By Gary Stix The emerging academic discipline of neuroethics has been driven, in part, by the recognition that introducing brain scans as legal evidence is fraught with peril. Most neuroscientists think that a brain scan is unable to provide an accurate representation of the state of mind of a defendant or determine whether his frontal lobes predispose to some wanton action. The consensus view holds that studying spots on the wrinkled cerebral cortex that are bigger or smaller in some criminal offenders may hint at overarching insights into the roots of violence, but lack the requisite specificity to be used as evidence in any individual case. “I believe that our behavior is a production of activity in our brain circuits,” Steven E. Hyman of the Broad Institute of Harvard and MIT told a session at the American Association for the Advancement of Science’s annual meeting earlier this year. “But I would never tell a parole board to decide whether to release somebody or hold on to somebody, based on their brain scan as an individual, because I can’t tell what are the causal factors in that individual.” It doesn’t seem to really matter, though, what academic experts believe about the advisability of brain scans as Exhibit One at trial. The entry of neuroscience in the courtroom has already begun, big time. The introduction of a brain scan in a legal case was once enough to generate local headlines. No more. Hundreds of legal opinions each year have begun to invoke the science of mind and brain to bolster legal arguments—references not only to brain scans, but a range of studies that show that the amygdala is implicated in this or the anterior cingulate cortex is at fault for that. The legal establishment, in short, has begun a love affair with all things brain. © 2013 Scientific American

Keyword: Consciousness; Aggression
Link ID: 18955 - Posted: 11.21.2013

by Anil Ananthaswamy Can you tickle yourself if you are fooled into thinking that someone else is tickling you? A new experiment says no, challenging a widely accepted theory about how our brains work. It is well known that we can't tickle ourselves. In 2000, Sarah-Jayne Blakemore of University College London (UCL) and colleagues came up with a possible explanation. When we intend to move, the brain sends commands to the muscles, but also predicts the sensory consequences of the impending movement. When the prediction matches the actual sensations that arise, the brain dampens down its response to those sensations. This prevents us from tickling ourselves (NeuroReport, DOI: 10.1097/00001756-200008030-00002). Jakob Hohwy of Monash University in Clayton, Australia, and colleagues decided to do a tickle test while simultaneously subjecting people to a body swap illusion. In this illusion, the volunteer and experimenter sat facing each other. The subject wore goggles that displayed the feed from a head-mounted camera. In some cases the camera was mounted on the subject's head, so that they saw things from their own perspective, while in others it was mounted on the experimenter's head, providing the subject with the experimenter's perspective. Using their right hands, both the subject and the experimenter held on to opposite ends of a wooden rod, which had a piece of foam attached to each end. The subject and experimenter placed their left palms against the foam at their end. Next, the subject or the experimenter took turns to move the rod with their right hand, causing the piece of foam to tickle both of their left palms. © Copyright Reed Business Information Ltd.

Keyword: Attention
Link ID: 18954 - Posted: 11.21.2013

By Evelyn Boychuk, Ever since Toronto Mayor Rob Ford admitted to having smoked crack cocaine, various city councillors and media observers have publicly advised him to seek drug counselling. But in a CNN interview that aired Nov. 18, Ford continued to stand by his message: “I’m not an addict.” The ongoing saga of the mayor’s crack use has raised unanswered questions about how addictive the drug really is. It’s been commonly accepted that crack is more addictive than other drugs, but addictions researchers and drug counsellors say it’s hard to compare the addictiveness of specific substances because drug-taking is a highly individual experience. Robin Haslam, director of operations and procedures for Addiction Canada, says that he has never met someone who can “just casually smoke crack.” However, people have different thresholds of addiction. “I know people who have used crack once, and never touched it again. I also know people who smoked marijuana once, and became very impaired,” he says. Carl Hart, author of High Price: A Neuroscientist's Journey of Self-Discovery That Challenges Everything You Know About Drugs and Society, told CBC Radio’s Day 6 that crack “is not uniquely addictive, or it’s not something that is special, as we have all been taught.” Hart said that the percentage of people that become addicted to crack is lower than most think. “For example, 10 to 20 per cent of people will become addicted — that means that 80 to 90 per cent of people won’t become addicted.” © CBC 2013

