By Gary Stix First off, this study on a molecule tied to social interaction was conducted in animals. So I’m supposed to turn on the siren and the flashing red light here to let you know that the headline you just read might not apply in humans. Still, the animals in question, prairie voles, are a special case, models of faithfulness that put humans to shame when it comes to the delicate topic of monogamy. Once hitched, the rodents stick with their mates for life—an example of moral pulchritude in the animal kingdom that many of us human sinners can never hope to emulate. It could easily become the state animal for whole regions of the U.S. For just that alone, the implications of the experiment in question are particularly intriguing. The new research shows that oxytocin, the bonding hormone, is sometimes capable of turning the upstanding rodent into an anti-social lout, making the study results more compelling in many ways than if they were reported in errant humans. So the man-bites-dog headline stays. This all came up when Karen Bales, a professor at University of California, Davis, wanted to know what would happen if oxytocin gets administered for lengthy intervals, not the short-term dosing that has occurred in the multitude of previous vole studies that linked the hormone to monogamous behavior. In their experiment, Bales and team gave either a low, medium or high dose through the nose to 29 voles, and a saline solution to 14 controls At first, the animals became all cuddly as in previous studies But after three weeks, an entire vole childhood (from weaning to sexual maturity), they started breaking bad. Males did not engage in the normal behavior of “pair bonding,” that drives them to look for the girl of their dreams. And female voles’ natural mothering instinct seemed to disappear: when placed nearby young pups that were not their own, they didn’t dote, as they are wont to do. The cuddle hormone had turned the rodents into meanies. © 2012 Scientific American

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 17379 - Posted: 10.17.2012

(Relaxnews)—In a study of more than 90 men, scientists from the University of Bonn, Germany, found that subjects treated with a dose of testosterone before the study told fewer lies than those who received a placebo. "Testosterone has always been said to promote aggressive and risky behavior and posturing," says researcher and neuroscientist Bernard Weber. However, more recent studies indicate that it also fosters social behavior. Prior research has suggested that the hormone may actually cause people to be more "prosocial" in that they voluntarily act in the interest of others, writes the Atlantic magazine, but exactly how the hormone influences behaviors isn't understood. For this latest study, 46 subjects were treated with testosterone by applying it to the skin in gel form, while 45 subjects received a placebo. The next day, the subjects played a dice game in which it was easy for the men to lie to earn more money, with no possibility of being caught. The study was designed so that it was impossible even for the researchers to detect whether a subject was lying or not. Rather, they used statistics to analyze reported earnings that were higher than probability would allow, inferring from these how honest the subjects were being. While many people in the study lied about the game, there was a noticeable difference between the men boosted with testosterone and those who weren't—the testosterone group avoided the temptation to cheat more often. Blood tests confirmed the results that high testosterone levels were linked with more honest game playing. "Test subjects with the higher testosterone levels had clearly lied less frequently than untreated test subjects," says co-author Armin Falk. "This result clearly contradicts the one-dimensional approach that testosterone results in anti-social behavior." The study was published last week in the journal PLoS One . http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0046774 © 2012 NY Times Co.

Keyword: Hormones & Behavior
Link ID: 17378 - Posted: 10.17.2012

by Clare Wilson Why does making direct eye contact with someone give you that feeling of a special connection? Perhaps because it excites newly discovered "eye cells" in the amygdala, the part of the brain that processes emotions and social interactions. This new type of neuron was discovered in a Rhesus macaque. If humans have these neurons too, it may be that they are impaired in disorders such as autism and schizophrenia, which affect eye contact and social interactions. Katalin Gothard, a neurophysiologist at the University of Arizona in Tucson, and her team placed seven electrodes in the amygdala of a Rhesus macaque. The electrodes, each one-tenth the thickness of a human hair, allowed them to record activity in individual neurons as the macaque watched a video featuring another macaque. All the while, the team also tracked the macaque's gaze. Out of the 151 neurons the researchers could distinguish, 23 fired only when the macaque was looking at the eyes of the monkey in the video. Of these neurons, which the team call "eye cells", four fired more when the monkey in the video appeared to be gazing back at the laboratory macaque, as if the two animals were making eye contact. "These are cells that have been tuned by evolution to look at the eye, and they extract information about who you are, and most importantly, are you making eye contact with me," says Gothard. Other eye cells fired depending on whether the monkey in the video was behaving in a friendly, aggressive or neutral manner, but not in response to eye contact. © Copyright Reed Business Information Ltd.

