Chapter 14. Attention and Consciousness
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By Tara Haelle Identification and treatment issues surrounding attention deficit hyperactivity disorder (ADHD) are challenging enough. Now research is shedding light on long-term outcomes for people with ADHD. A recent study in Pediatrics reports that men who had ADHD in childhood are twice as likely to be obese in middle age, even if they no longer exhibit symptoms of ADHD. ADHD is a mental disorder characterized by hyperactivity, impulsivity, inattention and inability to focus. It affects approximately 6.8 percent of U.S. children ages 3 to 17 in any given year, according to a recent report by the CDC. Medications used to treat ADHD, such as Ritalin (methylphenidate) or Adderall (dextroamphetamine and amphetamine), are stimulants that can suppress appetite, however, a couple recent retrospective studies have pointed to a possible increased risk for obesity among adults diagnosed with ADHD as children. The new 33-year prospective study started with 207 healthy middle-class white boys from New York City between 6 and 12 years old, who had been diagnosed with ADHD. When the cohort reached an average age of 18, another 178 healthy boys without ADHD were recruited for comparison. At the most recent follow-up when the participants were an average age of 41, a total of 222 men remained in the study. A troubling pattern emerged: A comparison of the men’s self-reported height and weight revealed that twice as many men with childhood ADHD were obese than those without childhood ADHD. The average body mass index (BMI) of the men with childhood ADHD was 30.1 and 41.4 percent were obese, whereas those without the condition as kids reported an average BMI of 27.6 and an obesity rate of 21.6 percent. The association held even after the researchers controlled for socioeconomic status, depression, anxiety and substance abuse disorders. © 2013 Scientific American
By Bruce Bower In its idealized form, science resembles a championship boxing match. Theories square off, each vying for the gold belt engraved with “Truth.” Under the stern eyes of a host of referees, one theory triumphs by best explaining available evidence — at least until the next bout. But in the real world, science sometimes works more like a fashion show. Researchers clothe plausible explanations of experimental findings in glittery statistical suits and gowns. These gussied-up hypotheses charm journal editors and attract media coverage with carefully orchestrated runway struts, never having to battle competitors. Then there’s psychology. Even more than other social scientists — and certainly more than physical scientists — psychologists tend to overlook or dismiss hypotheses that might topple their own, says Klaus Fiedler of the University of Heidelberg in Germany. They explain experimental findings with ambiguous terms that make no testable predictions at all; they build careers on theories that have never bested a competitor in a fair scientific fight. In many cases, no one knows or bothers to check how much common ground one theory shares with others that address the same topic. Problems like these, Fiedler and his colleagues contended last November in Perspectives in Psychological Science, afflict sets of related theories about such psychological phenomena as memory and decision making. In the end, that affects how well these phenomena are understood. © Society for Science & the Public 2000 - 2013
Link ID: 18170 - Posted: 05.20.2013
by Emily Underwood If you are one of the 20% of healthy adults who struggle with basic arithmetic, simple tasks like splitting the dinner bill can be excruciating. Now, a new study suggests that a gentle, painless electrical current applied to the brain can boost math performance for up to 6 months. Researchers don't fully understand how it works, however, and there could be side effects. The idea of using electrical current to alter brain activity is nothing new—electroshock therapy, which induces seizures for therapeutic effect, is probably the best known and most dramatic example. In recent years, however, a slew of studies has shown that much milder electrical stimulation applied to targeted regions of the brain can dramatically accelerate learning in a wide range of tasks, from marksmanship to speech rehabilitation after stroke. In 2010, cognitive neuroscientist Roi Cohen Kadosh of the University of Oxford in the United Kingdom showed that, when combined with training, electrical brain stimulation can make people better at very basic numerical tasks, such as judging which of two quantities is larger. However, it wasn't clear how those basic numerical skills would translate to real-world math ability. © 2010 American Association for the Advancement of Science
Keyword: Learning & Memory
Link ID: 18168 - Posted: 05.18.2013
Linda Carroll TODAY contributor We all get lost or disoriented once in a while, but for Sharon Roseman, being lost is a way of life. A little quirk in her brain makes it impossible to recognize landmarks and find her way around neighborhoods that should have become familiar long ago. “I can literally see my house out the car window, but I have no clue that it’s my house,” Roseman told NBC’s Kristen Dahlgren. Roseman, 64, suffers from developmental topographical disorientation, or DTD, a disorder that had flown under brain researchers’ radar until very recently. DTD was first described as a single case study in a paper published online in 2008 in the journal Neuropsychologia. At the time, it was thought to be extremely rare, says the study’s lead author, Giuseppe Iaria, professor of cognitive neuroscience at the University of Calgary. But since then, Iaria has discovered nearly 1,000 other people with DTD and he thinks there may be a lot more. He currently estimates that about 2 percent of the population may be constantly coping with orientation and navigation problems caused by the disorder. DTD is a profound and disabling deficit. Nothing, not even the layout of a house you’ve lived in for decades, ever becomes familiar. And for Roseman that has made life very trying. When her kids would cry in the night, she would struggle to find her way to them.
