Alan Searleman In the scientific literature, the term eidetic imagery comes closest to what is popularly called photographic memory. The most common way to identify eidetikers (as people with eidetic imagery are often called) is by the Picture Elicitation Method. In it, an unfamiliar picture is placed on an easel and a person carefully scans the entire scene. After 30 seconds have elapsed, the picture is removed from view, and the person is asked to continue to look at the easel and to report anything that they can observe. People possessing eidetic imagery will confidently claim to still "see" the picture. In addition, they can scan it and examine different parts of it just as if the picture were still physically present. Consequently, one of the hallmarks of eidetic imagery is that eidetikers use the present tense when answering questions about the missing picture, and they can report in extraordinary detail what it contained. Eidetic images differ from other forms of visual imagery in several important ways. First, an eidetic image is not simply a long afterimage, since afterimages move around when you move your eyes and are usually a different color than the original image. (For example, a flash camera can produce afterimages: the flash is bright white, but the afterimage is a black dot, and the dot moves around every time you move your eyes.) In contrast, a true eidetic image doesn’t move as you move your eyes, and it is in the same color as the original picture. Second, a common visual image that we can all create from memory (such as an image of a bedroom) does not have the characteristics of most eidetic images, which almost always fade away involuntarily and part by part. Also, it is not possible to control which parts of an eidetic image fade and which remain visible. Unlike common visual images created from memory, most eidetic images last between about half a minute to several minutes only, and it is possible to voluntarily destroy an eidetic image forever by the simple act of blinking intentionally. Furthermore, once gone from view, rarely can an eidetic image ever be retrieved. © 1996-2007 Scientific American, Inc.

Keyword: Learning & Memory
Link ID: 10131 - Posted: 06.24.2010

Mark A. W. Andrews An itch, also known as pruritus, is a general sensation arising from the irritation of skin cells or nerve cells associated with the skin. While it can be a nuisance, pruritus serves as an important sensory and self-protective mechanism, as do other skin sensations such as touch, pain, vibration, cold and heat. It can alert us to harmful external agents, but can become unbearable if not treated. Pruritus is a dominant symptom of many skin diseases and also occurs in some diseases that affect the entire body. An itching sensation of the skin arises due to stimulation of pruriceptors—itch-sensing nerve endings—by mechanical, thermal or chemical mediators. These include: Chemicals for immune response (histamines) and pain relief (opiods) Neuropeptides, which include pain-regulating messengers released within the brain, such as endorphins The neurotransmitters acetylcholine and serotonin Prostaglandins, which are lipids that, among other functions, create the sensation of pain in spinal nerve cells Stimulation by any of these agents is typically related to inflammation, dryness or other damage to the skin, mucous membranes or conjunctiva of the eye. In general, pruritus involves activation of the pruriceptors of specialized nerve cells called C-fibers. These C-fibers are identical to those associated with the sensation of pain, but they are functionally distinct and only convey the itch sensation—they comprise about 5 percent of the total C-fibers in human skin. © 1996-2007 Scientific American, Inc.

Keyword: Pain & Touch
Link ID: 10130 - Posted: 06.24.2010

By Stephen Cave If I had free will, I would choose to be funnier. I would choose always to have the right witty riposte ready to disarm adversaries and delight friends. But sadly, it is not so. My lot is for the same lame old gags to hobble out whether I will them to or not, like embarrassing aunts at a wedding. Indeed if we had free will, we might all choose to have the punning powers of the Two Ronnies, combined with the benevolence of Bob Geldof. But we do not. And that is a fact, laboratory proven. But of course we have free will, you might be thinking. You could prove it by, for example, choosing to raise your arm at some point in the next five seconds. Go on then. Done it? There, that was easy. Of your own volition, at the time of your choice, you moved your arm: QED. But the American neuroscientist Benjamin Libet has shown that before every such movement, there is a distinctive build-up of electrical activity in the brain. And this build-up happens about half a second before your conscious ”decision” to move your arm. So by the time you think, ”OK, I’ll move my arm,” your body is halfway there. Which means your conscious experience of making a decision - the experience associated with free will - is just a kind of add-on, an after-thought that only happens once the brain has already set about its business. In other words, your brain is doing the real work, making your hands turn the pages of this magazine or reach over for your cup of tea, and all the time your conscious mind is tagging along behind. Copyright The Financial Times Limited 2007