Keyword: Drug Abuse
Link ID: 18953 - Posted: 11.21.2013

By Jason Tetro For millennia, the human race has sought to combat psychological disorders through the intervention of natural – and eventually synthetic – chemicals. Originally, the sources for these psychoactive substances were the various fruits and flowers, including the Areca tree (betel nut), the poppy (opium), and the coca plant (cocaine). But in the 20th Century, new actives were being created in the lab thanks in part to the discovery of lysergic acid, better known as LSD, in 1938. By the middle of the 1950s, the psychiatric community was fascinated by the idea that mental health could be restored through the direct use of drugs or in combination with traditional psychotherapy. The idea took off in the 1960s as research continued to elucidate the biology of psychiatry. It essentially created a new avenue for psychiatric treatment: psychopharmacology. This inevitably led to the synthesis of a new compound, 3-(p-trifluoromethylphenoxy)-N-methyl-3-phenylpropylamine, which eventually became known as fluoxetine, and then, as we have all come to know it, Prozac. By the late 1980s, it was known by another name: the wonder drug. Today, pharmacologic compounds for psychiatric treatment are numerous and up to 20% of all Americans are taking some type of psychotropic medication totalling some $34 billion dollars annually. While there have been calls for a reduction in use of these chemicals, primarily due to the fact that many are ineffective, there is a constant pressure from the public to have all their problems solved by a pill.

Keyword: Depression; Schizophrenia
Link ID: 18952 - Posted: 11.21.2013

By James Gallagher Health and science reporter, BBC News The damage caused by concussion can be detected months after the injury and long after patients feel like they have recovered, brain scans show. Concussion has become highly controversial in sport, with concerns raised that players are putting their brain at risk. Researchers at the University of New Mexico said athletes may be being returned to action too quickly. While UK doctors said the attitude to head injury was "too relaxed" in sport. Debate over concussion and head injury has lead to resignations over new rules in rugby, controversy in football after a player was kept on the field after being knocked out, and has been a long-standing issue in American football. Concussion is an abnormal brain function that results from an external blast, jolt or impact to the head. Even if the knock does not result in a skull fracture, the brain can still experience a violent rattling that leads to injury. Because the brain is a soft gelatinous material surrounded by a rigid bony skull, such traumatic injuries can cause changes in brain function, such as bleeding, neuron damage and swelling. Research shows that repetitive concussions increase the risk of sustained memory loss, worsened concentration or prolonged headaches. Long-term The US study, published in the journal Neurology, compared the brains of 50 people who had mild concussion with 50 healthy people. BBC © 2013

Keyword: Brain Injury/Concussion
Link ID: 18951 - Posted: 11.21.2013

By JOYCE COHEN Earlier this fall, Seattle Seahawks fans at CenturyLink Field broke the world record for loudest stadium crowd with a skull-splitting 136.6 decibels. That volume, as the Seahawks’ website boasts, hits the scale somewhere between “serious hearing damage” and “eardrum rupture.” Just weeks later, Kansas City Chiefs fans at Arrowhead Stadium topped that number with 137.5 screaming decibels of their own. The measuring method used for the Guinness World Record has an edge of gimmickry. That A-weighted peak measurement, reached for a split second near the measuring device, displays the highest possible readout. For a vulnerable ear, however, game-day noise isn’t just harmless fun. With peaks and troughs, the decibel level of noise reaching a typical spectator averages in the mid-90s, but for a longer time. Such noise is enough to cause permanent damage and to increase the likelihood of future damage. “The extent to which hearing-related issues get so little attention is amazing and troubling,” said M. Charles Liberman, a professor of otology at Harvard Medical School and director of a hearing research lab at the Massachusetts Eye and Ear Infirmary. “Many people are damaging their ears with repeated noise exposure such that their hearing abilities will significantly diminish as they age, much more so than if they were more careful,” he said. Ears are deceptive. Even if they seem to recover from the muffling, ringing and fullness after a rousing game, they don’t really recover. It’s not just the tiny sensory cells in the cochlea that are damaged by noise, Dr. Liberman said, but also the nerve fibers between the ears and the brain that degrade over time. Copyright 2013 The New York Times Company

