Zoe Cormier Love really does change your brain — at least, if you’re a prairie vole. Researchers have shown for the first time that the act of mating induces permanent chemical modifications in the chromosomes, affecting the expression of genes that regulate sexual and monogamous behaviour. The study is published today in Nature Neuroscience1. Prairie voles (Microtus ochrogaster) have long been of interest to neuroscientists and endocrinologists who study the social behaviour of animals, in part because this species forms monogamous pair bonds — essentially mating for life. The voles' pair bonding, sharing of parental roles and egalitarian nest building in couples makes them a good model for understanding the biology of monogamy and mating in humans. Previous studies have shown that the neurotransmitters oxytocin and vasopressin play a major part in inducing and regulating the formation of the pair bond. Monogamous prairie voles are known to have higher levels of receptors for these neurotransmitters than do voles who have yet to mate; and when otherwise promiscuous montane voles (M. montanus) are dosed with oxytocin and vasopressin, they adopt the monogamous behaviour of their prairie cousins. Because behaviour seemed to play an active part in changing the neurobiology of the animals, scientists suspected that epigenetic factors were involved. These are chemical modifications to the chromosomes that affect how genes are transcribed or suppressed, as opposed to changes in the gene sequences themselves. © 2013 Nature Publishing Group

Keyword: Sexual Behavior; Epigenetics
Link ID: 18221 - Posted: 06.03.2013

By Ian Chant Kids are wildly better than adults at most types of learning—most famously, new languages. One reason may be that adults' brains are “full,” in a way. Creating memories relies in part on the destruction of old memories, and recent research finds that adults have high levels of a protein that prevents such forgetting. Whenever we learn something, brain cells become wired together with new synapses, the connections between neurons that enable communication. When a memory fades, those synapses weaken. Researchers led by Joe Tsien, a neuroscientist at the Medical College of Georgia, genetically engineered mice to have high levels of NR2A, part of a receptor on the surface of some neurons that regulates the flow of chemicals such as magnesium and calcium in and out of a cell. NR2A is known to be more prevalent in the brains of mammals as they age. The engineered mice, though young, had adult levels of NR2A, and they showed some difficulty forming long-term memories. More dramatically, their brains could barely weaken their synapses, a process that allows the loss of useless information in favor of more recent data. A similar process may govern short-term memories as well. When you hear a friend ask for coffee, the details of her order don't just slip away in your mind—your brain must produce a protein that actively destroys the synapses encoding that short-term memory, according to a 2010 paper in Cell. Much psychological research supports the idea that forgetting is essential to memory and emotional health. Tsien's new work, published January 8 in Scientific Reports, suggests that older brains hold on to their connections more dearly—which helps to explain why learning is more laborious as we age and why memory trouble later in life so often involves the accidental recall of outdated information. © 2013 Scientific American

Keyword: Learning & Memory; Development of the Brain
Link ID: 18220 - Posted: 06.03.2013

By JENNA WORTHAM ON a recent family outing, my mother and sister got into a shouting match. But they weren’t mad at each other — they were yelling at the iPhone’s turn-by-turn navigation system. I interrupted to say that the phone didn’t understand — or care — that they were upset. “Honey, we know,” my mom replied. “But it should!” She had a point. After all, computers and technology are becoming only smarter, faster and more intuitive. Artificial intelligence is creeping into our lives at a steady pace. Devices and apps can anticipate what we need, sometimes even before we realize it ourselves. So why shouldn’t they understand our feelings? If emotional reactions were measured, they could be valuable data points for better design and development. Emotional artificial intelligence, also called affective computing, may be on its way. But should it be? After all, we’re already struggling to cope with the always-on nature of the devices in our lives. Yes, those gadgets would be more efficient if they could respond when we are frustrated, bored or too busy to be interrupted, yet they would also be intrusive in ways we can’t even fathom today. It sounds like a science-fiction movie, and in some ways it is. Much of this technology is still in its early stages, but it’s inching closer to reality. Companies like Affectiva, a start-up spun out of the M.I.T. Media Lab, are working on software that trains computers to recognize human emotions based on their facial expressions and physiological responses. A company called Beyond Verbal, which has just raised close to $3 million in venture financing, is working on a software tool that can analyze speech and, based on the tone of a person’s voice, determine whether it indicates qualities like arrogance or annoyance, or both. © 2013 The New York Times Company

