Chapter 19. Language and Hemispheric Asymmetry
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|By Tori Rodriguez The safety of football continues to be a heated topic for players and parents, with mixed evidence regarding the effect of head injuries on mental illness. Past studies on the connection have often been methodologically flawed or yielded ambiguous results. Now a paper in April in the American Journal of Psychiatry, the largest study yet to investigate the link, finds that even a single head injury indeed increases the risk of later mental illness, especially if the injury occurs during adolescence. Using Danish medical registries, researchers led by physician Sonja Orlovska of the University of Copenhagen studied 113,906 people who had been hospitalized for head injuries over a 23-year period. They discovered that in addition to cognitive symptoms caused by structural damage to the brain (such as delirium), these people were subsequently more likely than the general population to develop several psychiatric illnesses. Risk increased by 65 percent for schizophrenia and 59 percent for depression. Risk was highest in the first year postinjury but remained significantly elevated throughout the next 15 years. After the team controlled for several potential confounders, such as accident proneness and a family history of psychiatric problems, they found the strongest injury-related predictor for later onset of schizophrenia, depression and bipolar disorder was a head trauma experienced between the ages of 11 and 15. “Previous studies have shown that head injury induces inflammation in the brain, which causes several changes—for example, an increased permeability of the blood-brain barrier,” Orlovska says. Normally the barrier protects the brain from potentially harmful contents in the bloodstream, but injury-induced inflammation may allow these substances access to the brain. “For some individuals, this might initiate damaging processes in the brain,” she says. © 2014 Scientific American,
by Jason M. Breslow As the NFL nears an end to its long-running legal battle over concussions, new data from the nation’s largest brain bank focused on traumatic brain injury has found evidence of a degenerative brain disease in 76 of the 79 former players it’s examined. The findings represent a more than twofold increase in the number of cases of chronic traumatic encephalopathy, or CTE, that have been reported by the Department of Veterans Affairs’ brain repository in Bedford, Mass. Researchers there have now examined the brain tissue of 128 football players who, before their deaths, played the game professionally, semi-professionally, in college or in high school. Of that sample, 101 players, or just under 80 percent, tested positive for CTE. To be sure, players represented in the data represent a skewed population. CTE can only be definitively identified posthumously, and many of the players who have donated their brains for research suspected that they may have had the disease while still alive. For example, former Chicago Bears star Dave Duerson committed suicide in 2011 by shooting himself in the chest, reportedly to preserve his brain for examination. Nonetheless, Dr. Ann McKee, the director of the brain bank, believes the findings suggest a clear link between football and traumatic brain injury. “Obviously this high percentage of living individuals is not suffering from CTE,” said McKee, a neuropathologist who directs the brain bank as part of a collaboration between the VA and Boston University’s CTE Center. But “playing football, and the higher the level you play football and the longer you play football, the higher your risk.” ©1995-2014 WGBH Educational Foundation
Keyword: Brain Injury/Concussion
Link ID: 20146 - Posted: 10.01.2014
By Melissa Dahl If you are the sort of person who has a hard time just watching TV — if you’ve got to be simultaneously using your iPad or laptop or smartphone — here’s some bad news. New research shows a link between juggling multiple digital devices and a lower-than-usual amount of gray matter, the stuff that’s made up of brain cells, in the region of the brain associated with cognitive and emotional control. More details, via the press release: The researchers at the University of Sussex's Sackler Centre for Consciousness used functional magnetic resonance imaging (fMRI) to look at the brain structures of 75 adults, who had all answered a questionnaire regarding their use and consumption of media devices, including mobile phones and computers, as well as television and print media. They found that, independent of individual personality traits, people who used a higher number of media devices concurrently also had smaller grey matter density in the part of the brain known as the anterior cingulate cortex (ACC), the region notably responsible for cognitive and emotional control functions. But a predilection for using several devices at once isn’t necessarily causing a decrease in gray matter, the authors note — this is a purely correlational finding. As Earl Miller, a neuroscientist at MIT who was not involved in this research, wrote in an email, “It could be (in fact, is possibly more likely) that the relationship is the other way around.” In other words, the people who are least content using just one device at a time may have less gray matter in the first place.
