Anatomist Santiago Ramon y Cajal was the first to see--and illustrate--what neurons really do. His exquisitely detailed drawings changed our understanding of the brain and nervous system. Cajal relentlessly pursued his microcopic study of animal tissues, leading to an essential discovery: Brain signals jump from cell to cell rather than flow through a continuous web of fibers, as was believed at the time. Cajal began to study histology because it was cheap. He was a man of poor health and modest means, and examining stained specimens required little more than a microscope and patience. The fact that he had no access to the fancy tools of leading bacteriologists--he held only an obscure academic post in the scientific backwater of Zaragoza, Spain--turned him toward the study of animal tissues and cells. These "captivating scenes in the life of the infinitely small," as he called them in his autobiography, Recollections of My Life, went on to inspire ideas that overturned how scientists understood the brain and the nerves.? Here are two of his cutaway views of the cerebellum, which coordinates movement. The top drawing has a rich diversity of cells, including treelike Purkinje cells, seen in red and tan, and stellate cells, shown in black. The bottom drawing is a longitudinal cross section of the cerebellum. Copyright © 2011, Kalmbach Publishing Co.

Keyword: Brain imaging
Link ID: 15501 - Posted: 06.28.2011

by Kai Kupferschmidt BERLIN—Patients suffering from the agony of cluster headaches will take anything to dull the pain, even LSD, it turns out. Results from a pilot study presented here on Saturday at the International Headache Congress reveal that six patients treated with 2-bromo-LSD, a nonhallucinogenic analog of LSD, showed a significant reduction in cluster headaches per day; some were free of the attacks for weeks or months. "Some of these patients are still reporting significant relief more than a year after they were treated with the compound," says John Halpern, a psychiatrist at Harvard Medical School in Boston and one of the investigators involved in the study. "Nobody has ever reported these kinds of results." Cluster headaches, sometimes referred to as "suicide headaches" because of the almost unbearable pain they cause sufferers, usually involve just one side of the face; patients often liken the pain to someone trying to pull their eye out for hours. They can occur in bouts lasting many weeks, with several attacks a day. "What causes these attacks is still not clear," says Peter Goadsby, a headache expert at the University of California, San Francisco, who is not connected with the research. But recent studies suggest that changes in the structure of the hypothalamus are involved. Because that part of the brain is responsible for, among other things, circadian rhythms, the daily cycle of our body that dictates when we sleep but also regulates body temperature and blood pressure, it could explain the periodicity of attacks and why they seem to occur particularly often around the solstices. © 2010 American Association for the Advancement of Science

Keyword: Pain & Touch; Drug Abuse
Link ID: 15500 - Posted: 06.28.2011

By Molly Zametkin, Afew weeks ago, after completing my last class of college, I Googled my name. I knew I wouldn’t like what I saw, but I did it anyway. Eight hundred forty-five Google hits later, I was having a panic attack about what prospective employers and graduate schools would find: my tainted online reputation. Rewind five years. It’s my senior year of high school. I’ve been accepted to several colleges, and I’ve just come to terms with the fact that I grew up with attention-deficit hyperactivity disorder and finally begun to embrace the diagnosis as part of who I am. Accepting that I had attention issues was a breakthrough for me. I had spent my entire academic career struggling with shame and stigma. I hated being labeled ADHD; it made me feel as if people would think I was hyper, lazy, unmotivated and unfocused, which simply wasn’t the case. I remember finding it hard to resist chatting with my classmates when we were supposed to be doing assignments, and I was always doing my homework at the very last minute, but I also remember my teachers telling me I was a “bright” little girl. I was creative, I liked to work hard and I got good grades. Yet even when people told me I was bright, it felt as if they were saying, “You’re bright . . . for someone who has an attention problem.” I truly hated having my teachers and my parents think I was abnormal or flawed. During my senior year of high school, however, I learned that a family friend with whom I was close had ADHD and wasn’t ashamed of it at all. She was beautiful, popular and smart, and she freely broadcast the fact that she was living with ADHD and taking stimulant medications to treat it. Somehow, her open attitude relieved me. I began to think, “Hey, if she has ADHD and people still think she’s cool, no one’s opinion of me will change if I ‘come out’ with the fact that I have it, too.” © 1996-2011 The Washington Post