Keyword: Emotions; Robotics
Link ID: 18219 - Posted: 06.03.2013

Rebecca J. Rosen What would you draw if somebody told you to draw a neuron? According to a new study, your sketch will depend on how much science education you have, but not in the way you'd expect. In the image above, the top row -- those detailed, labeled, neat renderings -- are the work of undergraduates. The bottom row, with their janky, sparse lines, come from the leaders of neuroscience research laboratories. That martini-glass looking thing over there on the left? That's a neuron, as drawn by a professional scientist. The middle row, some intermediary step, shows drawings from postdocs and graduate students. These drawings come from a new study published in the journal Science Education. Its authors, a team at King's College London led by education professor David Hay, found that nearly every single undergraduate student they studied (all but three of 126) faithfully reproduced textbook-style neurons, something akin to a canonical image from an 1899 book detailing the brain, which, the authors say, "has enjoyed an unusually pervasive influence." These drawings are "typified by a multipolar cell body and truncated, feathery dendritic processes around a clearly demarcated nucleus." Many of the drawings were annotated. For the "trainee scientists" -- those in PhD programs or completing a postdoc -- the neurons appeared more like what would be seen in a microscope image. Nuclei were excluded, the number of dendrites was reduced, and orientation was inconsistent -- all characterizing neurons as you would see them "in nature" not in the pages of a textbook. © 2013 by The Atlantic Monthly Group

Keyword: Brain imaging; Attention
Link ID: 18218 - Posted: 06.03.2013

by Paul Gabrielsen Take a whiff, men. A chemical component of other guys' sweat makes men more cooperative and generous, new research says. The study is the first to show that this pheromone, called androstadienone, influences other men's behavior and reinforces the developing finding that humans are susceptible and responsive to these chemical signals. Pheromones are everywhere in the animal world. Bugs in particular give off these chemicals to sound an alarm, identify a food source, or attract a mate. And smitten animals may indeed have "chemistry" together—pheromone signals are a subconscious part of their communication. Scientists didn't know if humans played that game as well. But in the last 30 years, they've identified both male and female putative pheromones that are linked to mood and reproductive cycles. Some fragrancemakers have even incorporated them into their products, hoping to add an extra emotional punch to colognes and perfumes. Real-life pheromones don't smell so nice, however: The specialized glands that produce these chemical compounds are located near the armpit, where they mix with sweat. Previous investigations focused on the chemicals as sexual attractants—studying a male pheromone's effect on female mood and behavior, for example. Turns out that women aren't the only ones susceptible to the power of male pheromones. Evolutionary biologist Markus Rantala of the University of Turku in Finland crafted an experiment in which 40 men in their mid-20s played a computer game in which two players decided how to share €10. One player offers a possible split, and the other decides whether to accept or reject it. Each participant took a turn making or deciding on offers. © 2010 American Association for the Advancement of Science

Keyword: Chemical Senses (Smell & Taste); Aggression
Link ID: 18217 - Posted: 06.01.2013

