By NATALIE ANGIER I stopped eating pork about eight years ago, after a scientist happened to mention that the animal whose teeth most closely resemble our own is the pig. Unable to shake the image of a perky little pig flashing me a brilliant George Clooney smile, I decided it was easier to forgo the Christmas ham. A couple of years later, I gave up on all mammalian meat, period. I still eat fish and poultry, however and pour eggnog in my coffee. My dietary decisions are arbitrary and inconsistent, and when friends ask why I’m willing to try the duck but not the lamb, I don’t have a good answer. Food choices are often like that: difficult to articulate yet strongly held. And lately, debates over food choices have flared with particular vehemence. In his new book, “Eating Animals,” the novelist Jonathan Safran Foer describes his gradual transformation from omnivorous, oblivious slacker who “waffled among any number of diets” to “committed vegetarian.” Last month, Gary Steiner, a philosopher at Bucknell University, argued on the Op-Ed page of The New York Times that people should strive to be “strict ethical vegans” like himself, avoiding all products derived from animals, including wool and silk. Killing animals for human food and finery is nothing less than “outright murder,” he said, Isaac Bashevis Singer’s “eternal Treblinka.” But before we cede the entire moral penthouse to “committed vegetarians” and “strong ethical vegans,” we might consider that plants no more aspire to being stir-fried in a wok than a hog aspires to being peppercorn-studded in my Christmas clay pot. This is not meant as a trite argument or a chuckled aside. Plants are lively and seek to keep it that way. The more that scientists learn about the complexity of plants — their keen sensitivity to the environment, the speed with which they react to changes in the environment, and the extraordinary number of tricks that plants will rally to fight off attackers and solicit help from afar — the more impressed researchers become, and the less easily we can dismiss plants as so much fiberfill backdrop, passive sunlight collectors on which deer, antelope and vegans can conveniently graze. It’s time for a green revolution, a reseeding of our stubborn animal minds. Copyright 2009 The New York Times Company

Keyword: ADHD
Link ID: 13596 - Posted: 06.24.2010

By JASCHA HOFFMAN Psychologists have many ways to get inside our heads: they can give us questionnaires, track our eyes, time how long we take to respond to cues and measure the blood flow to our brains. But how close can these methods get to the texture of our inner lives? Russell T. Hurlburt, a psychologist at the University of Nevada, Las Vegas, has spent decades refining another way to study the mind. Dr. Hurlburt, a former aeronautical engineer, took up the study of psychology while playing trumpet at military funerals during the Vietnam War. Frustrated by the lack of attention to everyday experiences in the field of psychology, he arrived at the university in 1976 with an unconventional plan to investigate the mental lives of his subjects: ask them for descriptions. In “Describing Inner Experience? Proponent Meets Skeptic” (M.I.T. Press, 2007), Dr. Hurlburt, 64, presents the case of Melanie, a young woman who was fitted with a beeper that randomly prompted her to record everything in her awareness several times a day. In later interviews, she reconstructed these moments, often under rigorous cross-examination. The resulting mental freeze-frames are remarkably diverse. On the third day of Melanie’s experiment, as her boyfriend was asking her a question about insurance, she was trying to remember the word “periodontist.” On the fourth day, she was having a strong urge to go scuba diving. On the sixth day, she was picking flower petals from the sink while hearing echoes of the phrase “nice long time” in her head. Copyright 2009 The New York Times Company

