By JIM HOLT Most of us have no doubt that our fellow humans are conscious. We are also pretty sure that many animals have consciousness. Some, like the great ape species, even seem to possess self-consciousness, like us. Others, like dogs and cats and pigs, may lack a sense of self, but they certainly appear to experience inner states of pain and pleasure. About smaller creatures, like mosquitoes, we are not so sure; certainly we have few compunctions about killing them. As for plants, they obviously do not have minds, except in fairy tales. Nor do nonliving things like tables and rocks. All that is common sense. But common sense has not always proved to be such a good guide in understanding the world. And the part of our world that is most recalcitrant to our understanding at the moment is consciousness itself. How could the electrochemical processes in the lump of gray matter that is our brain give rise to — or, even more mysteriously, be — the dazzling technicolor play of consciousness, with its transports of joy, its stabs of anguish and its stretches of mild contentment alternating with boredom? This has been called “the most important problem in the biological sciences” and even “the last frontier of science.” It engrosses the intellectual energies of a worldwide community of brain scientists, psychologists, philosophers, physicists, computer scientists and even, from time to time, the Dalai Lama. Copyright 2007 The New York Times Company

Keyword: Miscellaneous
Link ID: 10982 - Posted: 06.24.2010

LONDON - Patients taking the Sanofi-Aventis anti-obesity drug Acomplia have well over double the risk of depression and anxiety, researchers said, adding to the bad news for a drug already linked to suicidal thoughts. Danish researchers reviewed four studies featuring 4,105 patients and found that people taking 20 milligrams per day of the drug were 2.5 times more likely to discontinue treatment due to depressive disorders and three times more likely to stop because of anxiety than those who received a placebo. The findings published in the Lancet journal follow a U.S. advisory panel decision in June that the drug should not be approved in the world’s largest drugs market because it may increase suicidal thoughts and depression. “Taken together with the recent U.S. Food and Drug Administration finding of increased risk of suicide during treatment with rimonabant, we recommend increased alertness by physicians to these potentially severe psychiatric reactions,” Arne Astrup of the University of Copenhagen and colleagues wrote. A study in the British Medical Journal on Friday also found that people taking anti-obesity drugs — including Acomplia — would only see “modest” weight loss with many remaining significantly obese or overweight. Copyright 2007 Reuters

Keyword: Obesity; Depression
Link ID: 10981 - Posted: 06.24.2010

By Larry Greenemeier The mere thought of being interrogated—by a parent, boss or significant other—is enough to make one's blood pressure rise and pulse and breathing rates race. But contrary to popular belief, these signs of anxiety are not reliable indicators of a person's honesty. Instead, researchers are looking into the brain to separate liars from truth tellers. The act of lying or suppressing the truth triggers activities in the brain that send blood to the prefrontal cortex (located just above the eye sockets), which controls several psychological processes, including the one that takes place when a person crafts a new rather than a known response to something. "Lying is an example of this type of executive response, because it involves withholding a truthful response," says Sean Spence, a professor of general adult psychiatry at the University of Sheffield in England. "When you know the answer to a question, the answer is automatic; but to avoid telling me the true answer requires something more." Spence and colleagues use functional Magnetic Resonance Imaging (fMRI) technology to determine whether someone is fibbing by tracing blood flow to certain areas of the brain, which indicates changes in neuronal activity at the synapses (gaps between the neurons). "If you're using fMRI, the scanner is detecting a change in the magnetic properties in the blood," he says. More specifically, hemoglobin molecules in red blood cells exhibit different magnetic properties depending on the amount of oxygen they contain. The most active brain regions use—and thereby contain—the most oxygen. © 1996-2007 Scientific American Inc.