Keyword: Miscellaneous
Link ID: 10129 - Posted: 06.24.2010

CHICAGO - The arch of an eyebrow or the curve of a lip tells chimps a lot about each other, a finding that may give scientists new understanding about the evolution of human communication, researchers reported Friday. Human faces can be easy to read, but sometimes people must look in different places on the face to get an accurate picture. “What we know from humans is that even a single movement added to an expression can change the entire meaning,” said Lisa Parr, director of the Yerkes National Primate Research Center at Emory University in Atlanta. “It can significantly affect the outcome of interactions.” Until now, little research has been done on understanding how chimpanzees communicate through facial expressions, said Parr, speaking at an international conference of chimpanzee cognition at Chicago’s Lincoln Park Zoo. “There could be a whole realm of chimp communication we don’t have the capability of understanding,” she said. Chimpanzees are humans’ closest relatives, with just a 1.23 percent difference between the genetic codes of people and chimps. Scientists believe studying the behavior of chimpanzees lends insights into human evolution. © 2007 MSNBC.com

Keyword: Emotions
Link ID: 10128 - Posted: 06.24.2010

By MARIA CHENG LONDON -- New "landmark" research finds that alcohol and tobacco are more dangerous than some illegal drugs like marijuana or Ecstasy and should be classified as such in legal systems, according to a new British study. In research published Friday in The Lancet magazine, Professor David Nutt of Britain's Bristol University and colleagues proposed a new framework for the classification of harmful substances, based on the actual risks posed to society. Their ranking listed alcohol and tobacco among the top 10 most dangerous substances. Nutt and colleagues used three factors to determine the harm associated with any drug: the physical harm to the user, the drug's potential for addiction, and the impact on society of drug use. The researchers asked two groups of experts _ psychiatrists specializing in addiction and legal or police officials with scientific or medical expertise _ to assign scores to 20 different drugs, including heroin, cocaine, Ecstasy, amphetamines, and LSD. Nutt and his colleagues then calculated the drugs' overall rankings. In the end, the experts agreed with each other _ but not with the existing British classification of dangerous substances. Heroin and cocaine were ranked most dangerous, followed by barbiturates and street methadone. Alcohol was the fifth-most harmful drug and tobacco the ninth most harmful. Cannabis came in 11th, and near the bottom of the list was Ecstasy. © 2007 The Associated Press

Keyword: Drug Abuse
Link ID: 10127 - Posted: 06.24.2010

Fresh evidence that suggests monkeys can learn skills from each other, in the same manner as humans, has been uncovered by a University of Cambridge researcher. Dr Antonio Moura, a Brazilian researcher from the Department of Biological Anthropology, has discovered signs that Capuchin monkeys in Brazil bang stones as a signalling device to ward off potential predators. While not conclusive, his research adds to a mounting body of evidence that suggests other species have something approaching human culture. A strong case has already been made for great apes having a capacity for social learning, but until now there has been no evidence of material culture among the “new world” primates of Central or South America, which include Capuchins. Dr Moura carried out his research in the Serra da Capivara National Park, in the Piaui state of north-east Brazil, during which he observed bouts of stone-banging, primarily among a group of 10 monkeys. As he approached, the monkeys would first search for a suitable loose stone, then hit it on a rock surface several times. The act was apparently an aggressive one, directed at Dr Moura as a potential predator, but as the group became used to his presence in the area the stone-banging decreased. Furthermore, in a large minority of cases, adults and juvenile monkeys were seen banging the stones together without paying him any attention at all – suggesting that the younger monkeys were learning the skill from their more experienced elders. Captive monkeys released into the area that joined the study group also appeared to be learning to bang stones from the others. © University of Cambridge 1998-2006

