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By Michael Balter Have you ever wondered why you say “The boy is playing Frisbee with his dog” instead of “The boy dog his is Frisbee playing with”? You may be trying to give your brain a break, according to a new study. An analysis of 37 widely varying tongues finds that, despite the apparent great differences among them, they share what might be a universal feature of human language: All of them have evolved to make communication as efficient as possible. Earth is a veritable Tower of Babel: Up to 7000 languages are still spoken across the globe, belonging to roughly 150 language families. And they vary widely in the way they put sentences together. For example, the three major building blocks of a sentence, subject (S), verb (V), and object (O), can come in three different orders. English and French are SVO languages, whereas German and Japanese are SOV languages; a much smaller number, such as Arabic and Hebrew, use the VSO order. (No well-documented languages start sentences or clauses with the object, although some linguists have jokingly suggested that Klingon might do so.) Yet despite these different ways of structuring sentences, previous studies of a limited number of languages have shown that they tend to limit the distance between words that depend on each other for their meaning. Such “dependency” is key if sentences are to make sense. For example, in the sentence “Jane threw out the trash,” the word “Jane” is dependent on “threw”—it modifies the verb by telling us who was doing the throwing, just as we need “trash” to know what was thrown, and “out” to know where the trash went. Although “threw” and “trash” are three words away from each other, we can still understand the sentence easily. © 2015 American Association for the Advancement of Science.
By Roni Caryn Rabin For years experts have urged physicians to screen infants and toddlers for autism in order to begin treatment as early as possible. But now an influential panel of experts has concluded there is not enough evidence to recommend universal autism screening of young children. The findings, from a draft proposal by the U.S. Preventive Services Task Force published Monday, are already causing consternation among specialists who work with autistic children. “I was in a meeting when I read this, and I started feeling like I’d have chest pain,” said Dr. Susan E. Levy, a pediatrician who helped write the American Academy of Pediatrics guidelines urging universal screening of all babies, with standardized screening tools at both 18 and 24 months. “I would hate to see people stop screening.” Dr. David Grossman, a pediatrician and vice chairman of the U.S. Preventive Services Task Force, emphasized that the panel’s draft proposal was a call for more research and not intended to change practices. About half of all pediatricians routinely screen toddlers for autism. “This doesn’t mean ‘don’t screen.’ ” Dr. Grossman said. “It means there is not enough evidence to make a recommendation.” Dr. Grossman also noted that the panel’s conclusion applied only to routine screening of healthy children without symptoms. A child displaying symptoms associated with autism should always be evaluated, he said. “If a parent comes in and says, ‘My child isn’t looking at me,’ that’s not a screening,” Dr. Grossman said. “You hear that as a doctor and you say, ‘That needs to be looked at,’ and you embark on a series of tests.” Despite those reassurances, autism experts worry that the panel’s lack of support for early autism screening could undermine efforts to identify and treat children as early as possible. The task force is an independent panel of experts in prevention and primary care appointed by the federal Department of Health and Human Services. The task force wields enormous influence in the medical community. In 2009, the panel issued controversial screening guidelines for breast cancer, stating that routine mammograms should start at 50 rather than 40. © 2015 The New York Times Company
Link ID: 21262 - Posted: 08.04.2015
Richard Harris One of the frequent trials of parenthood is dealing with a picky eater. About 20 percent of children ages 2 to 6 have such a narrow idea of what they want to eat that it can make mealtime a battleground. A study published Monday in the journal Pediatrics shows that, in extreme cases, picky eating can be associated with deeper trouble, such as depression or social anxiety. The study followed a broad spectrum of children who had come to Duke University for routine medical care. Most kids dislike some foods (broccoli is a common villain), but the researchers counted a child as a severely picky eater if his or her food choices were so limited that it made meals at home difficult, and meals out all but impossible. Those extreme cases were rare — just 3 percent of all kids. But, as a group, they were twice as likely as the children who weren't picky to have a diagnosis of depression, and seven times as likely to have been diagnosed with social anxiety, according to the study. Nancy Zucker, director of the Duke Center for Eating Disorders, says parents of children who are extremely finicky may find it useful to seek help, because the kids may not simply outgrow the behavior on their own. And even if they eventually do, it can be disruptive to child and family alike in the meantime. A big question is what to do about less extreme cases, which in the Duke study made up 17 percent of all children. These children have a list of foods that they are reluctant to stray beyond. © 2015 NPR