Keyword: Attention
Link ID: 13595 - Posted: 06.24.2010

By Carolyn Butler Of all the relationships in my life, by far the most on-again, off-again has been with coffee: From that initial, tentative dalliance in college to a serious commitment during my first real reporting job to breaking up altogether when I got pregnant, only to fail miserably at quitting my daily latte the second time I was expecting. More recently the relationship has turned into full-blown obsession and, ironically, I often fall asleep at night dreaming of the delicious, satisfying cup of joe that awaits, come morning. While I love the mere ritual of drinking coffee, I have definitely come to rely on the caffeine to make me feel more alert, energetic and often just plain better, every single day. And yet because I don't like feeling dependent on anything, I occasionally wonder whether I should give it up for good, especially when I have a particularly jittery afternoon. Can something that tastes and feels this good not be bad for you? Rest assured: Not only has current research shown that moderate coffee consumption isn't likely to hurt you, it may actually have significant health benefits. "Coffee is generally associated with a less health-conscious lifestyle -- people who don't sleep much, drink coffee, smoke, drink alcohol," explains Rob van Dam, an assistant professor in the departments of nutrition and epidemiology at the Harvard School of Public Health. He points out that early studies failed to account for such issues and thus found a link between drinking coffee and such conditions as heart disease and cancer, a link that has contributed to java's lingering bad rep. "But as more studies have been conducted -- larger and better studies that controlled for healthy lifestyle issues -- the totality of efforts suggests that coffee is a good beverage choice." © 2009 The Washington Post Company

Keyword: Drug Abuse
Link ID: 13594 - Posted: 06.24.2010

By Steve Connor The ancient Egyptian pyramids, the Parthenon of Athens, Mona Lisa’s face and the head of George Clooney all have one thing in common. Their attractiveness is said to be based on the “golden ratio”, which is supposed to be the most aesthetically pleasing shape to the human eye. The golden ratio, also known as the divine proportion, produces a shape similar to a widescreen television or a cinema screen and describes a rectangle with a length roughly one and half times its width. The proportion is said to pervade art, architecture and nature. The modernist architect Le Corbusier used the golden ration for conferring harmonius proportions on everything from door handles to high-rise buildings, whereas the surrealist painter Salvadore Dali deliberately incorporated the rule into his painting Sacrament of the Last Supper. Now a theoretical mathematician has come up with what he believes is a possible reason why the human eye finds shapes in these proportions so particularly appealing. It comes down to how easy it is for the eye and the brain to scan such an image for important details, based on our evolutionary history. Professor Adrian Bejan of Duke University in North Carolina said that the golden ratio – which was first identified mathematically by Euclid in 3rd Century BC – just happens to be the most efficient shape for visual scanning, which could explain why it is behind so many works of art and architectural wonders. ©independent.co.uk

Keyword: Vision
Link ID: 13593 - Posted: 06.24.2010

By Tom Wilkinson Here is what can, and does, happen: The child gets out of bed and climbs out a window. Or gets out of bed, walks down a hallway, perhaps goes down a flight of stairs, navigates through a room or two, opens a door, walks out on the patio and, maybe, steps into the backyard swimming pool. The child is sleepwalking. According to some estimates, up to 17 percent of children have a sleepwalking experience between ages 4 and 12, peaking between ages 8 and 12. It is less prevalent among adults, affecting perhaps 4 percent of that population, although it can be more hazardous in that group. Sleepwalking has been part of the human experience probably since there has been a human experience -- it was mentioned in literature before Hippocrates -- but not much is known about it even now. How it happens, yes; why, not so much. It usually occurs during the first third of the night's sleep, and the characteristics are similar: Sleepwalkers often have open eyes, although they have a confused or glassy look. They might talk, although not clearly. Waking them will result in serious confusion, so experts say it is best not to. "Monitor it, but let it run its course, unless they are headed out the front door," said Jodi Mindell, a clinical psychologist and professor of psychiatry at St. Joseph's University in Philadelphia. It can help to guide them back to bed, where they will probably fall back asleep and have no memory of what transpired after they wake up. © 2009 The Washington Post Company