Posted by Dr. Claire McCarthy Thumbnail image for sleep.jpgAccording to a study just released, the number of hours kids sleep at night is more affected by genetics than by bedtime or how quiet or dark it is. While daytime naps can be affected and changed by messing with the environment, nighttime sleep is a more wired thing. This doesn’t surprise me at all, actually. For years I’ve been hearing from parents about how much their children sleep, and there is remarkable variation. Some kids sleep a lot at night and a lot during the day too, while others truly barely sleep at all—and yet, for the most part, they seem to get the sleep they need. It’s hard to explain this variation to parents, who understandably think that all kids of a certain age must need roughly the same amount of sleep. That’s just one of the conversations I seem to have again and again about sleep. When I read the study I thought: this would be a great opportunity to write a blog about the things I wish all parents knew about sleep. So here they are: Every child needs a different amount of sleep, as the study points out. It depends on age, to some extent, but it also depends on genetics, what they do during the day and all sorts of factors we don’t understand yet. So instead of counting hours, look at your kid. Are they generally tired or cranky during the day? If so, they may need more sleep. If they are healthy, act rested, have enough energy, get along with others (and are doing okay in school if they go to school), they are probably getting enough sleep. © 2013 NY Times Co.

Keyword: Sleep
Link ID: 18216 - Posted: 06.01.2013

by Helen Thomson Sean O'Connor is a very rational man. But he also tried, unsuccessfully, to sever his spine, and still feels a need to be paralysed. Sean has body integrity identity disorder (BIID), which causes him to feel that his limbs just don't belong to his body. Sean's legs function correctly and he has full sensation in them, but they feel disconnected from him. "I don't hate my limbs – they just feel wrong," he says. "I'm aware that they are as nature designed them to be, but there is an intense discomfort at being able to feel my legs and move them." The cause of his disorder has yet to be pinpointed, but it almost certainly stems from a problem in the early development of his brain. "My earliest memories of feeling I should be paralysed go back to when I was 4 or 5 years old," says Sean. The first case of BIID was reported in the 18th century, when a French surgeon was held at gunpoint by an Englishman who demanded that one of his legs be removed. The surgeon, against his will, performed the operation. Later, he received a handsome payment from the Englishman, with an accompanying letter of thanks for removing "a limb which put an invincible obstacle to my happiness" (Experimental Brain Research, DOI: 10.1007/s00221-009-2043-7). We now think that there are at least two forms of BIID. In one, people wish that part of their body were paralysed. Another form causes people to want to have a limb removed. BIID doesn't have to affect limbs either – there have been anecdotal accounts of people wishing they were blind or deaf. © Copyright Reed Business Information Ltd.

Keyword: Attention
Link ID: 18215 - Posted: 06.01.2013

By Stuart McMillen A classic experiment into drug addiction science. Would rats choose to take drugs if given a stimulating environment and social company?

Keyword: Drug Abuse; Learning & Memory
Link ID: 18214 - Posted: 06.01.2013

Sally Satel From the recent announcement of President Obama's BRAIN Initiative to the Technicolor brain scans ("This is your brain on God/love/envy etc") on magazine covers all around, neuroscience has captured the public imagination like never before. Understanding the brain is of course essential to developing treatments for devastating illnesses like schizophrenia and Parkinson's. More abstract but no less compelling, the functioning of the brain is intimately tied to our sense of self, our identity, our memories and aspirations. But the excitement to explore the brain has spawned a new fixation that my colleague Scott Lilienfeld and I call neurocentrism -- the view that human behavior can be best explained by looking solely or primarily at the brain. The critical question, though, is whether this neural disruption proves that the addict's behavior is involuntary, and that he is incapable of self-control. It does not. Sometimes the neural level of explanation is appropriate. When scientists develop diagnostic tests or a medications for, say, Alzheimer's disease, they investigate the hallmarks of the condition: amyloid plaques that disrupt communication between neurons, and neurofibrillary tangles that degrade them. Other times, a neural explanation can lead us astray. In my own field of addiction psychiatry, neurocentrism is ascendant -- and not for the better. Thanks to heavy promotion by the National Institute on Drug Abuse, part of the National Institutes of Health, addiction has been labeled a "brain disease." © 2013 by The Atlantic Monthly Group.