Keyword: Evolution; Aggression
Link ID: 10126 - Posted: 06.24.2010

Philip Ball The wonderful acoustics for which the ancient Greek theatre of Epidaurus is renowned may come from exploiting complex acoustic physics, new research shows. The theatre, discovered under a layer of earth on the Peloponnese peninsula in 1881 and excavated, has the classic semicircular shape of a Greek amphitheatre, with 34 rows of stone seats (to which the Romans added a further 21). Its acoustics are extraordinary: a performer standing on the open-air stage can be heard in the back rows almost 60 metres away. Architects and archaeologists have long speculated about what makes the sound transmit so well. Now Nico Declercq and Cindy Dekeyser of the Georgia Institute of Technology in Atlanta say that the key is the arrangement of the stepped rows of seats. They calculate that this structure is perfectly shaped to act as an acoustic filter, suppressing low-frequency sound — the major component of background noise — while passing on the high frequencies of performers' voices1. It's not clear whether this property comes from chance or design, Declercq says. But either way, he thinks that the Greeks and Romans appreciated that the acoustics at Epidaurus were something special, and copied them elsewhere. ©2007 Nature Publishing Group

Keyword: Hearing
Link ID: 10125 - Posted: 06.24.2010

Experience in the early development of new neurons in specific brain regions affects their survival and activity in the adult brain, new research shows. How these new neurons store information about these experiences may explain how they can affect learning and memory in adults. A team of researchers headed by Fred Gage, PhD, of the Salk Institute, found that experience enhances the survival of new neurons in a brain area called the dentate gyrus, and that more of these new neurons were activated when exposed to the same experience later. This change in function may be a mechanism for long-term memory. The findings are published in the March 21 issue of The Journal of Neuroscience. "The results identify a critical period for experience-induced enhancement of new neuron survival in the hippocampus," says Elizabeth Gould, PhD, of Princeton University, who was not affiliated with the study. The hippocampus contains the dentate gyrus. After injecting mice with a chemical used to mark proliferating cells, the researchers exposed the animals to an "enriched cage" environment, containing tunnels, shelters, and a running wheel. After several weeks, the researchers again exposed the mice in the same enriched experience. They discovered that the enriched experience increased new neuron survival and that more new neurons were activated by re-exposure to the same environment. To determine if the increase in neuronal activity was due to having the same experience or if any new experience was sufficient to achieve this effect, the researchers exposed mice to the enriched cage first and then a water maze task. While both cases promoted new neuron survival, more new neurons were activated in mice that had repeated the same experience but not in those that were exposed to the different experience (the water maze).

Keyword: Neurogenesis; Learning & Memory
Link ID: 10124 - Posted: 03.23.2007

Scientists led by UCL (University College London) have induced dyscalculia in subjects without the maths learning difficulty for the first time. The study, which finds that the right parietal lobe is responsible for dyscalculia, potentially has implications for diagnosis and management through remedial teaching. Dyscalculia is just as prevalent in the population as dyslexia and attention deficit hyperactivity disorder – around 5% of the population is affected. However, dyscalculia has not been given the same attention as other disorders and the underlying brain dysfunction causing dyscalculia is still a mystery. It is hoped that this study will provide a better understanding of the condition and lead to better diagnosis and treatment. Dr Roi Cohen Kadosh, of the UCL Institute of Cognitive Neuroscience, said: “This is the first causal demonstration that the parietal lobe is the key to understanding developmental dyscalculia. Most people process numbers very easily – almost automatically – but people with dyscalculia do not. We wanted to find out what would happen when the areas relevant to maths learning in the right parietal lobes were effectively knocked out for several hundred milliseconds. We found that stimulation to this brain region during a maths test radically impacted on the subjects’ reaction time. “This provides strong evidence that dyscalculia is caused by malformations in the right parietal lobe and provides sold grounds for further study on the physical abnormalities present in dyscalculics’ brains."