Keyword: Emotions; Brain imaging
Link ID: 10980 - Posted: 06.24.2010

By Elizabeth Quill Your mother may have warned that you'd get a tummy ache if you scarfed down your food, but for one Australian snake, eating too fast could be deadly. The death adder dines on frogs, but some of them are poisonous. So the snake has learned patience: After striking a particular poisonous frog, it waits for its victim's toxin to degrade before it dines. The finding could help ecologists decipher how one species can outevolve another. The death adder stabs unsuspecting frogs with its fangs, injecting venom to kill its supper. The frogs have fought back, however, evolving various defenses--longer legs for bigger jumps or chemical substances that taste nasty and can kill. Ecologists Ben Phillips and Richard Shine, both of the University of Sydney, Australia, decided to study the snake's general feeding behavior. And when they did, they stumbled upon a strange twist in this evolutionary arms race. The team dropped frogs of various species in the snakes' glass pens and kept a video camera rolling to record the action as the snakes captured their prey. The snakes gobbled up nontoxic frogs right after injecting them with venom, but they took more time with two other species, the researchers report in the December issue of The American Naturalist. The snake waited 10 minutes before munching on the marbled frog, which produces a gluelike substance on its skin when irritated. © 2007 American Association for the Advancement of Science.

Keyword: Neurotoxins
Link ID: 10979 - Posted: 06.24.2010

Brian Vastag Scrutinizing the first days of development in abnormal embryonic stem cells, researchers have uncovered a basic mechanism underlying fragile X syndrome, the most common inherited cause of mental retardation in boys. "It could have important implications for treatment," says W. Ted Brown, cochair of the scientific committee of the National Fragile X Foundation, which helped fund the work. The research also highlights the value of embryonic stem cells for studying genetic diseases, says Yang Xu, a stem cell researcher at the University of California, San Diego. Fragile X syndrome is caused by a mutation in a gene called fmr1. By stopping the gene from making its protein, the mutation leads to learning disabilities, elongated facial features, speech and language difficulties, emotional problems, and other symptoms. In boys, who have only one copy of the X chromosome, a single bad fmr1 gene inherited from either parent induces the disorder. Fragile X syndrome more rarely affects girls, who have two X chromosomes. While researchers have long known that the fragile X mutation shuts down the gene, they were unsure how or at what developmental stage the disruption occurs. To study the shutdown, Nissim Benvenisty and his colleagues at the Hebrew University in Jerusalem created three embryonic stem cell lines carrying the mutation. ©2007 Science Service.

Keyword: Development of the Brain; Genes & Behavior
Link ID: 10978 - Posted: 06.24.2010

Roxanne Khamsi Contrary to what one might expect, the hormone melatonin – which helps regulate sleep cycles in humans and other animals – might actually disrupt memory formation, suggests a study in fish. Zebrafish exposed to melatonin take four times longer to recall a learned behaviour than usual, researchers report. The scientists do not know whether melatonin supplements have a negative impact on memory in people, but they believe more research into this hormone pathway is necessary. They add that a drug that blocks the influence of melatonin improved memory in the zebrafish when given at night. Zebrafish can retain information for days, according to Gregg Roman at the University of Houston, Texas, US. So Roman and his colleagues trained these fish to follow the path of a moving light source beamed through the side of the tank. Fish typically have an instinct to swim away from light – but in this experiment they received a mild shock when they did so. On average, it took the fish about 20 minutes to learn to stick close to the light. More importantly, when they were re-tested a day later, the zebrafish still remembered that they needed to keep close to the light. © Copyright Reed Business Information Ltd.

Keyword: Sleep; Learning & Memory
Link ID: 10977 - Posted: 06.24.2010

Michael Hopkin How are long term memories laid down while we sleep?PunchstockResearch on slumbering rats has shed light on how the brain processes its recent experiences into long-term memories. The experiment suggests that the brain creates such memories by 'playing back' the day's events several times faster than they actually happened. The study, carried out by neuroscientists at the University of Arizona in Tucson, boosts the theory that the brain region responsible for organizing long-term recall, known as the medial prefrontal cortex (mPFC), consolidates memory by playing back events during sleep. It also shows that the brain is quicker at re-running these events than it is at actually performing them. The researchers, led by Bruce McNaughton, trained two rats to run to a series of different locations within an area during 50-minute activity sessions. After the task, they allowed the rats to sleep for up to an hour. During the experiment, the researchers monitored the activity of selected brain cells in the rats' mPFC. While performing the task, the cells showed a characteristic pattern of activity. During the subsequent sleep, the same cells showed the same patterns, but at a higher speed. During sleep, the rats' brain replayed this characteristic activity at roughly six or seven times the original speed, McNaughton and his colleagues report in this week's Science. © 2007 Nature Publishing Group