Keyword: Drug Abuse
Link ID: 18213 - Posted: 06.01.2013

By Gary Stix Unraveling the mystery of consciousness remains perhaps the biggest challenge in all neuroscience, so big and amorphous that most brain scientists won’t go near the topic, leaving philosophers to speculate about the a prioris. Even defining what consciousness is quickly devolves into lengthy and often ponderous treatises. The World Science Festival assembled a panel of luminaries who will attempt to make sense of this sprawling theme in the allotted 90 minutes. They included Mélanie Boly, a researcher and physician who has performed studies on minimally conscious patients; Christof Koch, a leading researcher on the neural basis of consciousness; Colin McGinn, known for his work on the philosophy of mind, and Nicholas Schiff, a physician-scientist who specializes in disorders of consciousness. Click below here to see these leading lights gathered at NYU’s Skirball Center for the Performing Arts on May 30 to take on whether Homo sapiens is the only conscious species, the question of whether consciousness transcends the physical boundaries of the brain, and an exploration of the biochemical processes that underlie the life of the mind. The session, entitled “The Whispering Mind: The Enduring Conundrum of Consciousness,” is moderated by ABC Nightline co-anchor Terry Moran. © 2013 Scientific American

Keyword: Consciousness
Link ID: 18212 - Posted: 06.01.2013

By Tina Hesman Saey Genetic factors may exert a tiny influence on how much schooling a person ends up with, a new study suggests. But the main lesson of the research, experts say, should be that attributing cultural and socioeconomic traits to genes is a dicey enterprise. “If there is a policy implication, it’s that there’s even more reason to be skeptical of genetic determinism,” says sociologist Jeremy Freese of Northwestern University in Evanston, Ill. Published May 30 in Science by a group of more than 200 researchers, the study does mark the first time genetic factors have been reproducibly associated with a social trait, says Richard Ebstein, a behavioral geneticist at the National University of Singapore. “It announces to social scientists that some things they’ve been studying that make a difference to health and life success do have a base in genetics.” But even if it does survive further inspection — and many similar links between genes and social characteristics have not — the study accounts for no more than 2 percent of whatever it is that makes one person continue school while someone in similar circumstances chooses to move on to something else. Previous studies comparing twins and family members have suggested that not-yet-identified genetic factors can explain 40 percent of people’s educational attainment; factors such as social groups, economic status and access to education would explain the other 60 percent. That percentage attributed to genetics is similar to the heritability of physical and medical characteristics such as weight and risk of heart disease.That makes a hunt for the genetic factors underlying educational attainment an attractive prospect. © Society for Science & the Public 2000 - 2013

Keyword: Genes & Behavior; Intelligence
Link ID: 18211 - Posted: 06.01.2013

Kerri Smith When Karl Deisseroth moved into his first lab in 2004, he found himself replacing a high-profile tenant: Nobel-prizewinning physicist Steven Chu. “His name was still on the door when I moved in,” says Deisseroth, a neuroscientist, of the basement space at Stanford University in California. The legacy has had its benefits. When chemistry student Feng Zhang dropped by looking for Chu, Deisseroth convinced him to stick around. “I don't think he knew who I was. But he got interested enough.” Deisseroth is now a major name in science himself. He is associated with two blockbuster techniques that allow researchers to show how intricate circuits in the brain create patterns of behaviour. The development of the methods, he says, came from a desire to understand mechanisms that give rise to psychiatric disease — and from the paucity of techniques to do so. “It was extremely clear that for fundamental advances in these domains I would have to spend time developing new tools,” says Deisseroth. His measured tone and laid-back demeanour belie the frenzy that his lab's techniques are generating in neuroscience. First came optogenetics1, which involves inserting light-sensitive proteins from algae into neurons, allowing researchers to switch the cells on and off with light. Deisseroth developed the method shortly after starting his lab, working with Zhang and Edward Boyden, a close collaborator at the time. Optogenetics has since been adopted by scientists around the world to explore everything from the functions of neuron subtypes to the circuits altered in depression or autism. Deisseroth has lost count of how many groups are using it. “We sent clones to thousands of laboratories,” he says. © 2013 Nature Publishing Group

