Chapter 15. Emotions, Aggression, and Stress
Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.
Virginia Hughes When Brian Dias became a father last October, he was, like any new parent, mindful of the enormous responsibility that lay before him. From that moment on, every choice he made could affect his newborn son's physical and psychological development. But, unlike most new parents, Dias was also aware of the influence of his past experiences — not to mention those of his parents, his grandparents and beyond. Where one's ancestors lived, or how much they valued education, can clearly have effects that pass down through the generations. But what about the legacy of their health: whether they smoked, endured famine or fought in a war? As a postdoc in Kerry Ressler's laboratory at Emory University in Atlanta, Georgia, Dias had spent much of the two years before his son's birth studying these kinds of questions in mice. Specifically, he looked at how fear associated with a particular smell affects the animals and leaves an imprint on the brains of their descendants. Dias had been exposing male mice to acetophenone — a chemical with a sweet, almond-like smell — and then giving them a mild foot shock. After being exposed to this treatment five times a day for three days, the mice became reliably fearful, freezing in the presence of acetophenone even when they received no shock. Ten days later, Dias allowed the mice to mate with unexposed females. When their young grew up, many of the animals were more sensitive to acetophenone than to other odours, and more likely to be startled by an unexpected noise during exposure to the smell. Their offspring — the 'grandchildren' of the mice trained to fear the smell — were also jumpier in the presence of acetophenone. What's more, all three generations had larger-than-normal 'M71 glomeruli', structures where acetophenone-sensitive neurons in the nose connect with neurons in the olfactory bulb. In the January issue of Nature Neuroscience1, Dias and Ressler suggested that this hereditary transmission of environmental information was the result of epigenetics — chemical changes to the genome that affect how DNA is packaged and expressed without altering its sequence. © 2014 Nature Publishing Group,
By LISA FELDMAN BARRETT CAN you detect someone’s emotional state just by looking at his face? It sure seems like it. In everyday life, you can often “read” what someone is feeling with the quickest of glances. Hundreds of scientific studies support the idea that the face is a kind of emotional beacon, clearly and universally signaling the full array of human sentiments, from fear and anger to joy and surprise. Increasingly, companies like Apple and government agencies like the Transportation Security Administration are banking on this transparency, developing software to identify consumers’ moods or training programs to gauge the intent of airline passengers. The same assumption is at work in the field of mental health, where illnesses like autism and schizophrenia are often treated in part by training patients to distinguish emotions by facial expression. But this assumption is wrong. Several recent and forthcoming research papers from the Interdisciplinary Affective Science Laboratory, which I direct, suggest that human facial expressions, viewed on their own, are not universally understood. The pioneering work in the field of “emotion recognition” was conducted in the 1960s by a team of scientists led by the psychologist Paul Ekman. Research subjects were asked to look at photographs of facial expressions (smiling, scowling and so on) and match them to a limited set of emotion words (happiness, anger and so on) or to stories with phrases like “Her husband recently died.” Most subjects, even those from faraway cultures with little contact with Western civilization, were extremely good at this task, successfully matching the photos most of the time. Over the following decades, this method of studying emotion recognition has been replicated by other scientists hundreds of times. In recent years, however, at my laboratory we began to worry that this research method was flawed. In particular, we suspected that by providing subjects with a preselected set of emotion words, these experiments had inadvertently “primed” the subjects — in effect, hinting at the answers — and thus skewed the results. © 2014 The New York Times Company
Link ID: 19316 - Posted: 03.03.2014