by Helen Thomson My, what big eyes you have – you must be trying really hard. A study of how pupils dilate with physical effort could allow us to make strenuous tasks seem easier by zapping specific areas of the brain. We know pupils dilate with mental effort, when we think about a difficult maths problem, for example. To see if this was also true of physical exertion, Alexandre Zenon at the Catholic University of Louvain in Belgium, measured the pupils of 18 volunteers as they squeezed a device which reads grip strength. Sure enough, the more force they exerted, the larger their pupils. To see whether pupil size was related to actual or perceived effort, the volunteers were asked to squeeze the device with four different grip strengths. Various tests enabled the researchers to tell how much effort participants felt they used, from none at all to the most effort possible. Comparing the results from both sets of experiments suggested that pupil dilation correlated more closely with perceived effort than actual effort. The fact that both mental effort and perceived physical effort are reflected in pupil size suggests there is a common representation of effort in the brain, says Zenon. To see where in the brain this might be, the team looked at which areas were active while similar grip tasks were being performed. Zenon says they were able to identify areas within the supplementary motor cortex – which plays a role in movement – associated with how effortful a task is perceived to be. © Copyright Reed Business Information Ltd.
Link ID: 20121 - Posted: 09.27.2014
By Smitha Mundasad Health reporter, BBC News A spice commonly found in curries may boost the brain's ability to heal itself, according to a report in the journal Stem Cell Research and Therapy. The German study suggests a compound found in turmeric could encourage the growth of nerve cells thought to be part of the brain's repair kit. Scientists say this work, based in rats, may pave the way for future drugs for strokes and Alzheimer's disease. But they say more trials are needed to see whether this applies to humans. Researchers from the Institute of Neuroscience and Medicine in Julich, Germany, studied the effects of aromatic-turmerone - a compound found naturally in turmeric. Rats were injected with the compound and their brains were then scanned. Particular parts of the brain, known to be involved in nerve cell growth, were seen to be more active after the aromatic-turmerone infusion. Scientists say the compound may encourage a proliferation of brain cells. In a separate part of the trial, researchers bathed rodent neural stem cells (NSCs) in different concentrations of aromatic-tumerone extract. NSCs have the ability to transform into any type of brain cell and scientists suggest they could have a role in repair after damage or disease. Dr Maria Adele Rueger, who was part of the research team, said: "In humans and higher developed animals their abilities do not seem to be sufficient to repair the brain but in fish and smaller animals they seem to work well." Picture of the spice turmeric Turmeric belongs to the same plant family as ginger BBC © 2014
By SAM BORDEN Bellini, a Brazilian soccer star who led the team that won the 1958 World Cup and was honored with a statue outside the Estádio do Maracanã in Rio de Janeiro, had a degenerative brain disease linked to dozens of boxers and American football players when he died in March at age 83. At the time, his death was attributed to complications related to Alzheimer’s disease. But researchers now say he had an advanced case of chronic traumatic encephalopathy, or C.T.E., which is caused by repeated blows to the head and has symptoms similar to those of Alzheimer’s. C.T.E. can be diagnosed only posthumously, and few brains of former soccer players have been examined. Bellini is the second known case, according to Dr. Ann McKee, a neuropathologist at Boston University and the Veterans Affairs Medical Center in Bedford, Mass., who assisted in examining Bellini’s brain. McKee was also involved this year when researchers found C.T.E. in the brain of a 29-year-old man from New Mexico who had played soccer semiprofessionally. McKee said in an interview that she was aware of a third former soccer player who had C.T.E. but that she was not yet authorized to publicly identify the person. As C.T.E. began to gain widespread attention about six years ago, it was often thought of as an American problem. Many of the early cases of the disease, for which there is no known cure, were connected to boxers and American football players. © 2014 The New York Times Company
Keyword: Brain Injury/Concussion
Link ID: 20110 - Posted: 09.24.2014
Jia You In the future, a nurse could determine whether a baby is likely to develop a reading disorder simply by attaching a few electrodes to its scalp and watching its brain waves respond to human speech. Such is the scenario suggested by a new study, which finds a potential biological indicator of how well preschool children perceive rhythm, an ability linked to language development. “It’s really impressive to work with children this young, who are not often looked at,” says Aniruddh Patel, a cognitive neuroscientist at Tufts University in Medford, Massachusetts, who was not involved with the research. Spoken language consists of sound waves occurring over multiple timescales. A syllable, for example, takes place over a quarter of a second, while a sentence unfolds over a few seconds. To make sense of this complex auditory information, humans use rhythmic cues such as stress and pause to discern words and syllables. Adults and school-aged children with reading disorders, however, struggle to pick up on these rhythmic patterns. Scientists estimate that dyslexia and other reading disabilities plague about 5% to 10% of the population. Detecting such impairments early could lead to more effective intervention, but observing telltale signs in younger children who have not learned to read has proven a challenge. So biologist Nina Kraus of Northwestern University in Evanston, Illinois, and her colleagues looked for automatic brain responses that can track language development in preschoolers, who have not learned to read. © 2014 American Association for the Advancement of Science