By Andrea Alfano Forget the insult “fathead.” We may actually owe our extraordinary smarts to the fat in our brain. A study published in Neuron in February revealed that the variety of fat molecules found in the human neocortex, the brain region responsible for advanced cognitive functions such as language, evolved at an exceptionally fast rate after the human-ape split. The researchers analyzed the concentrations of 5,713 different lipids, or fat molecules and their derivatives, present in samples of brain, kidney and muscle tissues taken from humans, chimpanzees, macaques and mice. Lipids have a variety of critical functions in all cells, including their role as the primary component of a cell's membrane. They are particularly important in the brain because they enable electrical signal transmission among neurons. Yet until this study, it was unknown whether the lipids in the human brain differed significantly from lipids in other mammals. The team discovered that the levels of various lipids found in human brain samples, especially from the neocortex, stood out. Humans and chimps diverged from their common ancestor around the same time, according to much evolutionary evidence. Because the two species have had about the same amount of time to rack up changes to their lipid profiles, the investigators expected them to have roughly the same number of species-specific lipid concentrations, explains computational biologist and study leader Kasia Bozek of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. Indeed, lipid changes in the cerebellum, a primitive part of the brain similar in all vertebrates, were comparable between humans and chimps. But the human neocortex has accumulated about three times more lipid changes than the chimpanzee cortex has since we split from our common ancestor. © 2015 Scientific American
Link ID: 21260 - Posted: 08.04.2015
A protein previously linked to acute symptoms following a traumatic brain injury (TBI), may also be responsible for long-term complications that can result from TBI, according to research from the National Institute of Nursing Research (NINR), a component of the National Institutes of Health. Using an ultra-sensitive technology, researchers — led by NIH Lasker Clinical Research Scholar and Chief of NINR’s Brain Injury Unit, Tissue Injury Branch Jessica Gill, Ph.D., R.N., — were able to measure levels of the protein, tau, in the blood months and years after individuals (in this case, military personnel) had experienced TBI. They found that these elevated levels of tau — a protein known to have a role in the development of Alzheimer’s disease and Parkinson’s disease — are associated with chronic neurological symptoms, including post-concussive disorder (PCD), during which an individual has symptoms such as headache and dizziness in the weeks and months after injury. These chronic neurological symptoms have been linked to chronic traumatic encephalopathy (CTE) — progressive brain degeneration that leads to dementia following repetitive TBIs — independent of other factors such as depression and post-traumatic stress disorder (PTSD). The study and an accompanying editorial appear in the August 3 issue of JAMA Neurology. “Our study was limited to identifying the effects of tau accumulation in military personnel who experienced long-term neurological symptoms after a TBI. With further study, our findings may provide a framework for identifying patients who are most at risk for experiencing chronic symptoms related to TBI. Identifying those at risk early in the progression of the disease provides the best opportunity for therapies that can lessen the cognitive declines that may result from these long-term effects,” said Dr. Gill, the study’s lead author.
Keyword: Brain Injury/Concussion
Link ID: 21259 - Posted: 08.04.2015
By Ariana Eunjung Cha Children who suffer an injury to the brain -- even a minor one -- are more likely to experience attention issues, according to a study published Monday in the journal Pediatrics. The effects may not be immediate and could occur long after the incident. Study author Marsh Konigs, a doctoral candidate at VU University Amsterdam, described the impact as "very short lapses in focus, causing children to be slower." Researchers looked at 113 children, ages six to 13, who suffered from traumatic brain injuries (TBIs) ranging from a concussion that gave them a headache or caused them to vomit, to losing consciousness for more than 30 minutes, and compared them with a group of 53 children who experienced a trauma that was not head-related. About 18 months after the children's accidents, parents and teachers were asked to rate their attention and other indicators of their health. They found that those with TBI had more lapses in attention and other issues, such as anxiety, a tendency to internalize their problems and slower processing speed. Based on studies of adults who experienced attention issues after suffering from a brain injury, doctors have theorized for years that head injuries in children might be followed by a "secondary attention deficit hyperactivity disorder." This study appears to confirm that association.