Sara Reardon Two monkeys sit at computer screens, eyeing one another as they wait for a promised reward: apple juice. Each has a choice — it can either select a symbol that results in juice being shared equally, or pick one that delivers most of the juice to itself. But being selfish is risky. If its partner also chooses not to share, neither gets much juice. This game, the ‘prisoner’s dilemma’, is a classic test of strategy that involves the simultaneous evaluation of an opponent’s thinking. Researchers have now discovered — and manipulated — specific brain circuits in rhesus macaques (Macaca mulatta) that seem to be involved in the animals’ choices, and in their assessments of their partners’ choices. Investigating the connections could shed light on how social context affects decision-making in humans, and how disorders that affect social skills, such as autism spectrum disorder, disrupt brain circuitry. “Once we have identified that there are particular neural signals necessary to drive the processes, we can begin to tinker,” says Michael Platt, a neurobiologist at Duke University in Durham, North Carolina. Neurobiologists Keren Haroush and Ziv Williams of Harvard Medical School in Boston, Massachusetts, zoomed in on neural circuits in rhesus macaques by implanting electrode arrays into a brain area called the dorsal anterior cingulate cortex (dACC), which is associated with rewards and decision-making. The arrays recorded the activity of hundreds of individual neurons. When the monkeys played the prisoner’s dilemma (see ‘A juicy experiment’) against a computer program, they rarely chose to cooperate. But when they played with another monkey that they could see, they were several times more likely to choose to share the juice. © 2014 Nature Publishing Group
|By Lila Stanners Beauty seems mysterious and subjective. Scientists have long attempted to explain why the same object can strike some individuals as breathtaking and others as repulsive. Now a study finds that applying stimulation to a certain brain area enhances people's aesthetic appreciation of visual images. First, participants viewed 70 abstract paintings and sketches and 80 representational (realistic) paintings and photographs and rated how much they liked each one. Then they rated a similar set of images after receiving transcranial direct-current stimulation or sham stimulation. Transcranial direct-current stimulation sends small electrical impulses to the brain through electrodes attached to the head. The technique is noninvasive and cannot be felt, so subjects in the trials were not aware when they received real stimulation. The researchers aimed the impulses at the left dorsolateral prefrontal cortex, an area just behind the brow that is known to be a region critical for emotional processing. They found that the stimulation increased participants' appreciation of representational images, according to the study published online in October 2013 inSocial Cognitive and Affective Neuroscience. The scientists believe the stimulation facilitated a shift from object recognition to aesthetic appraisal for the figurative images; the abstract art was probably being processed by a different area of the brain. This study is one of many recent successful attempts at subtly altering cognition with noninvasive brain stimulation. Some experiments have found that stimulating certain areas allows people to solve math problems or puzzles that formerly had them stumped. Other work suggests these techniques can enhance motor learning, helping athletes or musicians improve at a new sport or a new instrument more rapidly. Experts are quick to point out, however, that these effects are modest enhancements at best—thought induction remains firmly in the realm of science fiction. © 2014 Scientific American
When you hear a friend’s voice, you immediately picture her, even if you can’t see her. And from the tone of her speech, you quickly gauge if she’s happy or sad. You can do all of this because your human brain has a “voice area.” Now, scientists using brain scanners and a crew of eager dogs have discovered that dog brains, too, have dedicated voice areas. The finding helps explain how canines can be so attuned to their owners’ feelings. “It’s absolutely brilliant, groundbreaking research,” says Pascal Belin, a neuroscientist at the University of Glasgow in the United Kingdom, who was part of the team that identified the voice areas in the human brain in 2000. “They’ve made the first comparative study using nonhuman primates of the cerebral processing of voices, and they’ve done it with a noninvasive technique by training dogs to lie in a scanner.” The scientists behind the discovery had previously shown that humans can readily distinguish between dogs’ happy and sad barks. “Dogs and humans share a similar social environment,” says Attila Andics, a neuroscientist in a research group at the Hungarian Academy of Sciences at Eötvös Loránd University in Budapest and the lead author of the new study. “So we wondered if dogs also get some social information from human voices.” To find out, Andics and his colleagues decided to scan the canine brain to see how it processes different types of sounds, including voices, barks, and natural noises. In humans, the voice area is activated when we hear others speak, helping us recognize a speaker’s identity and pick up on the emotional content in her voice. If dogs had voice areas, it could mean that these abilities aren’t limited to humans and other primates. © 2014 American Association for the Advancement of Science