Link ID: 18155 - Posted: 05.14.2013
by Helen Thomson "I've been in a crowded elevator with mirrors all around, and a woman will move and I'll go to get out the way and then realise: 'oh that woman is me'." Heather Sellers has prosopagnosia, more commonly known as face blindness. "I can't remember any image of the human face. It's simply not special to me," she says. "I don't process them like I do a car or a dog. It's not a visual problem, it's a perception problem." Heather knew from a young age that something was different about the way she navigated her world, but her condition wasn't diagnosed until she was in her 30s. "I always knew something was wrong – it was impossible for me to trust my perceptions of the world. I was diagnosed as anxious. My parents thought I was crazy." The condition is estimated to affect around 2.5 per cent of the population, and it's common for those who have it not to realise that anything is wrong. "In many ways it's a subtle disorder," says Heather. "It's easy for your brain to compensate because there are so many other things you can use to identify a person: hair colour, gait or certain clothes. But meet that person out of context and it's socially devastating." As a child, she was once separated from her mum at a grocery store. Store staff reunited the pair, but it was confusing for Heather, since she didn't initially recognise her mother. "But I didn't know that I wasn't recognising her." © Copyright Reed Business Information Ltd
Link ID: 18119 - Posted: 05.04.2013
by Lizzie Wade If you were a rat living in a completely virtual world like in the movie The Matrix, could you tell? Maybe not, but scientists studying your brain might be able to. Today, researchers report that certain cells in rat brains work differently when the animals are in virtual reality than when they are in the real world. The neurons in question are known as place cells, which fire in response to specific physical locations in the outside world and reside in the hippocampus, the part of the brain responsible for spatial navigation and memory. As you walk out of your house every day, the same place cell fires each time you reach the shrub that's two steps away from your door. It fires again when you reach the same place on your way back home, even though you are traveling in the opposite direction. Scientists have long suspected that these place cells help the brain generate a map of the world around us. But how do the place cells know when to fire in the first place? Previous research showed that the cells rely on three different kinds of information. First, they analyze "visual cues," or what you see when you look around. Then, there are what researchers call "self-motion cues." These cues come from how your body moves in space and are the reason you can still find your way around a room with the lights out. The final type of information is the "proximal cues," which encompass everything else about the environment you're in. The smell of a bakery on your way to work, the sounds of a street jammed with traffic, and the springy texture of grass in a park are all proximal cues. © 2010 American Association for the Advancement of Science.
By Scott O. Lilienfeld and Hal Arkowitz A German children's book from 1845 by Heinrich Hoffman featured “Fidgety Philip,” a boy who was so restless he would writhe and tilt wildly in his chair at the dinner table. Once, using the tablecloth as an anchor, he dragged all the dishes onto the floor. Yet it was not until 1902 that a British pediatrician, George Frederic Still, described what we now recognize as attention-deficit hyperactivity disorder (ADHD). Since Still's day, the disorder has gone by a host of names, including organic drivenness, hyperkinetic syndrome, attention-deficit disorder and now ADHD. Despite this lengthy history, the diagnosis and treatment of ADHD in today's children could hardly be more controversial. On his television show in 2004, Phil McGraw (“Dr. Phil”) opined that ADHD is “so overdiagnosed,” and a survey in 2005 by psychologists Jill Norvilitis of the University at Buffalo, S.U.N.Y., and Ping Fang of Capitol Normal University in Beijing revealed that in the U.S., 82 percent of teachers and 68 percent of undergraduates agreed that “ADHD is overdiagnosed today.” According to many critics, such overdiagnosis raises the specter of medicalizing largely normal behavior and relying too heavily on pills rather than skills—such as teaching children better ways of coping with stress. Yet although data point to at least some overdiagnosis, at least in boys, the extent of this problem is unclear. In fact, the evidence, with notable exceptions, appears to be stronger for the undertreatment than overtreatment of ADHD. © 2013 Scientific American,