Cerebral palsy, the most common cause of physical disability in children, has long been thought to result from brain injury in the fetus. But new Canadian research is challenging that notion, finding that at least one in 10 cases likely has an underlying genetic cause. So ingrained has medical dogma been around the root causes of cerebral palsy that "when I showed the results to our clinical geneticists, initially they didn't believe it," he said. About two in every 1,000 babies born are affected by cerebral palsy. An estimated 50,000 Canadian children and adults have the condition, which leads to varying degrees of motor impairment, including muscle spasticity and involuntary movements. Symptoms can include epilepsy as well as learning, speech, hearing and visual impairments. Some with the disorder are mildly affected, while others can't walk or communicate. Traditionally, cerebral palsy was believed to be caused by a stroke or infection of the brain in the developing fetus, or by birth asphyxia — a lack of oxygen to the infant during delivery. But genetic testing of a group of affected children from across Canada found that in 10 per cent of cases, structural changes to the DNA appear to have given rise to the condition. The research team, which includes physicians at the McGill University Health Centre in Montreal, performed genome sequencing tests on 115 children with cerebral palsy and their parents. ©2015 CBC/Radio-Canada.
By Nancy Szokan “This is a story of a family who made mistakes.” Thus Janet Sternburg begins her memoir of a close-knit Jewish family living in Boston. Her grandfather, Philip, was a cold, angry man who abandoned his wife and six children not long after the only son in the family, Bennie, was diagnosed as schizophrenic. As Bennie became increasingly violent and untreatable, the family — advised by a Harvard professor of psychiatry — agreed to submit him to a prefrontal lobotomy. More than a decade later, one of Bennie’s sisters, Francie, sank into a debilitating depression — relentlessly weeping, attempting suicide — and again, the solution was seen to be a lobotomy. While she was growing up, Sternburg accepted the lobotomies as her family’s normalcy. It was decades later, when she was an adult living in California, that it occurred to her to question why such terrible measures had been taken. “The years came back to me when my aunt and uncle were driven to our house” for a regular visit, she writes. As the grandmother cooked and the aunts and uncles talked and played cards, the two lobotomized siblings “sat blankly on the couch — Bennie at one end, virtually unmoving, my aunt crumpled into the far corner. . . . With the sharp return of memories came the realization that even as a child I had a slight awareness . . . that something wrong had been done.” But she also knew her relatives as good and generous people. So she set out to learn what happened, and why. “White Matter: A Memoir of Family and Medicine” is Sternburg’s tale of what she discovered, put in the context of her family’s history.
Joe Palca The sea snail Conus magus looks harmless enough, but it packs a venomous punch that lets it paralyze and eat fish. A peptide modeled on the venom is a powerful painkiller, though sneaking it past the blood-brain barrier has proved hard. The sea snail Conus magus looks harmless enough, but it packs a venomous punch that lets it paralyze and eat fish. A peptide modeled on the venom is a powerful painkiller, though sneaking it past the blood-brain barrier has proved hard. Courtesy of Jeanette Johnson and Scott Johnson Researchers are increasingly turning to nature for inspiration for new drugs. One example is Prialt. It's an incredibly powerful painkiller that people sometimes use when morphine no longer works. Prialt is based on a component in the venom of a marine snail. Prialt hasn't become a widely used drug because it's hard to administer. Mandë Holford is hoping to change that. She and colleagues explain how in their study published online Monday in the journal Scientific Reports. Holford is an associate professor of chemical biology at Hunter College in New York and on the scientific staff of the American Museum of Natural History. As is so often the case in science, her path to working on Prialt wasn't exactly a direct one. She's a chemist, and her first passion was peptides — short strings of amino acids that do things inside cells. "I started out with this love for peptides," Holford says, then laughs. "Love! Sounds weird to say you love peptides out loud." © 2015 NPR
Keyword: Pain & Touch
Link ID: 21255 - Posted: 08.04.2015