Keyword: Vision
Link ID: 17377 - Posted: 10.17.2012

The Crack Team That Removes & Preserves People's Brains Just Hours After They Die by Jeff Wheelwright On average, the residents of Sun City, Arizona, occupy their domiciles for a dozen years. When they depart—almost always by dying—they often leave their brains behind. The stages of physical and mental decline take them from their dream house to a hospital off Del Webb Boulevard, then to a nursing home, and finally back to the medical complex, where researchers harvest their most important organ. Hoping to do good for science, they have enrolled in the Brain and Body Donation Program of the Banner Sun Health Research Institute—widely considered the world’s preeminent brain bank. A large base of well-
documented donors in close proximity sets the Sun City program apart from other repositories, which often have scant information about patients who may be scattered and diverse. Here, healthy, active seniors who eventually die of, say, heart disease, can be compared with others who develop neurodegenerative disorders. Because the two sets of subjects have similar backgrounds, lifestyles, and ethnic traits, changes relating to a brain disease should be easier to detect. The institute is also famed for its crack autopsy team, which responds so quickly that no more than three hours elapse from the time a donor expires to the time that the brain is removed and preserved. “We’re not the biggest brain bank in the world, but we have the highest-quality tissue,” says pathologist Thomas Beach, the program director, who notes that donors must live within a 50-mile radius of the morgue. © 2012, Kalmbach Publishing Co.

Keyword: Miscellaneous
Link ID: 17376 - Posted: 10.17.2012

By NICHOLAS BAKALAR A new study suggests that prenatal exposure to mercury is associated with symptoms of attention deficit hyperactivity disorder, but the greater a mother’s consumption of fish — a source of mercury — the less likely her child is to suffer these symptoms. The apparently paradoxical findings, published online last week in Archives of Pediatrics & Adolescent Medicine, come from an analysis of 607 children born between 1993 and 1998. The researchers reviewed data on the amounts of mercury in the mothers’ hair, comparing them against dietary records. At ages 7 to 10, the children underwent neuropsychological examinations. After controlling for fish consumption and many other factors, the scientists found an association between several A.D.H.D.-related behaviors and levels of mercury above one microgram per gram in the maternal hair samples. At the same time, they found that after adjusting for mercury levels, mothers who ate more than two servings of fish per week — more than the 12 ounces that government guidelines suggest — were less likely to have children with A.D.H.D.-related behaviors. “All fish has some mercury in it, but there are very different levels,” said the lead author, Sharon K. Sagiv, an assistant professor at Boston University. The findings may seem contradictory, she added, but “they highlight an important public health issue: Eating fish is good for you, but eating fish that is high in mercury is not.” Copyright 2012 The New York Times Company

Keyword: ADHD; Neurotoxins
Link ID: 17375 - Posted: 10.16.2012

By Kate Kelland and Reuters, Children with attention-deficit hyperactivity disorder who take stimulants such as Ritalin tend to feel that the drugs help them control their behavior and do not turn them into “robots,” as many skeptics assume, a study reported on Monday. The research, which for the first time asked children taking ADHD drugs what they felt about their treatment and its effects, found that many said medication helped them manage their impulsivity and make better decisions. “With medication, it’s not that you’re a different person. You’re still the same person, but you just act a little better,” said Angie, an 11-year-old American who took part in the study and was quoted in a report about its findings. The results are likely to further fuel the debate about whether children with ADHD, some as young as 4 years old, should be given stimulants. ADHD is one of the most common childhood disorders in the United States, where parents report that 9.5 percent of children ages 4 and older have received such a diagnosis, according to the Centers for Disease Control and Prevention. In Britain, where the authors of the study are based, experts estimate that between 5 and 10 percent of children and adolescents have ADHD. Symptoms of the disorder include difficulty staying focused, hyperactivity and problems with controlling disruptive or aggressive behavior. © 1996-2012 The Washington Post