Alison Abbott Thinking about a professor just before you take an intelligence test makes you perform better than if you think about football hooligans. Or does it? An influential theory that certain behaviour can be modified by unconscious cues is under serious attack. A paper published in PLoS ONE last week1 reports that nine different experiments failed to replicate this example of ‘intelligence priming’, first described in 1998 (ref. 2) by Ap Dijksterhuis, a social psychologist at Radboud University Nijmegen in the Netherlands, and now included in textbooks. David Shanks, a cognitive psychologist at University College London, UK, and first author of the paper in PLoS ONE, is among sceptical scientists calling for Dijksterhuis to design a detailed experimental protocol to be carried out indifferent laboratories to pin down the effect. Dijksterhuis has rejected the request, saying that he “stands by the general effect” and blames the failure to replicate on “poor experiments”. An acrimonious e-mail debate on the subject has been dividing psychologists, who are already jittery about other recent exposures of irreproducible results (see Nature 485, 298–300; 2012). “It’s about more than just replicating results from one paper,” says Shanks, who circulated a draft of his study in October; the failed replications call into question the underpinnings of ‘unconscious-thought theory’. © 2013 Nature Publishing Group
By ALAN SCHWARZ FRESNO, Calif. — Lisa Beach endured two months of testing and paperwork before the student health office at her college approved a diagnosis of attention deficit hyperactivity disorder. Then, to get a prescription for Vyvanse, a standard treatment for A.D.H.D., she had to sign a formal contract — promising to submit to drug testing, to see a mental health professional every month and to not share the pills. “As much as it stunk, it’s nice to know, ‘O.K., this is legit,' ” said Ms. Beach, a senior at California State University, Fresno. The rigorous process, she added, has deterred some peers from using the student health office to obtain A.D.H.D. medications, stimulants long abused on college campuses. “I tell them it takes a couple months,” Ms. Beach said, “and they’re like, ‘Oh, never mind.’ ” Fresno State is one of dozens of colleges tightening the rules on the diagnosis of A.D.H.D. and the subsequent prescription of amphetamine-based medications like Vyvanse and Adderall. Some schools are reconsidering how their student health offices handle A.D.H.D., and even if they should at all. Various studies have estimated that as many as 35 percent of college students illicitly take these stimulants to provide jolts of focus and drive during finals and other periods of heavy stress. Many do not know that it is a federal crime to possess the pills without a prescription and that abuse can lead to anxiety, depression and, occasionally, psychosis. Although few experts dispute that stimulant medications can be safe and successful treatments for many people with a proper A.D.H.D. diagnosis, the growing concern about overuse has led some universities, as one student health director put it, “to get out of the A.D.H.D. business.” © 2013 The New York Times Company
By JAMES GORMAN TRONDHEIM, Norway — In 1988, two determined psychology students sat in the office of an internationally renowned neuroscientist in Oslo and explained to him why they had to study with him. Unfortunately, the researcher, Per Oskar Andersen, was hesitant, May-Britt Moser said as she and her husband, Edvard I. Moser, now themselves internationally recognized neuroscientists, recalled the conversation recently. He was researching physiology and they were interested in the intersection of behavior and physiology. But, she said, they wouldn’t take no for an answer. “We sat there for hours. He really couldn’t get us out of his office,” Dr. May-Britt Moser said. “Both of us come from nonacademic families and nonacademic places,” Edvard said. “The places where we grew up, there was no one with any university education, no one to ask. There was no recipe on how to do these things.” “And how to act politely,” May-Britt interjected. “It was just a way to get to the point where we wanted to be. But seen now, when I know the way people normally do it,” he said, smiling at the memory of his younger self, “I’m quite impressed.” So, apparently, was Dr. Andersen. In the end, he yielded to the Mosers’ combination of furious curiosity and unwavering determination and took them on as graduate students. They have impressed more than a few people since. In 2005, they and their colleagues reported the discovery of cells in rats’ brains that function as a kind of built-in navigation system that is at the very heart of how animals know where they are, where they are going and where they have been. They called them grid cells. © 2013 The New York Times Company
Link ID: 18099 - Posted: 04.30.2013
By Ferris Jabr On any given day, millions of conversations reverberate through New York City. Poke your head out a window overlooking a busy street and you will hear them: all those overlapping sentences, only half-intelligible, forming a dense acoustic mesh through which escapes an exclamation, a buoyant laugh, a child’s shrill cry now and then. Every spoken consonant and vowel begins as an internal impulse. Electrical signals crackle along branching neurons in brain regions specialized for language and movement; further pulses spread across facial nerves, surge toward the throat and chest and zip down the spine. The diaphragm contracts—pulling air into the lungs—and relaxes, pushing air into that birdcage of calcium and cartilage—the larynx—within which wings of tissue draw near one another and hum. As this vibrating air enters the mouth, the tongue guides its flow and the lips give each breath a final shape and sound. Liberated syllables travel between one person and another in waves of colliding air molecules. All these conversations are matched in number and complexity by much more elusive discourses. The human brain loves soliloquy. Even when speaking with others—and especially when alone—we continually talk to ourselves in our heads. Such speech does not require the bellows in the chest, quivering flaps of tissue in the throat or a nimble tongue; it does not need to disturb even one hair cell in our ears, nor a single particle of air. We can speak to ourselves without making a sound. Stick your head out that same window above the crowded street and you will hear nothing of what people are saying to themselves privately. All that inner dialogue remains submerged beneath the ocean of human speech, like a novel written in invisible ink behind the text of another book. © 2013 Scientific American,
