Links for Keyword: Aggression

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By Jonathan Lambert Your dog’s ability to learn new tricks may be less a product of your extensive training than their underlying genetics. Among 101 dog breeds, scientists found that certain behavioral traits such as trainability or aggression were more likely to be shared by genetically similar breeds. While past studies have looked into the genetic underpinnings of dog behaviors for certain breeds, this research — published October 1 in the Proceedings of the Royal Society B — is the first to investigate a wide swath of breed diversity and find a strong genetic signal. “Anecdotally, everyone knows that different dogs have different behavioral traits,” says Noah Snyder-Mackler, a geneticist at the University of Washington in Seattle. “But we didn’t know how much or why.” Humans and dogs have lived together for at least 15,000 years (SN: 7/6/17). But only within the last 300 years or so have breeders produced varieties such as Chihuahuas and Great Danes. So, Snyder-Mackler and his colleagues considered how 101 dog breeds behave while searching for genetic similarities among breeds sharing certain personality traits. Data came from two dog genotype databases and from C-BARQ, a survey that asks owners to rank their pure-bred dog’s propensity for certain behaviors, like chasing or aggressiveness toward strangers. As a result, the study didn’t have genetic and behavioral data from the same canine individuals, which could help highlight rare genetic variants that may be nonetheless important to diversity in behaviors. © Society for Science & the Public 2000–2019

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 13: Memory, Learning, and Development
Link ID: 26667 - Posted: 10.03.2019

/ By Rod McCullom In recent years, a steadily increasing volume of data has demonstrated that peer victimization — the clinical term for bullying — impacts hundreds of millions of children and adolescents, with the effects sometimes lasting years and, possibly, decades. The problem is even recognized as a global health challenge by the World Health Organization and the United Nations. And yet, researchers maintain there is still a limited understanding of how the behavior may physically shape the developing brain. Researchers believe more than 3.2 million American students experience bullying every year. That’s about 1 percent of the nation’s total population. Bullying is usually defined as repeated and intentional verbal, physical, and anti-social behavior that seeks to intimidate, harm, or marginalize someone perceived as smaller, weaker, or less powerful. Among younger children, common forms of bullying include abusive language and physical harm. This behavior may grow subtler with age as adolescent bullies routinely exclude, insult, and mock their targets. Sometimes this behavior escalates into “mobbing” among groups of bullies in school, work, or cyberspace. Researchers believe more than 3.2 million American students experience bullying every year. That’s about 1 percent of the nation’s total population. Among these students, about 10 to 15 percent experience “chronic” or persistent bullying that will last more than six continuous months. Experiencing chronic peer victimization is associated with lower academic achievement, higher unemployment rates, depression, anxiety, post-traumatic stress disorder, substance abuse, and self-harm and suicidal thoughts. Copyright 2019 Undark

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 13: Memory, Learning, and Development
Link ID: 26596 - Posted: 09.10.2019

By Iliana Magra LONDON — On a spring afternoon last year, Neil Fraser was walking down the main shopping street in Aberdeen, a port city in northeastern Scotland, when something strange happened. The bacon-and-chicken sandwich he was halfway through eating suddenly vanished from his hand. The culprit? A hungry bird he hadn’t seen coming. “The sea gull flew in from behind me,” Mr. Fraser, a manager at the Old Schoolhouse pub in the city, said by phone on Wednesday. The bird knocked down his hand and, before he realized what was happening, it was all over: “The sandwich and the sea gull were both gone.” Aggressive gulls trying to snatch people’s food, and at times succeeding, have been a longstanding nuisance in Britain, and various solutions have been proposed over the years, including not feeding the birds, holding a stick or umbrella overhead and installing wires on roofs that they use for nesting. The Old Schoolhouse pub even reportedly offered customers water pistols to deflect the birds. Now, new research proposes a different approach: staring them down. A study published in the journal Biology Letters on Wednesday by the Royal Society, the world’s oldest continuous scientific society, suggested that making eye contact might be key to fending off herring gulls, a familiar sight in British seaside towns. The study, conducted late last year in coastal towns in Cornwall, in southwestern England, focused on that species, which are white-, gray- and black-feathered, with beaks of yellow and red. The researchers tried to test 74 birds by placing potato chips in front of an experimenter. Just 27 of the gulls bit the bait — a factor that the research team attributed to whether the experimenter was facing toward or away from the gull. © 2019 The New York Times Company

