William G. Eberhard, William T. Wcislo A basic fact of life is that the size of an animal’s brain depends to some extent on its body size. A long history of studies of vertebrate animals has demonstrated that the relationship between brain and body mass follows a power-law function. Smaller individuals have relatively larger brains for their body sizes. This scaling relationship was popularized as Haller’s Rule by German evolutionary biologist Bernhard Rensch in 1948, in honor of Albrecht von Haller, who first noticed the relationship nearly 250 years ago. Little has been known, however, about relative brain size for invertebrates such as insects, spiders and nematodes, even though they are among Earth’s more diverse and abundant animal groups. But a recent wave of studies of invertebrates confirms that Haller’s Rule applies to them as well, and that it extends to much smaller body sizes than previously thought. These tiny animals have been able to substantially shift their allometric lines—that is, the relationship between their brain size and their overall body size—from those of vertebrates and other invertebrates. Animals that follow a given allometric line belong to the same grade and changes from one grade to another are known as grade shifts. The result is that different taxonomic groups have different, variant, versions of Haller’s Rule. The mechanisms that are responsible for grade shifts are only beginning to be understood. But this combination of generality and variability in Haller’s Rule appears to call into question some basic assumptions regarding the uniformity of how the central nervous system functions among animals. It also reveals a number of overlooked design challenges faced by tiny organisms. Because neural tissue is metabolically expensive, minute animals must pay relatively higher metabolic costs to power their proportionally larger brains, and they thus face different ecological challenges. © Sigma Xi, The Scientific Research Society

Keyword: Evolution
Link ID: 16651 - Posted: 04.16.2012

By Erica Westly Nerve cells in our limbs can regenerate after injury, but neurons in the central nervous system, which includes the brain and spinal cord, cannot. Figuring out why this is the case is critical to helping brain and spinal cord injuries heal. A study published in the January 26 issue of Neuron may offer a promising solution. Not only did the researchers, Rachid El Bejjani and Marc Hammarlund of Yale University, identify what appears to be a key chemical regulator of neuron repair, but drugs that target this regulator already exist, making the path to clinical treatments easier. The molecule they identified, called Notch, is a receptor that influences many biochemical pathways inside cells. Scientists used to think that Notch was active only during fetal and childhood development, but increasing evidence suggests that Notch is also involved in neurodegenerative conditions such as Alzheimer’s disease and stroke. Using C. elegans, a microscopic worm, El Bejjani and Hammarlund showed that Notch impeded neurons from healing themselves. When they blocked Notch’s activity with a drug, the neurons’ growth improved. The drug used in the study is already being tested in rodents and humans for potential use in Alz­hei­mer’s and other disorders, although whether it can help damaged neurons regenerate in mammals is unclear. “We know that the Notch pathway is con­served in vertebrates, but we don’t know if the re­generation mechanism is conserved,” Hammarlund says. If Notch stops neurons from growing back in humans as it does in C. elegans, it could be a major breakthrough in spinal cord medicine. © 2012 Scientific American

Keyword: Regeneration; Alzheimers
Link ID: 16650 - Posted: 04.14.2012

Mo Costandi Researchers have come up with a way to help prevent recovering drug addicts from relapsing — without using other pharmaceuticals to help. The approach involves modifying addicts' behaviour by weakening their memory of drug taking, which relieves their cravings and might help to prevent relapse. Addicts tend to associate a drug's effects with drug-taking equipment and a certain environment, which can make them vulnerable to relapse if they encounter those conditions. The technique, studied by Lin Lu of the National Institute of Drug Dependence at Peking University in Beijing and his colleagues, aims to break that link by briefly reactivating the memory of drug taking and following it with an 'extinction session' of repeated exposure to the same memory cues. The short reminder of drug-taking seems to take the memory out of storage and make it easier to overwrite. Existing therapies try to help addicts to unlearn their habit by, for example, showing them videos of people injecting, and having them handle syringes while not under the influence of the drug. This reduces cravings in the clinic, but not when addicts return to their usual surroundings. Other approaches tested in rats involved using memory-blocking drugs to change memories of past drug use, but these are not approved for use in humans. To boost the technique's effectiveness, Lu and his team combined the approach with a process called memory reconsolidation. During reconsolidation, information is retrieved from long-term storage and reactivated to strengthen the memory. After retrieval, however, the information becomes temporarily unstable and thus prone to alteration. Their work is published today in Science1. © 2012 Nature Publishing Group