Keyword: Brain imaging
Link ID: 18210 - Posted: 05.30.2013

Posted by Gary Marcus A few weeks ago, while staying with my in-laws, my four-month-old son woke up at two-thirty in the morning. He was hungry, and, knowing that he would not be coaxed back to sleep without a bottle, I brought him downstairs to the kitchen, where his crying stopped abruptly. He clearly recognized that he had arrived in an unfamiliar place, and he became fully absorbed in understanding where he was and how he’d gotten there. He was searingly alert; he craned his head and his eyes darted around. The eight minutes or so that it took it to warm the bottle, usually a time of intense complaint, passed with hardly a peep. I became convinced that, for the first time, my son was fully, consciously aware of his surroundings. As a scientist, I realize that my experience was subjective. But the leading scientific journal, Science, just published the results of an experiment that endeavored to look objectively at the rudiments of consciousness in infants. This work, conducted by the cognitive psychologists Sid Kouider, Stanislas Dehaene, and Ghislaine Dehaene-Lambertz, is an examination of brain waves in babies between five and fifteen months old, aimed at constructing what the scientists refer to as a “biological signature of consciousness.” The background of this experiment is a theory called the “global workspace” model of consciousness, according to which perceptual awareness involves two stages of neural activity. The first is a purely sensory activation, typically in the back of the brain. The second stage reflects a kind of “ignition,” and is achieved only for stimuli that are consciously perceived. © 2013 Condé Nast.

Keyword: Consciousness; Development of the Brain
Link ID: 18209 - Posted: 05.30.2013

Karen Ravn Babies learn to babble before they learn to talk, at first simply repeating individual syllables (as in ba-ba-ba), and later stringing various syllables together (as in ba-da-goo). Songbirds exhibit similar patterns during song-learning, and the capacity for this sort of syllable sequencing is widely believed to be innate and to emerge full-blown — a theory that is challenged by a paper published on Nature's website today1. A study of three species — zebra finches, Bengalese finches and humans — reports that none of the trio has it that easy. Their young all have to learn how to string syllables together slowly, pair by pair. “We discovered a previously unsuspected stage in human vocal development,” says first author Dina Lipkind, a psychologist now at Hunter College in New York. The researchers began by training young zebra finches (Taeniopygia guttata) to sing a song in which three syllables represented by the letters A, B and C came in the order ABC–ABC. They then trained the birds to sing a second song in which the same syllables were strung together in a different order, ACB–ACB. Eight out of seventeen birds managed to learn the second song, but they did not do so in one fell swoop. They learned it as a series of syllable pairs, first, say, learning to go from A to C, then from C to B and finally from B to A. And they didn’t do it overnight, as the innate-sequencing theory predicts. Instead, on average, they learned the first pair in about ten days, the second in four days and the third in two days. © 2013 Nature Publishing Group

Keyword: Language; Development of the Brain
Link ID: 18208 - Posted: 05.30.2013

by Emily Underwood Without a way to forecast whether the early warning signs of autism will develop into severe impairment, parents of children with the disorder are left with one harrowing option: Wait and see. Now, a new study suggests that a distinct ripple of brain waves measured while toddlers listen to words can reliably predict how they will fare in a range of cognitive areas up to age 6—the longest-term forecast yet achieved. In addition to pointing toward more effective treatments, the discovery could help reveal how early social abilities facilitate the development of language. Many children with autism spectrum disorder (ASD) have begun to display telltale social and language deficits by the time they're toddlers; they fail to play or make eye contact with others, for example, or to say short sentences such as "drink milk." Although scientists have long considered the brain systems that govern these two types of deficits as separate, a growing body of evidence suggests that they are actually deeply intertwined, says Patricia Kuhl, a cognitive neuroscientist at the University of Washington, Seattle, and lead author of the new study. One of Kuhl's first important clues that social deficits might hinder language acquisition in autism came from her 2005 study of "Motherese"—the exaggerated, sing-song baby talk that parents instinctively shower on their children. When given the choice between listening to samples of Motherese or computer-generated tones, Kuhl found that preschoolers with autism "actually preferred the Robovoice," she says. This lack of interest in human speech not only correlated with the severity of a child's autistic symptoms, Kuhl notes, but with a lack of typical brain response to subtle changes in syllables, such as the switch from "ba" to "da." That's bad news, she says, because "picking up these tiny changes means the difference between learning language or not." © 2010 American Association for the Advancement of Science