Keyword: Hearing
Link ID: 18950 - Posted: 11.21.2013

Jessica Wright A tiny fiber-optic probe inserted into the reward center of the mouse brain monitors how the mouse feels about meeting a peer — or a golf ball. The unpublished technique was presented last week at the at the 2013 Society for Neuroscience annual meeting in San Diego. Mice feel the most satisfaction when sniffing another mouse’s rear and when walking away from a golf ball, the study found. The new technique is one of only a few ways to read the electrical activity of neurons in freely moving mice and is the most noninvasive, making it ideal for monitoring social interactions. The method takes advantage of a fluorescent molecule that lights up only in the presence of calcium, which rushes into the cell when neurons fire. The researchers used mice engineered to express this molecule only in neurons that make dopamine — the chemical messenger that mediates a sense of reward — in the ventral tegmental area (VTA). The researchers placed the cable in the VTA, the source of most of the brain’s dopamine neurons. The fiber-optic cable is 400 micrometers in diameter, and could probably be half that size, says Lisa Gunaydin, who developed the method as a graduate student in Karl Deisseroth’s lab at Stanford University in California. When neurons expressing the fluorescent molecule fire, the cable reads these as a series of spikes. In the study, the researchers gave thirsty mice sweet water and, as expected, their dopamine activity in the VTA spiked each time they drank. When the mice interact with a new mouse, or a golf ball, the dopamine neurons fire more on the first encounter but dull with repeated visits, suggesting that the mice are most excited by novelty. © Copyright 2013 Simons Foundation

Keyword: Drug Abuse
Link ID: 18949 - Posted: 11.21.2013

By Helen Briggs BBC News A condition where people experience a mixing of the senses, such as tasting words, has been linked with autism. Research suggests synaesthesia is nearly three times as common in adults with autism spectrum disorder than in the general population. The two conditions may share common features such as unusual wiring of the brain, say UK scientists. The study helps understanding of how people with autism experience life, says the National Autistic Society. Synaesthesia is a condition where one sense automatically triggers another. Some people experience tastes when they read or hear words, some perceive numbers as shapes, others see colours when they hear music. People with synaesthesia might say: "The letter q is dark brown," or: "The word 'hello' tastes like coffee," for example. Following anecdotal evidence of links between synaesthesia and Asperger's syndrome, researchers at the Autism Research Centre at Cambridge University set out to test the idea. More than 200 study participants - 164 adults diagnosed with high-functioning autism or Asperger's syndrome, and 97 adults without autism - were asked to fill in questionnaires to measure synaesthesia and autism traits. The study found one in five adults with autism spectrum conditions - a range of related developmental disorders, including autism and Asperger's syndrome - had synaesthesia compared with about 7% of people with no signs of the disorders. Prof Simon Baron-Cohen, who led the research, told BBC News: "Synaesthesia involves a mixing of the senses and it's a very subjective private experience, so the only way we know it's happening is if you ask people to report on their experiences. BBC © 2013

Keyword: Autism
Link ID: 18948 - Posted: 11.20.2013

By Rahul K. Parikh, The message showed up on my desk one day while I was seeing a patient. Its choppy shorthand read: “Admits to injecting testosterone. Now decreased libido. Call back to discuss.” The caller was a 15-year-old lacrosse player who hadn’t been part of my practice long. Like many boys in his age group, he rarely came to the office. When I responded to his message later that afternoon, the young man carried his end of the conversation with the typical terseness of a teenager. “Where did you get the steroids?” I asked. “On the Internet.” “How long did you use them?” “A few months.” “And what are you experiencing now?” He told me his nipples were sore and swollen. “I’ve been more tired and moody as well.” My patient was experiencing classic side effects of steroid use. About 6 percent of teenagers admit to using performance-enhancing drugs, according to a recent survey, though it’s easy to assume that that number is low. How many teens would admit to using such drugs, even anonymously to a researcher? And yet here was one teen, forced by the drug’s side effect, having to make an embarrassing confession to me and his family. (Details of this case have been altered to protect patient privacy.) Despite my patient’s fear, I was confident that a young, healthy teenager who briefly used steroids would bounce back, though it might take some time — and patience — for his symptoms to dissipate. When I explained this to my patient, he told me that he wanted his testosterone level tested, to make sure there wasn’t something more seriously wrong. I got the sense that he thought there was some way I could magically undo the harm he had caused himself. I paused and considered his request, which came across more like an order. © 1996-2013 The Washington Post