Keyword: Miscellaneous
Link ID: 10123 - Posted: 06.24.2010

Scientists say they have developed a 3D scanner that can accurately determine if a person is truly obese. Currently, doctors gauge fatness with a calculation of body mass index (BMI). But BMI is flawed - people with lots of muscle are considered overweight. Instead of relying on weight and height measurements, as BMI does, the scan takes into account body shape and how much fat a person carries. Birmingham's Heartlands Hospital has been testing this Body Volume Index. One human guinea pig who has tested the BVI scanner is 19-year-old rower Ashley Granger. He is 6ft 2ins (1.88m) tall and according to his BMI of 28 is at the top end of the overweight category, borderline obese. His BVI scan correctly showed that he carries very little fat and that his weight is largely down to muscle. Fitness trainer Matt Roberts said: "Muscle weighs more than fat does. And you can hide away fat but be quite thin looking. So it's important that we don't just use BMI alone." (C)BBC

Keyword: Obesity
Link ID: 10122 - Posted: 03.23.2007

By Noah Shachtman The U.S. military is working on computers than can scan your mind and adapt to what you're thinking. Since 2000, Darpa, the Pentagon's blue-sky research arm, has spearheaded a far-flung, nearly $70 million effort to build prototype cockpits, missile control stations and infantry trainers that can sense what's occupying their operators' attention, and adjust how they present information, accordingly. Similar technologies are being employed to help intelligence analysts find targets easier by tapping their unconscious reactions. It's all part of a broader Darpa push to radically boost the performance of American troops. "Computers today, you have to learn how they work," says Navy Commander Dylan Schmorrow, who served as Darpa's first program manager for this Augmented Cognition project. He now works for the Office of Naval Research. "We want the computer to learn you, adapt to you." So much of what's done today in the military involves staring at a computer screen -- parsing an intelligence report, keeping track of fellow soldiers, flying a drone airplane -- that it can quickly lead to information overload. Schmorrow and other Augmented Cognition (AugCog) researchers think they can overcome this, though. The idea -- to grossly over-simplify -- is that people have more than one kind of working memory, and more than one kind of attention; there are separate slots in the mind for things written, things heard and things seen. © 2007 CondéNet Inc

Keyword: Attention; Brain imaging
Link ID: 10121 - Posted: 06.24.2010

The NIH National Institute of Neurological Disorders and Stroke (NINDS) today is launching a large-scale clinical trial to learn if the nutritional supplement can slow the progression of Parkinson's disease (PD). While creatine is not an approved therapy for PD or any other condition, it is widely thought to improve exercise performance. The potential benefit of creatine for PD was identified by Parkinson’s researchers through a new rapid method for screening potential compounds. The double-blind, placebo-controlled, phase III study is one of the largest PD clinical trials to date. It will enroll 1720 people with early-stage PD at 52 medical centers in the United States and Canada. "This study is an important step toward developing a therapy that could change the course of this devastating disease," says Elias A. Zerhouni, M.D., director of the NIH. "The goal is to improve the quality of life for people with Parkinson's for a longer period of time than is possible with existing therapies." Currently there is no treatment that has been shown to slow the progression of PD. The trial is the first large study in a series of NINDS-sponsored clinical trials called NET-PD (NIH Exploratory Trials in Parkinson's Disease). NINDS has organized this large network of sites to allow researchers to work with PD patients over a long period of time, with a goal of finding effective and lasting treatments. NET-PD builds on a developmental research process — from laboratory research to pilot studies in a select group of patients, to the definitive phase III trial of effectiveness in people with Parkinson’s disease.

Keyword: Parkinsons
Link ID: 10120 - Posted: 06.24.2010

Michael Hopkin British scientists asked by the government to rank the harm of different drugs of abuse today publish their results in the Lancet1. The new system, which puts alcohol and tobacco below heroin but above cannabis, is an attempt to provide a scientific — if still simplistic — way to compare the social and health tolls taken by recreational drugs. "The current drug classification system is rather arbitrary in terms of the way it assesses harm," says David Nutt of the University of Bristol, UK, and one of the team who devised the new system. Current British drug laws, he says, are shaped by political prejudice as much as by the actual threats posed by the substances. Recreational drugs pose various types of threat — from the possibility of an accidental overdose causing sudden death, to a parent's desire for alcohol pulling them away from their responsibilities at home. Comparing such physical and social harms, for both long-term and short-term effects, is very difficult. Nutt and his colleagues used a simple system to approach the problem. They set up three categories of threat — physical harm, dependence, and social harm — and divided each of these into three sub-categories (see 'The categories of harm'). They then asked experts - including psychiatrists specializing in addiction, members of police, forensic experts, chemists and doctors - to give up to 20 drugs a score out of three for each of the nine categories. The average scores for each of the three main categories of threat were then simply added together and averaged again to calculate an overall score out of three. ©2007 Nature Publishing Group