Keyword: Drug Abuse; Learning & Memory
Link ID: 16649 - Posted: 04.14.2012

Sandrine Ceurstemont, editor, New Scientist TV An illusion that tricks your brain twice is helping to uncover how we perceive ghostly images. The new animation, created by Irene Sperandio from the University of Western Ontario in London, Canada, and colleagues, combines an after-image effect with a common size illusion to investigate how these colourful apparitions are generated. While watching the video above, fix your eyes on the dot in the centre. A bluish contour should start to emerge around the red circle, which is the beginning of the after-image. At the same time, the second effect alters your perception of the static circle's size. Since the main circle is surrounded by a group of smaller ones, it appears to be larger than it actually is. Once the animation stops, a ghostly blue circle should appear when you look at the grey background. But instead of being the same size as the original circle, it should appear to be slightly larger due to adaptation induced by viewing it in the context of the surrounding discs. "The size of the after-image should correspond to the perceived size of the static inner circle which is affected by the flickering stimuli," says Sperandio. Since the flashing circles don't produce an after-image, this suggests that the effect is residual. © Copyright Reed Business Information Ltd.

Keyword: Vision
Link ID: 16648 - Posted: 04.14.2012

by Erin Loury Monkeys banging on typewriters might never reproduce the works of Shakespeare, but they may be closer to reading Hamlet than we thought. Scientists have trained baboons to distinguish English words from similar-looking nonsense words by recognizing common arrangements of letters. The findings indicate that visual word recognition, the most basic step of reading, can be learned without any knowledge of spoken language. The study builds on the idea that when humans read, our brains first have to recognize individual letters, as well as their order. "We're actually reading words much like we identify any kind of visual object, like we identify chairs and tables," says study author Jonathan Grainger, a cognitive psychologist at France's National Center for Scientific Research, and Aix-Marseille University in Marseille, France. Our brains construct words from an assembly of letters like they recognize tables as a surface connected to four legs, Grainger says. Much of the current reading research has stressed that readers first need to have familiarity with spoken language, so they can connect sounds (or hand signs for the hearing-impaired) with the letters they see. Grainger and his colleagues wanted to test whether it's possible to learn the letter patterns of words without any idea of what they mean or how they sound—that is, whether a monkey could do it. The scientists used a unique testing facility, consisting of a trailer with computers set up next to a baboon enclosure, which the animals could enter at will and perform trials on the touch-screen computers for as long as they pleased. The computers cued up the appropriate test for each of the six study baboons using microchips in their arms. When letters appeared on the monitor, the baboons got wheat rewards for touching the correct shape on the screen: an oval on the right of the screen if the word was real, and a cross on the left if it was nonsense (see video). © 2010 American Association for the Advancement of Science.

Keyword: Language; Evolution
Link ID: 16647 - Posted: 04.14.2012

By Bruce Bower PORTLAND, Ore. — In a cooperative venture aimed at understanding the most uncooperative of acts, researchers studying different African communities of wild chimpanzees have pooled their data and found that the apes sometimes kill each other nearly everywhere they’ve been studied. Chimp homicides occurred most frequently in groups with the most adult males, anthropologist Michael Wilson of the University of Minnesota in Minneapolis reported April 12 at the American Association of Physical Anthropologists’ annual meeting. Wilson persuaded researchers at 10 wild chimp sites, containing a total of 17 communities, to contribute their findings on lethal attacks collected over the past several decades. Chimps spend most of their time in peaceful pursuits, such as playing, foraging and grooming each other. Yet researchers, beginning with Jane Goodall more than 40 years ago, have described occasional chimp homicides. Some investigators have speculated that these animals get lethally riled up by human intrusions, such as deforestation, hunting and feeding of chimps by eco-tourists. But the new study found that chimp communities with the most documented killings had no or only rare encounters with humans. Groups of males carried out most killings, and most victims were male adults and infants in neighboring communities. “The new findings suggest that killing is an evolved strategy, mainly for adult males to eliminate rivals and competitors for mates,” Wilson said. © Society for Science & the Public 2000 - 2012