Keyword: Autism; Language
Link ID: 18207 - Posted: 05.30.2013

By ALAN SCHWARZ An analysis published Wednesday by the American Medical Association said children with attention deficit hyperactivity disorder who take stimulant medication do not have a lower risk over all for later substance abuse, contradicting the longstanding and influential message that such medicines tend to deter those with the disorder from abusing other substances. The paper, written by three researchers at the University of California, Los Angeles, examined data from 15 previous studies on the subject and determined that, on average, medications like Adderall and Ritalin had no effect one way or the other on whether children abused alcohol, marijuana, nicotine or cocaine later in life. A 2003 study in the journal Pediatrics had concluded that the introduction of stimulant medication to children with A.D.H.D. reduced the risk of such abuse later in life, a finding that has been repeated by doctors and pharmaceutical companies not only to assuage parents’ fears of medication but also to suggest that the pills would protect their children from later harm. “I always doubted the whole ‘protection’ argument, and I wasn’t the only one, but that message was really out there,” said Liz Jorgensen, an adolescent addiction specialist at Insight Counseling in Ridgefield, Conn. “Hopefully, this message will be heard loud and clear.” The study comes amid growing concern about the persistent rise in A.D.H.D. diagnoses and prescriptions for medication among children. A recent New York Times analysis of data collected by the Centers for Disease Control and Prevention found that 11 percent of all children ages 4 through 17 — 6.4 million over all — had received a diagnosis of A.D.H.D. from a medical professional. The diagnosis rate rose to 19 percent for boys of high school age. © 2013 The New York Times Company

Keyword: ADHD; Drug Abuse
Link ID: 18206 - Posted: 05.30.2013

By Stan Alcorn After decades languishing in jars in the closet of an animal lab at the University of Texas, approximately 90 brains removed from mental patients are finally being documented--by a photographer and by college freshmen. Photographer Adam Voorhes found the collection a few years ago when he came to Dr. Tim Schallert's lab at UT Austin in search of a brain to help illustrate a Scientific American article. "It was something about `protecting your brain' or `barriers for the brain,'" Voorhes told me. "They wanted to photograph a human brain in like a bell jar or a case or armor. Anything to show a brain being protected." Voorhes got the normal brain he needed, and was about to take it back to his studio to photograph, when Dr. Schallert asked if he wanted to see some more abnormal brains. Voorhes described being led through an animal research facility to a storage closet with one wall lined with chemicals, and another wall lined with jars full of brains unlike any he had ever seen before. "Some of them are huge, some of them are really tiny. There was one that had no wrinkles at all," he said. "I don't even know how to explain it." The brains had been amassed over the course of 30 years by a medical pathologist at the Austin State Hospital, who preserved them after routine autopsies. When they were discovered in the mid-1980s, they were the subject of a high-profile battle , as institutions vied to house and study them. "Harvard Scientists Lose Minds: University of Texas Wins Brain Collection" ran one headline. © 2013 Scientific American