By LISA FELDMAN BARRETT OUR senses appear to show us the world the way it truly is, but they are easily deceived. For example, if you listen to a recorded symphony through stereo speakers that are placed exactly right, the orchestra will sound like it’s inside your head. Obviously that isn’t the case. But suppose you completely trusted your senses. You might find yourself asking well-meaning but preposterous scientific questions like “Where in the brain is the woodwinds section located?” A more reasonable approach is not to ask a where question but a how question: How does the brain construct this experience of hearing the orchestra in your head? I have just set the stage to dispel a major misconception about emotions. Most people, including many scientists, believe that emotions are distinct, locatable entities inside us — but they’re not. Searching for emotions in this form is as misguided as looking for cerebral clarinets and oboes. Of course, we experience anger, happiness, surprise and other emotions as clear and identifiable states of being. This seems to imply that each emotion has an underlying property or “essence” in the brain or body. Perhaps an annoying co-worker triggers your “anger neurons,” so your blood pressure rises; you scowl, yell and feel the heat of fury. Or the loss of a loved one triggers your “sadness neurons,” so your stomach aches; you pout, feel despair and cry. Or an alarming news story triggers your “fear neurons,” so your heart races; you freeze and feel a flash of dread. Such characteristics are thought to be the unique biological “fingerprints” of each emotion. Scientists and technology companies spend enormous amounts of time and money trying to locate these fingerprints. They hope someday to identify your emotions from your facial muscle movements, your body changes and your brain’s electrical signals. © 2015 The New York Times Company
Link ID: 21254 - Posted: 08.02.2015
RACHEL MARTIN, HOST: Every day, according to the Centers for Disease Control, 44 Americans die because they have overdosed on prescription painkillers. The CDC calls it an epidemic, and drug companies are responding by trying to develop versions of the most addictive painkillers, opioids, that will diminish a user's physical craving for the medicine. Now, to do this, to create these less addictive drugs, pharmaceutical companies are recruiting thousands of self-identified drug users to test their products. David Crow is a reporter for the Financial Times. He's just published a big report on this, and he joins me now to talk more about it. Thanks so much for being with us. Opioids, as we mentioned, are the worst in terms of their addictive quality. These companies are trying to come up with drugs that will achieve the same painkilling effect without the addictiveness. So this is actually possible? CROW: What they're trying to do is develop a new generation of opioid painkillers that have features that make them harder to abuse. Some of the strategies that have been pursued include hard shells that make it harder to crush up the pill so that you can snort it or gumming agents that make it harder to put into a syringe so that you can inject it. And some companies are experimenting with putting different chemicals in the center of the pill that will remain dormant. But if it's tampered with, that chemical would be released, and it would counteract the effect of the opioid. They're testing these drugs on recreational drug users. And the participants go through a screening process where they have to wash out, where they don't have any opioid in their system, and also where they're given a drug called naloxone, which cuts off the effects of opioids. And at that point, if you were addicted or physically dependent, your body would show signs of withdrawal. And that is the screening process. © 2015 NPR
Teresa Shipley Feldhausen Move over, umami. Fat is the newest member of the pantheon of basic tastes, joining salty, sweet, sour, bitter and savory, or umami. Researchers at Purdue University in West Lafayette, Ind., conducted taste tests pitting a variety of fats against flavors in the other taste categories, such as monosodium glutamate for umami. The result: People recognize some fats as separate from the other five taste categories, even with plugged noses. The researchers dub this sixth sense oleogustus. For instance, nearly two-thirds of tasters identified one type of fat — linoleic acid, found in vegetable and nut oils — as a distinct flavor. Texture wasn’t a factor; the researchers whipped up tasting samples that gave the same mouthfeel. Pure oleogustus doesn’t invoke notes of olive oil or fresh butter. It’s unpleasant, the researchers report online July 3 in Chemical Senses. Mix oleogustus with some of the other five flavors, however, and you could end up with doughnuts or potato chips. Citations C.A. Running, B.A. Craig and R.D. Mattes. Oleogustus: The unique taste of fat. Chemical Senses. Published online July 3, 2015. doi: 10.1093/chemse/bjv036. © Society for Science & the Public 2000 - 2015.
