question that’s been desperately needed for many years,” says Jim Coan, a clinical psychologist at the University of Virginia in Charlottesville who was not involved in the project. “Most researchers in this area, including myself, have selected samples that are strongly right-handed, just in order to avoid mess in the data.” Past studies have suggested that the spots targeted by both kinds of stimulation—located in the left hemisphere—are likely to process “approach” emotions such as happiness, curiosity, and anger, which drive people to reach out and engage with the world. Some studies have also hinted that the brain’s right hemisphere is more involved in so-called “avoidance” emotions such as sorrow and fear. But the studies that support this separation of emotion into the two halves of the brain have relied almost exclusively on right-handed individuals. To figure out whether something else was happening with lefties, University of Chicago in Illinois neuroscientist Daniel Casasanto designed two studies: one to link personality to patterns of brain activity and another to measure the outcome of common brain stimulation treatments in right-handed and left-handed individuals. The brain stimulation treatments were originally designed to treat depression by boosting feelings of happiness and engagement, which motivate “approach” behaviors such as exploring the world and interacting with friends. © 2016 American Association for the Advancement of Science.
Cathleen O'Grady When we speak, listen, read, or write, almost all of the language processing that happens in our brains goes on below the level of conscious awareness. We might be aware of grasping for a particular forgotten word, but we don’t actively think about linguistic concepts like morphemes (the building blocks of words, like the past tense morpheme “-ed”). Psycholinguists try to delve under the surface to figure out what’s actually going on in the brain, and how well this matches up with our theoretical ideas of how languages fit together. For instance, linguists talk about morphemes like “-ed”, but do our brains actually work with morphemes when we’re producing or interpreting language? That is, do theoretical linguistic concepts have any psychological reality? An upcoming paper in the journal Cognition suggests an unusual way to investigate this: by testing synaesthetes. Synaesthesia comes in many forms. Some synaesthetes associate musical tones or notes with particular colours; others attach personalities to letters or numbers. A huge number of synaesthetes have associations that are in some way linguistic, and one of the most common forms of all is grapheme-colour (GC) synaesthesia, which is the association of colours with particular letters or numbers. For instance, a GC synaesthete might have a consistent perception of the letter “A” being red. This association often extends to a whole word, so “ant” might be red, too. © 2016 Guardian News and Media Limited
Link ID: 21937 - Posted: 02.27.2016
By Michael Balter About 90% of bird species live in monogamous pairs, but that doesn’t mean they don’t fool around on the side. The females of most monogamous species breed with outside males at least occasionally. Male birds have evolved two main ways to combat such cuckoldry: They either aggressively drive away rival males, or they cement the pair bond by singing lovely duets with their partners. Which works better, making love or making war? Researchers working with the red-backed fairywren (Malurus melanocephalus), native to Australia, put the question to the test by conducting the experiment in the video above. The team mounted a taxidermically stuffed male fairywren on a branch (upper left) in a male-female pair’s territory and then observed what happened. In this case, the live male attacks its artificial rival once, but then spends most of the next minute duetting with its female partner (who is light gray and white). The researchers analyzed data from various trials involving up to 51 males, using parameters such as how long they delayed before attacking the artificial mount, how long before beginning a duet, and how many duets they sang with the females. These data were then correlated with genetic paternity tests of 186 offspring in the nests of the supposedly monogamous birds. Although the percentage of cuckoldry was high—47% of the offspring had been fathered by outside males—those males that quickly responded to the threat of a rival by repeatedly duetting with their partners were much more likely to be the fathers of the offspring in their nests, the team reports online today in Biology Letters. On the other hand, there was no correlation between how aggressive the males were to the artificial rival and the paternity rate, the researchers found. © 2016 American Association for the Advancement of Science
Rae Ellen Bichell "I am what I like to call 'new stroke'," says Troy Hodge, a 43-year-old resident of Carol County, Md. With a carefully trimmed beard and rectangular hipster glasses, Hodge looks spry. But two years ago, his brain stopped communicating for a time with the left half of his body. He was at home getting ready for work as a food service director at a nearby nursing home. Hodge remembers entering the downstairs bathroom to take his blood pressure medications. He sat down on the bathroom floor and couldn't get up. He says he felt so hot, he actually splashed some toilet water on his face because he couldn't reach the sink. When Hodge didn't show up for work, a colleague got worried and came over. She called 911 when she found him on the floor. "I remember telling her not to let me die," says Hodge, "and from then on I really don't remember that much." He woke up a day or so later at a trauma center one state over, in Delaware. "Troy experienced what we call an intracerebral hemorrhage, which basically just means bleeding within the substance of the brain," says Dr. Steven Kittner, a neurologist at the University of Maryland School of Medicine. Hodge's high blood pressure probably damaged the tiny vessels in his brain, Kittner says. Hodge is one of many Americans having strokes at a younger age. About 10 percent of all strokes occur in people between 18 and 50 years old, and the risk factors include some that Hodge had: high blood pressure, overweight, off-kilter cholesterol, smoking and diabetes. © 2016 npr