Keyword: ADHD; Attention
Link ID: 15499 - Posted: 06.28.2011

By RONI CARYN RABIN Doctors are warning cocaine users they may develop a painful, disfiguring skin reaction after taking the drug, because it often is mixed with levamisole, a veterinary medicine that can set off severe allergic reactions. In a paper published online June 9 in The Journal of the American Academy of Dermatology, physicians at the University of California, Los Angeles, described six patients who developed patches of purple, discolored skin after using cocaine. A few suffered permanent disfigurement to the ears, and several experienced neutropenia, abnormally low white blood cell counts. The patients — two from Torrance, Calif., and four from Rochester — “may represent the tip of the iceberg as a looming public health problem,” the authors wrote. Almost 70 percent of cocaine in the United States is adulterated with levamisole, an antiparasitic drug banned for human use, according to the Department of Justice. In December 2009, the federal Centers for Disease Control reported that 21 cocaine users in New Mexico and Washington State had developed agranulocytosis, an acute systemic disease. One of the patients died. Though only a small fraction of cocaine users will have acute reactions, Dr. Noah Craft, a dermatologist at Harbor-U.C.L.A. Medical Center and an author of the report, said, “It’s like playing Russian roulette.” © 2011 The New York Times Company

Keyword: Drug Abuse
Link ID: 15498 - Posted: 06.28.2011

Erika Check Hayden Scientists have identified the molecular players central to an incurable brain injury common in premature babies, and have shown how such injuries might one day be treated, sparing people from lifelong conditions such as cerebral palsy. In babies born before their lungs are fully developed, lack of oxygen can disrupt nerve cells' ability to make a protective coating, called myelin, that makes up the brain's 'white matter'. Without myelin, brain cells die, leaving children vulnerable to neurological deficits such as cerebral palsy. Some 20% of babies born before 6.5 months gestation experience lasting brain damage (see The most vulnerable brains). "We have become very good at keeping these premature babies alive, but we have no strategy to prevent the long-term neurological consequences that can occur in them," says Vittorio Gallo, a neuroscientist at the Children's National Medical Center in Washington DC. Writing in Nature Neuroscience1, David Rowitch at the University of California, San Francisco, and his colleagues point the way towards such a strategy. By studying the brains of babies who had died after incurring brain injuries caused by a lack of oxygen, they discovered that a gene called AXIN2 was expressed in infants with white-matter brain injuries. © 2011 Nature Publishing Group,

Keyword: Development of the Brain; Brain Injury/Concussion
Link ID: 15497 - Posted: 06.27.2011

by Andy Coghlan They may not have verbs, nouns or past participles, but birds challenge the notion that humans alone have evolved grammatical rules. Bengal finches have their own versions of such rules – known as syntax – says Kentaro Abe of Kyoto University, Japan. "Songbirds have a spontaneous ability to process syntactic structures in their songs," he says. To show a sense of syntax in the animals, Abe's team played jumbled "ungrammatical" remixes of finch songs to the birds and measured the response calls. Although many animals, including dogsMovie Camera, parrotsMovie Camera and apes are known to interpret and construct "sentences", and recognise human words for individual objects, Abe says that only his finches have been shown to have a form of grammar in their utterances. Similar claims have been made for whale songSpeaker, however. In the wild, Bengal finches call back vigorously whenever they hear unfamiliar songs, usually from intruding finches. In the lab, Abe and colleague Dai Watanabe of the Japan Science and Technology Agency in Saitama exploited these reactions to gauge whether finches could notice "ungrammatical" songs. The rules First, they played finches unfamiliar songs repeatedly until the birds got used to them and stopped overreacting. Then they jumbled up syllables within each song and replayed these versions to the birds. © Copyright Reed Business Information Ltd.

Keyword: Language; Evolution
Link ID: 15496 - Posted: 06.27.2011

By Nadia Drake Indiana Jones, intrepid cinematic archaeologist, is famously afraid of snakes. Perhaps he wouldn’t need to be if he had a new ointment developed by scientists in Australia. Quickly applying a nitric oxide–containing ointment near the bite site slows the spread of some venoms, including the notorious eastern brown snake’s, the researchers report online June 26 in Nature Medicine. “This treatment might make all the difference between dying on the road and getting to the hospital in time,” says physician and emeritus professor of tropical medicine David Warrell of the University of Oxford, who was not involved with the study. Worldwide, snakebite causes approximately 100,000 deaths and 400,000 limb amputations each year. Physiologist Dirk van Helden at the University of Newcastle and his colleagues showed that in humans, applying an ointment containing nitric oxide within one minute of a simulated snakebite slows the transit of injected tracer molecules. Foot-to-groin venom travel times increased from an average of 13 minutes without the ointment to an average of 54 minutes with the ointment applied in a 5-centimeter diameter circle just up the limb from the bite site. The group also tested the effects of the cream on rats injected with venom from the brown snake (Pseudonaja textilis). Its potent venom travels through the body’s lymphatic system, eventually halting respiration and causing death. “It’s particularly nasty, one of the most toxic things in the world,” says van Helden. © Society for Science & the Public 2000 - 2011