Keyword: Chemical Senses (Smell & Taste)
Link ID: 21252 - Posted: 08.02.2015
Steve Connor A computer game designed by neuroscientists has helped patients with schizophrenia to recover their ability to carry out everyday tasks that rely on having good memory, a study has found. Patients who played the game regularly for a month were four times better than non-players at remembering the kind of things that are critical for normal, day-to-day life, researchers said. The computer game was based on scientific principles that are known to “train” the brain in episodic memory, which helps people to remember events such as where they parked a car or placed a set of keys, said Professor Barbara Sahakian of Cambridge University, the lead author of the study. People recovering from schizophrenia suffer serious lapses in episodic memory which prevent them from returning to work or studying at university, so anything that can improve the ability of the brain to remember everyday events will help them to lead a normal life, Professor Sahakian said. Schizophrenia affects about one in every hundred people and results in hallucinations and delusions (Rex) Schizophrenia affects about one in every hundred people and results in hallucinations and delusions (Rex) “This kind of memory is essential for everyday learning and everything we do really both at home and at work. We have formulated an iPad game that could drive the neural circuitry behind episodic memory by stimulating the ability to remember where things were on the screen,” Professor Sahakian said. © independent.co.uk
By Gary Stix A decline in hearing acuity is not only an occurrence that happens in the aged. An article in the August Scientific American by M. Charles Liberman, a professor of otology and laryngology at Harvard Medical School and director of the Eaton-Peabody Laboratories at Massachusetts Eye and Ear, focuses on relatively recent discoveries that show the din of a concert or high-decibel machine noise is enough to cause some level of hearing damage. After reading the article check out this video by medical illustrator Brandon Pletsch and its narrated animation explaining how the sensory system that detects sound functions. © 2015 Scientific American
Link ID: 21250 - Posted: 08.02.2015
Alison Abbott Six years might seem like a long time to spend piecing together the structure of a scrap of tissue vastly smaller than a bead of sweat. But that is how long it has taken a team led by cell biologist Jeff Lichtman from Harvard University in Cambridge, Massachusetts, to digitally reconstruct a tiny cube of mouse brain tissue. The resulting three-dimensional map1 is the first complete reconstruction of a piece of tissue in the mammalian neocortex, the most recently evolved region of the brain. Covering just 1,500 cubic microns, it is still a far cry from reconstructing all 100 billion or so cells that make up the entire human brain. But Christof Koch, president of the Allen Institute for Brain Science in Seattle, Washington, notes that the various technologies involved will speed up “tremendously” over the next decade: “I would call this a very exciting promissory note,” he says. Lichtman’s team already has its eyes on a much bigger challenge: reconstructing a cubic millimetre of rodent neocortex — a piece of tissue around 600,000 times larger than the present achievement. The researchers will be doing this as part of a consortium that earlier this month received preliminary approval for major funding by the US government agency IARPA (Intelligence Advanced Research Projects Activity), which promotes high-risk, high pay-off research. The goal of the consortium, based at Harvard and at the Massachusetts Institute of Technology (MIT) in Cambridge, is to map the function as well as the anatomy of this tiny brain volume, while also working out how it computes information as an animal learns. © 2015 Nature Publishing Group,
Keyword: Brain imaging
Link ID: 21249 - Posted: 08.01.2015
By David Noonan Leaping through the air with ease and spinning in place like tops, ballet dancers are visions of the human body in action at its most spectacular and controlled. Their brains, too, appear to be special, able to evade the dizziness that normally would result from rapid pirouettes. When compared with ordinary people's brains, researchers found in a study published early this year, parts of dancers' brains involved in the perception of spinning seem less sensitive, which may help them resist vertigo. For millions of other people, it is their whole world, not themselves, that suddenly starts to whirl. Even the simplest task, like walking across the room, may become impossible when vertigo strikes, and the condition can last for months or years. Thirty-five percent of adults older than 39 in the U.S.—69 million people—experience vertigo at one time or another, often because of damage to parts of the inner ear that sense the body's position or to the nerve that transmits that information to the brain. Whereas drugs and physical therapy can help many, tens of thousands of people do not benefit from existing treatments. “Our patients with severe loss of balance have been told over and over again that there's nothing we can do for you,” says Charles Della Santina, an otolaryngologist who studies inner ear disorders and directs the Johns Hopkins Vestibular NeuroEngineering Laboratory. Steve Bach's nightmare started in November 2013. The construction manager was at home in Parsippany, N.J. “All of a sudden the room was whipping around like a 78 record,” says Bach, now age 57. He was curled up on the living room floor in a fetal position when his daughter found him and called 911. He spent the next five days in the hospital. © 2015 Scientific American
Keyword: Movement Disorders
Link ID: 21248 - Posted: 08.01.2015