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 26486 - Posted: 08.12.2019

By R. Douglas Fields From his sniper’s perch on the 32nd floor of the Mandalay Bay hotel in Las Vegas, a lone gunman fired 1,000 bullets from high-powered rifles into a crowd of concertgoers in 2017, murdering 58 innocent people and injuring 869 others. After he committed suicide at the crime scene, the mass murderer’s brain was shipped to Stanford University to seek a possible biological explanation for this depraved incident. What could the scientists possibly find during such an inspection? Quite a lot, in fact. No genetic test for homicidal behavior is in the offing. But this type of investigation can add insight into how violence is controlled by the brain. Using the same experimental methods that have enabled the tracing of brain circuits responsible for other complex human activities—including walking, speech and reading—neuroscientists now can pinpoint pathways that underlie aggressive behaviors. These new findings help to expose the underlying mechanisms at work in acts of extreme violence, such as the Las Vegas atrocity, but they also help to explain the more commonplace road rage and even a mother’s instantaneous response to any threat to her child. Physical, sometimes deadly violence is the hub of nature’s survival-of-the fittest struggle, and all animals have evolved specialized neural circuitry to execute—and control—aggressive behavior. In pioneering experiments on cats beginning in the late 1920s, Walter Hess discovered a locus deep within the hypothalamus, a brain area that unleashes violent aggression. It turns out that this is the same spot where other powerful compulsive urges and behaviors are activated, including sex, eating and drinking. When Hess stimulated this knot of neurons using a wire electrode inserted into the brain of a docile cat, the feline instantly launched into a hissing rage, attacking and killing another animal in its cage. The human brain has this same neural structure, labeled the hypothalamic attack area.

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 8: Hormones and Sex
Link ID: 26195 - Posted: 05.02.2019

By James Gorman If you want to know what makes hummingbirds tick, it’s best to avoid most poetry about them. Bird-beam of the summer day, — Whither on your sunny way? Whither? Probably off to have a bloodcurdling fight, that’s whither. John Vance Cheney wrote that verse, but let’s not point fingers. He has plenty of poetic company, all seduced by the color, beauty and teeny tininess of the hummingbird but failed to notice the ferocity burning in its rapidly beating heart. The Aztecs weren’t fooled. Their god of war, Huitzilopochtli, was a hummingbird. The Aztecs loved war, and they loved the beauty of the birds as well. It seems they didn’t find any contradiction in the marriage of beauty and bloodthirsty aggression. Scientists understood that aggression was a deep and pervasive part of hummingbird life. But they, too, have had their blind spots. The seemingly perfect match of nectar-bearing flowers to slender nectar-sipping beaks clearly showed that hummingbirds were shaped by co-evolution. It seemed clear that, evolutionarily, plants were in charge. Their need for reliable pollinators produced flowers with a shape that demanded a long slender bill. Hummingbird evolution obliged. But hummingbirds also heard the call of battle, which demanded a different evolutionary course. Some of those slender, delicate beaks have been reshaped into strong, sharp and dangerous weapons. In a recent paper organizing and summing up 10 years of research, Alejandro Rico-Guevara and his colleagues at the University of California, Berkeley, shared evidence gathered by high-speed video about how the deadly beaks are deployed in male-to-male conflict. Like the horns of bighorn sheep or the giant mandibles of stag beetles, hummingbird beaks are used to fight off rivals for mates. This is sexual selection, a narrow part of natural selection, in which the improvement of mating chances is the dominant force. © 2019 The New York Times Company

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 8: Hormones and Sex
Link ID: 25937 - Posted: 02.06.2019

By Elizabeth Pennisi A 9-year study has uncovered some unusual behavior by common bottlenose dolphins (Tursiops truncatus) living off the coast of Slovenia. Within one population of this species, the animals have divided into two groups that avoid contact by hunting at different times of day—a social strategy not known in marine mammals. Researchers used photographs of the dolphins’ dorsal fins to individually identify them. They made many observations of 38 of the animals, carefully recording the time, date, and location of each sighting. The marine mammals divided into two major groups of 19 and 13 animals each, with six animals loosely making up a third group, the team reports today in Marine Biology. The 19 members of the larger group tended to hang out—and likely hunt—while following fishing trawlers in the Bay of Trieste, which is located at the eastern top of Italy’s “boot.” The second group’s cadre of 13 never associated with boats when in the Bay of Trieste. Although the dolphins hunted in the same area, they rarely saw each other, the researchers discovered, because the larger group was in that area only between 7 a.m. and 1 p.m. local time, whereas the smaller group showed up between 6 p.m. and 9 p.m. Other studies have documented groups of dolphins that divide up the waters where they hunt, but this is the first time these marine mammals have been shown to timeshare the sea, the researchers note. Although they don’t know why—or how—the dolphins set these schedules, the fact that the animals are never in the same place likely diminishes unfriendly encounters and reduces direct competition for food. © 2018 American Association for the Advancement of Science