Keyword: Sleep; Development of the Brain
Link ID: 13592 - Posted: 06.24.2010

By BENEDICT CAREY SAN DIEGO — On a gray Wednesday afternoon here in early December, scientists huddled around what appeared to be a two-gallon carton of frozen yogurt, its exposed top swirling with dry-ice fumes. As the square container, fixed to a moving platform, inched toward a steel blade mounted level with its surface, the group held its collective breath. The blade peeled off the top layer, rolling it up in slow motion like a slice of pale prosciutto. “Almost there,” someone said. Off came another layer, another, and another. And then there it was: a pink spot at first, now a smudge, now growing with every slice like spilled rosé on a cream carpet — a human brain. Not just any brain, either, but the one that had belonged to Henry Molaison, known worldwide as H. M., an amnesiac who collaborated on hundreds of studies of memory and died last year at age 82. (Mr. Molaison agreed to donate his brain years ago, in consultation with a relative.) “You can see why everyone’s so nervous,” said Jacopo Annese, an assistant professor of radiology at the University of California, San Diego, as he delicately removed a slice with an artist’s paintbrush and placed it in a labeled tray of saline solution. “I feel like the world is watching over my shoulder.” And so it was: thousands logged on to view the procedure via live Webcast. The dissection marked a culmination, for one thing, of H. M.’s remarkable life, and of more than a year of preparation for just this moment, orchestrated by Suzanne Corkin, a memory researcher at the Massachusetts Institute of Technology who had worked with Mr. Molaison for the last five decades of his life. Copyright 2009 The New York Times Company

Keyword: Learning & Memory
Link ID: 13591 - Posted: 06.24.2010

By SEAN B. CARROLL Have you ever tried to think up the worst meal you could imagine? How about blue-ringed octopus, floral egg crab, basket shell snails and puffer fish. Sure, some people may think these are delicacies, and puffer fish is certainly treated as such in parts of Asia. But each dish has something more important in common: they are all deadly. Each of these animals is chock full of a powerful neurotoxin called tetrodotoxin. First isolated from the puffer fish, tetrodotoxin is among the most potent toxins known. It is 100 times as toxic by weight as potassium cyanide — two milligrams can kill an adult human — and it is not destroyed by cooking. Just half an ounce of the fish liver, known as fugu kimo in Japan and eaten by daring connoisseurs, can be lethal. When ingested, the toxin paralyzes nerves and muscles, which leads to respiratory failure and, in some cases each year, death. In 1975, the Kabuki actor Bando Mitsugoro VIII ordered four fugu kimo in a restaurant in Kyoto, claiming he could resist the poison. He was wrong. Tetrodotoxin is found in more than just marine creatures. It is present in high concentrations in the skin of certain newts in North America and Japan, and in several kinds of frogs in Central and South America and Bangladesh. The widespread occurrence of tetrodotoxin poses some intriguing riddles. First, how is it that such different animals, belonging to separate branches of the animal kingdom, have all come to possess the same deadly poison? And how is it that they are able to tolerate high levels of tetrodotoxin while others cannot? Copyright 2009 The New York Times Company

Keyword: Neurotoxins
Link ID: 13590 - Posted: 06.24.2010

By Carina Storrs Clinical depression can zap the pleasure out of an enjoyable meal or the thrill out of winning a prize, among other symptoms. Not surprisingly, a region of the brain involved in reward and motivation, called the nucleus accumbens, has been associated with depression. But up to now, it had been unclear what went wrong with this region in the brains of people suffering from clinical depression. A study in the December 21 issue of Proceedings of the National Academy of Sciences suggests that the problem is not merely a lack of activity in the nucleus accumbens (NAcc). This region still became activated after depressed participants looked at images associated with positive emotions. But, after looking at a series of both positive and negative images, NAcc activity eventually faded, suggesting that the reward center cannot sustain happiness in depressed people. To arrive at this finding, a research team led by Richard J. Davidson at the University of Wisconsin in Madison examined the levels of activation in the brains of 27 depressed and 19 healthy individuals via functional magnetic resonance imaging (fMRI). During 37-minute fMRI sessions, participants viewed an assortment of 72 positive images for 10 seconds each. To try to simulate the combination of daily "highs" and "lows" that are typically experienced, the researchers randomly intermixed those 72 images with 72 negative photos. The researchers asked the participants, four seconds into each viewing, either to enhance, suppress or sustain (aka, not change) their response to the image. For example, "in response to a stunning natural scene, a participant might imagine being in that scene or one of their own choosing" to enhance his or her reaction, the authors wrote. © 1996-2009 Scientific American Inc