Keyword: Aggression; Evolution
Link ID: 16646 - Posted: 04.14.2012

By JAMES GORMAN The puzzle of consciousness is so devilish that scientists and philosophers are still struggling with how to talk about it, let alone figure out what it is and where it comes from. One problem is that the word has more than one meaning. Trying to plumb the nature of self-awareness or self-consciousness leads down one infamous rabbit hole. But what if the subject is simply the difference in brain activity between being conscious and being unconscious? Scientists and doctors certainly know how to knock people out. Michael T. Alkire at the University of California, Irvine, put it this way in an article in Science in 2008: “How consciousness arises in the brain remains unknown,” he wrote. “Yet, for nearly two centuries our ignorance has not hampered the use of general anesthesia for routinely extinguishing consciousness during surgery.” And a good thing, too. Setting aside what philosophers call “the hard problem” (self-awareness), a lot has been learned about the boundary between being awake and alert and being unconscious since ether was used in 1846 to put a patient under for surgery. Researchers have used anesthesia, recently in combination with brain scans, as a tool to see what happens in the brain when people fade in and out of consciousness — which parts turn on and which turn off. For instance, in a recent study, investigators showed that a person could respond to a simple command to open his eyes (the subjects were all right-handed men) when the higher parts of the brain were not yet turned on. The finding may be useful in deciding how to measure the effects of anesthetics, and it adds another data point to knowledge of what’s going on in the brain. © 2012 The New York Times Company

Keyword: Consciousness; Sleep
Link ID: 16645 - Posted: 04.14.2012

By James Gallagher Health and science reporter, BBC News People with Huntington's disease, a debilitating brain condition, appear have a "protection" from cancer, according to a study in Sweden. Nearly 40 years of medical records showed patients with Huntington's had half the normal expected risk of developing tumours. Researchers, writing in The Lancet Oncology, said the reason was unclear. Cancer Research UK said the findings presented another avenue to explore in tackling cancer. Academics at Lund University analysed Swedish hospital data from 1969 to 2008. They found 1,510 patients with Huntington's disease. During the study period, 91 of those patients subsequently developed cancer. The authors said that was 53% lower than the levels expected for the general population. Huntington's is one of a group of illnesses called "polyglutamine diseases". Data from other polyglutamine diseases also showed lower levels of cancer. The authors said: "We found that the incidence of cancer was significantly lower among patients with polyglutamine diseases than in the general population. "The mechanisms behind the protective effects against cancer are unclear and further research is warranted." BBC © 2012

Keyword: Huntingtons
Link ID: 16644 - Posted: 04.12.2012

by Chris Mooney JOHN HIBBING used to be a traditional political scientist. He studied elections, ran opinion polls and researched why some politicians opt to retire rather than wait around to be defeated by challengers. "About as traditional as it gets," he says. Roughly a decade ago, though, Hibbing shifted to a new approach that is starting to revolutionise how we think about politics. He began to explore whether political preferences might be partly based in biology. The idea initially met with great scepticism from his peers. But Hibbing and his collaborators at the Political Physiology Lab at the University of Nebraska-Lincoln now have a stack of scientific publications backing the idea. For example, when they measure the physical reactions of liberals and conservatives to aversive stimuli, they find major differences. Tough-on-crime, pro-military conservatives have a more pronounced startle reflex after hearing a sudden loud noise. They also show stronger skin responses when shown threatening images and look at them more rapidly and for longer. It is conventional to think about political ideology as a set of ideas people consciously hold about the way society should be ordered. A tacit assumption is that we come to these beliefs rationally, by reading and thinking about the issues. If we differ, it is because we reason to different conclusions. Hibbing's results suggest otherwise. "One of the things we're trying to get people to realise is that those who disagree with them politically really do experience the world in a different fashion," he says. © Copyright Reed Business Information Ltd.