2014 by Dan Jones The vast majority of people think we have free will and are the authors of our own life stories. But if neuroscientists were one day able to predict our every action based on brain scans, would people abandon this belief in droves? A new study concludes that such knowledge would not by itself be enough to shake our confidence in our own volition. Many neuroscientists, such as the late Francis Crick, have argued that our sense of free will is no more than the behaviour of a vast assembly of nerve cells. This is tied to the idea of determinism, which has it that every effect is preceded by a cause, with cause and effect connected by physical laws. This is why the behaviour of physical systems can be predicted – even the brain, in principle. As author Sam Harris puts it: "If determinism is true, the future is set – and this includes all our future states of mind and our subsequent behaviour." If people lost their belief in their own free will, that would have important consequences for how we think about moral responsibility, and even how we behave. For example, numerous studies have shown that when people are led to reject free will they are more likely to cheat, and are also less bothered about punishing other wrongdoers. For those who argue that what we know about neuroscience is incompatible with free will, predicting what our brain is about to do should reveal the illusory nature of free will, and lead people to reject it. Experimental philosopher Eddy Nahmias at Georgia State University in Atlanta dubs this view "willusionism". He recently set out to test it. © Copyright Reed Business Information Ltd.
Link ID: 20102 - Posted: 09.22.2014
2014 by Helen Thomson Shall I compare thee to... well, no one actually. A 76-year-old woman has developed an incredibly rare disorder – she has the compulsive urge to write poetry. Her brain is now being studied by scientists who want to understand more about the neurological basis for creativity. In 2013, the woman arrived at a UK hospital complaining of memory problems and a tendency to lose her way in familiar locations. For the previous two years, she had experienced occasional seizures. She was diagnosed with temporal lobe epilepsy and treated with the drug lamotrigine, which stopped her seizures. However, as they receded, a strange behaviour took hold. She began to compulsively write poetry – something she hadn't shown any interest in previously. Suddenly, the woman was writing 10 to 15 poems a day, becoming annoyed if she was disrupted. Her work rhymed but the content was banal if a touch wistful – a style her husband described as doggerel (see "Unstoppable creativity"). About six months after her seizures stopped, the desire to write became less strong, although it still persists to some extent. Doctors call the intense desire to write hypergraphia. It typically occurs alongside schizophrenia and an individual's output is usually rambling and disorganised. "It was highly unusual to see such highly structured and creative hypergraphia without any of the other behavioural disturbances," says the woman's neurologist, Jason Warren at University College London. © Copyright Reed Business Information Ltd
By Elizabeth Pennisi "What's for dinner?" The words roll off the tongue without even thinking about it—for adults, at least. But how do humans learn to speak as children? Now, a new study in mice shows how a gene, called FOXP2, implicated in a language disorder may have changed between humans and chimps to make learning to speak possible—or at least a little easier. As a uniquely human trait, language has long baffled evolutionary biologists. Not until FOXP2 was linked to a genetic disorder that caused problems in forming words could they even begin to study language’s roots in our genes. Soon after that discovery, a team at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, discovered that just two bases, the letters that make up DNA, distinguished the human and chimp versions of FOXP2. To try to determine how those changes influenced the gene's function, that group put the human version of the gene in mice. In 2009, they observed that these "humanized" mice produced more frequent and complex alarm calls, suggesting the human mutations may have been involved in the evolution of more complex speech. Another study showed that humanized mice have different activity in the part of the brain called the striatum, which is involved in learning, among other tasks. But the details of how the human FOXP2 mutations might affect real-world learning remained murky. To solve the mystery, the Max Planck researchers sent graduate student Christiane Schreiweis to work with Ann Graybiel, a neuroscientist at the Massachusetts Institute of Technology in Cambridge. She's an expert in testing mouse smarts by seeing how quickly they can learn to find rewards in mazes. © 2014 American Association for the Advancement of Science