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 18947 - Posted: 11.20.2013

Ewen Callaway New genome sequences from two extinct human relatives suggest that these ‘archaic’ groups bred with humans and with each other more extensively than was previously known. The ancient genomes, one from a Neanderthal and one from a different archaic human group, the Denisovans, were presented on 18 November at a meeting at the Royal Society in London. They suggest that interbreeding went on between the members of several ancient human-like groups living in Europe and Asia more than 30,000 years ago, including an as-yet unknown human ancestor from Asia. “What it begins to suggest is that we’re looking at a ‘Lord of the Rings’-type world — that there were many hominid populations,” says Mark Thomas, an evolutionary geneticist at University College London who was at the meeting but was not involved in the work. The first Neanderthal1 and the Denisovan2 genome sequences revolutionized the study of ancient human history, not least because they showed that these groups interbred with anatomically modern humans, contributing to the genetic diversity of many people alive today. All humans whose ancestry originates outside of Africa owe about 2% of their genome to Neanderthals; and certain populations living in Oceania, such as Papua New Guineans and Australian Aboriginals, got about 4% of their DNA from interbreeding between their ancestors and Denisovans, who are named after the cave in Siberia’s Altai Mountains where they were discovered. The cave contains remains deposited there between 30,000 and 50,000 years ago. © 2013 Nature Publishing Group

Keyword: Evolution
Link ID: 18946 - Posted: 11.20.2013

By BENEDICT CAREY Curing insomnia in people with depression could double their chance of a full recovery, scientists are reporting. The findings, based on an insomnia treatment that uses talk therapy rather than drugs, are the first to emerge from a series of closely watched studies of sleep and depression to be released in the coming year. A student demonstrating equipment at Colleen Carney’s sleep lab at Ryerson University. Dr. Carney is the lead author of a new report about the effects of insomnia treatment on depression. The new report affirms the results of a smaller pilot study, giving scientists confidence that the effects of the insomnia treatment are real. If the figures continue to hold up, the advance will be the most significant in the treatment of depression since the introduction of Prozac in 1987. Depression is the most common mental disorder, affecting some 18 million Americans in any given year, according to government figures, and more than half of them also have insomnia. Experts familiar with the new report said that the results were plausible and that if supported by other studies, they should lead to major changes in treatment. “It would be an absolute boon to the field,” said Dr. Nada L. Stotland, professor of psychiatry at Rush Medical College in Chicago, who was not connected with the latest research. “It makes good common sense clinically,” she continued. “If you have a depression, you’re often awake all night, it’s extremely lonely, it’s dark, you’re aware every moment that the world around you is sleeping, every concern you have is magnified.” The study is the first of four on sleep and depression nearing completion, all financed by the National Institute of Mental Health. They are evaluating a type of talk therapy for insomnia that is cheap, relatively brief and usually effective, but not currently a part of standard treatment. © 2013 The New York Times Company

Keyword: Depression; Sleep
Link ID: 18945 - Posted: 11.19.2013

Dara Mohammadi At the beginning of next year, Clive Holmes will attempt to do something remarkable. But you'd never guess it from meeting this mild-mannered psychiatrist with a hint of a Midlands accent. In fact, you could be sitting in his office in the Memory Assessment and Research Centre at Southampton University and be unaware that he was up to anything out of the ordinary – save for a small whiteboard behind his desk, on which he's drawn a few amorphous blobs and squiggles. These, he'll assure you, are components of the immune system. As a psychiatrist, he's had little formal training in immunology, but has spent much of his time of late trying to figure how immune cells in the body communicate with others in the brain. These signals into the brain, he thinks, accelerate the speed at which neurons – nerve cells in the brain – are killed in late-stage Alzheimer's disease and at the beginning of next year he hopes to test the idea that blocking these signals can stop or slow down disease progression. If he shows any dent on disease progression, he would be the first to do so. Despite the billions of pounds pumped into finding a cure over the last 30 years, there are currently no treatments or prevention strategies. "Drug development has been largely focused on amyloid beta," says Holmes, referring to the protein deposits that are characteristically seen in the brains of people with Alzheimer's and are thought to be toxic to neurons, "but we're seeing that even if you remove amyloid, it seems to make no difference to disease progression." © 2013 Guardian News and Media Limited