Link ID: 18095 - Posted: 04.30.2013
By Meghan Rosen A child who is good at learning math may literally have a head for numbers. Kids’ brain structures and wiring are associated with how much their math skills improve after tutoring, researchers report April 29 in the Proceedings of the National Academy of Sciences. Certain measures of brain anatomy were even better at judging learning potential than traditional measures of ability such as IQ and standardized test results, says study author Kaustubh Supekar of Stanford University. These signatures include the size of the hippocampus — a string bean–shaped structure involved in making memories — and how connected the area was with other parts of the brain. The findings suggest that kids struggling with their math homework aren’t necessarily slacking off, says cognitive scientist David Geary of the University of Missouri in Columbia. “They just may not have as much brain region devoted to memory formation as other kids.” The study could give scientists clues about where to look for sources of learning disabilities, he says. Scientists have spent years studying brain regions related to math performance in adults, but how kids learn is still “a huge question,” says Supekar. He and colleagues tested IQ and math and reading performance in 24 8- and 9-year-olds, then scanned their brains in an MRI machine. The scans measured the sizes of different brain structures and the connections among them. “It’s like creating a circuit diagram,” says study leader Vinod Menon, also of Stanford. © Society for Science & the Public 2000 - 2013
Keyword: Learning & Memory
Link ID: 18094 - Posted: 04.30.2013
By YUDHIJIT BHATTACHARJEE One summer night in 2011, a tall, 40-something professor named Diederik Stapel stepped out of his elegant brick house in the Dutch city of Tilburg to visit a friend around the corner. It was close to midnight, but his colleague Marcel Zeelenberg had called and texted Stapel that evening to say that he wanted to see him about an urgent matter. The two had known each other since the early ’90s, when they were Ph.D. students at the University of Amsterdam; now both were psychologists at Tilburg University. In 2010, Stapel became dean of the university’s School of Social and Behavioral Sciences and Zeelenberg head of the social psychology department. Stapel and his wife, Marcelle, had supported Zeelenberg through a difficult divorce a few years earlier. As he approached Zeelenberg’s door, Stapel wondered if his colleague was having problems with his new girlfriend. Zeelenberg, a stocky man with a shaved head, led Stapel into his living room. “What’s up?” Stapel asked, settling onto a couch. Two graduate students had made an accusation, Zeelenberg explained. His eyes began to fill with tears. “They suspect you have been committing research fraud.” Stapel was an academic star in the Netherlands and abroad, the author of several well-regarded studies on human attitudes and behavior. That spring, he published a widely publicized study in Science about an experiment done at the Utrecht train station showing that a trash-filled environment tended to bring out racist tendencies in individuals. And just days earlier, he received more media attention for a study indicating that eating meat made people selfish and less social. © 2013 The New York Times Company
Link ID: 18090 - Posted: 04.29.2013
The Brain: Our Food-Traffic Controller By KATHLEEN A. PAGE and ROBERT S. SHERWIN IMAGINE that, instead of this article, you were staring at a plate of freshly baked chocolate chip cookies. The mere sight and smell of them would likely make your mouth water. The first bite would be enough to wake up brain areas that control reward, pleasure and emotion — and perhaps trigger memories of when you tasted cookies like these as a child. That first bite would also stimulate hormones signaling your brain that fuel was available. The brain would integrate these diverse messages with information from your surroundings and make a decision as to what to do next: keep on chewing, gobble down the cookie and grab another, or walk away. Studying the complex brain response to such sweet temptations has offered clues as to how we might one day control a profound health problem in the country: the obesity epidemic. The answer may partly lie in a primitive brain region called the hypothalamus. The hypothalamus, which monitors the body’s available energy supply, is at the center of the brain’s snack-food signal processing. It keeps track of how much long-term energy is stored in fat by detecting levels of the fat-derived hormone leptin — and it also monitors the body’s levels of blood glucose, minute-to-minute, along with other metabolic fuels and hormones that influence satiety. When you eat a cookie, the hypothalamus sends out signals that make you less hungry. Conversely, when food is restricted, the hypothalamus sends signals that increase your desire to ingest high-calorie foods. The hypothalamus is also wired to other brain areas that control taste, reward, memory, emotion and higher-level decision making. These brain regions form an integrated circuit that was designed to control the drive to eat. © 2013 The New York Times Company