Keyword: Emotions
Link ID: 16643 - Posted: 04.12.2012

By GRETCHEN REYNOLDS, Columnist Statistically, people who exercise are much less likely than inactive people to abuse drugs or alcohol. But can exercise help curb addictions? Some research shows that exercise may stimulate reward centers in the brain, helping to ease cravings for drugs or other substances. But according to an eye-opening new study of cocaine-addicted mice, dedicated exercise may in some cases make it even harder to break an addiction. The study, conducted by researchers at the Beckman Institute for Advanced Science and Technology at the University of Illinois in Urbana-Champaign, began by dividing male mice into those that had or did not have running wheels in their cages. All of the mice were injected with a chemical that marks newly created brain cells. The animals then sat in their cages or ran at will for 30 days. Afterward, the mice were placed in small multiroom chambers in the lab and introduced to liquid cocaine. They liked it. Researchers frequently use a model known as “conditioned place preference” to study addiction in animals. If a rodent returns to and stubbornly plants itself in a particular place where it has received a drug or other pleasurable experience, then the researchers conclude that the animal has become habituated. It badly wants to repeat the experience that it associates with that place. All of the mice displayed a decided place preference for the spot within their chamber where they received cocaine. They had learned to associate that location with the pleasures of the drug. All of the mice had, essentially, become addicts. © 2012 The New York Times Company

Keyword: Drug Abuse
Link ID: 16642 - Posted: 04.12.2012

Caroline Morley, online picture researcher Originating in ancient China, acupuncture has been used for 2500 years. Traditional Chinese medicine holds that disease is caused by blockages and imbalances of energy (known as chi) flowing through meridians in the body, and can be eased by inserting needles at specific points. Since the 1970s, acupuncture has become more popular outside east Asia. Once widely considered a quack medicine, there is now tentative support for its use in certain conditions from respected official bodies such as the World Health Organization, the National Health Service in the UK and the National Institutes of Health in the US. There is evidence that acupuncture is effective in treating a range of conditions including spinal injuries, infertility and the side effects of chemotherapy , and that its effects aren't entirely due to the placebo effect. However, despite extensive research, the mechanism of this ancient healing art remains unknown. For example, the two vision-related points GB37 (gall bladder) and UB60 (urinary bladder) showed deactivation in visual brain areas like the cuneus. The team concluded that acupuncture seems to affect the brain's processing of both physical sensations and thought. For now, though, the source of our chi remains elusive. Journal reference: PLoS One, DOI: 10.1371/journal.pone.0032960 © Copyright Reed Business Information Ltd.

Keyword: Pain & Touch
Link ID: 16641 - Posted: 04.12.2012

by Helen Fields The average adult human's brain weighs about 1.3 kilograms, has 100 billion or so neurons, and sucks up 20% of the oxygen we breathe. It's much bigger than an animal our size needs. According to a new computer model, the brains of humans and related primates are so large because we evolved to be social creatures. If we didn't play well with others, our brains would be puny. The idea behind the so-called social intelligence hypothesis is that we need pretty complex computers in our skulls to keep track of all the complex relationships we have with each other—who's a friend, who's an enemy, who's higher in the social ranks. Some studies have supported this idea, showing for example that bigger-brained primates tend to live in bigger social groups. The same appears to hold true for dolphins. But these studies only identified associations between brain and group size; they don't show how evolution might have worked. Since they didn't have a few million years of time on their hands, Ph.D. student Luke McNally and colleagues at Trinity College Dublin simulated evolution on a computer. They started with 50 simple brains. Each had just three to six neurons. The researchers then made each brain challenge the others to one of two classic games: the prisoner's dilemma or the snowdrift game. In the prisoner's dilemma, two people have been taken in for questioning by the police. If both keep their mouths shut, they'll both be set free. If one sells out the other, the snitch will get off and the other will do a long stint in jail. If they tell on each other, both get shorter sentences. © 2010 American Association for the Advancement of Science.