Keyword: Sleep; Learning & Memory
Link ID: 10976 - Posted: 06.24.2010

Patients taking anti-obesity drugs lose only "modest" amounts of weight, and many remain significantly obese or overweight, research reveals. Fat pills like orlistat reduced weight by less than 5kg (11 pounds) or 5% of total body weight - which guidelines say makes their use unjustified. Experts said the Canadian work in the British Medical Journal shows pills are no substitute for healthy living. Eating less and exercising more is essential, they said. Over a billion people worldwide are overweight or obese, making the anti-obesity drug market big business. An estimated $1.2 billion was spent on anti-obesity drugs worldwide in 2005. The latest work by Professor Raj Padwal and his team at the University of Alberta suggests in many cases these pills achieve little in terms of weight loss. They reviewed the evidence from thirty placebo-controlled trials, involving nearly 20,000 people, where adults took one of three anti-obesity drugs - orlistat, sibutramine or rimonabant - for a year or longer. The National Institute for health and Clinical Excellence recommends stopping the use of anti-obesity drugs if 5% of total body weight is not lost after three months. All of the volunteers in the trials were deemed obese, and weighed an average of 100kg (15.7 stone). Orlistat reduced weight by 2.9kg, sibutramine by 4.2kg and rimonabant by 4.7kg. Patients taking the weight loss pills were significantly more likely to achieve 5%-10% weight loss, compared to those who took a dummy drug, however. But is was unclear whether the weight loss achieved was enough to have big health and survival benefits. (C)BBC

Keyword: Obesity
Link ID: 10975 - Posted: 11.17.2007

By Matt Kaplan Royalty has its privileges, even in the insect world. Queen honey bees can choose the sex of their offspring, a new study shows. Like a sharp stinger, that finding pokes a hole in the notion that queens are merely mindless egg layers and that worker bees have the final say on whether the queen lays eggs that give rise to males or females. Every young queen goes on a mating flight and then stores the sperm she collects from multiple matings for the rest of her life, using it up bit by bit as she lays eggs. Males, called drones, emerge from unfertilized eggs, and females emerge from fertilized ones and become the workers. So if the queen adds sperm to an egg, it will produce a female; if she withholds sperm, the egg will produce a male. That would appear to give the queen control over the sex of her offspring. However, the dogma among entomologists is that workers control the type of eggs the queen lays. The workers build the cavities, known as cells, in which the queen will lay her eggs. A queen will lay an unfertilized egg in a particular cell only if the cell is big enough to accommodate a male larva, which is bigger than a female one. So by controlling how many cells they build of each size, the workers can limit how many male offspring the queen produces. Despite these constraints, the queen can still tip the gender balance of the hive, report Katie Wharton and a team of entomologists at Michigan State University in East Lansing. To prove it, they confined queens inside their hives in specially built cages. © 2007 American Association for the Advancement of Science.

Keyword: Sexual Behavior
Link ID: 10974 - Posted: 06.24.2010

Eric Hand How, exactly, does a bat shoot sonar beams out of its nose? Rolf Müller, a computational physicist at Shandong University in Jinan, China, has combed the caves of Southeast Asia to find out. “We are looking at different species to understand their physical tricks,” says Müller, who models the way that bat noses act like antenna, and how their ears work as dishes to collect sound. The work matters not just to biophysicists who want to understand how animals evolve complex systems, but also to roboticists trying to find new ways of navigating in situations in which light sensors don’t work so well, including at night or underwater. Few biophysical studies of bat noses have been done. One researcher bent back a bat’s noseleaf — the complex structure surrounding its nostrils — to see what would happen; another scientist smeared the delicate structures with petroleum jelly. Both procedures messed up the bats’ navigation. To get a better picture of what’s going on in a bat nose, Müller took X-ray scans of the face of a Rufous horseshoe bat (Rhinolophus rouxii ), compiling scans to build a three-dimensional computer model of the nose cavities. He then shot sound waves of differing frequencies through the modelled nose to see where they resonated, and how they were emitted from the noseleaf. Zhuang, Q. & Müller, R. , Phys. Rev. E 76, 051902 (2007). © 2007 Nature Publishing Group –