by Helen Thomson "I feel like I have been dropped into my body. I know this is my voice and these are my memories, but they don't feel like they belong to me." It happened out of the blue. Louise Airey was 8 years old, off sick from school, when suddenly she felt like she had been dropped into her own body. "It's just so difficult to verbalise what this feels like," she says. "All of a sudden you're hyper aware, and everything else in the world seems unreal, like a movie." She panicked, but told no one. The feeling soon passed but returned several times until, at the age of 19, a migraine triggered a sensation of being disconnected from the world that was to last 18 months. When she was in her 30s she was diagnosed with depersonalisation disorder – an altered sense of self with all-encompassing feelings of not occupying your own body, and detachment from your thoughts and actions. It has come and gone throughout her life, but since a traumatic pregnancy 20 months ago, these feelings have remained constant. "Other people seem like robots," Airey says. "It's like I'm watching a film, like I'm on my own in the centre of everything and nothing else is real. I'll be speaking to my children and I'll catch my voice talking and it seems really alien and foreign. It makes you feel very separated and lonely from everything, like you're the only person that is real." Depersonalisation disorder is not as rare as you might think, says Anthony David at King's College London and the Maudsley Hospital: it may affect almost 1 per cent of the British population (Social Psychiatry and Psychiatric Epidemiology, DOI: 10.1007/s00127-010-0327-7). We've all probably experienced mild versions of it at some point, in the unreal, spaced-out feeling you might get while severely jet-lagged or hung-over, for example. © Copyright Reed Business Information Ltd.
Link ID: 18077 - Posted: 04.27.2013
By DONALD G. McNEIL Jr. Konzo, a disease that comes from eating bitter cassava that has not been prepared properly — that is, soaked for days to break down its natural cyanide — has long been known to cripple children. The name, from the Yaka language of Central Africa, means “tied legs,” and victims stumble as if their knees were bound together. Now researchers have found that children who live where konzo is common but have no obvious physical symptoms may still have mental deficits from the illness. Cassava, also called manioc or tapioca, is eaten by 800 million people around the world and is a staple in Africa, where bitter varieties grow well even in arid regions. When properly soaked and dried, and especially when people have protein in their diet, bitter cassava is “pretty safe,” said Michael J. Boivin, a Michigan State psychiatry professor and lead author of a study published online by Pediatrics. “But in times of war, famine, displacement and hardship, people take shortcuts.” In the Democratic Republic of Congo, Dr. Boivin and colleagues gave tests of mental acuity and dexterity to three groups of children. Two groups were from a village near the Angolan border with regular konzo outbreaks: Half had leg problems; half did not but had cyanide in their urine. The third was from a village 125 miles away with a similar diet but little konzo because residents routinely detoxified cassava before cooking it. © 2013 The New York Times Company
By Breanna Draxler When you lose something important—a child, your wallet, the keys—your brain kicks into overdrive to find the missing object. But that’s not just a matter of extra concentration. Researchers have found that in these intense search situations your brain actually rallies extra visual processing troops (and even some other non-visual parts of the brain) to get the job done. It has to do with the way your brain processes images in the first place. When you see objects, your brain sorts them into broad categories—about 1,000 of them. The various elements we perceive trigger a pattern of different categorical areas in our brains. For example, if you see a woman carrying an umbrella while walking her dog in the park, your brain might catalog it as “people,” “tools” and “animals.” But when you lose something, your brain reacts a little differently. It expands the category of the object you’re looking for to include related categories and turns down the perception of other, non-related categories, to allow you to focus more intently on the object of interest. To see what this altered categorization looked like during a search, researchers at UC Berkeley used functional magnetic resonance imaging (fMRI) to record changes in five people’s brain activity as they looked for objects in movies. The objects they sought were categorized broadly, paralleling how our brains separate items into generalized groups like “vehicles” and “people.” During hour-long search sessions, the researchers found that regardless of whether the participants found the objects they were looking for, their brains cast a wider visual net than they would if they were watching passively.
