By Fergus Walsh Medical correspondent A Canadian man who was believed to have been in a vegetative state for more than a decade, has been able to tell scientists that he is not in any pain. It's the first time an uncommunicative, severely brain-injured patient has been able to give answers clinically relevant to their care. Scott Routley, 39, was asked questions while having his brain activity scanned in an fMRI machine. His doctor says the discovery means medical textbooks will need rewriting. Vegetative patients emerge from a coma into a condition where they have periods awake, with their eyes open, but have no perception of themselves or the outside world. Mr Routley suffered a severe brain injury in a car accident 12 years ago. None of his physical assessments since then have shown any sign of awareness, or ability to communicate. But the British neuroscientist Prof Adrian Owen - who led the team at the Brain and Mind Institute, University of Western Ontario - said Mr Routley was clearly not vegetative. BBC © 2012

Keyword: Attention; Consciousness
Link ID: 17487 - Posted: 11.13.2012

by Elizabeth Norton Stop that noise! Many creatures, such as human babies, chimpanzees, and chicks, react negatively to dissonance—harsh, unstable, grating sounds. Since the days of the ancient Greeks, scientists have wondered why the ear prefers harmony. Now, scientists suggest that the reason may go deeper than an aversion to the way clashing notes abrade auditory nerves; instead, it may lie in the very structure of the ear and brain, which are designed to respond to the elegantly spaced structure of a harmonious sound. "Over the past century, researchers have tried to relate the perception of dissonance to the underlying acoustics of the signals," says psychoacoustician Marion Cousineau of the University of Montreal in Canada. In a musical chord, for example, several notes combine to produce a sound wave containing all of the individual frequencies of each tone. Specifically, the wave contains the base, or "fundamental," frequency for each note plus multiples of that frequency known as harmonics. Upon reaching the ear, these frequencies are carried by the auditory nerve to the brain. If the chord is harmonic, or "consonant," the notes are spaced neatly enough so that the individual fibers of the auditory nerve carry specific frequencies to the brain. By perceiving both the parts and the harmonious whole, the brain responds to what scientists call harmonicity. In a dissonant chord, however, some of the notes and their harmonics are so close together that two notes will stimulate the same set of auditory nerve fibers. This clash gives the sound a rough quality known as beating, in which the almost-equal frequencies interfere to create a warbling sound. Most researchers thought that phenomenon accounted for the unpleasantness of a dissonance. © 2010 American Association for the Advancement of Science

Keyword: Hearing
Link ID: 17486 - Posted: 11.13.2012

By SINDYA N. BHANOO Fairywrens teach their chicks a password, a unique note, to differentiate them from imposters. “We call this an incubation call,” said Mark Hauber, an animal behaviorist at Hunter College at the City University of New York and an author of the study, which appears in the journal Current Biology. “The more times the mother calls, the better the mimicry of the chicks.” The teaching begins a few days before the birds hatch. And while “the cuckoo chick is very adaptable and tries out many begging calls until it sounds similar to the fairywren,” Dr. Hauber said, it also has a shorter incubation period. So it hatches several days before fairywren chicks, leaving it little time to practice and perfect the passwordlike call of the fairywren mother. Generally, when a cuckoo hatches it throws out the other eggs in the nest. When a mother does not hear her unique call from her babies, she abandons the nest. Male fairywrens help their mates care for their young, so the mother teaches her mate and any other helpers the password through the performance of a special song. “In the future we’d like to do some brain imaging on the embryos using noninvasive functional M.R.I.’s,” Dr. Hauber said. “We want to see how these embryos are listening, practicing and learning these relevant vocalizations.” © 2012 The New York Times Company

Keyword: Sexual Behavior; Learning & Memory
Link ID: 17485 - Posted: 11.13.2012

by Greg Miller Seeing someone yawn or hearing someone laugh makes you likely to follow suit. The same goes for scratching an itch. Now, for the first time, researchers have investigated the neural basis of contagious itch, identifying several brain regions whose activity predicts how susceptible people are to feeling itchy when they see someone else scratch. Researchers in the United Kingdom showed volunteers video clips of people scratching an arm or a spot on their chest. Sure enough, subjects reported feeling more itchy, and most scratched themselves at least once during the experiment. When a subset of the volunteers watched the videos inside an functional magnetic resonance imaging scanner, the scans revealed activity in several of the same brain regions known to fire up in response to an itch-inducing histamine injection. Activity in three of these areas correlated with subjects' self-reported itchiness, the team reports online today in the Proceedings of the National Academy of Sciences. Personality tests suggest that the trait that best predicts susceptibility to contagious itch is neuroticism, not empathy, as some researchers have suggested. © 2010 American Association for the Advancement of Science