Keyword: Alzheimers
Link ID: 18944 - Posted: 11.19.2013

By Sandra G. Boodman, Dorsey Davidge felt her thrumming anxiety burst into barely controlled panic as she watched her 14-year-old daughter Cate Chapin struggle to get from her bedroom to the bathroom. During the last week of January, the eighth-grader contracted what appeared to be a bad case of the flu. After a week, a doctor decided she had pneumonia, a diagnosis that was later changed to a possible infectious disease. Davidge, a single mother who lives in McLean, had maintained her equanimity during the early days of Cate’s illness. But when she saw that her older daughter was unable to walk 10 feet without stopping midway to rest, she was shocked by how cadaverous-looking Cate had become in a matter of weeks. “I was really scared for the first time,” Davidge said. “She was in­cred­ibly weak, and I thought, “ ‘Oh, my God, my child is just wasting away.’ ” By then, the 5-foot-2 Cate, a skinny 95 pounds before she got sick, had shriveled to a little over 80 pounds. She had no appetite, was barely drinking anything and seemed unable to consume more than a quarter of a bagel at a sitting. “That day was the last straw,” Davidge recalled. She telephoned Cate’s pediatrician, who agreed that the girl needed to be admitted immediately to a Northern Virginia hospital. It would take another harrowing month — which included the insertion of a feeding tube to help restore Cate’s weight, consultations with a bevy of specialists and numerous tests — before doctors figured out what was actually wrong, a diagnosis made possible after Cate developed a seemingly unrelated condition that sent her to an ophthalmologist. © 1996-2013 The Washington Post

Keyword: Anorexia & Bulimia
Link ID: 18943 - Posted: 11.19.2013

By EMILY ANTHES Humans have no exclusive claim on intelligence. Across the animal kingdom, all sorts of creatures have performed impressive intellectual feats. A bonobo named Kanzi uses an array of symbols to communicate with humans. Chaser the border collie knows the English words for more than 1,000 objects. Crows make sophisticated tools, elephants recognize themselves in the mirror, and dolphins have a rudimentary number sense. Anolis evermanni lizards normally attack their prey from above. The lizards were challenged to find a way to access insects that were kept inside a small hole covered with a tightfitting blue cap. And reptiles? Well, at least they have their looks. In the plethora of research over the past few decades on the cognitive capabilities of various species, lizards, turtles and snakes have been left in the back of the class. Few scientists bothered to peer into the reptile mind, and those who did were largely unimpressed. “Reptiles don’t really have great press,” said Gordon M. Burghardt, a comparative psychologist at the University of Tennessee at Knoxville. “Certainly in the past, people didn’t really think too much of their intelligence. They were thought of as instinct machines.” But now that is beginning to change, thanks to a growing interest in “coldblooded cognition” and recent studies revealing that reptile brains are not as primitive as we imagined. The research could not only redeem reptiles but also shed new light on cognitive evolution. Because reptiles, birds and mammals diverged so long ago, with a common ancestor that lived 280 million years ago, the emerging data suggest that certain sophisticated mental skills may be more ancient than had been assumed — or so adaptive that they evolved multiple times. © 2013 The New York Times Company