Keyword: Neurotoxins
Link ID: 15495 - Posted: 06.27.2011

By JOHN TAGLIABUE AMSTERDAM — It has not been a good year for Ahmet Kilic. Sales are down in the store where for the last two and a half years he has sold groceries and meat, slaughtered according to halal conditions. The store, on the southern edge of this Dutch city, was started 22 years ago by his brother and uncle, natives of Turkey, who took it over from its former Dutch owners. But many of the Turks who are their clients have moved farther out of the city; moreover, customer access is blocked by work to lay tram tracks on the street in front. “Things are not good,” he said, tallying up sausage, an all-beef variety, and Turkish white cheese, which the Greeks call feta, for a shopper. Now he fears they could get worse. The Dutch Parliament will vote Tuesday on a bill that, if enacted, will effectively require even Jewish and Muslim butchers to stun animals — mechanically, electrically or with gas — before they are slaughtered, eliminating an exception in current law. A tiny animal rights party, which has two seats in Parliament, proposed the bill, arguing that failing to stun the animals before slaughter subjects them to unnecessary pain. The debate over the bill has divided the Dutch. Because the bill would mainly affect Muslims, of whom there are about 1.2 million in a Dutch population of about 16 million, compared with a Jewish population of 50,000, the debate has become a focus of Dutch animosity toward Muslims. © 2011 The New York Times Company

Keyword: Animal Rights
Link ID: 15494 - Posted: 06.27.2011

By David Eagleman On the steamy first day of August 1966, Charles Whitman took an elevator to the top floor of the University of Texas Tower in Austin. The 25-year-old climbed the stairs to the observation deck, lugging with him a footlocker full of guns and ammunition. At the top, he killed a receptionist with the butt of his rifle. Two families of tourists came up the stairwell; he shot at them at point-blank range. Then he began to fire indiscriminately from the deck at people below. The first woman he shot was pregnant. As her boyfriend knelt to help her, Whitman shot him as well. He shot pedestrians in the street and an ambulance driver who came to rescue them. The evening before, Whitman had sat at his typewriter and composed a suicide note: I don’t really understand myself these days. I am supposed to be an average reasonable and intelligent young man. However, lately (I can’t recall when it started) I have been a victim of many unusual and irrational thoughts. By the time the police shot him dead, Whitman had killed 13 people and wounded 32 more. The story of his rampage dominated national headlines the next day. And when police went to investigate his home for clues, the story became even stranger: in the early hours of the morning on the day of the shooting, he had murdered his mother and stabbed his wife to death in her sleep. It was after much thought that I decided to kill my wife, Kathy, tonight … I love her dearly, and she has been as fine a wife to me as any man could ever hope to have. I cannot rationa[l]ly pinpoint any specific reason for doing this … © 2011 by The Atlantic Monthly Group.

Keyword: Attention; Aggression
Link ID: 15493 - Posted: 06.27.2011

By Tina Hesman Saey College students probably won’t heed the advice, but new research confirms that sleeping is essential for learning and remembering. Sleep’s function has long been a mystery (SN: 10/24/09, p. 16), but many researchers have gathered evidence that it is important for learning and memory. Two new studies confirm that sleep plays a central role in solidifying memories and preparing the brain for new learning. Tickling a few neurons located at the top of the fruit fly brain triggers the insects to sleep, researchers led by Paul Shaw at Washington University in St. Louis discovered. Turning on the sleep-initiating brain cells makes short-term memories into long-lived ones, the researchers report June 24 in Science. A separate study in the same issue of Science, by researchers at the University of Wisconsin–Madison, describes microscopic evidence that during sleep, connections between brain cells are pruned. The group had indirect evidence that sleep prepares the brain for learning the next day through pruning, but the new study presents direct confirmation. The findings “confirm that learning and memory were important way back in the evolution of sleep,” says Marcos Frank, a neuroscientist at the University of Pennsylvania. He was not involved in either study. © Society for Science & the Public 2000 - 2011