Keyword: Pain & Touch; Emotions
Link ID: 17484 - Posted: 11.13.2012

By NICHOLAS BAKALAR High blood pressure may cause harmful brain changes in people as young as 40, a study suggests. In the report, published online Nov. 2 in Lancet Neurology, researchers measured blood pressure in 579 men and women whose average age was 39, then examined their brains with magnetic resonance imaging. After adjusting for smoking, hypertension treatment and total cranial volume, they found that higher systolic blood pressure — the most common form of hypertension — was associated with decreases in gray matter volume and significant injury to white matter. Moreover, there was a dose-response relationship: The higher the blood pressure, the greater the visible changes. These changes also occur in people over 55 with high blood pressure and are associated with decreased cognitive performance. Essentially, these young people with high blood pressure had brains that were older than their chronological age. The authors acknowledge that their sample was mostly healthy, white volunteers, and that the study represents a snapshot, not a long-term picture. The senior author, Dr. Charles DeCarli, a neurologist at the University of California, Davis, urged caution. “Most people at this age have no symptoms at all, even if they have high blood pressure,” he said. “Get your blood pressure measured when you’re young, and treated if necessary.” Copyright 2012 The New York Times Company

Keyword: Alzheimers
Link ID: 17483 - Posted: 11.13.2012

By James Gallagher Health and science reporter, BBC News Adding "calm down" genes to hyperactive brain cells has completely cured rats of epilepsy for the first time, say UK researchers. They believe their approach could help people who cannot control their seizures with drugs. The study, published in the journal Science Translation Medicine, used a virus to insert the new genes into a small number of neurons. About 50 million people have epilepsy worldwide. However, drugs do not work for up to 30% of them. The alternatives include surgery to remove the part of the brain that triggers a fit or to use electrical stimulation. The brain is alive with electrical communication with individual neurons primed to fire off new messages. However, if a group of neurons become too excited they can throw the whole system into chaos leading to an epileptic seizure. Researchers at University College London have developed two ways of manipulating the behaviour of individual cells inside the brain in order to prevent those seizures. Both use viruses injected into the brain to add tiny sections of DNA to the genetic code of just a few thousand neurons. One method boosts the brain cells' natural levels of inhibition in order to calm them down. This treatment is a form of gene therapy, a field which is often criticised for failing to deliver on decades of promise. BBC © 2012

Keyword: Epilepsy; Genes & Behavior
Link ID: 17482 - Posted: 11.13.2012

By Charles Q. Choi People with schizophrenia often experience the unnerving feeling that outside forces are controlling them. Other times they feel an illusory sense of power over uncontrollable events. Now scientists find these symptoms may arise from disabilities in predicting or recognizing their own actions. The findings suggest new therapies for treating schizophrenia, which afflicts an estimated 1 percent of the world population. To see where this confusion might stem from, researchers tested two ways people are known to link actions and their outcomes. We either predict the effects of our movements or retrospectively deduce a causal connection. Healthy participants and schizophrenic patients were asked to look at a clock and occasionally push a button. Most of the time the button push was followed by a tone. The participants then told researchers what time they had pushed the button and when the tone had occurred. Healthy volunteers reported later times for each button push if it was followed by a tone. This result suggests that awareness of a link between the two events causes people to perceive less time between them. Participants also tended to estimate later button pushes even in the few cases when no tone was emitted, revealing that the subjects were predicting they would hear the sound, says psychiatrist and cognitive neuroscientist Martin Voss of Charité University Hospital and St. Hedwig Hospital in Berlin. © 2012 Scientific American