Keyword: ADHD
Link ID: 17374 - Posted: 10.16.2012

By Jason G. Goldman Television has a bad side. According to a report from the University of Michigan, the average American child has seen sixteen thousand murders on TV by age 18. Indeed, programs explicitly designed for kids often contain more violence than adult programming, and that violence is often paired with humor. Every single animated feature film produced by US production houses between 1937 and 1999 contained violence, and the amount of violence increased throughout that time period. Researchers from the University of Michigan found that just being awake and in the room with a TV on more than two hours a day – even if the kids aren’t explicitly paying attention to the TV – was a risk factor for being overweight at ages three and four-and-a-half. This may be related to the fact that two thirds of the twenty thousand television commercials the average child sees each year are for food. The American Academy of Pediatrics, in their wisdom, recommend that children under age two have zero hours of screen time. (Meanwhile, a bevy of DVDs are marketed to parents of children age zero to 2, promising to “teach your child about language and logic, patterns and sequencing, analyzing details and more.”) Despite the warning, however, many parents of infants age 0 to 2 do allow their children some screen time. In 2007, Frederick J. Zimmerman of the University of Washington (now at UCLA) wondered what the effects of TV watching were on those infants. He collected data from 1008 parents about the infants’ TV habits, as well as the amount of time they spent doing things like reading (with parents), playing, and so on. He also administered, for each child, a survey called the MacArthur-Bates Communicative Development Inventory (CDI). The CDI is a standard tool used by developmental psychologists to assess language development in infants and children. He and his team then looked to see if there were statistical relationships between time spent watching TV (and the other activities) and language abilities, as measured by the CDI. Here’s the catch: they only included infants whose TV watching consisted entirely of infant-directed programming. That is, TV programs especially designed for infants age 0 to 2. If the infants were shown other sorts of TV programs, they were not included in the study. © 2012 Scientific American,

Keyword: Development of the Brain
Link ID: 17373 - Posted: 10.16.2012

By HENRY FOUNTAIN SAINT-LOUIS, France — Denis Spitzer wants to beat dogs at their own game. At a binational armaments and security research center here in eastern France, Dr. Spitzer and his colleagues are working on a sensor to detect vapors of TNT and other explosives in very faint amounts, as might emanate from a bomb being smuggled through airport security. Using microscopic slivers of silicon covered with forests of even smaller tubes of titanium oxide, they aim to create a device that could supplement, perhaps even supplant, the best mobile bomb detector in the business: the sniffer dog. But emulating the nose and brain of a trained dog is a formidable task. A bomb-sniffing device must be extremely sensitive, able to develop a signal from a relative handful of molecules. And it must be highly selective, able to distinguish an explosive from the “noise” of other compounds. While researchers like Dr. Spitzer are making progress — and there are some vapor detectors on the market — when it comes to sensitivity and selectivity, dogs still reign supreme. “Dogs are awesome,” said Aimee Rose, a product sales director at the sensor manufacturer Flir Systems, which markets a line of explosives detectors called Fido. “They have by far the most developed ability to detect concealed threats,” she said. But dogs get distracted, cannot work around the clock and require expensive training and handling, Dr. Rose said, so there is a need for instruments. © 2012 The New York Times Company

Keyword: Chemical Senses (Smell & Taste); Robotics
Link ID: 17372 - Posted: 10.16.2012