By GRETCHEN REYNOLDS Watching participants in slopestyle and half-pipe skiing and snowboarding flip, curl, cartwheel and otherwise contort themselves in the air during the Winter Olympics competition, many of us have probably wondered not only how the athletes managed to perform such feats but also why. Helpfully, a recent study of the genetics of risk-taking intimates that their behavior may be motivated, at least in part, by their DNA. For some time, scientists and many parents have suspected that certain children are born needing greater physical stimulation than others, suggesting that sensation seeking, as this urge is known in psychological terms, has a genetic component. A thought-provoking 2006 study of twins, for instance, concluded that risk-taking behavior was shared by the pairs to a much greater extent than could be accounted for solely by environmental factors. If one twin sought out risks, the other was likely to do so as well. But finding which genes or, more specifically, which tiny snippets of DNA within genes, might be influencing the desire to huck oneself off of a snow-covered slope has proven to be troublesome. In recent years, scientists zeroed in on various sections of genes that affect the brain’s levels of or response to the neurotransmitter dopamine, a substance that is known to influence our feelings of pleasure, reward and gratification. People who engage in and enjoy extreme, daredevil conduct, researchers presumed, would likely process dopamine differently than those of us content to watch. But the results of some early genetic studies comparing dopamine-related portions of genes with sensation seeking were inconsistent. Some found that people with certain variations within genes, including a gene called DRD4 that is believed to be closely involved in the development and function of dopamine receptors in our brain, gravitated toward risky behavior. Others, though, found no such links. But most of these studies focused on so-called deviant risk-taking, such as gambling and drug addiction. © 2014 The New York Times Company
By Geoffrey Mohan Stress can damage the brain. The hormones it releases can change the way nerves fire, and send circuits into a dangerous feedback loop, leaving us vulnerable to anxiety, depression and post-traumatic stress disorder. But how stress accomplishes its sinister work on a cellular level has remained mysterious. Neuroscientists at a UC Berkeley lab have uncovered evidence that a well-known stress hormone trips a switch in stem cells in the brain, causing them to produce a white matter cell that ultimately can change the way circuits are connected in the brain. This key step toward hardening wires, the researchers found, may be at the heart of the hyper-connected circuits associated with prolonged, acute stress, according to the study published online Tuesday in the journal Molecular Psychiatry. The findings strengthen an emerging view that cells once written off as little more than glue, insulation and scaffolding may regulate and reorganize the brain's circuitry. Researchers examined a population of stem cells in the brain’s hippocampus, an area critical to fusing emotion and memory, and one that has been known to shrink under the effects of prolonged acute stress. Under normal circumstances, these cells form new neurons or glia, a type of white matter. Los Angeles Times Copyright 2014
Elephants, both African and Asian, have long been considered empathetic animals. They help baby elephants stuck in mud holes, use their trunks to lift other elephants that are injured or dying, and even reportedly reassure distressed individual elephants with a gentle touch of their trunk. But it’s one thing to witness something that looks like consolation, and another to prove that this is what elephants are doing. Now, scientists have shown that African elephants do indeed get distressed when they see others in trouble, and they reach out to console them—just as we do when we see someone suffering. Elephants, thus, join a short list of other animals, including great apes, canines, and some birds, that scientists have shown to reassure others. The study “is the first to investigate responses to distress by Asian elephants,” which “is inherently difficult to assess because one has to wait for opportunities to arise spontaneously,” says Shermin de Silva, an behavioral ecologist at the Uda Walawe Elephant Research Project in Sri Lanka. It would not be ethical to intentionally create stressful situations for the animals as a test, she notes—which is why, until now, researchers have had to rely on well-documented, but anecdotal observations of wild and captive elephants to back up claims that they reassure each other. Joshua Plotnik, a behavioral ecologist at Mahidol University in Kanchanaburi, Thailand, and Frans de Waal, a primatologist at Emory University, got around this problem by comparing Asian elephants’ behaviors during times of stress to periods when little upset them. For one to two weeks every month for nearly a year, Plotnik spent 30 to 180 minutes daily watching and recording 26 captive Asian elephants. The animals ranged in age from 3 to 60 years old and lived at the 30-acre Elephant Nature Park in northern Thailand. Most of the elephants, aside from mother-juvenile pairs, were unrelated, and did not live in family groups as wild elephants do. Instead, the park’s Mahouts, or keepers, organized them into six groups which they then guided through a daily routine—bathing and feeding them in the morning, and tethering them at night. But during the day, the elephants were left alone to roam and graze at will. © 2014 American Association for the Advancement of Science