Keyword: Sleep; Learning & Memory
Link ID: 15492 - Posted: 06.25.2011

By Bruce Bower Math doesn’t add up for some kids, and a weak number sense may be partly to blame. An evolutionarily ancient ability to estimate quantities takes a big hit in children with severe, instruction-resistant math difficulties, say psychologist Michèle Mazzocco of Johns Hopkins University in Baltimore and her colleagues. In contrast, below-average, average and superior math students estimate amounts comparably well, the researchers report in a paper published online June 16 in Child Development. “It’s possible that developmental routes to mathematical learning disability share a core deficit in numerical estimation,” Mazzocco says. Math learning disability, or dyscalculia, affects an estimated 5 to 7 percent of school children. Dyscalculia is defined as consistent, extremely low scores on math achievement tests. Causes of this problem remain poorly understood. Mazzocco’s new findings coincide with results from an ongoing study of more than 300 Missouri school children tested annually since kindergarten. By third grade, kids with math learning disability display several types of thinking hitches, says psychologist and investigation director David Geary of the University of Missouri in Columbia. In some cases of dyscalculia, youngsters have trouble gauging whether one set of items is more numerous than another. Others can’t estimate the number of items that they briefly see, quickly forget verbal information, can’t hold related pieces of information in mind or struggle in all of these areas. © Society for Science & the Public 2000 - 2011

Keyword: Development of the Brain
Link ID: 15491 - Posted: 06.25.2011

Ferris Jabr, reporter Toddlers with autism are more likely to have brain regions that are out of sync. The discovery could help doctors to diagnose the disorder at an earlier age. Coordination of brainwaves is thought to help different areas of the brain communicate effectively with one another. To see whether abnormal synchronisation may occur in autism, Ilan Dinstein at the Weizmann Institute of Science in Rehovot in Israel, and colleagues, analysed the brain activity of 72 toddlers as they slept inside functional MRI scanners. The toddlers, who were aged between 1 and 3-and-a-half years old, were classed as either "normally developing", or diagnosed as having delayed language skills or autism. Dinstein's team aggregated data from several different scanning sessions, zeroing in on brain regions that previous studies have shown are synchronised in typically developing children such as the inferior frontal gyrus (IFG) - linked with language comprehension and attention - and the superior temporal gyrus (STG) - involved in auditory processing. Such regions remain synchronised even in the complete absence of external stimuli during rest or sleep. Abnormal synchronisation appeared in significantly more autistic children than the other two groups. Using this data, the researchers were then able to reverse engineer the results to try to predict whether a child has autism based solely on synchronised brain activity. © Copyright Reed Business Information Ltd.

Keyword: Autism
Link ID: 15490 - Posted: 06.25.2011

Seil Collins, reporter A gene therapy treatment in monkeys may pave the way to curing the blind. Treating blindness has always been an appealing target for gene therapy due to the eye being one of the few sites in the body endowed with the ability to tolerate foreign substances without eliciting an inflammatory immune response. Although gene therapy has been used to partially restore sight in people who are blind from defects in the pigmented layer of the eye, providing the same treatment for those who are blind through loss of photoreceptor cells - the cells that respond to light - has proven a greater challenge. To find out whether it would be possible to deliver genes that would eventually restore photoreceptor cells, Luk Vandenberghe at the University of Pennsylvania in Philadelphia, and colleagues used two adeno-associated viruses, called AAV2 and AAV8, to deliver genes into monkey retinas. The viruses were marked with a green fluorescent protein, visible here in the photos of the monkey retinas after injection. By monitoring the green markers, the researchers were able to assess the minimum dose at which the viruses could deliver working genes into the retinal cells. A dose of AAV8 performed best, presenting an important step in using gene therapy to treat and restore photoreceptor cells in humans. © Copyright Reed Business Information Ltd.

Keyword: Vision; Genes & Behavior
Link ID: 15489 - Posted: 06.25.2011

Andy Coghlan, reporter It's not quite a case of "stop taking the pills", but the elderly should avoid any unnecessary drugs that block the neurotransmitter acetylcholine, researchers warned today. As widely reported, they concluded after a 2-year study on 13,000 men and women over 65 that taking anticholinergic - acetylcholine-blocking - drugs raises the risk of death and dementia in the elderly. What makes the findings potentially alarming is that the offending drugs include many commonly prescribed, routine medications for hay fever, depression, heart health - and even eye drops for glaucoma. The researchers rated the strength of the acetylcholine-blocking action for each drug on a scale from 0 (no effect) to 3 (severe effect). Using this scale, they investigated possible links between the combined strength of drugs that individual participants took and their chances of dying or developing dementia during the study. About half the participants were taking acetylcholine-blocking drugs, and the average rating score was 1.8. The most alarming finding was in the 500 or so "heavy" users taking drugs with a combined rating of 4 or more. Twenty per cent of them died by the end of the study compared with only 7 per cent of those taking no anticholinergic drugs. Likewise, participants taking drugs with a cumulative rating of 5 or more showed evidence of accelerated cognitive decline. They averaged scores 4 per cent lower than normal in cognitive function tests. You can see Chris Fox of the University of East Anglia, which led the study, interviewed here about the results. © Copyright Reed Business Information Ltd.