Keyword: Hearing
Link ID: 10973 - Posted: 06.24.2010

CBC News New research suggests that the formation of memory may be the result of pairing stimulation in a certain region of the brain with a sensory experience. A team of scientists from the University of California found that by activating the nucleus basalis — a neuron-filled part of the brain believed to modulate the brain's interpretation of sensory information — while playing a particular sound, they could alter the neuronal response to the tones in rats. They said this finding may be a key to understanding memory formation. Previous research has shown that the sensory cortex, the part of the brain responsible for receiving and interpreting information from the senses, has a plastic quality, which allows it to reorganize itself in response to important experiences. "In this way, cortical representations of the sensory environment can incorporate new information about the world, depending on the relevance of value of particular stimuli," the study explained. For their experiment, the researchers played tones of different frequencies in a "pseudo-random" sequence to adult rats. The cortical neurons reacted equally to all the tones. Then, they played a tone repetitively for two to five minutes and electrically stimulated the nucleus basalis. © CBC 2007

Keyword: Learning & Memory
Link ID: 10972 - Posted: 06.24.2010

If you ever had a set of Micronauts — toy robots with removable body parts — you probably had fun swapping their heads, imagining how it would affect their behavior. Scientists supported by the National Institutes of Health have been performing similar experiments on ion channels — pores in our nerve cells — to sort out the channels' key functional parts. In the November 15 issue of Nature, one group of researchers shows that a part of ion channels called the paddle is uniquely transplantable between different channels. Writing in the same issue, another group exploited this property to probe the three-dimensional structure of ion channels on an atomic scale. "The effects of many toxins and therapeutic drugs, as well as some diseases, can be wholly explained by changes in ion channel function," says Story Landis, Ph.D., director of the National Institute of Neurological Disorders and Stroke (NINDS), part of the NIH. "We also know that ion channels are at least a contributing player in epilepsy, chronic pain, Parkinson's disease and other disorders. As we learn more about how channels work, we're able to pursue more approaches to treatment." Ion channels are proteins that control the flow of electrically charged salt particles (ions) across the nerve cell membrane. It's the opening and closing of these channels that enables nerve cells to fire off bursts of electrical activity. A built-in voltmeter, called a voltage sensor, pops the channel open when the nerve cell is ready to fire. The papers in Nature hone in on a part of the voltage sensor called the paddle, named for its shape.

Keyword: Miscellaneous
Link ID: 10971 - Posted: 06.24.2010

Mason Inman It takes only a tiny magnetic field to see clear through a person's head, a new study shows. A method called ultra-low field magnetic resonance imaging (MRI) has captured its first, blurry shots of a human brain, revealing activity as well as structure. MRI scanners image the human body by detecting how hydrogen atoms respond to magnetic fields. They typically require fields of a few tesla – about 10,000 to 100,000 times stronger than the Earth's magnetic field. The powerful magnets necessary make scanners pricey and also dangerous for people with metal implants. The new device hits a sample with a 30 millitesla magnetic field, about 100 times weaker than is normally used in MRI. The device then uses a 46 microtesla magnetic field – about the same as the Earth's magnetic field – to capture images of the sample. The first target for the device was the head of lead researcher Vadim Zotev of Los Alamos National Laboratory in New Mexico, US (see image, top right). Larger objects"The cost of MRI can be reduced dramatically," Zotev told New Scientist. The new set-up uses several ultra-sensitive sensors called superconducting quantum interference devices (SQUIDs), which have to be kept at very low temperatures. "The most expensive part of our system is the liquid helium cryostat, which costs about $20,000," Zotev adds. © Copyright Reed Business Information Ltd