Keyword: Depression; Drug Abuse
Link ID: 13589 - Posted: 06.24.2010

A now deceased NHL player had a brain condition linked to concussions — the first time a professional hockey player has been diagnosed with the disease. Reggie Fleming played 13 crushing seasons as a defenceman and forward during the 1960s and 1970s. Fleming was one of the National Hockey League's hardest hitters in the days before helmets. After Fleming died on July 11 at the age of 73, he became the first NHL player to have his brain examined by the Sports Legacy Institute, which is studying the long-term impact of concussions. "We discovered that Mr. Fleming was suffering from chronic traumatic encephalopathy when he died," said Chris Nowinski, co-director of the institute in Boston. "It's a progressive degenerative disease." Chronic traumatic encephalopathy CTE is characterized by a build-up of a toxic protein called tau — the same abnormal protein found in Alzheimer's disease. At first, the abnormal protein impairs normal brain function and eventually kills brain cells. The symptoms — memory impairment, emotional instability, erratic behaviour, depression and problems with impulse control and eventually dementia — are similar to Alzheimer's, which is why athletes may be misdiagnosed. But the proteins are distributed in different parts of the brain. © CBC 2009

Keyword: Brain Injury/Concussion; Alzheimers
Link ID: 13588 - Posted: 06.24.2010

By BENEDICT CAREY BUFFALO — Many 4-year-olds cannot count up to their own age when they arrive at preschool, and those at the Stanley M. Makowski Early Childhood Center are hardly prodigies. Most live in this city’s poorer districts and begin their academic life well behind the curve. But there they were on a recent Wednesday morning, three months into the school year, counting up to seven and higher, even doing some elementary addition and subtraction. At recess, one boy, Joshua, used a pointer to illustrate a math concept known as cardinality, by completing place settings on a whiteboard. “You just put one plate there, and one there, and one here,” he explained, stepping aside as two other students ambled by, one wearing a pair of clown pants as a headscarf. “That’s it. See?” For much of the last century, educators and many scientists believed that children could not learn math at all before the age of five, that their brains simply were not ready. But recent research has turned that assumption on its head — that, and a host of other conventional wisdom about geometry, reading, language and self-control in class. The findings, mostly from a branch of research called cognitive neuroscience, are helping to clarify when young brains are best able to grasp fundamental concepts. Copyright 2009 The New York Times Company

Keyword: Development of the Brain
Link ID: 13587 - Posted: 06.24.2010

Owen Flanagan, contributor I use the term "neuro-enthusiasta" for those given to excessive excitement over what brain science teaches. I have been warning, often in these pages, of its mostly amusing excesses and its tendency to produce newspaper headlines exclaiming that the brain "lights up" when people think and feel various things. Still, I did not foresee "neuro-" becoming a universal prefix. We have neuro-economics, neuro-theology, neuro-aesthetics and now, if Iain McGilchrist is to be believed, neuro-history. Plato, long before neuroscience, spoke of the struggle in the soul between Reason, Appetite and Temperament. This, neurologically speaking, has turned out to be the struggle between the brain's upper and lower regions. It's so last century. master_emissary_cover.jpgThe new story is the battle between the brain's hemispheres. "The left hemisphere is competitive, and its concern, its prime motivation is power," McGilchrist writes. The right, in contrast, is personal, empathetic and "primary", experiencing things in the lovey-dovey way we did in the old days when we sat around campfires singing Kumbaya. (Music, predictably, is so right brain). If the left hemisphere has its way, McGilchrist warns, the world will seem "relatively mechanical, an assemblage of more or less disconnected 'parts'... utilitarian in ethic; overconfident of its own take on reality, and lacking insight to its problems". © Copyright Reed Business Information Ltd.