Keyword: Schizophrenia; Attention
Link ID: 17481 - Posted: 11.13.2012

David Cyranoski In December 2010, Robin Ali became suddenly excited by the usually mundane task of reviewing a scientific paper. “I was running around my room, waving the manuscript,” he recalls. The paper described how a clump of embryonic stem cells had grown into a rounded goblet of retinal tissue. The structure, called an optic cup, forms the back of the eye in a growing embryo. But this one was in a dish, and videos accompanying the paper showed the structure slowly sprouting and blossoming. For Ali, an ophthalmologist at University College London who has devoted two decades to repairing vision, the implications were immediate. “It was clear to me it was a landmark paper,” he says. “He has transformed the field.” 'He' is Yoshiki Sasai, a stem-cell biologist at the RIKEN Center for Developmental Biology in Kobe, Japan. Sasai has impressed many researchers with his green-fingered talent for coaxing neural stem cells to grow into elaborate structures. As well as the optic cup1, he has cultivated the delicate tissue layers of the cerebral cortex2 and a rudimentary, hormone-making pituitary gland3. He is now well on the way to growing a cerebellum4 — the brain structure that coordinates movement and balance. “These papers make for the most addictive series of stem-cell papers in recent years,” says Luc Leyns, a stem-cell scientist at the Free University of Brussels. Sasai's work is more than tissue engineering: it tackles questions that have puzzled developmental biologists for decades. How do the proliferating stem cells of an embryo organize themselves seamlessly into the complex structures of the body and brain? And is tissue formation driven by a genetic program intrinsic to cells, or shaped by external cues from neighbouring tissues? © 2012 Nature Publishing Group

Keyword: Development of the Brain; Stem Cells
Link ID: 17480 - Posted: 11.13.2012

By Wynne Parry and LiveScience The realm of sleep and dreams has long been associated with strangeness: omens or symbols, unconscious impulses and fears. But this sometimes disturbing world of inner turmoil, fears and desires is grounded in our day-to-day experience, sleep researchers say. "The structure and content of thinking looks very much like the structure and content of dreaming. They may be the product of the same machine," said Matthew Wilson, a neuroscientist at MIT and a panelist at the New York Academy of Sciences discussion "The Strange Science of Sleep and Dreams" on Friday (Nov. 9). His work and others' explores the crucial link between dreams and learning and memory. Dreams allow the brain to work through its conscious experiences. During them, the brain appears to apply the same neurological machinery used during the day to examine the past, the future and other aspects of a person's (or animal's) inner world at night. Memory is the manifestation of this inner world, Wilson said. "What we remember is the result of dreams rather than the other way around," he said. His work, and that of fellow panelist Erin Wamsley, a sleep scientist at Beth Israel Medical Center/Harvard Medical School, focuses on the relationship between memory and dreams in non-REM sleep. Vivid dreams often occur during REM sleep, named for the rapid eye movement associated with it, however, non-REM sleep also brings dreams but they are more fragmentary. © 2012 Scientific American

Keyword: Sleep
Link ID: 17479 - Posted: 11.13.2012

By Maggie Fox, NBC News Doctors trying to find some of the causes of autism put another piece into the puzzle on Monday: They found women who had flu while they were pregnant were twice as likely to have a child later diagnosed with autism. Those who had a fever lasting a week or longer -- perhaps caused by flu or maybe by something else -- were three times as likely to have an autistic child. The study of 96,000 children in Denmark raises as many questions as it answers. But it fits in with a growing body of evidence that suggests that, in at least some cases, something is going on with a mother’s immune system during pregnancy that affects the developing child’s brain. Autism seems to be a growing problem in the United States. According to the U.S. Centers for Disease Control and Prevention, autism spectrum disorder affects one in 88 children, including about one in 54 boys. The autism spectrum refers to a broad range of symptoms, from the relatively mild social awkwardness of Asperger’s syndrome to profound mental retardation, debilitating repetitive behaviors and an inability to communicate. Scientists agree that it’s not just a matter of better diagnosis; the numbers seem to be growing because more children are indeed developing autism. But no one is sure why. Genetics are a large factor -- if one twin has autism the other twin is very likely to -- but genes don’t explain it all. © 2012 NBCNews.com

Keyword: Autism; Epigenetics
Link ID: 17478 - Posted: 11.12.2012

By JIM DENT Three days before his death last week at 88, Darrell Royal told his wife, Edith: “We need to go back to Hollis” — in Oklahoma. “Uncle Otis died.” “Oh, Darrell,” she said, “Uncle Otis didn’t die.” Royal, a former University of Texas football coach, chuckled and said, “Well, Uncle Otis will be glad to hear that.” The Royal humor never faded, even as he sank deeper into Alzheimer’s disease. The last three years, I came to understand this as well as anyone. We had known each other for more than 40 years. In the 1970s, Royal was a virile, driven, demanding man with a chip on his shoulder bigger than Bevo, the Longhorns mascot. He rarely raised his voice to players. “But we were scared to death of him,” the former quarterback Bill Bradley said. Royal won 3 national championships and 167 games before retiring at 52. He was a giant in college football, having stood shoulder to shoulder with the Alabama coach Bear Bryant. Royal’s Longhorns defeated one of Bryant’s greatest teams, with Joe Namath at quarterback, in the 1965 Orange Bowl. Royal went 3-0-1 in games against Bryant. Royal and I were reunited in the spring of 2010. I barely recognized him. The swagger was gone. His mind had faded. Often he stared aimlessly across the room. I scheduled an interview with him for my book “Courage Beyond the Game: The Freddie Steinmark Story.” Still, I worried that his withering mind could no longer conjure up images of Steinmark, the undersize safety who started 21 straight winning games for the Longhorns in the late 1960s. Steinmark later developed bone cancer that robbed him of his left leg. © 2012 The New York Times Company