by Michael Marshall There's a downside to everything. When humans evolved bigger brains, we became the smartest animal alive and were able to colonise the entire planet. But for our minds to expand, a new theory goes, our cells had to become less willing to commit suicide – and that may have made us more prone to cancer. When cells become damaged or just aren't needed, they self-destruct in a process called apoptosis. In developing organisms, apoptosis is just as important as cell growth for generating organs and appendages – it helps "prune" structures to their final form. By getting rid of malfunctioning cells, apoptosis also prevents cells from growing into tumours. "Reduced apoptotic function is well known to be associated with cancer onset," says John McDonald of the Georgia Institute of Technology in Atlanta. McDonald compared skin cells from humans, chimpanzees and macaques and found that, compared to cells from other primates, our cells are reluctant to undergo apoptosis. When exposed to apoptosis-triggering chemicals, human cells responded significantly less than the chimp and macaque cells. Fewer human cells died, and they did not change shape in the ways cells do when preparing to die. In 2009, McDonald found that genes promoting apoptosis are down-regulated – essentially suppressed – in humans, and those turning it off are up-regulated (Medical Hypotheses, doi.org/bgkshp). Genes involved in apoptosis are also known to have changed rapidly during human evolution. The new study adds to the evidence that apoptosis is down-regulated in human cells. © Copyright Reed Business Information Ltd.

Keyword: Apoptosis; Development of the Brain
Link ID: 17371 - Posted: 10.16.2012

by Jessica Hamzelou Never underestimate the value of a good night's sleep. Not only does a lack of shut-eye leave you irritable, it has been linked to diabetes and weight gain, though no one understood why. To investigate, Matthew Brady at the University of Chicago and his colleagues tested fat cells taken from the bellies of seven adults after four nights of sleeping up to 8 and a half hours, and then again after four nights on a measly 4 and a half hours. The team found that after sleep deprivation fat cells from the same person were on average 30 per cent less responsive to insulin – a hormone that makes muscle, liver and fat cells take up glucose after a meal. High blood glucose levels are linked to diabetes. Fat cells also normally release the appetite-regulating hormone leptin. Brady suggests that if sleep-deprived cells are generally malfunctioning, this mechanism may also be disrupted, affecting weight gain. "We were surprised at how robust the response was," says Brady. "Four nights of sleep curtailment represents a real-world situation, such as sitting for final exams or having a newborn in the house." Journal reference: Annals of Internal Medicine, DOI: 10.7326/0003-4819-157-8-201210160-00005 © Copyright Reed Business Information Ltd.

Keyword: Obesity; Sleep
Link ID: 17370 - Posted: 10.16.2012

By Megan Gannon Something "uncanny" seems familiar yet alien at the same time, often stirring a feeling of fear or revulsion. For example, we tend to feel creeped out around lifelike robots and animatronics that fall in the "uncanny valley," the divide between the fully human and the not-exactly-human. New research suggests this type of reaction might start in infancy. Scientists in Japan studied how 57 babies reacted to pictures of faces. The infants were shown real photographs — either of the child's mother or a complete stranger — and natural-looking morphed images that combined either the mother's face and a stranger's face or two strangers' faces. In previous studies, researchers showed that infants tend to stare at pictures of both mothers and strangers for about the same amount of time, but measures of their neural responses suggest they process the two faces differently. "Infants like both familiarity and novelty in objects," Yoshi-Taka Matsuda of Tokyo's Riken Brain Science Institute said in a statement. "We wondered how their preference might change when they encountered objects that are intermediate between familiarity and novelty." Using an eye-tracking system, the researchers found the infants looked at the photos of their mothers longer than the "half-mother" hybrid faces. This effect strengthened with the infant's age, the team said. There was no significant difference in the infants' preference between the real and morphed photos of strangers. © 2012 NBCNews.com