Link ID: 21921 - Posted: 02.22.2016
Leo Benedictus It seems so obvious when you hear it, yet it could have shaped society for centuries without our knowing. According to research presented by Dr Daniel Casasanto to the American Association for the Advancement of Science annual conference in Washington DC, people just prefer things that are in front of their favourite hand. It could be products on a shelf, or applicants for a job. “Righties would on average choose the person or product on the right; lefties, on average, the person or product on the left,” Dr Casasanto explained. And, from his research conducted at the University of Chicago, it is easy to see how this could have serious political implications. “We found in a large simulated election, that compared to lefties, righties will choose the candidate they see on the right of the ballot paper about 15% more,” Dr Casasanto said. His theory, in simple terms, is that because people go through life with a “fluent side” and a “clumsy side”, they develop a kind of unconscious favouritism, even for things that don’t require them to use their hands. “It seems blindingly obvious that you will have a preference for that bit of space where you operate more frequently,” says Professor Philip Corr, a psychologist at City University, London. “You’ll feel more comfortable operating in that part of the world. Intuitively it makes sense to me.” Many papers have been published on the subject, but we still don’t really know why people don’t all use the same hand - or an even balance of the two, as do most primates.
By Ariana Eunjung Cha The scariest form of stroke involves the pooling of blood in the brain. When this begins, there has been very little that can be done to stop it. Even with open brain surgery, blood often clots so fast that it's impossible to remove, and an estimated 60 percent to 80 percent of patients who suffer from this condition don't survive. Of those who do pull through, 90 percent are left severely impaired. Researchers, however, believe they may have finally found a way to improve a patient's odds. Speaking at the 2016 International Stroke Conference in Los Angeles, they reported that using a clot-busting heart drug not only appeared to reduce the fatality percentage, it also appeared to increase patients' chances of a functional recovery, which in the past has been extremely rare. Issam Awad, a professor of surgery at the University of Chicago who is co-chair of the study, said the therapy could potentially "be the difference between going home instead of going to a nursing home." The study involved 500 patients with hemorrhagic or bleeding stroke from 73 sites around the world. Through a brain catheter, they were treated either with saline, which served as the control, or the drug Alteplase, which is known as a tissue plasminogen activator, or tPA, and has been used in people with heart attacks or blood clots near the lungs. In the five years of follow-up from 2009 to 2015, those who received tPA were 10 percent less likely to die than those who received saline.
Link ID: 21911 - Posted: 02.19.2016
Sidharth Gupta always dazzled people with his intelligence. “Everybody used to praise my brother’s brain,” says Isha Gupta , two years his junior. “Everybody. Like, ‘Oh Sidharth, he’s very smart. He’s got a very sharp brain.’ That’s something that I’ve heard all my life. And his brain is what gave up on him.” Two years ago, “Sid” was the picture of exuberance and ambition. Having established his own marketing and event planning business in his native India, he moved to Toronto in 2011 to work as an account executive at Canada’s largest advertising agency, MacLaren McCann. According to Isha, Sid had big dreams. The event management company in India was just the beginning; he was planning to grow it into a worldwide marketing business. Thirty years old at the time, Sid was smart, savvy, on the ball — and always up for fun. He had “insane energy,” says colleague Zain Ali . “He could work all day and then party late and then get back to work the next day.” “Sid was very happy-go-lucky,” says another work friend, Rishi Gupta (no relation). “He had that same smile on his face all the time. He wanted to be part of the party, to have a good time.” That was Sid’s frame of mind on Feb. 20, 2014, as he geared up for a marketing launch at the Canadian International Auto Show in Toronto. After he and Zain put in 12 hours setting up an interactive display for the new Camaro Z28, Sid joined a few friends to celebrate Rishi’s birthday. ©2016 CBC/Radio-Canada.
Fergus Walsh Medical correspondent When I picked up the human brain in my hands, several things ran through my mind. My immediate concern was I might drop it or that it would fall apart in my hands - fortunately neither happened. Second, I was struck by how light the human brain is. I should say this was half a brain - the right hemisphere - the left had already been sent for dissection. The intact human brain weighs only around 3lbs (1.5kg) - just 2% of body-weight, and yet it consumes 20% of its energy. The brain I was holding had been steeped in formalin, a preserving fluid, for about three weeks and is one of several hundred brains donated every year for medical research. It was only after I'd got used to the feel of the brain in my hands that I could then start to wonder about how such a simple-looking structure could be capable of so much. This brain had experienced, processed, interpreted an entire human life - the thoughts, emotions, language, memory, emotion, cognition, awareness, and consciousness - all the things that make us human and each of us unique. You may think yuck, but I'm with the scientists and surgeon who declare: "Brains are beautiful". The pathology team at the Bristol Brain Bank had kindly allowed us to film as part of the BBC "In the Mind" season, looking at many aspects of mental health. My brief was to examine some of the latest advances in neuroscience. There is a genuine sense of excitement among researchers about the direction and progress being made in our knowledge of the brain. © 2016 BBC.