Keyword: Alzheimers
Link ID: 17477 - Posted: 11.12.2012

By Laura Sanders The effects of a baby’s rough start can linger. An early stressful environment during a baby girl’s first year was associated with altered brain behavior and signs of anxiety in her late teens, scientists report online November 11 in Nature Neuroscience. Although the results are preliminary, they may help reveal how negative experiences early on can sculpt the brain. Studies in animals have pointed out how tough times in childhood can influence the brain and the animals’ behavior later in life. But it’s been hard to figure out how that process works in people, says Lawrence Price, a psychiatrist and clinical neuroscientist at Brown University in Providence, R.I. “One of the real advances of this paper is that it helps move us along on that pathway,” he says. The study, led by Cory Burghy of the University of Wisconsin–Madison, drew from the Wisconsin Study of Family and Work, which in 1990 recruited pregnant women in southern Wisconsin at prenatal visits. Three times during the first year of their babies’ lives, the mothers reported whether they were experiencing stressful situations such as depression, marital conflict, money woes or parenting stress. Researchers assumed that women who reported higher stress levels created a more stressful situation for their baby. Four and a half years later, daughters whose moms reported higher levels of stress had more of the stress hormone cortisol in their blood. That observation suggests the girls had trouble shutting down a hyperactive stress response. The same effect wasn’t found in boys. © Society for Science & the Public 2000 - 2012

Keyword: Stress; Sexual Behavior
Link ID: 17476 - Posted: 11.12.2012

By MICHAEL TRIMBLE IN 2008, at a zoo in Münster, Germany, a gorilla named Gana gave birth to a male infant, who died after three months. Photographs of Gana, looking stricken and inconsolable, were ubiquitous. “Heartbroken gorilla cradles her dead baby,” Britain’s Daily Mail declared. Crowds thronged the zoo to see the grieving mother. Sad as the scene was, the humans, not Gana, were the only ones crying. The notion that animals can weep — apologies to Dumbo, Bambi and Wilbur — has no scientific basis. Years of observations by the primatologists Dian Fossey, who observed gorillas, and Jane Goodall, who worked with chimpanzees, could not prove that animals cry tears from emotion. In his book “The Emotional Lives of Animals,” the only tears the biologist Marc Bekoff were certain of were his own. Jeffrey Moussaieff Masson and Susan McCarthy, the authors of “When Elephants Weep,” admit that “most elephant watchers have never seen them weep.” It’s true that many mammals shed tears, especially in response to pain. Tears protect the eye by keeping it moist, and they contain antimicrobial proteins. But crying as an embodiment of empathy is, I maintain, unique to humans and has played an essential role in human evolution and the development of human cultures. Within two days an infant can imitate sad and happy faces. If a newborn mammal does not cry out (typically, in the first few weeks of life, without tears) it is unlikely to get the attention it needs to survive. Around three to four months, the relationship between the human infant and its environment takes on a more organized communicative role, and tearful crying begins to serve interpersonal purposes: the search for comfort and pacification. As we get older, crying becomes a tool of our social repertory: grief and joy, shame and pride, fear and manipulation. © 2012 The New York Times Company