Keyword: Brain imaging
Link ID: 18205 - Posted: 05.30.2013

“Which way do you swing?” It’s such a simple, but loaded question. Social-economic issues aside, even the biological basis of sexual preference is hotly debated. Homosexual behavior isn’t limited to humans; it’s evolutionarily conserved in species as diverse as the lowly fruit fly to the mighty lion. Some argue that genes are involved, but so far the hunt for “gay genes” have only led to dead ends (and a lot of controversy!). Sex hormones are the next suspect, but they seem to only change sex drive, not so much preference. Now this study suggests that the answer may be as simple as one SINGLE neurotransmitter: serotonin. First off, why serotonin? We know that serotonin is involved in sexual behaviour. SSRI antidepressants, like Celexa and Zoloft, work by increasing the amount of serotonin in the synapses. This relieves depressive symptoms, but has the unfortunate side effect of lowering libido. Many other studies converge to support the same simple conclusion: more serotonin=less sexual behaviour, less serotonin= more sexual behaviour. But what about PREFERENCE? The same group published a highly controversial study a few years ago, in which they argued that abolishing serotonin in male mice wiped out their preference for females. These mice showed sexual interest in both males and females, and mounted both sexes equally when given the chance. It caused quite a stir back then, with many pointing out that their conclusions were premature. One major problem is that serotonin-lacking mice are much more likely to engage in sexual behavior. Hence, they might have just been so horny that they didn’t care to pick-and-choose, mounting everything within sight regardless of gender.

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 18204 - Posted: 05.30.2013

by Douglas Heaven Putting a digital face to the abusive voices in their head could help people with schizophrenia. Results of a preliminary trial, announced today at the Wellcome Trust in London, demonstrated how people with schizophrenia could overcome their auditory hallucinations by conversing with an avatar representation of the voice in their head. At the start of the trial, 16 people with schizophrenia created an on-screen avatar that best matched what they imagined the voice in their head to look like – much like a police photo-fit. They then chose a male or female voice closely resembling the one they hear. By conversing with a therapist via the avatar, the volunteers reported reduced levels of distress and higher self-esteem. Three people stopped hearing the hallucinatory voice altogether – including one who had lived with it for 16 years. Hearing voices is a common symptom of schizophrenia, which affects about 1 per cent of the population worldwide. The hallucinations can stop people from thinking clearly and prevent them from working and sustaining social relationships. The voices are also typically abusive, telling the person to harm themselves or others. "It's hard to imagine what it's like to hear a disembodied voice," says Julian Leff at University College London, who led the trial. People often say that the helplessness is the worst thing, he says. They cannot control the voices and they feel dominated. © Copyright Reed Business Information Ltd.

Keyword: Schizophrenia
Link ID: 18203 - Posted: 05.30.2013

by John Bohannon WASHINGTON, D.C.—People may grow wiser with age, but they don't grow smarter. Many of our mental abilities decline after midlife, and now researchers say that they've fingered a culprit. A study presented here last week at the annual meeting of the Association for Psychological Science points to microbleeding in the brain caused by stiffening arteries. The finding may lead to new therapies to combat senior moments. This isn't the first time that microbleeds have been suspected as a cause of cognitive decline. "We have known [about them] for some time thanks to neuroimaging studies," says Matthew Pase, a psychology Ph.D. student at Swinburne University of Technology in Melbourne, Australia. The brains of older people are sometimes peppered with dark splotches where blood vessels have burst and created tiny dead zones of tissue. How important these microbleeds are to cognitive decline, and what causes them, have remained open questions, however. Pase wondered if high blood pressure might be behind the microbleeds. The brain is a very blood-hungry organ, he notes. "It accounts for only 2% of the body weight yet receives 15% of the cardiac output and consumes 20% of the body's oxygen expenditure." Rather than getting the oxygen in pulses, the brain needs a smooth, continuous supply. So the aorta, the largest blood vessel branching off the heart, smooths out blood pressure before it reaches the brain by absorbing the pressure with its flexible walls. But as people age, the aorta stiffens. That translates to higher pressure on the brain, especially during stress. The pulse of blood can be strong enough to burst vessels in the brain, resulting in microbleeds. © 2010 American Association for the Advancement of Science

Keyword: Stroke; Learning & Memory
Link ID: 18202 - Posted: 05.30.2013