Link ID: 21904 - Posted: 02.17.2016
By Jordana Cepelewicz As the Panthers and Broncos faced off in the third quarter of last night’s Super Bowl, wide receiver Philly Brown suffered a possible concussion—and to the disappointment of Panthers fans, he never returned to the game. But for good reason: concussions are now known to be much more serious injuries than once thought. And the danger may not be limited to the immediate repercussions. Researchers have already linked more severe traumatic brain injury to later suicide—particularly in military veterans and professional athletes—and have more recently explored the connection between concussion and depression. Now, new research published in the Canadian Medical Association Journal shows that even mild concussions sustained in ordinary community settings might be more detrimental than anyone anticipated; the long-term risk of suicide increases threefold in adults if they have experienced even one concussion. That risk increases by a third if the concussion is sustained on a weekend instead of a weekday—suggesting recreational concussions are riskier long-term than those sustained on the job. “The typical patient I see is a middle-aged adult, not an elite athlete,” says Donald Redelmeier, a senior scientist at the University of Toronto and one of the study’s lead authors. “And the usual circumstances for acquiring a concussion are not while playing football; it is when driving in traffic and getting into a crash, when missing a step and falling down a staircase, when getting overly ambitious about home repairs—the everyday activities of life.” Redelmeier and his team wanted to examine the risks of the concussions acquired under those circumstances. © 2016 Scientific American
Laura Sanders The brain can bounce back after a single head hit, but multiple hits in quick succession don’t give the brain time to recover, a new study suggests. Although the finding comes from mice, it may help scientists better understand the damage caused by repetitive impacts such as those sustained in football, soccer and other contact sports. The results, published in the March issue of the American Journal of Pathology, hint that a single, mild head hit isn’t necessarily cause for alarm. “There are things to be afraid of after a concussion,” says study coauthor Mark Burns of Georgetown University Medical Center in Washington, D.C. “But not every concussion is going to cause long-term damage.” Burns and his colleagues subjected some mice to a single, mild head hit. The relatively weak hit consistently slowed anesthetized mice’s return to consciousness, but didn’t cause major trauma. The impact was designed to mimic a mild traumatic brain injury, or concussion, in a person. Tests a day after the impact showed that about 13 percent of dendritic spines, docking sites that help connect brain cells, had vanished in a particular part of the brain. Three days after the injury, these missing connections reappeared, even surpassing the original number of connections. This fluctuating number of dendritic spines may actually help the brain recover, Burns says. “The cells weren’t dying,” he says. “They were responding to the injury.” © Society for Science & the Public 2000 - 2016.
Keyword: Brain Injury/Concussion
Link ID: 21867 - Posted: 02.06.2016
By JOHN BRANCH Shortly before he died in July, the former N.F.L. quarterback Ken Stabler was rushed away by doctors, desperate to save him, in a Mississippi hospital. His longtime partner followed the scrum to the elevator, holding his hand. She told him that she loved him. Stabler said that he loved her, too. “I turned my head to wipe the tears away,” his partner, Kim Bush, said recently. “And when I looked back, he looked me dead in the eye and said, ‘I’m tired.’ ” They were the last words anyone in Stabler’s family heard him speak. “I knew that was it,” Bush said. “I knew that he had gone the distance. Because Kenny Stabler was never tired.” The day after Stabler died on July 8, a victim of colon cancer at 69, his brain was removed during an autopsy and ferried to scientists in Massachusetts. It weighed 1,318 grams, or just under three pounds. Over several months, it was dissected for clues, as Stabler had wished, to help those left behind understand why his mind seemed to slip so precipitously in his final years. On the neuropathologist’s scale of 1 to 4, Stabler had high Stage 3 chronic traumatic encephalopathy, or C.T.E., the degenerative brain disease believed to be caused by repeated blows to the head, according to researchers at Boston University. The relationship between blows to the head and brain degeneration is still poorly understood, and some experts caution that other factors, like unrelated mood problems or dementia, might contribute to symptoms experienced by those later found to have had C.T.E. Stabler, well known by his nickname, the Snake (“He’d run 200 yards to score from 20 yards out,” Stabler’s junior high school coach told Sports Illustrated in 1977), is one of the highest-profile football players to have had C.T.E. The list, now well over 100 names long, includes at least seven members of the Pro Football Hall of Fame, including Junior Seau, Mike Webster and Frank Gifford. © 2016 The New York Times Company
Keyword: Brain Injury/Concussion
Link ID: 21861 - Posted: 02.04.2016