Keyword: Emotions; Evolution
Link ID: 17475 - Posted: 11.12.2012

By SETH S. HOROWITZ HERE’S a trick question. What do you hear right now? If your home is like mine, you hear the humming sound of a printer, the low throbbing of traffic from the nearby highway and the clatter of plastic followed by the muffled impact of paws landing on linoleum — meaning that the cat has once again tried to open the catnip container atop the fridge and succeeded only in knocking it to the kitchen floor. The slight trick in the question is that, by asking you what you were hearing, I prompted your brain to take control of the sensory experience — and made you listen rather than just hear. That, in effect, is what happens when an event jumps out of the background enough to be perceived consciously rather than just being part of your auditory surroundings. The difference between the sense of hearing and the skill of listening is attention. Hearing is a vastly underrated sense. We tend to think of the world as a place that we see, interacting with things and people based on how they look. Studies have shown that conscious thought takes place at about the same rate as visual recognition, requiring a significant fraction of a second per event. But hearing is a quantitatively faster sense. While it might take you a full second to notice something out of the corner of your eye, turn your head toward it, recognize it and respond to it, the same reaction to a new or sudden sound happens at least 10 times as fast. This is because hearing has evolved as our alarm system — it operates out of line of sight and works even while you are asleep. And because there is no place in the universe that is totally silent, your auditory system has evolved a complex and automatic “volume control,” fine-tuned by development and experience, to keep most sounds off your cognitive radar unless they might be of use as a signal that something dangerous or wonderful is somewhere within the kilometer or so that your ears can detect. © 2012 The New York Times Company

Keyword: Attention; Hearing
Link ID: 17474 - Posted: 11.12.2012

By Lindsey Emery, Men’s Health When most people finish a hard workout, they want a reward — possibly a sandwich, or some pancakes, or maybe even a burger and fries. What they don’t want? To not eat anything. And yet, a few recent studies found that moderate intensity aerobic training could actually decrease your appetite or increase your feelings of fullness or satiety. Strange, right? Previous research has shown that people who exercise often reward themselves with food, increasing overall calorie consumption, and often sabotaging their weight loss goals. So, what gives? “Exercise can definitely suppress hunger,” says Barry Braun, director of the Energy Metabolism Laboratory at the University of Massachusetts, Amherst, who has co-authored multiple studies on the subject. How, why, and for how long afterward is something researchers are still working out. They do know that workouts trigger changes in the hunger hormone ghrelin and the satiety hormones, PYY and GLP-1 — though research has yet to establish the exact relationship. A recent study published in the journal Metabolism found that perceived fullness — both while fasting and after eating — was higher among participants after 12 weeks of aerobic training, but not after resistance training for the same amount of time. And another study out of Brigham Young University revealed that women appeared to be less interested in food on mornings when they walked on a treadmill for 45 minutes than on days they didn’t. © 2012 NBCNews.com

Keyword: Obesity
Link ID: 17473 - Posted: 11.10.2012

By Noah Hutton and Ferris Jabr "Nothing quite like it exists yet, but we have begun building it," Henry Markram wrote in the June 2012 issue of Scientific American. He was referring to a "fantastic new scientific instrument"—a biologically realistic and detailed model of a working human brain hosted on supercomputers. Markram, who directs the Brain Mind Institute at the École Polytechnique Fédérale de Lausanne in Switzerland, has been working on the Blue Brain Project, more recently known as the Human Brain Project, since 2005. "A digital brain will be a resource for the entire scientific community: researchers will reserve time on it, as they do on the biggest telescopes, to conduct their experiments," Markram wrote in SA. "They will use it to test theories of how the human brain works in health and in disease. They will recruit it to help them develop not only new diagnostic tests for autism or schizophrenia but also new therapies for depression and Alzheimer's disease. The wiring plan for tens of trillions of neural circuits will inspire the design of brainlike computers and intelligent robots. In short, it will transform neuroscience, medicine and information technology." Markram has claimed, at various times, that he can complete this ambitious project within 10 years. His critics argue that his ultimate goal is unachievable because the human brain is too complex to simultaneously simulate at every level, from the molecule to the cortex. Say one wanted to build an exact replica of a large and intricate circuit board. One would first need to map every wire linking every component and then re-create these links. In the same way, making a model of the human brain requires knowing the trillions of connections between its neurons. A map of all the connections between neurons in a brain is called a connectome, and no such map exists for the human brain. In fact, the only organism with a complete connectome is the tiny nematode C. elegans, which has 302 neurons total. The human brain has more than 80 billion neurons and 100 trillion connections between those cells. © 2012 Scientific American

Keyword: Brain imaging; Development of the Brain
Link ID: 17472 - Posted: 11.10.2012

by Will Ferguson For the first time, an electrical device has been powered by the ear alone. The team behind the technology used a natural electrochemical gradient in cells within the inner ear of a guinea pig to power a wireless transmitter for up to five hours. The technique could one day provide an autonomous power source for brain and cochlear implants, says Tina Stankovic, an auditory neuroscientist at Harvard University Medical School in Boston, Massachusetts. Nerve cells use the movement of positively charged sodium ions and negatively charged potassium ions across a membrane to create an electrochemical gradient that drives neural signals. Some cells in the cochlear have the same kind of gradient, which is used to convert the mechanical force of the vibrating eardrum into electrical signals that the brain can understand. Tiny voltage A major challenge in tapping such electrical potential is that the voltage created is tiny – a fraction of that generated by a standard AA battery. "We have known about DC potential in the human ear for 60 years but no one has attempted to harness it," Stankovic says. Now, Stankovic and her colleagues have developed an electronic chip containing several tiny, low resistance electrodes that can harness a small amount of this electrical activity without damaging hearing. © Copyright Reed Business Information Ltd.