by Clare Wilson AS MANY as 1 in 10 cases of schizophrenia may be triggered by an autoimmune reaction against brain cells, according to early trial results shared with New Scientist. The finding offers the possibility of gentler treatments for this devastating mental illness. Last month, doctors at a conference at the Royal Society of Medicine in London were told to consider an autoimmune cause when people first show symptoms of schizophrenia. People with schizophrenia experience symptoms of psychosis, such as hallucinations, delusions and paranoia. It affects 1 per cent of people in the West and is thought to be caused by overactive dopamine signalling pathways in the brain. Anti-psychotic drugs don't always work wellMovie Camera and have serious side effects. Previous studies had found that antibodies that target the NMDA receptor on neurons trigger brain inflammation, leading to seizures, comas – and sometimes psychosis (Annals of Neurology, doi.org/fdgnpc). In the past few years, these antibodies have also been found in the blood of people whose only symptom is psychosis. In 2010, Belinda Lennox at the University of Oxford tested 46 people with recent onset of psychosis for antibodies known to target neurons. Three people – about 6 per cent – tested positive (Neurology, doi.org/chs532). "The question is whether a larger percentage of cases might have other antibodies which we cannot yet detect," says Robin Murray at the Institute of Psychiatry in London, who wasn't involved in the research. Now Lennox is conducting a larger trial. Early results suggest other antibodies could well be involved. © Copyright Reed Business Information Ltd.
By James Gallagher Health and science reporter, BBC News Brain scans show a complex string of numbers and letters in mathematical formulae can evoke the same sense of beauty as artistic masterpieces and music from the greatest composers. Mathematicians were shown "ugly" and "beautiful" equations while in a brain scanner at University College London. The same emotional brain centres used to appreciate art were being activated by "beautiful" maths. The researchers suggest there may be a neurobiological basis to beauty. The likes of Euler's identity or the Pythagorean identity are rarely mentioned in the same breath as the best of Mozart, Shakespeare and Van Gogh. The study in the journal Frontiers in Human Neuroscience gave 15 mathematicians 60 formula to rate. One of the researchers, Prof Semir Zeki, told the BBC: "A large number of areas of the brain are involved when viewing equations, but when one looks at a formula rated as beautiful it activates the emotional brain - the medial orbito-frontal cortex - like looking at a great painting or listening to a piece of music." The more beautiful they rated the formula, the greater the surge in activity detected during the fMRI (functional magnetic resonance imaging) scans. "Neuroscience can't tell you what beauty is, but if you find it beautiful the medial orbito-frontal cortex is likely to be involved, you can find beauty in anything," he said. To the the untrained eye there may not be much beauty in Euler's identify, but in the study it was the formula of choice for mathematicians. BBC © 2014
It seems simple: People are more likely to cooperate if everyone plays fair. But a new study suggests that fairness itself arises from an unlikely source: spite. Researchers made a mathematical model based on the so-called ultimatum game. In it, two players are offered a reward, and the first player makes an offer for how it should be split up. If the second player agrees, then they divide it accordingly. But if the second player refuses, then neither gets the reward. As shown in the image above, depending on the interaction of the players, the outcome can be classified as altruism, cooperation, selfishness, or spite. Previous experiments have shown that, over multiple rounds of the game, a culture of cooperation evolves where everyone makes fair offers. But the new study, published online today in the Proceedings of the Royal Society B, finds that when players start out using multiple different strategies, by making fair or unfair offers, and rejecting or accepting unfair offers, some will act out of spite. These spiteful players deny the first player the reward at a cost to himself. The calculations further show that the antisocial behavior will eventually cause fairness to become the most successful option, because there is no reason to reject a fair offer. In essence, fairness evolves in spite of spite, when players start out using different strategies. Though they warn against generalizing to humans, the researchers point out that if fairness is the basis for a moral society, then paradoxically, spite may have played a role in the evolution of morality. © 2014 American Association for the Advancement of Science.