Keyword: Alzheimers
Link ID: 15488 - Posted: 06.25.2011

Sandrine Ceurstemont, video producer Psychologist Alan Stubbs has large prints on his office walls that often catch visitors off guard: by glancing at the images the whole area seems to light up. Now you can experience the same illusion by looking at the video above. As you stare at each image, move your head towards the screen and then back again. The bright spot should appear to spread quite dramatically. This illusion, discovered by Alan Stubbs at the University of Maine and Simone Gori at the University of Padua, Italy, contradicts the way we typically perceive size and brightness. When we move closer to an object, it appears to be the same size even though the size of the image on our retina has changed. Similarly, the brightness of an object usually remains constant despite changes in illumination. Since we're typically looking around at a 3D environment, our brain automatically makes these adjustments to help us make sense of our surroundings. So why does this illusion break these rules? Stubbs and Gori noticed that the edges of the bright spot have to be blurry for the effect to occur. "One possible explanation could be that our visual system cannot bring the blurred boundaries into focus and for this reason the correction of the brain for size constancy does not occur," they write. Another possibility is that the brightness gradient suggests to our brain that we are looking at a 3D tunnel, with a light at the end. In this case, it's simply an error of interpretation and our brain is behaving as if it was presented with the actual scenario. © Copyright Reed Business Information Ltd

Keyword: Vision
Link ID: 15487 - Posted: 06.25.2011

by Sara Reardon When paleontologist Richard Owen dug up a dinosaur in 1842, he thought it looked like a reptile—a "terrible lizard" with scales, slow-moving legs, and cold blood. But many dinosaurs are now known to have been fast, powerful, and energetic. And since the 1960s, scientists have argued over whether the cold-blooded physiology of a lumbering reptile could have powered something nimble and speedy like a Velociraptor. Now, scientists using a technique once reserved for climatologists have found that big four-legged dinos had body temperatures similar to those of mammals—evidence that they either were warm-blooded or were better at conserving body heat than modern reptiles are. Evolutionary biologist Robert Eagle of the California Institute of Technology in Pasadena heard about a technique from Caltech colleagues, who were using it to reconstruct ancient climates. By analyzing minerals in old rocks, geochemists can determine the relative amounts of different chemical isotopes: atoms of the same chemical element that vary slightly in mass. Different isotopes tend to form depending on whether a chemical reaction took place at high or low temperatures. The method, called "clumped-isotope thermometry," focuses on a reaction involving the bond between carbon and oxygen. The lower the temperature at which a mineral forms, the more the rare isotopes carbon-13 and oxygen-18 tend to bond, or "clump," together. By studying CO2 trapped in minerals, geochemist John Eiler of Caltech and other researchers were trying to determine how warm Earth had been when they formed. © 2010 American Association for the Advancement of Science.

Keyword: Evolution
Link ID: 15486 - Posted: 06.25.2011

by Elizabeth Norton Life for those with a genetic disease called Prader-Willi syndrome, which affects an estimated one out of 15,000 people, can be challenging both for the patient and his or her family. Sufferers have an insatiable hunger that can lead to life-threatening obesity if access to food is not restricted. And worse, they have behavioral problems akin to autism. Tantrums and tears are common because these patients have difficulty understanding the motives of others and controlling their own emotions. But treatment with the brain hormone oxytocin may help bring both emotions and eating into balance, according to a new study. Several clues pointed to the potential of oxytocin, often thought of as the "trust hormone." Research conducted on the brain tissue donated after death from Prader-Willi patients showed that the hypothalamus (the body's thermostat) has abnormalities in the nerve cells that produce this hormone. Moreover, the hypothalamus releases oxytocin in response to touching, social interactions, relaxation, and trust—all the things people with Prader-Willi syndrome have trouble with. And oxytocin treatments have improved the social skills of autistic patients. Finally, the hormone is thought to contribute to feelings of fullness after eating, "satiety" in scientific parlance. To see whether oxytocin could benefit individuals with Prader-Willi syndrome, endocrinologist Maïthé Tauber of the Children's Hospital in Toulouse, France, and colleagues injected oxytocin or a placebo into the noses of 24 adult patients. The researchers monitored the patients' behavior; they also used cartoon stories to test patients' grasp of social interactions and pictures of faces to see how well they could recognize emotions. © 2010 American Association for the Advancement of Science