By Katy Waldman On May 10, 1915, renowned poet-cum-cranky-recluse Robert Frost gave a lecture to a group of schoolboys in Cambridge, Massachusetts. “Sounds in the mouths of men,” he told his audience, “I have found to be the basis of all effective expression.” Frost spent his career courting “the imagining ear”—that faculty of the reader that assigns to each sentence a melodic shape, one captured from life and tailored to a specific emotion. In letters and interviews, he’d use the example of “two people who are talking on the other side of a closed door, whose voices can be heard but whose words cannot be distinguished. Even though the words do not carry, the sound of them does, and the listener can catch the meaning of the conversation. This is because every meaning has a particular sound-posture.” Frost’s preoccupation with the music of speech—with what we might call “tone of voice,” or the rise and fall of vocal pitch, intensity, and duration—has become a scientific field. Frost once wrote his friend John Freeman that this quality “is the unbroken flow on which [the semantic meanings of words] are carried along like sticks and leaves and flowers.” Neuroimaging bears him out, revealing that our brains process speech tempo, intonation, and dynamics more quickly than they do linguistic content. (Which shouldn’t come as a huge surprise: We vocalized at each other for millions of years before inventing symbolic language.) Psychologists distinguish between the verbal channel—which uses word definitions to deliver meaning—and the vocal channel—which conveys emotion through subtle aural cues. The embedding of feelings in speech is called “emotional prosody,” and it’s no accident that the term prosody (“patterns of rhythm or sound”) originally belonged to poetry, which seeks multiple avenues of communication, direct and indirect. Frost believed that you could reverse-engineer vocal tones into written language, ordering words in ways that stimulated the imagining ear to hear precise slants of pitch. He went so far as to propose that sentences are “a notation for indicating tones of voice,” which “fly round” like “living things.”
By SINDYA N. BHANOO Male zebra finches learn their courtship songs from their fathers. Now, a new study details the precise changes in brain circuitry that occur during that process. As a young male listens to his father’s song, networks of brain cells are activated that the younger bird will use later to sing the song himself, researchers have found. As the learning process occurs, inhibitory cells suppress further activity in the area and help sculpt the song into a permanent memory. “These inhibitory cells are really smart — once you’ve gotten a part of the song down, the area gets locked,” said Michael Long, a neuroscientist at NYU Langone Medical Center and an author of the new study, which appears in the journal Science. Zebra finches learn their courtship song from their fathers and reach sexual maturity in about 100 days. At this point, they ignore their fathers’ tutoring altogether, Dr. Long said. In their study, he and his colleagues played recorded courtship songs to young and old birds and monitored neural activity in their brains. In sexually mature birds, the courtship song did not elicit any neural response. Understanding the role of the inhibitory cells in the brain could help researchers develop ways to manipulate this network, Dr. Long said. “Maybe we could teach old birds new tricks,” he said. “And extrapolating widely, maybe we could even do this in mammals, maybe even humans, and enrich learning.” © 2016 The New York Times Company
By Emily Underwood The boisterous songs a male zebra finch sings to his mate might not sound all that melodious to humans—some have compared them to squeaky dog toys—but the courtship tunes are stunningly complex, with thousands of variations. Now, a new study helps explain how the birds master such an impressive repertoire. As they learn from a tutor, usually their father, their brains tune out phrases they’ve already studied, allowing them to focus on unfamiliar sections bit by bit. The mechanism could help explain how other animals, including humans, learn complex skills, scientists say. The study is a “technical tour de force,” and “an important advance in our understanding of mechanisms of vocal learning and of motor learning generally,” says Erich Jarvis, a neuroscientist at Duke University in Durham, North Carolina. Many species—including humans, chimpanzees, crows, dolphins, and even octopuses—learn complex behaviors by imitating their peers and parents, but little is known about how that process works on a neuronal level. In the case of zebra finches, young males spend the whole of their teenage lives trying to copy their fathers, says Michael Long, a neuroscientist at New York University in New York City. It comes out “all wrong” at first, but after practicing hundreds of times, the birds “sound a lot like dad.” In the new study, Long’s graduate student Daniela Vallentin used a tiny electrode implant to record the activity of neurons in a region of the finch brain called the HVC, which is essential for birdsong learning and production. Weighing less than a penny, the implant can be affixed to a bird’s head and record activity in the brains of freely moving and singing birds, Long says. The researchers also used a powerful light microscope to visualize the activity of individual neurons as the birds listened to a fake “tutor” bird that taught young finches only one “syllable” of a song at a time. © 2016 American Association for the Advancement of Science.