|By Simon Makin For decades two very different treatments of depression have existed side by side. Medications act on molecules, cells and synapses in the brain. Psychological therapies focus on cognition and behavior, trying to alter negatively biased thinking. Now a new theory suggests that these interventions may work in more similar ways than anyone realized, providing an opportunity to better integrate the two approaches. More important, it may help provide patients faster, more reliable relief from this crippling condition. Antidepressant drugs increase the levels of certain chemical messengers in the brain, such as serotonin and norepinephrine. Yet exactly how these neurotransmitters affect mood is unknown. “There was a missing link between the cellular, molecular and synaptic bases of these drugs, on the one hand, and what they affect in humans, which is their experiences, perceptions, memories and feelings,” says Catherine Harmer, a neuroscientist at the University of Oxford. The psychological explanation, meanwhile, describes depression in terms of distorted information processing. Depressed people are thought to process perceptions, experiences and memories with a negative bias. Many studies confirm that depressed individuals show increased sensitivity to sad faces, greater memory for negative material and reduced responsiveness to rewards as compared with healthy people. Successful therapies teach patients how to correct for this clouded vision. Harmer now believes that antidepressants may also work by altering this negative emotional processing. About a decade ago she and her colleagues tested the effects of commonly prescribed antidepressants on healthy volunteers and found that many of the drugs skewed emotional processing to the positive. Previous research had shown that antidepressants also change these measures in depressed people, but studies included only patients who had been on medication for six to eight weeks because the drugs were assumed to take that long to kick in. © 2014 Scientific American
By Maggie Fox Researchers looking for simple ways to treat autism say they may have explained why at least some cases occur: It all has to do with the stress babies undergo at birth. They’re already testing a simple drug for treating kids with autism and say their findings may point to ways to treat the disorder earlier in life. It’s all experimental, but the study, published in the journal Science, should inspire other researchers to take a closer look. “This is exciting stuff to people in the field, because it’s getting at a basic mechanism," says Andrew Zimmerman of the University of Massachusetts Medical School, who reviewed the study. Yehezkel Ben-Ari of the Mediterranean Institute of Neurobiology in Marseille, France, and colleagues have been treating children with autism with a diuretic called bumetanide that reduces levels of chloride in cells. Diuretics lower blood pressure by making people urinate more, reducing fluid. Ben-Ari has had mixed success in his trials in kids, and wanted to prove his theory that chloride was the key. He worked with two rodent “models” of autism — they’re the closest things scientists have for replicating autism in a human. One has mutated genes linked with autism, and another develops autism when given valproate, an epilepsy drug blamed for causing autism in the children of mothers who take it while pregnant. They looked at what was going on in the brains of the mouse and rat pups just before and after birth. Then they gave the mouse and rat moms bumetanide — and fewer of their newborns showed autistic-like behaviors.