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 25798 - Posted: 12.20.2018

By Melinda Wenner Moyer Intuitively, it makes sense Splatterhouse and Postal 2 would serve as virtual training sessions for teens, encouraging them to act out in ways that mimic game-related violence. But many studies have failed to find a clear connection between violent game play and belligerent behavior, and the controversy over whether the shoot-‘em-up world transfers to real life has persisted for years. A new study published on October 1 in Proceedings of the National Academy of Sciences tries to resolve the controversy by weighing the findings of two dozen studies on the topic. The meta-analysis does tie violent video games to a small increase in physical aggression among adolescents and preteens. Yet debate is by no means over. Whereas the analysis was undertaken to help settle the science on the issue, researchers still disagree on the real-world significance of the findings. This new analysis attempted to navigate through the minefield of conflicting research. Many studies find gaming associated with increases in aggression, but others identify no such link. A small but vocal cadre of researchers have argued much of the work implicating video games has serious flaws in that, among other things, it measures the frequency of aggressive thoughts or language rather than physically aggressive behaviors like hitting or pushing, which have more real-world relevance. © 2018 Scientific American

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 25518 - Posted: 10.02.2018

By Frankie Schembri Some of the deadliest mass shootings in U.S. history, including lone gunmen killing 26 people at the First Baptist Church in Sutherland Springs, Texas, and 17 students and staff at Marjory Stoneman Douglas High School in Parkland, Florida, have occurred in the past 2 years. These tragedies were preventable, says Garen Wintemute, an emergency medicine physician at the University of California (UC), Davis, Medical Center, and the director of UC Davis’s Violence Prevention Research Program. Wintemute has studied gun violence for more than 30 years and is one of the few researchers to approach the matter as an issue of public health. He has gone undercover at gun shows to document illegal activity and worked with California lawmakers to establish gun policies. Wintemute writes about his solutions to gun violence in an opinion piece published this week in The New England Journal of Medicine. Science chatted with him about the unique factors behind mass shootings and which policy interventions are most effective. This interview has been edited for clarity and length. Q: What does it mean to approach gun violence from a public health perspective? A: Firearm violence has been seen traditionally as a crime problem. But gun violence is one of our leading causes of death and injury, and the implications of this violence are huge in terms of the safety and health of our overall population. So, we treat it as we would any other major health problem. We ask: Where does it come from? How does it get amplified? Who is at risk for developing this problem? Can we learn enough to create a treatment or prevention strategy? © 2018 American Association for the Advancement of Science

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 25503 - Posted: 09.28.2018

By Frankie Schembri For animals unlucky enough to run into a carnivorous songbird known as the shrike, a quiet scurry through the woods can quickly morph into a dance with death. Loggerhead shrikes (Lanius ludovicianus), aka butcherbirds, impale their prey on spiky plants or barbed wire before delivering a death blow to the neck with their hooked beaks. Now, a new study shows how the birds can take down lizards and mice with body masses more than twice their own. Scientists used a high-speed video camera to film 28 shrikes attacking large vertebrate prey at a zoological research center on San Clemente Island in California. When the researchers examined the slowed-down footage, they found that in nearly all fatal attacks, the shrikes would first latch onto the necks of their prey, vigorously shaking them up and down. By using their prey’s neck as a pivot to whip them in wavelike motion, the shrikes could cause fatal damage to cervical vertebrae and spinal cords, the researchers report today in Biology Letters. When the team analyzed the shaking motions, they found that the shrikes could exert up to 6 gs of accelerative force. By comparison, humans in low-speed, rear-end car crashes can experience head accelerations of 2 to 12 gs, enough to cause whiplash. On a mouse’s smaller spine, these forces can be fatal. © 2018 American Association for the Advancement of Science