Keyword: Brain imaging
Link ID: 10970 - Posted: 06.24.2010

Kerri Smith SAN DIEGO Recordings from electrodes in the human brain may offer the first objective way to measure the intensity of pain. Researchers say that they have found a neural signal that correlates with the amount of pain that an individual feels. The signal could be used to refine pain-relief techniques that involve stimulating the brain with electricity, they say. Single cells have previously been identified in the human brain that are active in pain, but their response is binary, signalling either pain or no pain. Now, Morten Kringelbach of the psychiatry department at the University of Oxford, UK, and his colleagues have identified low-frequency brain waves that emanate from two regions buried deep within the brain when a patient is in pain. The more pain that is experienced, the longer the waves last. Kringelbach's team recorded activity from two electrodes positioned in the thalamus and the periaqueductal grey area of 12 awake people who had been undergoing deep-brain stimulation (DBS) for chronic pain. During the recording, the team touched either a painful or pain-free area of the patients' bodies and had patients rate their pain every minute. The duration of the waves — dubbed “pain spindles” — correlated with how intensely the patients felt their pain. “It is an objective measure that correlates with a subjective measure,” says Kringelbach, who presented the findings at the Society for Neuroscience meeting in San Diego, California, last week. © 2007 Nature Publishing Group

Keyword: Pain & Touch
Link ID: 10969 - Posted: 06.24.2010

Roxanne Khamsi Monkeys invest less energy in a task if they see other monkeys receiving better rewards for the same effort, researchers report. They say that their experiment provides new evidence that non-human primates can feel envy. The findings could also help explain why humans have such a keen sense of fairness, according to experts. Previous studies have found that monkeys put less effort into a task when they see cage-mates receiving tastier treats for completing the same task. But scientists have not felt confident in saying why the poorly rewarded animals slack off. Some people have suggested the primates that refuse to repeat the task are simply greedy and therefore only willing to work for a bigger reward. Alternately, it has been proposed that the monkeys stop performing the task because they have received large rewards in the past and feel frustrated by the measly amounts offered in later trials. To understand the monkeys' reluctance to participate in the task, Frans de Waal at the Yerkes National Primate Research Center in Atlanta, Georgia, US, and colleagues decided to try several variations on this experiment. They trained 13 capuchin monkeys (Cebus apella) to retrieve a small rock and place it in the experimenter's hands. In exchange for completing this task, the animals received a reward. © Copyright Reed Business Information Ltd.

Keyword: Emotions; Attention
Link ID: 10968 - Posted: 06.24.2010

By Sandra G. Boodman For six years, Lee J. Nelson searched in vain for the cause of the unrelenting headache centered like a bull's-eye above the bridge of his nose. He consulted nearly 60 doctors, none of whom could find a physical explanation for his pain. He took 100 different medications, but even powerful narcotics brought no more than temporary relief. One doctor who considered his headache a symptom of severe depression suggested electroshock; a specialist at Johns Hopkins proposed last-ditch brain surgery reserved for intractable psychiatric problems. So the day in 2003 that the Northern Virginia consultant found the answer to his baffling and rare medical problem in a 40-year-old article in the National Library of Medicine, he was overcome. "It described patients just like me," Nelson recalled. "I started crying." For Nelson, now 55, and his wife, Neta, an executive at a small pharmaceutical company in Herndon, the discovery of that article in a British medical journal proved to be life-changing. It not only provided a diagnosis for a problem that had stumped dozens of specialists, but also described a surgical treatment for the malady that at times had driven Nelson to talk about suicide and his wife of nearly 30 years to contemplate divorce. © 2007 The Washington Post Company

Keyword: Pain & Touch
Link ID: 10967 - Posted: 06.24.2010

By BENEDICT CAREY Educators and psychologists have long feared that children entering school with behavior problems were doomed to fall behind in the upper grades. But two new studies suggest that those fears are exaggerated. One concluded that kindergartners who are identified as troubled do as well academically as their peers in elementary school. The other found that children with attention deficit disorders suffer primarily from a delay in brain development, not from a deficit or flaw. Experts say the findings of the two studies, being published today in separate journals, could change the way scientists, teachers and parents understand and manage children who are disruptive or emotionally withdrawn in the early years of school. The studies might even prompt a reassessment of the possible causes of disruptive behavior in some children. “I think these may become landmark findings, forcing us to ask whether these acting-out kinds of problems are secondary to the inappropriate maturity expectations that some educators place on young children as soon as they enter classrooms,” said Sharon Landesman Ramey, director of the Georgetown University Center on Health and Education, who was not connected with either study. In one study, an international team of researchers analyzed measures of social and intellectual development from over 16,000 children and found that disruptive or antisocial behaviors in kindergarten did not correlate with academic results at the end of elementary school. Copyright 2007 The New York Times Company