Keyword: Emotions; Development of the Brain
Link ID: 17369 - Posted: 10.15.2012

By LAURA GEGGEL For years, young people — often girls and young women — have frequented Web sites promoting anorexia and bulimia as a source of inspiration and tips on staying thin, even as online companies have worked to ban such content. Now, groups and Web sites focused on recovery from eating disorders are fighting back. “We need to be looking at these communities and see what we can learn from them, and what we can provide as a positive alternative,” said Claire Mysko, manager of Proud2Bme.org, a Web site and online community focused on healthy recovery that is financed by the nonprofit National Eating Disorders Association. “That’s what we’re trying to do here.” This Saturday, the group is taking its message to the University of South Florida in Tampa for its free annual Proud2Bme Summit. Attendees will be encouraged to engage in activities like taking a stand on Twitter against “body snarking,” a bullying tactic that draws attention to a person’s body or weight gain, and hear from speakers including Julia Bluhm, a 14-year-old who collected more than 86,000 signatures to petition Seventeen magazine to print one unaltered photo spread a month. “Our goal here is to make it a space where people can connect,” Ms. Mysko said. The site began in 2011 after the success of its Dutch counterpart, Proud2Bme.nl, whose co-founder Scarlet Hemkes struggled with anorexia and bulimia as a teenager and young adult and was horrified to find countless sites where girls competed to lose weight or shared tips on how to lie to parents about weight loss. Inspired by France’s move in 2008 to ban such sites — commonly called pro-ana (for pro-anorexia) sites — Ms. Hemkes collected 10,000 signatures with the hopes of inspiring similar Dutch legislation. When that didn’t work, she created a community on Hyves, a Facebook-like social network for girls with eating disorders, before founding Proud2Bme with a psychologist, Eric van Furth, in 2009. Copyright 2012 The New York Times Company

Keyword: Anorexia & Bulimia
Link ID: 17368 - Posted: 10.13.2012

Sitting exams and tests is often a nerve-racking experience, but being anxious beforehand may boost a candidate's grades, researchers say. A study published in the British Journal of Psychology finds being anxious only has a negative impact on results if a child's memory is poor. But if a young person has a good memory, a tendency to feel anxious is linked with getting better marks. The research assessed 96 children aged 12 to 14 in memory and anxiety tests. A questionnaire established how anxious the children usually felt, and the results were measured against their ability to perform computerised tests involving "complex" or working-memory skills. "We found that for individuals with low working-memory capacity, increases in [a tendency towards] anxiety were related to decreases in cognitive test performance," the study says. "For those with high working-memory capacity, however, the pattern of results was reversed. An increase in [a tendency towards] anxiety was linearly associated with higher test scores. "These effects were not better accounted for by gender, age, or time of testing." Poor memory The researchers say the results of the study should encourage education professionals to target help at anxious children with poor complex memory skills. BBC © 2012

Keyword: Stress; Learning & Memory
Link ID: 17367 - Posted: 10.13.2012

By ARTHUR A. STONE DESPITE the beating that Mondays have taken in pop songs — Fats Domino crooned “Blue Monday, how I hate blue Monday” — the day does not deserve its gloomy reputation. Two colleagues and I recently published an analysis of a remarkable yearlong survey by the Gallup Organization, which conducted 1,000 live interviews a day, asking people across the United States to recall their mood in the prior day. We scoured the data for evidence that Monday was bluer than Tuesday or Wednesday. We couldn’t find any. Mood was evaluated with several adjectives measuring positive or negative feelings. Spanish-only speakers were queried in Spanish. Interviewers spoke to people in every state on cellphones and land lines. The data unequivocally showed that Mondays are as pleasant to Americans as the three days that follow, and only a trifle less joyful than Fridays. Perhaps no surprise, people generally felt good on the weekend — though for retirees, the distinction between weekend and weekdays was only modest. Likewise, day-of-the-week mood was gender-blind. Over all, women assessed their daily moods more negatively than men did, but relative changes from day to day were similar for both sexes. And yet still, the belief in blue Mondays persists. Several years ago, in another study, I examined expectations about mood and day of the week: two-thirds of the sample nominated Monday as the “worst” day of the week. Other research has confirmed that this sentiment is widespread, despite the fact that, well, we don’t really feel any gloomier on that day. © 2012 The New York Times Company