Keyword: Laterality
Link ID: 13586 - Posted: 06.24.2010

By GEOFF DAVIES A Dalhousie University professor and an international team of researchers have discovered what makes us kick. Dr. Rob Brownstone, along with colleagues in New York and Scotland, discovered a group of nerve cells that are critical to regulating how much force muscles use when performing movements. "We knew that they had to be there," Dr. Brownstone said Friday, roughly a week after Neuron, the world’s leading neuroscience journal, published the findings. "But we couldn’t pinpoint them and we couldn’t say exactly what their role was in a behaving animal." The researchers located a group of cells that regulate how much force is used by motor neurons, nerve cells in the spinal cord that make muscles contract. The team used genetic techniques to locate and deactivate these new-found "modulatory" cells in mice. "When we did that, that’s when we found that the animals couldn’t contract their muscles in their legs as much as they needed to swim properly," Dr. Brownstone said. "This is a fundamental discovery about how the spinal cord works to produce movement." Further on down the line, this discovery could lead to breakthroughs in the treatment of Lou Gehrig’s disease, spinal cord injuries and other conditions, Dr. Brownstone said. © 2009 The Halifax Herald Limited

Keyword: ALS-Lou Gehrig's Disease
Link ID: 13585 - Posted: 06.24.2010

By Rob Stein About one out of every 110 U.S. children has been diagnosed with autism, according to a new federal estimate released Friday. An analysis of medical records from more than 307,000 8-year-olds in 2006 found that about 1 percent -- or one out of every 110 -- had been diagnosed with an "autism spectrum disorder," which includes a range of conditions including autism, the federal Centers for Disease Control and Prevention reported. The estimate is an increase in the prevalence of the condition from a previous CDC estimate of about 1 in 150 but is consistent with another estimate the agency released in October based on a telephone survey that concluded the condition was diagnosed in about 1 out of every 100 children. "The findings in this report are in line with other recently reported estimates," said Catherine Rice, a behavioral health scientist at the CDC's National Center on Birth Defects and Developmental Disabilities, whose report were published in the agency's Morbidity and Mortality Weekly Report. The reason for the increase remains unclear, she said. It could be due at least in part to more children being diagnosed with one of the conditions rather than an actual increase in how many children are developing the disability, she said. But "a true increase cannot be ruled out," she said, calling the estimate "concerning." Other factors that could be contributing to the increase include a rise in the average age that women are giving birth, and potentially air pollution, she said. But, Rice stressed "we have much to learn about the causes." © 2009 The Washington Post Company

Keyword: Autism
Link ID: 13584 - Posted: 06.24.2010

BY Prachi Patel No woman has yet won one of the three top mathematics awards–the Fields, the Abel, or the Wolf. It’s part of what’s often called the math gender gap, which in the United States starts early—at least twice as many boys as girls score in the 99th percentile on state-level math assessment tests. Five years ago, then Harvard president Lawrence Summers’s suggestion that women lack an ”intrinsic aptitude” for math and science drew a firestorm of protest, but he was drawing on a century-old hypothesis that males exhibit greater variability in many features, math included. By such reasoning, it is possible for girls to be as good as boys in math on average but to be less well represented in the upper (and lower) echelons. This, Summers said, is one reason there are fewer women in tenured science and engineering positions at top universities and research institutions. ”I would like nothing better than to be proved wrong,” he added. A recent study published in the Proceedings of the National Academy of Sciences might make him happy. In it, psychologists Janet Hyde and Janet Mertz, from the University of Wisconsin–Madison, used data from math aptitude tests to show that among top math performers, the gender gap doesn’t exist in some ethnic groups and in some countries. The researchers conclude that culture is the main reason more men excel at the highest math levels in most countries.