Keyword: Evolution; Intelligence
Link ID: 18942 - Posted: 11.19.2013

Female mice that compete in promiscuous environments have sexier smelling sons, research has found. Scientists in Utah, US, studied the pheromones produced in the urine of male mice. They found that those whose mothers competed for mates were more sexually attractive to females. But this success was short-lived: their life spans were shorter than mice with monogamous parents. Adam Nelson from the University of Utah completed the study alongside senior author Prof Wayne Potts. It is published in the journal Proceedings of the National Academy of Sciences. "Only recently have we started to understand that environmental conditions experienced by parents can influence the characteristics of their offspring. This study is one of the first to show this kind of 'epigenetic' process working in a way that increases the mating success of sons," said Prof Potts. Epigenetics is the study of how differences in a parent's environment can influence how its offspring's genes are expressed. The researchers studied domestic mice which are usually paired in a cage and therefore breed with only one partner. To reintroduce the social competition wild mice experience, lab mice were kept in "mouse barns" which were large enclosures divided by mesh to create territories. The mice were able to climb over the mesh to access nest boxes, feeding stations and drinking water. BBC © 2013

Keyword: Sexual Behavior; Aggression
Link ID: 18941 - Posted: 11.19.2013

By JOHN TIERNEY How aggressive is the human female? When the anthropologist Sarah B. Hrdy surveyed the research literature three decades ago, she concluded that “the competitive component in the nature of women remains anecdotal, intuitively sensed, but not confirmed by science.” Science has come a long way since then, as Dr. Hrdy notes in her introduction to a recent issue of Philosophical Transactions of the Royal Society devoted entirely to the topic of female aggression. She credits the “stunning” amount of new evidence partly to better research techniques and partly to the entry of so many women into scientific fields once dominated by men. The existence of female competition may seem obvious to anyone who has been in a high-school cafeteria or a singles bar, but analyzing it has been difficult because it tends be more subtle and indirect (and a lot less violent) than the male variety. Now that researchers have been looking more closely, they say that this “intrasexual competition” is the most important factor explaining the pressures that young women feel to meet standards of sexual conduct and physical appearance. The old doubts about female competitiveness derived partly from an evolutionary analysis of the reproductive odds in ancient polygynous societies in which some men were left single because dominant males had multiple wives. So men had to compete to have a chance of reproducing, whereas virtually all women were assured of it. But even in those societies, women were not passive trophies for victorious males. They had their own incentives to compete with one another for more desirable partners and more resources for their children. And now that most people live in monogamous societies, most women face the same odds as men. In fact, they face tougher odds in some places, like the many college campuses with more women than men. © 2013 The New York Times Company

Keyword: Aggression; Sexual Behavior
Link ID: 18940 - Posted: 11.19.2013

by Erika Engelhaupt When I was in graduate school, I once gassed out my lab with the smell of death. I was studying the products of plant decomposition, and I had placed copious quantities of duckweed into large tubs and let the mix decompose for a few weeks. Duckweed is a small floating aquatic plant; it looks harmless enough. But when I dragged my tubs into the lab and set up a pump and filtration system, all hell broke loose. The filter clogged, the back pressure threw the hose off the pump, and a spray of decomposed mess flew all over a poor professor who had come in to help. For the rest of the day, he smelled like a pile of dead raccoons. That day, I learned about cadaverine and putrescine. These two molecules are produced during the decomposition of proteins, when the amino acids lysine and ornithine break down, and they are largely responsible for the smell of rotting flesh. My mistake in the lab was to think that rotting plants are more innocuous than rotting animals. Duckweed, it turns out, has such high protein levels that it’s used as animal feed, and those proteins, like any proteins, can create a deathly stench. The smells of cadaverine and putrescine tend to provoke a strong reaction (as I learned once the duckweed stench subsided and my labmates were able to return to the lab). But not every animal finds the odors disgusting. Carrion flies, rats and other animals that eat or lay eggs in dead things are attracted to the molecules. So researchers have started to look for exactly how animals tune in to these smells. Pinning down animals' odor detectors gives researchers a way to study aversion or attraction to certain objects. And understanding how these behavioral responses work will, I believe, help researchers clarify why humans feel the distinct emotion known as disgust. © Society for Science & the Public 2000 - 2013.