Mo Costandi When we say that we are “in pain”, we usually mean that an injured body part is hurting us. But the phenomenon we call pain consists of more than just physical sensations, and often has mental and emotional aspects, too. Pain signals entering the black box of the brain can be subjected further processing, and these hidden thought processes can alter the way we perceive them. We still know very little about these non-physical aspects of pain, or about the brain processes responsible for them. We do know, however, that learning and mental imagery can both diminish and enhance the experience of felt pain. Two new studies now extend these findings – one shows that subliminal learning can also alter pain responses, and the other explains how mental imagery can do so. It’s well known that simple associative learning procedures can alter responses to pain. For example, newborn babies who have diabetic mothers and are repeatedly exposed to heel pricks in the first few days of life exhibit larger pain responses during subsequent blood tests than healthy infants. Learning also appears to explain the placebo effect, and why it is often so variable. Several years ago, Karin Jensen, who is now at Harvard Medical School, and her colleagues showed that subliminal cues can reactivate consciously-learned associations to either enhance or diminish pain responses. In their latest study, the researchers set out to determine the extent to which this type of learning can occur non-consciously. © 2015 Guardian News and Media Limited
Michael Sullivan It's 5:45 in the morning, and in a training field outside Siem Reap, home of Angkor Wat, Cambodia's demining rats are already hard at work. Their noses are close to the wet grass, darting from side to side, as they try to detect explosives buried just beneath the ground. Each rat is responsible for clearing a 200-square-meter (239-square-yard) patch of land. Their Cambodian supervisor, Hulsok Heng, says they're good at it. "They are very good," he says. "You see this 200 square meters? They clear in only 30 minutes or 35 minutes. If you compare that to a deminer, maybe two days or three days. The deminer will pick up all the fragmentation, the metal in the ground, but the rat picks up only the smell of TNT. Not fragmentation or metal or a nail or a piece of crap in the ground." That's right: Someone using a metal-detecting machine will take a lot longer to detect a land mine than a rat using its nose. There's plenty of work for the rats here in Cambodia. The government estimates there are 4 million to 6 million land mines or other pieces of unexploded ordnance — including bombs, shells and grenades — littering the countryside, remnants of decades of conflict. Neighboring Vietnam and Laos also have unexploded ordnance left over from the Vietnam War. Dozens of people are killed or maimed in the region every year — and there's a financial toll as well, since the presence of these potentially deadly devices decreases the amount of land available to farmers. © 2015 NPR
By Robert Gebelhoff Just in case sea snails aren't slow enough, new research has found that they get more sluggish when they grow old — and the discovery is helping us to understand how memory loss happens in humans. It turns out that the sea snail, which has a one-year lifespan, is actually a good model to study nerve cells and how the nervous system works in people. How neurons work is fundamentally identical in almost all animals, and the simplicity of the snail's body gives researchers the chance to view how different the system works more directly. "You can count the number of nerve cells that are relevant to a reflex," said Lynne Fieber, a professor at the University of Miami who leads research with the snails at the school. She and a team of researchers have been using the slimy little critters to learn how nerve cells respond to electric shock. They "taught" the snails to quickly contract their muscle tails by administering electric shocks and then poking the tails, a process called "sensitization." They then studied the responses at various ages. The scientists, whose work was published this week in the journal PlOS One, found that as the senior citizen specimens do not learn to contract from the shock very well. As the snails grow older, their tail startle reflex lessened, and then disappeared. So I guess you could say the frail snails' tails fail to avail (okay, I'll stop).
Kill, Fido! Docile ants become aggressive guard dogs after a secret signal from their caterpillar overlord. The idea turns on its head the assumption that the two species exchange favours in an even-handed relationship. The caterpillars of the Japanese oakblue butterfly (Narathura japonica) grow up wrapped inside leaves on oak trees. To protect themselves against predators like spiders and wasps, they attract ant bodyguards, Pristomyrmex punctatus, with an offering of sugar droplets. The relationships was thought to be a fair exchange of services in which both parties benefit. But Masaru Hojo from Kobe University in Japan noticed something peculiar: the caterpillars were always attended by the same ant individuals. “It also seemed that the ants never moved away or returned to their nests,” he says. They seemed to abandon searching for food, and were just standing around guarding the caterpillar. Intrigued, Hojo and his colleagues conducted lab experiments in which they allowed some ants to interact with the caterpillars and feed on the secretions, and kept others separate. Ants that ate the caterpillar’s secretions remained close to the caterpillar. They didn’t return to their nest. And whenever the caterpillar everted its tentacles – flipped them so they turned inside out – the ants moved around rapidly, acting aggressively. © Copyright Reed Business Information Ltd.