Keyword: Evolution
Link ID: 16640 - Posted: 04.12.2012

By Susan Milius Scientists may have been going in the wrong direction to find bird beaks’ built-in navigation sensors, says a provocative new study. Pigeons and other birds appear to use the Earth’s magnetic field, along with sights and sounds, to figure out where they’re flying. But the widely accepted identification of one set of magnetically sensitive cells is “totally wrong,” says neuroscientist David Keays of the Research Institute of Molecular Pathology in Vienna. He’s talking about work published in 2003 identifying clusters at six places in pigeons’ upper beaks as nerve cells. Those clusters have little crystals of iron compounds that might serve as biological compass needles, the earlier study proposed. For the new study, Keays and his colleagues looked for these cells in about 250,000 thin slices of tissue from beaks of more than 200 pigeons collected across Europe. Clusters of beak cells do contain iron, but it turns out that they’re not consistent in abundance or location, and most aren’t nerve cells at all, he says. Instead, they’re immune system cells called macrophages, he and his colleagues report online April 11 in Nature. “If that’s true, this could be really important,” says neuroethologist Henrik Mouritsen of Carl von Ossietzky University of Oldenburg in Germany. Discarding the old identification of beak sensors would mean researchers have to start from scratch looking for them. © Society for Science & the Public 2000 - 2012

Keyword: Animal Migration
Link ID: 16639 - Posted: 04.12.2012

By Frank Jordans GENEVA—Cases of dementia -- and the heavy social and financial burdens associated with them -- are set to soar in the coming decades as life expectancy and medical care improve in poorer countries, the World Health Organization says. Some 35.6 million people were living with dementia in 2010, but that figure is set to double to 65.7 million by 2030, the U.N. health agency said Wednesday. In 2050, it expects dementia cases to triple to 115.4 million. "The numbers are already large and are increasing rather rapidly," said Dr. Shekhar Saxena, the head of WHO's mental health division. Most dementia patients are cared for by relatives who shoulder the bulk of the current estimated annual cost of $604 billion. And the financial burden is expected to rise even faster than the number of cases, WHO said in its first substantial report on the issue. "The catastrophic cost drives millions of households below the poverty line," warned the agency's director-general, Margaret Chan. Dementia, a brain illness that affects memory, behavior and the ability to perform even common tasks, affects mostly older people. About 70 percent of cases are believed to be caused by Alzheimer's. In the last few decades, dementia has become a major public health issue in rich countries. But with populations in poor and middle-income countries projected to grow and age rapidly over the coming decades, WHO appealed for greater public awareness and better support programs everywhere. © 2012 NY Times Co.

Keyword: Alzheimers
Link ID: 16638 - Posted: 04.12.2012

By Laura Sanders Nerve cells from the brain’s emotion hub talk directly to a region that doles out attention, a study of monkeys shows. The connection, described in the April 11 Journal of Neuroscience, may help explain how people automatically focus on emotional events. “I’m really excited to see this in press,” says neurologist Helen Mayberg of Emory University School of Medicine in Atlanta. “This provides an anatomical explanation for why an emotionally salient event always bumps the board.” A clearer description of how emotions influence attention is important for understanding and treating psychiatric disorders such as anxiety and depression, both of which may involve perturbed attention systems. Although scientists knew that emotionally significant events quickly capture attention, it wasn’t clear how the process works. To find out, Basilis Zikopoulos and Helen Barbas, both of Boston University, started with a likely suspect — the amygdala. In humans, the amygdala is made up of two structures the shape and size of almonds, one on each side of the brain. Best known for its role in processing fear, the amygdala helps process other emotions, too, including pleasurable ones. The researchers injected dyes deep into the brains of 10 rhesus monkeys. The dyes traced individual neurons and their long, information-carrying tendrils called axons. This technique captured details that even the best human imaging techniques miss. “In humans, we just look at the major highways, so we don’t see the side streets,” Zikopoulos says. © Society for Science & the Public 2000 - 2012