Keyword: Chemical Senses (Smell & Taste); Emotions
Link ID: 18939 - Posted: 11.16.2013

By Tanya Lewis and LiveScience SAN DIEGO — Being a social butterfly just might change your brain: In people with a large network of friends and excellent social skills, certain brain regions are bigger and better connected than in people with fewer friends, a new study finds. The research, presented here Tuesday (Nov. 12) at the annual meeting of the Society for Neuroscience, suggests a connection between social interactions and brain structure. "We're interested in how your brain is able to allow you to navigate in complex social environments," study researcher MaryAnn Noonan, a neuroscientist at Oxford University, in England, said at a news conference. Basically, "how many friends can your brain handle?" Noonan said. Scientists still don't understand how the brain manages human behavior in increasingly complex social situations, or what parts of the brain are linked to deviant social behavior associated with conditions like autism and schizophrenia. Studies in macaque monkeys have shown that brain areas involved in face processing and in predicting the intentions of others are larger in animals living in large social groups than in ones living in smaller groups. To investigate these brain differences in humans, Noonan and her colleagues at McGill University, in Canada, recruited 18 participants for a structural brain-imaging study. They asked people how many social interactions they had experienced in the past month, in order to determine the size of their social networks. As was the case in monkeys, some brain areas were enlarged and better connected in people with larger social networks. In humans, these areas were the temporal parietal junction, the anterior cingulate cortex and the rostral prefrontal cortex, which are part of a network involved in "mentalization" — the ability to attribute mental states, thoughts and beliefs to another. © 2013 Scientific American

Keyword: Learning & Memory; Evolution
Link ID: 18938 - Posted: 11.16.2013

by Bob Holmes When it comes to evolution, there is no such thing as perfection. Even in the simple, unchanging environment of a laboratory flask, bacteria never stop making small tweaks to improve their fitness. That's the conclusion of the longest-running evolutionary experiment carried out in a lab. In 1988, Richard Lenski of Michigan State University in East Lansing began growing 12 cultures of the same strain of Escherichia coli bacteria. The bacteria have been growing ever since, in isolation, on a simple nutrient medium – a total of more than 50,000 E. coli generations to date. Every 500 generations, Lenski freezes a sample of each culture, creating an artificial "fossil record". This allows him to resurrect the past and measure evolutionary progress by comparing how well bacteria compete against each other at different points in the evolutionary process. No upper limit After 10,000 generations, Lenski thought that the bacteria might approach an upper limit in fitness beyond which no further improvement was possible. But the full 50,000 generations of data show that isn't the case. When pitted against each other in an equal race, new generations always grew faster than older ones. In other words, fitness never stopped increasing. Their results fit a mathematical pattern known as a power law, in which something can increase forever, but at a steadily diminishing rate. "Even if we extrapolate it to 2.5 billion generations, there's no obvious reason to think there's an upper limit," says Lenski. © Copyright Reed Business Information Ltd.

Keyword: Evolution
Link ID: 18937 - Posted: 11.16.2013

Helen Shen To researchers who study how living things move, the octopus is an eight-legged marvel, managing its array of undulating appendages by means of a relatively simple nervous system. Some studies have suggested that each of the octopus’s tentacles has a 'mind' of its own, without rigid central coordination by the animal’s brain1. Now neuroscientist Guy Levy and his colleagues at the Hebrew University in Jerusalem report that the animals can rotate their bodies independently of their direction of movement, reorienting them while continuing to crawl in a straight line. And, unlike species that use their limbs to move forward or sideways relative to their body's orientation, octopuses tend to slither around in all directions. The team presented its findings on 10 November at the annual meeting of the Society for Neuroscience in San Diego, California. The new description of octopus movement is “not how one would imagine that would happen, but it seems to give a lot of control to the animal", says Gal Haspel, a neuroscientist at the New Jersey Institute of Technology in Newark. Haspel studies worm locomotion, and he was also surprised by the researchers’ report that the octopus pushes itself with worm-like contractions of its tentacles. Different combinations flex together to produce movement in different directions. Levy, who began the research as part of a project to design and control flexible, octopus-like robots, says that the work could also help to uncover basic biological principles of locomotion. Levy’s team deconstructed octopus movement using a transparent tank rigged with a system of mirrors and video cameras, in which they tested nine adult common octopuses (Octopus vulgaris). © 2013 Nature Publishing Group

Keyword: Movement Disorders; Evolution
Link ID: 18936 - Posted: 11.16.2013