By JAMES GORMAN Males’ aggression toward each other is an old story throughout the animal kingdom. It’s not that females aren’t aggressive, but in many species, male-on-male battles are more common. Take fruit flies. “The males are more aggressive than females,” said David J. Anderson, a California Institute of Technology neuroscientist who knows their tussles well. Dr. Anderson runs a kind of fight club for fruit flies in his lab at Caltech, with the goal of understanding the deep evolutionary roots of very fundamental behaviors. Dr. Anderson, Kenta Asahina and a group of their colleagues recently identified one gene and a tiny group of neurons, sometimes as few as three, present only in the brains of male fruit flies, that can control aggression. The gene is also found in mammals, and has also been associated with aggression in some mammalian species, perhaps even in humans, although that is not clear. The discovery, reported in the journal Cell last month, does not tell the whole story of fly aggression. Some fighting is inextricably linked to food and mating, while the mechanism the scientists found is not. But it is a striking indication of how brain structure and chemistry work together, as well as a reminder that as different as humans and flies are, they are not always very far apart. The painstaking process of discovery, recounted step by step in the paper, gives a glimpse of modern brain research and the lengths to which scientists must go if they want to get down to the level of how neurons control behavior. “They did a huge amount of experiments,” said Ulrike Heberlein at the Janelia Farm research campus of the Howard Hughes Medical Institute. Dr. Heberlein also studies fly behavior and recently demonstrated another human-fly connection, showing that jilted male flies will turn to drink. © 2014 The New York Times Company
Link ID: 19203 - Posted: 02.04.2014
Alice Roberts Just how special do you think you are? How different do you think you are from other animals? Do you think of yourself as an animal or do you see yourself, and your fellow humans, as somehow set apart from the rest of the animal kingdom? Most of us – and I would unashamedly label us as the sensible majority of the population – accept that evolution is the best explanation for the pattern of life that we observe on the planet, both living and fossilised. However much creationists bang on about evolution being "just a theory", it beautifully explains all the evidence we have to hand (and there's masses of that: anatomical, genetic, palaeontological, embryological), without a single piece of evidence having turned up that threatens to bring the whole edifice tumbling down around our ears. So, I'm hoping you're a sensible sort of person and that you consider evolution to be as true as the spherical nature of the Earth, or the fact that the Earth orbits the sun and not vice versa. But just how comfortable are you with the idea of being a product of evolution? I think it's still, even among the most enlightened of us, really hard to come to terms with the idea that we are just another animal. A naked ape. The third chimpanzee, even. You have to admit, science has done a very good job at bringing us down a peg or two, at knocking us off the pedestal of our own construction. We can no longer view ourselves as a special creation, something created in the image of a deity and close to angels (whatever they are or look like). We can no longer see ourselves as the ultimate destination, as the pinnacle of evolution, either. Our species is just a tiny twig on the massive, dense tree of life. But that's so difficult to stomach! © 2014 Guardian News and Media Limited
by Laura Sanders Despite seeming like a bystander, your baby is attuned to your social life (assuming you have one, which, with a baby, would be amazing). Every time you interact with someone, your wee babe is watching, eagerly slurping up social conventions. Scientists already know that babies expect some social graces: They expect people in a conversation to look at each other and talk to other people, not objects, and are eager to see good guys rewarded and bad guys punished, scientists have found. Now, a new study shows that babies are also attuned to other people’s relationships, even when those relationships have nothing to do with them. Babies are pretty good at figuring out who they want to interact with. The answer in most cases: Nice people. And that makes sense. The helpless wailers need someone reliable around to feed, change and entertain them. So to find out how good babies are at reading other people’s social relationships, University of Chicago psychologists showed 64 9-month-old babies a video of two women eating. Sometimes the women ate from the same bowl and agreed that the food was delicious, or agreed that it was gross. Sometimes the women disagreed. Later, the women interacted again, either warmly greeting each other and smiling, or giving each other the cold shoulder, arms crossed with a “hmph.” Researchers then timed how long the babies spent looking at this last scene, with the idea that the longer the baby spent looking, the more surprising the scene was. © Society for Science & the Public 2000 - 2014.