Keyword: Hearing; Robotics
Link ID: 17471 - Posted: 11.10.2012

By Tia Ghose, LiveScience Humans can smell fear and disgust, and the emotions are contagious, according to a new study. The findings, published Nov. 5 in the journal Psychological Science, suggest that humans communicate via smell just like other animals. "These findings are contrary to the commonly accepted assumption that human communication runs exclusively via language or visual channels," write Gün Semin and colleagues from Utrecht University in the Netherlands. Most animals communicate using smell, but because humans lack the same odor-sensing organs, scientists thought we had long ago lost our ability to smell fear or other emotions. To find out, the team collected sweat from under the armpits of 10 men while they watched either frightening scenes from the horror movie "The Shining" or repulsive clips of MTV's "Jackass." Next, the researchers asked 36 women to take a visual test while they unknowingly inhaled the scent of men's sweat. When women sniffed "fear sweat," they opened their eyes wide in a scared expression, while those smelling sweat from disgusted men scrunched their faces into a repulsed grimace. (The team chose men as the sweat donors and women as the receivers because past research suggests women are more sensitive to men's scent than vice versa.) © 2012 NBCNews.com

Keyword: Chemical Senses (Smell & Taste); Emotions
Link ID: 17470 - Posted: 11.08.2012

Seizures during childhood fever are usually benign, but when prolonged, they can foreshadow an increased risk of epilepsy later in life. Now a study funded by the National Institutes of Health suggests that brain imaging and recordings of brain activity could help identify the children at highest risk. The study reveals that within days of a prolonged fever-related seizure, some children have signs of acute brain injury, abnormal brain anatomy, altered brain activity, or a combination. "Our goal has been to develop biomarkers that will tell us whether or not a particular child is at risk for epilepsy. This could in turn help us develop strategies to prevent the disorder," said study investigator Shlomo Shinnar, M.D., Ph.D. Dr. Shinnar is a professor of neurology, pediatrics and epidemiology and the Hyman Climenko Professor of Neuroscience Research at Montefiore Medical Center, Albert Einstein College of Medicine, New York City. Seizures that occur during the course of a high fever, known as febrile seizures, affect 3 to 4 percent of all children. Most such children recover rapidly and do not suffer long-term health consequences. However, having one or more prolonged febrile seizures in childhood is known to increase the risk of subsequent epilepsy. Some experts estimate that the risk of later epilepsy is 30-40 percent following febrile status epilepticus (FSE), a seizure or series of seizures that can last from 30 minutes to several hours. "While the majority of children fully recover from febrile status epilepticus, some will go on to develop epilepsy. We have no way of knowing yet who they will be," Dr. Shinnar said.

Keyword: Epilepsy; Development of the Brain
Link ID: 17469 - Posted: 11.08.2012

By GRETCHEN REYNOLDS In recent years, some research has suggested that a high-fat diet may be bad for the brain, at least in lab animals. Can exercise protect against such damage? That question may have particular relevance now, with the butter-and cream-laden holidays fast approaching. And it has prompted several new and important studies. The most captivating of these, presented last month at the annual meeting of the Society for Neuroscience in New Orleans, began with scientists at the University of Minnesota teaching a group of rats to scamper from one chamber to another when they heard a musical tone, an accepted measure of the animals’ ability to learn and remember. For the next four months, half of the rats ate normal chow. The others happily consumed a much greasier diet, consisting of at least 40 percent fat. Total calories were the same in both diets. After four months, the animals repeated the memory test. Those on a normal diet performed about the same as they had before; their cognitive ability was the same. The high-fat eaters, though, did much worse. Then, half of the animals in each group were given access to running wheels. Their diets didn’t change. So, some of the rats on the high-fat diet were now exercising. Some were not. Ditto for the animals eating the normal diet. For the next seven weeks, the memory test was repeated weekly in all of the groups. During that time, the performance of the rats eating a high-fat diet continued to decline so long as they didn’t exercise. Copyright 2012 The New York Times Company

Keyword: Obesity; Learning & Memory
Link ID: 17468 - Posted: 11.08.2012