By KEN BELSON The National Football League, which for years disputed evidence that its players had a high rate of severe brain damage, has stated in federal court documents that it expects nearly a third of retired players to develop long-term cognitive problems and that the conditions are likely to emerge at “notably younger ages” than in the general population. The findings are a result of data prepared by actuaries hired by the league and provided to the United States District Court judge presiding over the settlement between the N.F.L. and 5,000 former players who sued the league, alleging that it had hidden the dangers of concussions from them. “Thus, our assumptions result in prevalence rates by age group that are materially higher than those expected in the general population,” said the report, prepared by the Segal Group for the N.F.L. “Furthermore, the model forecasts that players will develop these diagnoses at notably younger ages than the generation population.” The statements are the league’s most unvarnished admission yet that the sport’s professional participants sustain severe brain injuries at far higher rates than the general population. They also appear to confirm what scientists have said for years: that playing football increases the risk of developing neurological conditions like chronic traumatic encephalopathy, a degenerative brain disease that can be identified only in an autopsy. “This statement clears up all the confusion and doubt manufactured over the years questioning the link between brain trauma and long-term neurological impairment,” said Chris Nowinski, the executive director of the Sports Legacy Institute, who has for many years pressured the league to acknowledge the connection between football and brain diseases. © 2014 The New York Times Company
Keyword: Brain Injury/Concussion
Link ID: 20073 - Posted: 09.13.2014
By Lesley Evans Ogden Humans are noisy creatures, our cacophony of jet engines and jackhammering drowning out the communications of other species. In response, a number of animals, including marmosets and whales, turn up their own volume to be heard above the din, a phenomenon called the Lombard effect. A new study reveals that even fish “shout.” Researchers took a close look at the blacktail shiner (Cyprinella venusta), which is common to freshwater streams of the southeastern United States and whose short-distance acoustic signals are often exposed to boat and road noise. Only male shiners make sounds; popping sounds called knocks are used aggressively toward other males, while staticky-sounding “growls” are used for courtship, both heard in the above video. When the scientists brought the fish back to the lab and cranked up white noise from an underwater amplifier, they found that shiner males emitted fewer, shorter pulses, and cranked up the volume of their acoustic signals to be heard above background noise. Published in Behavioral Ecology, it’s the first study documenting the Lombard effect in fish, suggesting that freshwater fish are another group potentially impacted by our ever-increasing hubbub. © 2014 American Association for the Advancement of Science
By Virginia Morell A dog’s bark may sound like nothing but noise, but it encodes important information. In 2005, scientists showed that people can tell whether a dog is lonely, happy, or aggressive just by listening to his bark. Now, the same group has shown that dogs themselves distinguish between the barks of pooches they’re familiar with and the barks of strangers and respond differently to each. The team tested pet dogs’ reactions to barks by playing back recorded barks of a familiar and unfamiliar dog. The recordings were made in two different settings: when the pooch was alone, and when he was barking at a stranger at his home’s fence. When the test dogs heard a strange dog barking, they stayed closer to and for a longer period of time at their home’s gate than when they heard the bark of a familiar dog. But when they heard an unknown and lonely dog barking, they stayed close to their house and away from the gate, the team reports this month in Applied Animal Behaviour Science. They also moved closer toward their house when they heard a familiar dog’s barks, and they barked more often in response to a strange dog barking. Dogs, the scientists conclude from this first study of pet dogs barking in their natural environment (their owners’ homes), do indeed pay attention to and glean detailed information from their fellows’ barks. © 2014 American Association for the Advancement of Science
Erin Allday When a person suddenly loses the ability to speak or to understand what others are saying, the hardships that cascade from that loss can be overwhelming - from the seemingly trite to the devastatingly depressing. What hit Derrick Wong, 49, hardest was losing the ability to tell a joke. Ralph Soriano, 56, hates taking his car to the mechanic, knowing he will barely understand what's being said. "Girls," said Luke Waterman, 30, with a sigh. Flirting used to come easy. All three men - actually a pretty happy, hopeful gang for the most part - are longtime members of a group therapy program at the Aphasia Center of California, an Oakland nonprofit that offers treatment and ongoing education to people who have suffered communication disorders as a result of stroke or other brain injury. The nonprofit specializes in long-term therapy, an area of aphasia treatment that has taken off in the past few years. For many decades, doctors and speech pathologists assumed that patients had a window of six months to a year to recover language skills lost to a brain injury. Now, anecdotal reports and clinical research suggest that the window is much wider, and may even stay open a lifetime. "There is evidence that people can improve and regain skills, even years after a stroke," said Blair Menn, a speech language pathologist at Kaiser Permanente Medical Center in Redwood City. © 2014 Hearst Communications, Inc.