A food poisoning bacterium may be implicated in MS, say US researchers. Lab tests in mice by the team from Weill Cornell Medical College revealed a toxin made by a rare strain of Clostridium perfringens caused MS-like damage in the brain. And earlier work by the same team, published in PLoS ONE, identified the toxin-producing strain of C. perfringens in a young woman with MS. But experts urge caution, saying more work is needed to explore the link. No-one knows the exact cause of Multiple sclerosis (MS), but it is likely that a mixture of genetic and environmental factors play a role. It's a neurological condition which affects around 100,000 people in the UK. Most cases of human infection occur as food poisoning - diarrhoea and stomach cramps that usually resolve within a day or so. More rarely, the bacterium can cause gas gangrene. And a particular strain of C. perfringens, Type B, which the Weill team says it identified in a human for the first time, makes a toxin that can travel through blood to the brain. In their lab studies on rodents the researchers found that the toxin, called epsilon, crossed the blood-brain barrier and killed myelin-producing cells - the typical damage seen in MS. BBC © 2014
Christie Nicholson reports. Advocates claim numerous health benefits for meditation, many of which are supported by studies on the practice. Still, meditation has not become part of mainstream medicine. So researchers at Johns Hopkins University analyzed 47 previously published clinical trials to narrow down the most effective use for meditation as medical therapy. The studies involved more than 3,500 patients suffering from various issues including stress, addiction, depression, anxiety, diabetes, heart disease, cancer and chronic pain. The meta-analysis is in the journal JAMA Internal Medicine. [Madhav Goyal et al, Meditation Programs for Psychological Stress and Well-being: A Systematic Review and Meta-analysis] Apparently practicing just 30 minutes of meditation per day significantly decreases the symptoms of anxiety and depression. An 8-week training program in mindfulness meditation – where participants have to focus on the current moment – led to optimal improvement in lowering anxiety, depression and pain. And the improvements continued over the six months following the training. For depression and anxiety, the effects of meditation were as strong as for those achieved by taking antidepressant medication. However, meditation failed to significantly affect any of the other conditions, such as heart disease or cancer. Nevertheless, while some might view meditation as sitting and doing nothing, doing nothing does something. © 2014 Scientific American
By SINDYA N. BHANOO In pursuit of a mate, male fruit flies often engage in combat, battling one another with their front legs. But when the flies are brothers, they are more likely to cooperate, researchers are reporting. In a new study in the journal Nature, Tommaso Pizzari, a zoologist at the University of Oxford, and colleagues write that brother flies live longer as a result. And there are clear benefits for females who live among brothers: They have a longer reproductive life span, a faster rate of egg production and a greater chance of laying eggs that mature to adulthood. The researchers exposed female flies in a laboratory to several different sets of males — three brothers; two brothers and an unrelated male; and three unrelated males. The most peaceful groups were the ones with three brothers, perhaps because supporting one’s kin is an alternative way to pass on common genes. “You can improve your reproductive success yourself or help individuals who also share your genes,” Dr. Pizzari said. Although fruit flies have been extensively studied in labs, the structure of their natural societies remain a bit of a mystery. © 2014 The New York Times Compan
|By Meredith Knight When most of us imagine someone in pain, we feel uncomfortable and want to help. Psychopaths do not: a callousness toward others' suffering is the central feature of a psychopathic personality. Now an imaging study finds that psychopathic inmates have deficits in a key empathy circuit in the brain, pointing to a potential therapeutic target. Jean Decety, a psychologist at the University of Chicago, and his colleagues used functional MRI to scan the brains of 121 male prison inmates while they looked at photos of a painful moment, such as a foot stepping on a nail or a finger being smashed in a drawer. The inmates were instructed to imagine the scenario happening to themselves or to another person, a perspective-switching technique that easily elicits empathy in most people. Inmates who scored the highest on a standard psychopathy test showed a normal response in pain perception and brain centers for emotion when imagining the pain for themselves. Yet when asked to imagine the scenario happening to others, their brains did not show typical connectivity between the amygdala, an area important for fear and emotional processing, and the ventromedial prefrontal cortex, a region vital for emotion regulation, empathy and morality. Some results even indicated that pleasure regions might have become active instead. The brain areas that are undercommunicating in psychopathy “are key for experiencing empathetic concern and caring for one another, which is what empathy is all about and what individuals who score high on psychopathy do not have,” Decety says. © 2014 Scientific American