Keyword: Emotions; Attention
Link ID: 16637 - Posted: 04.12.2012

By Jeanna Bryner and LiveScience Homophobes should consider a little self-reflection, suggests a new study finding those individuals who are most hostile toward gays and hold strong anti-gay views may themselves have same-sex desires, albeit undercover ones. The prejudice of homophobia may also stem from authoritarian parents, particularly those with homophobic views as well, the researchers added. "This study shows that if you are feeling that kind of visceral reaction to an out-group, ask yourself, 'Why?'" co-author Richard Ryan, a professor of psychology at the University of Rochester, said in a statement. "Those intense emotions should serve as a call to self-reflection." The research, published in the April 2012 issue of the Journal of Personality and Social Psychology, reveals the nuances of prejudices like homophobia, which can ultimately have dire consequences. [The 10 Most Destructive Human Behaviors] "Sometimes people are threatened by gays and lesbians because they are fearing their own impulses, in a sense they 'doth protest too much,'" Ryan told LiveScience. "In addition, it appears that sometimes those who would oppress others have been oppressed themselves, and we can have some compassion for them too, they may be unaccepting of others because they cannot be accepting of themselves." Ryan cautioned, however, that this link is only one source of anti-gay sentiments. © 2012 Scientific American,

Keyword: Sexual Behavior; Emotions
Link ID: 16636 - Posted: 04.12.2012

By Stephani Sutherland If you have ever jumped at a loud noise and felt an adrenaline rush, you have experienced the effects of corticotropin-releasing hormone (CRH). In the body, this hormone triggers the familiar fight-or-flight response—racing heart, shortness of breath, sweaty palms. In the brain, however, it acts as a chemical messenger, playing a role in anxiety and depression. That role, a new study suggests, is more complex than anyone expected. Because animal research from the past decade found that CRH contributes to anxiety and depression, drugs were developed that would block its actions in the brain. Clinical trials of these anti­anxiety and antidepressant drugs in human patients, however, have been disappointing. The new study, published last September in Science, shows why. Jan M. Deussing, a molecular biologist at the Max Planck Institute of Psychiatry in Munich, and his colleagues genetically altered mice so that some of their brain cells would be unable to detect the presence of CRH because they lacked the proper receptors. When the receptors were missing from neurons that produce the neurotransmitter glutamate, the mice displayed less anxiety, as expected. Yet when the receptors were missing from neurons that produce dopamine, the mice became more anxious. These two different neuron types, when interacting with CRH, “have exactly opposite effects in terms of anxiety-related behavior,” Deussing says. Be­cause the unsuccessful drugs limited the amount of the hormone available to all types of neurons, they ended up blocking its actions at neurons that both produce and prevent anxiety. The finding reaf­firms scientists’ growing understanding that mood disorders do not result from a simple chemical imbalance—too much or too little of one neurotransmitter—but rather from subtle changes in many systems in the brain. “The network is much more complex than we thought before,” Deussing says. © 2012 Scientific American

Keyword: Stress; Hormones & Behavior
Link ID: 16635 - Posted: 04.12.2012

Tim Parks “There are no images.” This was the first time I noticed Riccardo Manzotti. It was a conference on art and neuroscience. Someone had spoken about the images we keep in our minds. Manzotti seemed agitated. The girl sitting next to me explained that he built robots, was a genius. “There are no images and no representations in our minds,” he insisted. “Our visual experience of the world is a continuum between see-er and seen united in a shared process of seeing.” I was curious, if only because, as a novelist I’d always supposed I was dealing in images, imagery. This stuff might have implications. So we had a beer together. Manzotti has a degree in engineering and another in philosophy. He teaches in the psychology department at IULM University, Milan. The move from engineering to philosophy was prompted by conceptual problems he’d run into when first seeking to build robots. What does it mean that a subject sees an object? “People say the robot stores images of the world through its video camera. It doesn’t, it stores digital data. It has no images.” Manzotti is what they call a radical externalist: for him consciousness is not safely confined within a brain whose neurons select and store information received from a separate world, appropriating, segmenting, and manipulating various forms of input. Instead, he offers a model he calls Spread Mind: consciousness is a process shared between various otherwise distinct processes which, for convenience’s sake we have separated out and stabilized in the words subject and object. Language, or at least our modern language, thus encourages a false account of experience. © 1963-2012 NYREV, Inc.