Keyword: Depression; Emotions
Link ID: 17366 - Posted: 10.13.2012

by Douglas Heaven I spy, with my mechanical eye. It seems a simple mechanical change plays a role in sensory perception in fruit flies, and possibly in many other animals, including humans. The eyes of the common fruit fly (Drosophila melanogaster) contain clusters of light-sensitive cells organised into rods. When light strikes one of these cells, it triggers a series of chemical reactions. These cause a protein called a transient receptor potential (TRP) ion channel to open. When it's open, the TRP allows charged particles to flow into the cell, causing the cell to send a signal to the fly's brain. TRP channels play a part in sensory perception in many animals, from nematodes to humans. But nobody knew how the chemical signals make the TRP channel open. Shrinking rods "Everyone's been looking for years and years at the chemical messengers," says Roger Hardie of the University of Cambridge, UK. A mechanical trigger was never considered. "No one thought to look," he says. With Kristian Franze, Hardie found that the chemical signals change the surface area of the cell's outer membrane by destroying some of its constituent molecules. When several cells shrink like this, the entire rod contracts by up to 400 nanometres, a margin big enough to be seen with a microscope. "The whole membrane shrinks," says Hardie. "It's like a little muscle twitching." © Copyright Reed Business Information Ltd.

Keyword: Vision
Link ID: 17365 - Posted: 10.13.2012

When you hear the sound of a nail scratching a blackboard, the emotional and auditory part of your brain are interacting with one another, a new study reveals. The heightened activity and interaction between the amygdala, which is active in processing negative emotions, and the auditory parts of the brain explain why some sounds are so unpleasant to hear, scientists at Newcastle University have found. "It appears there is something very primitive kicking in," said Dr. Sukhbinder Kumar, the paper’s author. "It’s a possible distress signal from the amygdala to the auditory cortex." Researchers at the Wellcome Trust Centre for Neuroimaging at UCL and Newcastle University used functional magnetic resonance imaging (fMRI) to examine how the brains of 13 volunteers responded to a range of sounds. Listening to the noises inside the scanner, the volunteers rated them from the most unpleasant, like the sound of knife on a bottle, to the most pleasing, like bubbling water. Researchers were then able to study the brain response to each type of sound. "At the end of every sound, the volunteers told us by pressing a button how unpleasant they thought the sound was," Dr. Kumar said. Researchers found that the activity of the amygdala and the auditory cortex were directly proportional to the ratings of perceived unpleasantness. They concluded that the emotional part of the brain, the amygdala, in effect takes charge and modulates the activity of the auditory part of the brain, provoking our negative reaction. © CBC 2012

Keyword: Hearing; Emotions
Link ID: 17364 - Posted: 10.13.2012

By Nathan Seppa Men with high blood levels of lycopene — the compound that makes tomatoes red — are about half as likely to have a stroke as those low on lycopene, researchers in Finland report October 9 in Neurology. Some evidence suggests that lycopene quells inflammation, limits cholesterol production and inhibits blood clotting. But first and foremost, lycopene is a carotenoid, an antioxidant that sops up unstable molecules in the body called free radicals —agents that can induce DNA damage, kill cells, attack proteins and contribute to blood vessel disease. Lycopene’s direct effect on stroke risk is less clear. Studies have found that a diet rich in fruits and vegetables, meaning plenty of carotenoids, seems to reduce the risk of heart disease and stroke. But few studies have analyzed lycopene’s effect specifically on stroke risk over time, the researchers note. Jouni Karppi and colleagues at the University of Eastern Finland in Kuopio used blood tests to determine the lycopene levels of 1,031 men ages 46 to 65. Afterward, the men were monitored for a median of 12 years. The researchers tallied 67 strokes in the men over that span. Men with the lowest lycopene levels at the outset were more than twice as likely to have a stroke later as were those with the highest. “This is a very good study, and I’m really surprised they were able to find this relationship with only 67 strokes,” says Lyn Steffen, a nutritional epidemiologist at the University of Minnesota. © Society for Science & the Public 2000 - 2012