By NICHOLAS BAKALAR Childhood treatment with human growth hormone is strongly associated with an increased risk for stroke in early adulthood, a new study has found. The study adds evidence to previous reports suggesting an increased cardiac and cerebrovascular risk in children treated with growth hormone. Researchers studied 6,874 children, average age 11, who were small for their age but otherwise generally healthy and were treated with growth hormone from 1985 to 1996. They followed them to an average age of 28. There were 11 strokes in the group, four of them fatal. The analysis found that this was more than twice as many strokes as would be expected in a population this size, a statistically significant difference. The results, published online in the journal Neurology, were particularly striking for hemorrhagic stroke, the type caused by a ruptured blood vessel — there were more than seven times as many as would be expected. The authors acknowledged that they were unable to take into account some risk factors for stroke, such as family history and smoking. “Subjects on growth hormones should not panic on reading these results,” said the senior author, Dr. Joël Coste, a professor of biostatistics and epidemiology at the Hôtel Dieu hospital in Paris. “The doctor prescribing the hormone or the family doctor should be consulted and will be able to inform and advise patients.” © 2014 The New York Times Company
By Meeri Kim From ultrasonic bat chirps to eerie whale songs, the animal kingdom is a noisy place. While some sounds might have meaning — typically something like “I'm a male, aren't I great?” — no other creatures have a true language except for us. Or do they? A new study on animal calls has found that the patterns of barks, whistles, and clicks from seven different species appear to be more complex than previously thought. The researchers used mathematical tests to see how well the sequences of sounds fit to models ranging in complexity. In fact, five species including the killer whale and free-tailed bat had communication behaviors that were definitively more language-like than random. The study was published online Wednesday in the Proceedings of the Royal Society B. “We're still a very, very long way from understanding this transition from animal communication to human language, and it's a huge mystery at the moment,” said study author and zoologist Arik Kershenbaum, who did the work at the National Institute for Mathematical and Biological Synthesis. “These types of mathematical analyses can give us some clues.” While the most complicated mathematical models come closer to our own speech patterns, the simple models — called Markov processes — are more random and have been historically thought to fit animal calls. “A Markov process is where you have a sequence of numbers or letters or notes, and the probability of any particular note depends only on the few notes that have come before,” said Kershenbaum. So the next note could depend on the last two or 10 notes before it, but there is a defined window of history that can be used to predict what happens next. “What makes human language special is that there's no finite limit as to what comes next,” he said.
By Jane C. Hu Last week, people around the world mourned the death of beloved actor and comedian Robin Williams. According to the Gorilla Foundation in Woodside, California, we were not the only primates mourning. A press release from the foundation announced that Koko the gorilla—the main subject of its research on ape language ability, capable in sign language and a celebrity in her own right—“was quiet and looked very thoughtful” when she heard about Williams’ death, and later became “somber” as the news sank in. Williams, described in the press release as one of Koko’s “closest friends,” spent an afternoon with the gorilla in 2001. The foundation released a video showing the two laughing and tickling one another. At one point, Koko lifts up Williams’ shirt to touch his bare chest. In another scene, Koko steals Williams’ glasses and wears them around her trailer. These clips resonated with people. In the days after Williams’ death, the video amassed more than 3 million views. Many viewers were charmed and touched to learn that a gorilla forged a bond with a celebrity in just an afternoon and, 13 years later, not only remembered him and understood the finality of his death, but grieved. The foundation hailed the relationship as a triumph over “interspecies boundaries,” and the story was covered in outlets from BuzzFeed to the New York Post to Slate. The story is a prime example of selective interpretation, a critique that has plagued ape language research since its first experiments. Was Koko really mourning Robin Williams? How much are we projecting ourselves onto her and what are we reading into her behaviors? Animals perceive the emotions of the humans around them, and the anecdotes in the release could easily be evidence that Koko was responding to the sadness she sensed in her human caregivers. © 2014 The Slate Group LLC.