Keyword: Consciousness
Link ID: 16634 - Posted: 04.12.2012

By ANAHAD O’CONNOR About 28 million Americans have sleep apnea, which causes repeated awakenings and pauses in breathing during the night, sometimes resulting in loud snoring and gasps for air. For decades, the standard treatment has been “continuous positive airway pressure.” A mask worn at night pushes air into the nasal passages, enabling easier breathing. C.P.A.P. reduces and in some cases completely prevents episodes of apnea. But the mask is like something from a bad science fiction movie: big, bulky and obtrusive. Many patients simply refuse to wear it or rip it off while asleep. Studies show that about half of all people prescribed C.P.A.P. machines stop using them in one to three weeks. “For a lot of people out there, the C.P.A.P. machine turns into a doorstop,” said Dr. Joseph Golish, the former chief of sleep medicine at the Cleveland Clinic. “C.P.A.P. is very effective in the sleep lab. But when people go home, there’s a good chance they won’t use it, and the success rate of an unused C.P.A.P. machine is absolutely zero.” Now an alternative form of C.P.A.P. is gaining popularity: a patch that fits over the nostrils. Called Provent, the patch holds two small plugs, one for each nostril, that create just enough air pressure to keep the airways open at night. It is far less intrusive than the traditional C.P.A.P. machine. It is also more expensive, and it doesn’t work for every patient. Approved by the Food and Drug Administration in 2008, Provent has spread mostly by word of mouth. But it has caught on fast. Its manufacturer, Ventus Medical, says it has shipped one million of the devices in the past 12 months, up from a half million total in the two years prior. Doctors say it has given them a new weapon in the battle against sleep apnea, and many patients who struggled with C.P.A.P. call it a godsend. © 2012 The New York Times Company

Keyword: Sleep
Link ID: 16633 - Posted: 04.10.2012

By Ferris Jabr Rhesus macaques, which are some of the best studied of all monkeys, establish hierarchies in their social groups. Whenever two macaques tussle over a piece of food, say, or the right to mate, the monkey with the higher rank usually wins. Primatologists have established that monkeys of a lower social status are generally more stressed out than their dominant peers—low-ranking monkeys have higher levels of stress hormones, for instance. But what about differences in gene activity? Does one’s social stature change how one’s genes are expressed. Yes, concludes a new study that used differences in gene expression to identify a monkey’s social status with around 80 percent accuracy. Jenny Tung of Duke University and her colleagues—including several collaborators at the Yerkes National Primate Research Center—studied 10 groups of adult female rhesus macaques made up of five females each. Researchers formed the groups one female at a time, which allowed them to carefully construct the social hierarchy: females introduced earlier generally assumed a higher rank. In this way, the scientists knew exactly which monkey held rank 1, 2, 3, 4 and 5 in each group. Tung and her colleagues collected blood samples from the rhesus macaques, isolated the white blood cells and analyzed the DNA in those cells. They found 987 genes whose activity depended on social rank: 535 genes that were more highly expressed in high-ranking individuals and 452 genes with higher activity in low-ranking individuals. Many of these genes were involved with the immune system; in particular, genes involved in inflammation were more active in low-ranking individuals. Further testing revealed that low-ranking monkeys also had fewer cytotoxic T-cells, a kind of white blood cell that attacks infected and cancerous cells. Earlier research suggests that the stress of a low social rank compromises the immune system—which fits with the finding about T-cells—but may also trigger the immune system to respond when it does not need to, which fits with the finding about inflammation. Findings about the relationship between stress, social status and the immune system are not clear cut, however; for example, some studies have found that having a higher rank is more stressful than having a lower rank. © 2012 Scientific American

Keyword: Aggression; Genes & Behavior
Link ID: 16632 - Posted: 04.10.2012