Keyword: Stroke
Link ID: 17363 - Posted: 10.13.2012

Cort Pedersen at the University of North Carolina at Chapel Hill and his team gave 11 alcohol-dependent volunteers two daily doses of an oxytocin nasal spray or a placebo, during the first three days of a detox programme. The volunteers also received lorazepam - a detox drug - when their withdrawal symptoms reached a specific level. The oxytocin group had fewer alcohol cravings and milder withdrawal symptoms than the placebo group, and used just one-fifth of the lorazepam (Alcoholism: Clinical and Experimental Research, doi.org/jgp). "Four [oxytocin] volunteers didn't need any lorazepam at all," says Pedersen. This is good news because lorazepam is highly addictive. While it reduces anxiety and seizures during alcohol withdrawal, users can experience insomnia and cravings when they come off the drug. Although it is unclear how oxytocin - famed for its role in social bondingMovie Camera - helps to aid withdrawal, it has no known side effects. Pedersen hopes that alcoholics who take the hormone will therefore be less likely to experience the unpleasant symptoms that can lead to relapse. © Copyright Reed Business Information Ltd.

Keyword: Drug Abuse; Hormones & Behavior
Link ID: 17362 - Posted: 10.13.2012

By John McCarthy Humans can focus on one thing amidst many. “Searchlight of attention” is the metaphor. You recall a childhood friend’s face one moment, then perhaps the dog you loved back then, and then…what you will. Your son’s face on stage rivets your attention; the rest of the cast is unseen. No “ghost” in the brain aims that searchlight. What does? Neurons do, somehow, but how is a mystery that new research actually deepened. The experiment used monkeys. They can focus attention like people do. They can zero in on a red square on a screen full of distractions, for instance. When the square moves, a trained monkey will press a button. Electrodes inserted in a monkey neuron will reveal “firing” (minuscule electrical ripples) simultaneous with attention. This may locate brain areas by which the monkey watched that red square. It’s not only the explosive firing in neurons that instruments detect. They also spot the milder priming to fire, when the monkey expects (from training) that neurons are about to be stimulated. Neurons in a one area of the cortex fire when an object moves (but not, for instance, if it gets brighter but stays still.) If a monkey learns that an onscreen cue (a blip of light) signals that the red square is about to move, the cue alone primes the motion-sensing neurons. They also synchronize more tightly (i.e. reduce random noise among them.) Cues cock neurons, like a gun. It’s like Pavlov’s dogs salivating at the bell that preceded feeding. © 2012 Scientific American

Keyword: Attention
Link ID: 17361 - Posted: 10.11.2012

Virginia Hughes On a chilly, January night in 1986, Elizabeth Ebaugh carried a bag of groceries across the quiet car park of a shopping plaza in the suburbs of Washington DC. She got into her car and tossed the bag onto the empty passenger seat. But as she tried to close the door, she found it blocked by a slight, unkempt man with a big knife. He forced her to slide over and took her place behind the wheel. The man drove aimlessly along country roads, ranting about his girlfriend's infidelity and the time he had spent in jail. Ebaugh, a psychotherapist who was 30 years old at the time, used her training to try to calm the man and negotiate her freedom. But after several hours and a few stops, he took her to a motel, watched a pornographic film and raped her. Then he forced her back into the car. She pleaded with him to let her go, and he said that he would. So when he stopped on a bridge at around 2 a.m. and told her to get out, she thought she was free. Then he motioned for her to jump. “That's the time where my system, I think, just lost it,” Ebaugh recalls. Succumbing to the terror and exhaustion of the night, she fainted. Ebaugh awoke in freefall. The man had thrown her, limp and handcuffed, off the bridge four storeys above a river reservoir. When she hit the frigid water, she turned onto her back and started kicking. “At that point, there was no part of me that thought I wasn't going to make it,” she says. Few people will experience psychological and physical abuse as terrible as the abuse Ebaugh endured that night. But extreme stress is not unusual. In the United States, an estimated 50–60% of people will experience a traumatic event at some point in their lives, whether through military combat, assault, a serious car accident or a natural disaster. Acute stress triggers an intense physiological response and cements an association in the brain's circuits between the event and fear. If this association lingers for more than a month, as it does for about 8% of trauma victims, it is considered to be post-traumatic stress disorder (PTSD). The three main criteria for diagnosis are recurring and frightening memories, avoidance of any potential triggers for such memories and a heightened state of arousal. © 2012 Nature Publishing Group,

Keyword: Stress; Learning & Memory
Link ID: 17360 - Posted: 10.11.2012