Keyword: Sexual Behavior; Learning & Memory
Link ID: 13583 - Posted: 06.24.2010

By Melissa Lee Phillips Sometimes a difference between the sexes is not based on sex at all. Women have a finer sense of touch than men do, but a new study shows that this is simply because their fingertips tend to be smaller. Neuroscientist Daniel Goldreich of McMaster University in Hamilton, Canada, and his colleagues first became curious about the sex difference while studying differences between blind and sighted people. They found that blind people are better than those with normal vision at distinguishing fine textures but that, within each group, women are better than men. The researchers thought that the discrepancy might be the result of brain differences between men and women, but they first wanted to see if something simpler could explain it. So they tested 50 women and 50 men on a simple task: Each person touched a small, grooved surface and tried to identify the orientation of the grooves. As the grooves got closer together, it became more difficult to determine their direction. As expected, women performed better at this task than men did, but when the scientists looked at the results by finger size, they found that the sex difference disappeared: On average, men and women with the same size fingertips perform at the same level, the team reports in the 16 December issue of The Journal of Neuroscience. (Finger size does not explain all individual variability, however; there are differences between people with the same size fingers, perhaps as a result of differences in the mechanical properties of skin or in how each person's brain processes the information.) © 2009 American Association for the Advancement of Science.

Keyword: Pain & Touch; Sexual Behavior
Link ID: 13582 - Posted: 06.24.2010

A gene associated with a rare form of progressive deafness in males has been identified by an international team of researchers funded by the National Institute on Deafness and Other Communication Disorders. The gene, PRPS1, appears to be crucial in inner ear development and maintenance. The findings are published in the December 17 early online issue of the American Journal of Human Genetics. The gene is associated with DFN2, a progressive form of deafness that primarily affects males. Boys with DFN2 begin to lose their hearing in both ears roughly between the ages of 5 and 15, and over the course of several decades will experience hearing loss that can range from severe to profound. Their mothers, who carry the defective PRPS1 gene, may experience hearing loss as well, but much later in life and in a milder form. Families with DFN2 have been identified in the United States, Great Britain, and China. The NIDCD-funded researchers led by Xue Zhong Liu, M.D., Ph.D., of the University of Miami Miller School of Medicine, discovered that the PRPS1 gene encodes the enzyme phosphoribosylpyrophosphate (PRPP) synthetase 1, which produces and regulates PRPP (phospho-ribosylpyrophosphate), and appears to play a key role in inner ear development and maintenance. The four mutations identified in the PRPS1 gene cause a decrease in the production of the PRPP synthetase 1 protein that results in defects in sensory cells (called hair cells) in the inner ear, and eventually leads to progressive deafness.

Keyword: Hearing; Genes & Behavior
Link ID: 13581 - Posted: 12.19.2009

by Carl Zimmer When Samuel Morse established the first commercial telegraph, in 1844, he dramatically changed our expectations about the pace of life. One of the first telegraph messages came from that year’s Democratic National Convention in Baltimore, where the delegates had picked Senator Silas Wright as their vice presidential nominee. The president of the convention telegraphed Wright in Washington, D.C., to see if he would accept. Wright immediately wired back: No. Incredulous that a message could fly almost instantly down a wire, the delegates adjourned and sent a flesh-and-blood committee by train to confirm Wright’s response—which was, of course, the same. From such beginnings came today’s high-speed, networked society. Less famously but no less significantly, the telegraph also transformed the way we think about the pace of our inner life. Morse’s invention debuted just as researchers were starting to make sense of the nervous system, and telegraph wires were an inspiring model of how nerves might work. After all, nerves and telegraph wires were both long strands, and they both used electricity to transmit signals. Scientists knew that telegraph signals did not travel instantaneously; in one experiment, it took a set of dots and dashes a quarter of a second to travel 900 miles down a telegraph wire. Perhaps, the early brain investigators considered, it took time for nerves to send signals too. And perhaps we could even quantify that time. The notion that the speed of thought could be measured, just like the density of a rock, was shocking. Yet that is exactly what scientists did. In 1850 German physiologist Hermann von Helmholtz attached wires to a frog’s leg muscle so that when the muscle contracted it broke a circuit. He found that it took a tenth of a second for a signal to travel down the nerve to the muscle.