Keyword: Drug Abuse
Link ID: 10119 - Posted: 06.24.2010

Lucy Odling Smee Simply by inserting a piece of DNA that codes for a human eye pigment into the genome of a mouse, scientists have introduced a rainbow array of colour to the dull mix of yellows, blues and greys that normally make up a mouse's visual world. This suggests that the mammalian brain is very flexible and can interpret signals not normally encountered. It also hints that just a single genetic mutation could have added reds and greens to the visual palette of our ancestors tens of millions of years ago. Gerald Jacobs from the University of California in Santa Barbara and his colleagues have genetically engineered mice with a human pigment in their eye as well as the normal mouse pigments and shown that this does appear to give the mice the ability to see colours they could not see before. "The implications are astounding," says David Williams, an expert in vision at the University of Rochester in New York state. "It's stunning to think the rest of the nervous system in the mouse has developed to be able to process the new information." Most mammals have just two kinds of photopigment in their retinas: one is encoded in the X chromosome and the other in an autosomal (non-sex) chromosome. But many primates, including humans, have a third photopigment, encoded by a second gene on the X chromosome. This allows for a much broader appreciation of colour. ©2007 Nature Publishing Group

Keyword: Vision
Link ID: 10118 - Posted: 06.24.2010

Battling meningitis as a baby has a damaging effect on later academic achievement, a study suggests. Imperial College London found one in four teenagers who had meningitis in their first year failed to pass a single GSCE exam at grade C or above. Among comprehensive school pupils, meningitis survivors were twice as likely to fail to achieve the national standard of five grade C passes. The study appears in Archives of Disease in Childhood. It is essential that all cases of bacterial meningitis occurring during the first year of life are followed up fully It also found children who appeared to have escaped meningitis unscathed when assessed at age five did no better in their GCSE examinations than those with recognised disabilities. Meningitis is an inflammation of the brain lining - the meninges - which can cause serious disability or even death. The researchers compared the exam results of 461 students who survived meningitis as babies, with 289 students who had never developed the disease. They found 25% of the meningitis survivors failed to pass a single GSCE exam, compared with just 6.6% of the comparison group. Among comprehensive school attendees, 48% of meningitis survivors failed to achieve five grade C passes - the figure for the comparison group was 25%. (C)BBC

Keyword: Development of the Brain; Intelligence
Link ID: 10117 - Posted: 03.22.2007

BETHESDA, Md. – Researchers have identified a novel gene mutation that causes X-linked mental retardation for which there was no previously known molecular diagnosis, according to an article to be published electronically on Tuesday, March 20, 2007 in The American Journal of Human Genetics. Investigators F. Lucy Raymond (Cambridge Institute of Medical Research, University of Cambridge, Cambridge, UK) and Patrick S. Tarpey (Wellcome Trust Sanger Institute, Hixton, UK) describe the ZDHHC9 gene found in those with severe retardation as being mutated to the point of entirely losing function. "ZDHHC9 is a novel gene," explains Dr. Raymond. "This gene would not have been predicted to play a role in mental retardation based on the previous genetics work. It was found only because we were systematically looking at all the genes on the X chromosome irrespective of what they do." X-linked mental retardation is severe. Some patients require total care and may not have language ability. The condition runs in families and only affects the male offspring. So far only a few of these genes have been identified. Working through a large, international collaboration, the researchers collected genetic samples from 250 families in which at least two boys have mental retardation to help identify novel genes that cause X-linked mental retardation. The investigators systematically analyzed the X chromosome for gene mutations.