Keyword: Hormones & Behavior; Emotions
Link ID: 15485 - Posted: 06.25.2011

Recent years have seen a flood of media attention devoted to the relationship between the digital age and the human brain (in these pages and elsewhere; The New York Times has a whole series on the topic). New Yorker writer Adam Gopnik divides commentators on the subject into three camps: "the Never-Betters, the Better-Nevers, and the Ever-Wasers" -- that is, roughly speaking, those who see the Internet and all that goes along with it as unambiguously good for humanity; those who think just the opposite; and those who "insist that at any moment in modernity something like this is going on," and the upheavals of our own time aren't so different from those of any other. Cathy N. Davidson, author of the forthcoming book Now You See It: How the Brain Science of Attention Will Transform the Way We Live, Work, and Learn (Viking) could safely be deemed a Never-Better, with perhaps a dash of the Ever-Waser. The major technological changes of the past decade and a half present an array of "exciting opportunities," Davidson argues -- opportunities to promote efficiency, satisfaction and success at every stage from kindergarten through career. If we are inclined to side with the Better-Nevers, worrying that our brains never evolved for shifts of such magnitude -- if kids attend to text messages and video games with alacrity, but fall behind in school, while adults feel swamped by information overload and spread too thin by multitasking -- the trouble, in Davidson's view, is not with all our new technologies, but rather with our failure thus far to adapt and restructure ourselves and our institutions. In Now You See It, Davidson gathers data and anecdotes on a wide array of topics -- attention, learning, the American school system and its history, the modern workplace and how it came about -- to argue that the human brain is perfectly well-suited to the digital world, if only we are willing to rethink the classroom, the workplace, and how we measure success. © Copyright 2011 Inside Higher Ed

Keyword: Attention
Link ID: 15484 - Posted: 06.25.2011

By Stephen Adams, Medical Correspondent The research, which follows studies indicating that it slows the progress of Alzheimer's, suggests lithium could be a cheap therapy to combat a range of brain disorders common in the elderly. Scientists at the Buck Institute for Ageing in San Francisco made the finding in a study of mice. They hope to conduct their first trials in humans soon. Compounds of lithium - itself a soft alkali metal - have been used for over 50 years to treat mania and mood swings. But its effect on a range of neuro-degenerative diseases is only starting to be appreciated. Earlier this year a small-scale study of people with mild cognitive impairment -trouble with memory and thinking - found it delayed the onset of full-blown Alzheimer's. Psychiatrists believe it slows the formation of amyloid plaques and brain cell tangles thought to cause the disease. The American researchers think lithium works in a similar way to prevent Parkinson's, which is caused because specific brain nerve cells die. They said their study - the first in animals - showed it stopped the build up of toxic proteins and cell death. Prof Julie Andersen, of the Buck Institute, said trials in people to determine the correct dosage could start soon. © Copyright of Telegraph Media Group Limited 2011

Keyword: Parkinsons
Link ID: 15483 - Posted: 06.25.2011

By SINDYA N. BHANOO The cruel, persistent bullying that older siblings display toward younger ones does not have lifelong consequences — at least among blue-footed boobies, a new study finds. Boobies are marine birds that typically lay two eggs that hatch four days apart. During a four-month nesting period, the senior sibling is known to peck and attack its junior sibling incessantly until the younger bird becomes habitually submissive. Senior chicks end up gaining an advantage in terms of size, strength and motor coordination over their younger siblings. Younger siblings receive fewer feedings and less fish from parents, and during the first three weeks of life their weight is 11 percent lower. Younger chicks also suffer from elevated levels of stress hormones that are 109 percent higher than in senior chicks in the first 15 to 20 days of life. Yet all adult boobies seem equally capable of displaying aggression toward intruders approaching their nests, said Oscar Sánchez-Macouzet , an evolutionary biologist at the National Autonomous University of Mexico and the study’s first author. He and his colleagues report their findings in the journal Biology Letters. “To our surprise, former junior and senior chicks did not differ in their aggressiveness defending their nests,” he said. © 2011 The New York Times Company

Keyword: Aggression; Development of the Brain
Link ID: 15482 - Posted: 06.23.2011