Keyword: Miscellaneous
Link ID: 13580 - Posted: 06.24.2010

By Nathan Seppa It looks like nearsightedness is on the rise in the United States. Researchers tapped into a wide-ranging health survey to rate vision in the population in the early 1970s and roughly 30 years later. They compared eyesight information for more than 4,400 people tested in 1971 and 1972 with data from another set of 8,300 people tested from 1999 to 2004. This broad survey showed that 25 percent of those examined in the early 1970s were deemed to be nearsighted, compared with 42 percent examined three decades later, the researchers report in the December Archives of Ophthalmology. That’s an increase of 66 percent. Myopia severity also increased, with moderate nearsightedness doubling between the two time periods and severe cases, although uncommon, also rising sharply. Mild myopia cases increased slightly, from about 13 percent to 18 percent. This group included some people who did not need corrective lenses, says study coauthor Susan Vitale, an epidemiologist at the National Eye Institute in Bethesda, Md. When analyzing the more recent eye-exam data, the scientists used only diagnoses that were made with the same technology used in the 1970s — mainly standard eye tests and trial lenses. Including diagnoses made with more advanced technology that has become available only recently might have biased the comparison, Vitale says.. The cause of nearsightedness is poorly understood. Past research has linked added risk to both a genetic predisposition to nearsightedness and to excessive amounts of near work, the kind of tasks that require peering at written words or small objects. © Society for Science & the Public 2000 - 2009

Keyword: Vision
Link ID: 13579 - Posted: 06.24.2010

By Megan Talkington Many animals test their legs and totter forth only hours after they are born, but humans need a year before they take their first, hesitant steps. Is something fundamentally different going on in human babies? Maybe not. A new study shows that the time it takes for humans and all other mammals to start walking fits closely with the size of their brains. In past studies to develop a new animal model for the brain events that support motor development, neurophysiologist Martin Garwicz of Lund University in Sweden and his colleagues discovered that the schedules by which ferrets and rats acquire various motor skills, such as crawling and walking, are strikingly similar to each other; the progress simply happens faster for rats. That made them wonder how similar the timing of motor development might be among mammals in general. They compared the time between conception and walking in 24 species and looked at how well this duration correlated with a range of variables, including gestation time, adult body mass, and adult brain mass. As they report in this week's issue of PNAS, brain mass accounts for the vast majority (94%) of the variance in walking time between species. Species with larger brains, such as humans, tend to take longer to learn to walk. Strikingly, a model based on adult brain mass and walking time in the other 23 species almost perfectly predicts when humans begin to walk. "We've always considered humans the exception," Garwicz says, "But in fact, we start walking at exactly the time that would be expected from all other walking mammals." © 2009 American Association for the Advancement of Science

Keyword: Development of the Brain; Evolution
Link ID: 13578 - Posted: 06.24.2010

By Katherine Harmon In patients who have survived severe brain damage, judging the level of actual awareness has proved a difficult process. And the prognosis can sometimes mean the difference between life and death. New research suggests that some vegetative patients are capable of simple learning—a sign of consciousness in many who had failed other traditional cognitive tests. To determine whether patients are in a minimally conscious state (in which there is some evidence of perception or intentional movement) or have sunk into a vegetative state (in which neither exists), doctors have traditionally used a battery of tests and observations. Many of them require some subjective interpretation, such as deciding whether a patient’s movements are purposeful or just random. “We want to have an objective way of knowing whether the other person has consciousness or not,” says Mariano Sigman, who directs the Integrative Neuroscience Laboratory at the University of Buenos Aires. That desire stems in part from surprising neuroimaging work that showed that some vegetative patients, when asked to imagine performing physical tasks such as playing tennis, still had activity in premotor areas of their brains. In others, verbal cues sparked language sectors. A recent study found that about 40 percent of vegetative state diagnoses are incorrect. To explore possible tests of consciousness in patients, Sigman and his colleagues turned to classical conditioning: they sounded a tone and then sent a light puff of air to the patient’s eye. The air puff would cause a patient to blink or flinch the eye, but after repeated trials over half an hour, many patients would begin to anticipate the puff, blinking an eye after only hearing the tone. © 1996-2009 Scientific American Inc.

Keyword: Brain imaging
Link ID: 13577 - Posted: 06.24.2010