Keyword: ADHD; Aggression
Link ID: 10966 - Posted: 06.24.2010

By CARL ZIMMER If you have ever observed ants marching in and out of a nest, you might have been reminded of a highway buzzing with traffic. To Iain D. Couzin, such a comparison is a cruel insult — to the ants. Americans spend a 3.7 billion hours a year in congested traffic. But you will never see ants stuck in gridlock. Army ants, which Dr. Couzin has spent much time observing in Panama, are particularly good at moving in swarms. If they have to travel over a depression in the ground, they erect bridges so that they can proceed as quickly as possible. “They build the bridges with their living bodies,” said Dr. Couzin, a mathematical biologist at Princeton University and the University of Oxford. “They build them up if they’re required, and they dissolve if they’re not being used.” The reason may be that the ants have had a lot more time to adapt to living in big groups. “We haven’t evolved in the societies we currently live in,” Dr. Couzin said. By studying army ants — as well as birds, fish, locusts and other swarming animals — Dr. Couzin and his colleagues are starting to discover simple rules that allow swarms to work so well. Those rules allow thousands of relatively simple animals to form a collective brain able to make decisions and move like a single organism. Deciphering those rules is a big challenge, however, because the behavior of swarms emerges unpredictably from the actions of thousands or millions of individuals. “No matter how much you look at an individual army ant,” Dr. Couzin said, “you will never get a sense that when you put 1.5 million of them together, they form these bridges and columns. You just cannot know that.” Copyright 2007 The New York Times Company

Keyword: Intelligence
Link ID: 10965 - Posted: 06.24.2010

By PAUL VanDeCARR I grind my teeth at night. Have for years. It’s my secret shame. But now I have the comfort of knowing that at least 8 to 10 percent of the adult population shares my malady. It’s called sleep bruxism, and it refers to the grinding or clenching of teeth. There’s a waking version, too — an unconscious clenching of the teeth, most often owing to stress — but the origins are different and the effects are seldom anywhere near as bad as during sleep, when certain of the body’s protective mechanisms are turned off. Left untreated, it can cause damage to the teeth and surrounding tissue, headaches and jaw pain. Bruxism may be at least as old as the Bible, which describes hell as a state where there is “gnashing of teeth.” I might fairly be accused of hyperbole if I reversed the equation and declared that bruxism can turn sleep into a kind of hell. But you get the idea. It’s a real nuisance. “It’s much like having a large football player standing on the tooth,” says Dr. Noshir Mehta, chairman of general dentistry at Tufts University School of Dental Medicine and director of its Craniofacial Pain Center. Copyright 2007 The New York Times Company

Keyword: Sleep
Link ID: 10964 - Posted: 06.24.2010

Jennifer Viegas Nut-Chomper -- A toothy, nut-chomping large ape from Kenya may represent a new species that was, or was very close to being, the last common ancestor to gorillas, chimpanzees and humans, according to a new study that outlines the recently discovered, 10 million-year-old species. Called Nakalipithecus nakayamai, the ape lived within a critical window of evolutionary time. Lead author Yutaka Kunimatsu explained to Discovery News that molecular studies of living apes indicate gorillas, chimps and humans diverged from each other in Africa during the Late Miocene 11-5 million years ago. "Nakalipithecus is derived from Africa and from an appropriate age," Kunimatsu, a Kyoto University primate researcher, said. Fossil remains of the species, excavated by the researchers in the Samburu Hills of northern Kenya, include a jawbone and 11 telltale teeth. "Based on the dentition, (the ape) was approximately the size of female gorillas to orangutans and it had thick enamel and low, voluminous cusps on its cheek teeth," Kunimatsu explained, "so it is likely that this ape ate a considerable amount of hard objects, possibly nuts or seeds." © 2007 Discovery Communications

Keyword: Evolution
Link ID: 10963 - Posted: 06.24.2010