Jo Marchant People with genes that make it tough for them to engage socially with others seem to be better than average at hypnotizing themselves. A study published today in Psychoneuroendocrinology1 concludes that such individuals are particularly good at becoming absorbed in their own internal world, and might also be more susceptible to other distortions of reality. Psychologist Richard Bryant of the University of New South Wales in Sydney and his colleagues tested the hypnotizability of volunteers with different forms of the receptor for oxytocin, a hormone that increases trust and social bonding. (Oxytocin's association with emotional attachment also earned it the nickname of 'love hormone'.) Those with gene variants linked to social detachment and autism were found to be most susceptible to hypnosis. Hypnosis has intrigued scientists since the nineteenth-century physician James Braid used it to alleviate pain in a variety of medical conditions, but it has never been fully understood. Hypnotized people can undergo a range of unusual experiences, including amnesia, anaesthesia and the loss of the ability to move their limbs. But some individuals are more affected by hypnosis than others — and no one knows why. Hormones and hypnotism How susceptible someone is to persuasion is an important factor in how easily they can be hypnotized by someone else. Bryant and his colleagues have previously shown that spraying a shot of oxytocin up people’s noses makes them more hypnotizable, and more likely to engage in potentially embarrassing activities such as swearing or dancing at a hypnotist’s suggestion. © 2013 Nature Publishing Group,
By Susan Milius Zola the crow is about to face a test that has baffled animals from canaries to dogs. She’s a wild New Caledonian crow, and for the first time, she’s seeing a tidbit of meat dangling on a long string tied to a stick. She perches on the stick, bends down, grabs the string with her beak and pulls. But the string is too long. The meat still hangs out of reach. In similar tests, dogs, pigeons and many other species routinely falter. Some nibble at the string or keep tugging and dropping the same segment. Some pull at a string that’s not connected to food just as readily as a string that is. Eventually many get the hang of reeling in the tidbit, but they seem to learn by trial and error. Zola, however, does not fumble. On her first attempt, she anchors the first length of string by stepping on it and immediately bends down again for the next segment. With several more pulls and steps, Zola reels in the treat. Watching the crow, says Russell Gray, one of the researchers behind the string-pulling experiment, “people say, ‘Wow, it had a flash of insight.’ ” At first glance it seems Zola mentally worked through the problem as a human might, devising a solution in an aha moment. But Gray, of the University of Auckland in New Zealand, has had enough of such supposed animal geniuses. Asking whether the crow solves problems in the same way a human would isn’t a useful question, he says. He warns of a roller coaster that scientists and animal lovers alike can get stuck on: first getting excited and romanticizing a clever animal’s accomplishments, then crashing into disappointment when some killjoy comes up with a mundane explanation that’s not humanlike at all. © Society for Science & the Public 2000 - 2013
by Douglas Heaven A glimpse of consciousness emerging in the brains of babies has been recorded for the first time. Insights gleaned from the work may aid the monitoring of babies under anaesthesia, and give a better understanding of awareness in people in vegetative states – and possibly even in animals. The human brain develops dramatically in a baby's first year, transforming the baby from being unaware to being fully engaged with its surroundings. To capture this change, Sid Kouider at the Ecole Normale Supérieure in Paris, France, and colleagues used electroencephalography (EEG) to record electrical activity in the brains of 80 infants while they were briefly shown pictures of faces. In adults, awareness of a stimulus is known to be linked to a two-stage pattern of brain activity. Immediately after a visual stimulus is presented, areas of the visual cortex fire. About 300 milliseconds later other areas light up, including the prefrontal cortex, which deals with higher-level cognition. Conscious awareness kicks in only after the second stage of neural activity reaches a specific threshold. "It's an all-or-nothing response," says Kouider. Adults can verbally describe being aware of a stimulus, but a baby is a closed book. "We have learned a lot about consciousness in people who can talk about it, but very little in those who cannot," says Tristan Bekinschtein at the University of Cambridge, who was not involved in the work. © Copyright Reed Business Information Ltd.