By James Gallagher Health editor, BBC News website Stimulating the part of the brain which controls movement may improve recovery after a stroke, research suggests. Studies showed firing beams of light into the brains of mice led to the animals moving further and faster than those without the therapy. The research, published in Proceedings of the National Academy of Science, could help explain how the brain recovers and lead to new treatments. The Stroke Association said the findings were interesting. Strokes can affect memory, movement and the ability to communicate. Brain cells die when their supply of oxygen and sugars is cut off by a blood clot. Stroke care is focused on rapid treatment to minimise the damage, but some recovery is possible in the following months as the brain rewires itself. The team at Stanford University School of Medicine investigated whether brain stimulation aided recovery in animal experiments. They used a technique called optogenetics to stimulate just the neurons in the motor cortex - the part of the brain responsible for voluntary movements - following a stroke. After seven days of stimulation, mice were able to walk further down a rotating rod than mice which had not had brain stimulation. After 10 days they were also moving faster. The researchers believe the stimulation is affecting how the wiring of the brain changes after a stroke. They detected higher levels of chemicals linked to the formation of new connections between brain cells. Lead researcher Prof Gary Steinberg said it was a struggle to give people drugs to protect brain cells in time as the "time window is very short". BBC © 2014
Link ID: 19979 - Posted: 08.20.2014
|By Matthew H. Schneps “There are three types of mathematicians, those who can count and those who can’t.” Bad joke? You bet. But what makes this amusing is that the joke is triggered by our perception of a paradox, a breakdown in mathematical logic that activates regions of the brain located in the right prefrontal cortex. These regions are sensitive to the perception of causality and alert us to situations that are suspect or fishy — possible sources of danger where a situation just doesn’t seem to add up. Many of the famous etchings by the artist M.C. Escher activate a similar response because they depict scenes that violate causality. His famous “Waterfall” shows a water wheel powered by water pouring down from a wooden flume. The water turns the wheel, and is redirected uphill back to the mouth of the flume, where it can once again pour over the wheel, in an endless cycle. The drawing shows us a situation that violates pretty much every law of physics on the books, and our brain perceives this logical oddity as amusing — a visual joke. The trick that makes Escher’s drawings intriguing is a geometric construction psychologists refer to as an “impossible figure,” a line-form suggesting a three-dimensional object that could never exist in our experience. Psychologists, including a team led by Catya von Károlyi of the University of Wisconsin-Eau Claire, have used such figures to study human cognition. When the team asked people to pick out impossible figures from similarly drawn illustrations that did not violate causality, they were surprised to discover that some people were faster at this than others. And most surprising of all, among those who were the fastest were those with dyslexia. © 2014 Scientific American
By Victoria Gill Science reporter, BBC News Scientists in Brazil have managed to eavesdrop on underwater "turtle talk". Their recordings have revealed that, in the nesting season, river turtles appear to exchange information vocally - communicating with each other using at least six different sounds. This included chatter recorded between females and hatchlings. The researchers say this is the first record of parental care in turtles. It shows they could be vulnerable to the effects of noise pollution, they warn. The results, published recently in the Journal Herpetologica, include recordings of the strange turtle talk. They reveal that the animals may lead much more socially complex lives than previously thought. The team, including researchers from the Wildlife Conservation Society (WCS) and the National Institute of Amazonian Research carried out their study on the Rio Trombetas in the Amazon between 2009 and 2011. They used microphones and underwater hydrophones to record more than 250 individual sounds from the animals. The scientists then analysed these vocalisations and divided them into six different types, correlating each category with a specific behaviour. Dr Camila Ferrara, of the WCS Brazil programme, told BBC News: "The [exact] meanings aren't clear... but we think they're exchanging information. "We think sound helps the animals to synchronise their activities in the nesting season," she said. The noises the animals made were subtly different depending on their behaviour. For example, there was a specific sound when adults were migrating through the river, and another when they gathered in front of nesting beaches. There was a different sound again made by adults when they were waiting on the beaches for the arrival of their hatchlings. BBC © 2014