Keyword: Genes & Behavior; Intelligence
Link ID: 10116 - Posted: 06.24.2010

A quiet night's sleep is not an option for Derek Rogers or his wife - because he turns from a mild-mannered "Dr Jekyll" by day to a "Mr Hyde" by night. Mr Rogers, 70, from Bedford, has a rare sleep disorder which causes him to become violent when he sleep-walks. He has destroyed furniture, attacked his wife and injured himself during the night - but remembers nothing. Doctors at Papworth Hospital have found a drug which has successfully treated Mr Rogers' "unique" condition. Since he developed the condition in 1998, Mr Rogers has visited casualty up to three times a week. He has broken his nose, fractured his ribs and split his head open. South-African born Mr Rogers tried six different treatments before he was referred to the sleep clinic at Papworth Hospital in Cambridge. He said: "I am not violent - I do not swear or curse and I can't believe what I do at night." His wife Linda has had to sleep in a different room to avoid her husband lashing out. Doctors at Papworth decided to try a new £13,000 a year drug mix, which acts to break the circuit between the sleeping brain and muscles in the body. (C)BBC

Keyword: Sleep
Link ID: 10115 - Posted: 03.22.2007

John Whitfield Dogs wag their tails to the right when they see something they want to approach, and to the left when confronted with something they want to back away from, say researchers in Italy. The finding provides another example of how the right and left halves of the brain do different jobs in controlling emotions. Unfortunately, because dogs move about so much, the bias can only be detected using video analysis. It's not obvious enough for you to tell whether the next dog you encounter is going to lick your face or turn tail. "After discovering this, I look at every dog I meet, but my impression is that this is difficult to check outside the lab," says psychologist Giorgio Vallortigara of the University of Trieste. But it could be used in animal welfare, he suggests, to help gauge an animal's state of mind. Vallortigara and his colleagues tested 30 pet dogs of varying breeds, recruited through an obedience school at the University of Bari's veterinary faculty. Over a series of trials, they videoed each dog's response to being shown either their owner, a human stranger, a cat, or a Belgian shepherd malinois, a large dog breed similar to a German shepherd. ©2007 Nature Publishing Group

Keyword: Laterality
Link ID: 10114 - Posted: 06.24.2010

Kerri Smith A runaway train is speeding down the tracks towards five workmen. You and a stranger are standing on a bridge over the track. The only way to save the five is to push the stranger in front of the train to his death, and his body will stop it from reaching them. Do you push him? Most people answer that they could not personally push a stranger to his death, even though more lives would be saved than lost. But a new study published online in Nature finds that people with damage to a particular part of the frontal lobe reach the opposite — alarmingly utilitarian — conclusion1. Antonio Damasio at the University of Southern California in Los Angeles and his colleagues used a battery of dilemmas like this one to explore the role of emotion in moral decisions. Healthy subjects rejected most of the solutions that involved harming one person to save many lives, but the team found that people with damage to the ventromedial prefrontal cortex (VMPC), a brain area just behind the forehead, endorsed such decisions. These patients, whose brain damage resulted from stroke or the removal of a brain tumour, made perfectly normal decisions when the scenarios didn't have a moral component (is it all right to change a cake recipe if you don't like it?) or were asked to make less personal decisions (is it all right to push a heavy sculpture off a bridge to save the five workmen?). But when patients responded to more personal moral dilemmas, they were more than twice as likely as both normal controls and patients with brain damage that didn't include the VMPC to decide to harm one person — even their own child — to save more lives in the future. ©2007 Nature Publishing Group

Keyword: Emotions
Link ID: 10113 - Posted: 06.24.2010

Roxanne Khamsi Many patients suffering from severe depression "test positive" for post-traumatic stress disorder, regardless of whether or not they have actually experienced trauma, a new study reveals. Based on this finding, researchers say that psychiatrists need to identify more specific criteria for PTSD. Doing so, they suggest, will "save the diagnosis" from becoming too general and therefore misleading. Alexander Bodkin at Harvard's McLean Hospital in Belmont, Massachusetts, US, and colleagues recruited 101 patients with severe depression for their study. The participants answered questions about whether they had suffered symptoms of PTSD such as intrusive thoughts, emotional numbing, flashbacks and hopelessness. Two independent experts were then brought in to identify those subjects that had experienced a traumatic event, using standard tests issued by the American Psychiatric Association (APA). The experts were not told the patients' earlier reported symptoms. According to the APA's PTSD guidelines, trauma involves witnessing or experiencing "actual or threatened death or serious injury, or a threat to the physical integrity of oneself or others". The experience of trauma constitutes the primary criterion for PTSD. © Copyright Reed Business Information Ltd

Keyword: Depression; Stress
Link ID: 10112 - Posted: 06.24.2010