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 25417 - Posted: 09.05.2018

By Ingfei Chen Newtown, Connecticut. Las Vegas. Parkland, Florida. Annapolis, Maryland. And just two days ago, Jacksonville, Florida, where the details are still coming in. With each ghastly mass shooting in a school, workplace, or other public location, journalists scramble to piece together what happened, and speculation runs high as to whether the gunman had mental illness. But critics say the media coverage perpetuates deep-seated, stigmatizing attitudes about diagnoses such as schizophrenia or bipolar disorder. What can journalists do to cover the mental health connection in these mass murders in a responsible way? “Journalism is far too quick to try to guess at the ‘why’ behind these sorts of things, but speculation can have serious consequences.” Earlier this month, police investigators released a final report on the massacre at a Las Vegas concert last October, the deadliest shooting in modern American history. The motives of the 64-year-old gunman — a wealthy high-stakes gambler — remain unclear, they conceded, but he had burned through much of his fortune and shown potential signs of a troubled mind. While some news outlets made only brief reference to suspicions that the shooter may have had mental illness, others blared it. It’s a familiar theme. In recent years, the national conversation about gun violence has boiled down to a narrative — amplified by the media — that essentially blames mental illness as a prominent cause of these cold-blooded public mass shootings. Mental illness has become highly politicized in the gun-control debate, yet the link between psychiatric problems and violence isn’t so straightforward. And mental health advocates say the over-simplistic narrative unfairly labels millions of Americans who have a psychiatric diagnosis with the false stereotype of being dangerous. Copyright 2018 Undark

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 25396 - Posted: 08.29.2018

By Andrew R. Calderon In 1978, Thomas Barefoot was convicted of killing a police officer in Texas. During the sentencing phase of his trial, the prosecution called two psychiatrists to testify about Barefoot’s “future dangerousness,” a capital-sentencing requirement that asked the jury to determine if the defendant posed a threat to society. The psychiatrists declared Barefoot a “criminal psychopath,” and warned that whether he was inside or outside a prison, there was a “one hundred percent and absolute chance” that he would commit future acts of violence that would “constitute a continuing threat to society.” Informed by these clinical predictions, the jury sentenced Barefoot to death. Although such psychiatric forecasting is less common now in capital cases, a battery of risk assessment tools has since been developed that aims to help courts determine appropriate sentencing, probation and parole. Many of these risk assessments use algorithms to weigh personal, psychological, historical and environmental factors to make predictions of future behavior. But it is an imperfect science, beset by accusations of racial bias and false positives. Now a group of neuroscientists at the University of New Mexico propose to use brain imaging technology to improve risk assessments. Kent Kiehl, a professor of psychology, neuroscience and the law at the University of New Mexico, said that by measuring brain structure and activity they might better predict the probability an individual will offend again.

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 25339 - Posted: 08.16.2018

/ By Rod McCullom Eight years ago, New York University sociologist Patrick Sharkey published a paper whose conclusions shook the worlds of criminology and adolescent psychology. Researchers had long known that children exposed to violence and crime had poorer measures of memory, attention, planning, and focus — the cognitive processes collectively known as executive function — than peers whose lives were violence-free. But what Sharkey found, using data on 6,000 Chicago homicides from 1994 to 2002, was that a killing in a child’s neighborhood could significantly lower his or her scores on standardized tests — even if the child did not witness the killing or know the victim. He proposed that post-traumatic stress caused by exposure to violence could explain about half of the “achievement gap” between black and white students — a disparity that leads to persistent inequalities in education, income, careers, housing, and more. Similar findings have been documented in more recent studies, but one question has continued to vex researchers: Why? How does even indirect violence get under a child’s skin and into the brain? Now some intriguing interdisciplinary research — by psychologists, economists, and sociologists — suggests that a large part of the answer may lie in two biological pathways: sleep and the stress hormone cortisol. Researchers at Northwestern University, DePaul University, and NYU (including Sharkey) looked at 82 adolescents aged 11 to 18 who attended public schools in a “large Midwestern city.” (The school system asked for anonymity to participate in the study.) At least half the students had at least one violent crime in their neighborhood during the participation period, according to geocoded police report data collected by the researchers. The students wore activity-tracking watches that measured sleep-wake patterns, and most of them delivered three saliva samples daily for measuring cortisol levels. Copyright 2018 Undark

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 13: Memory, Learning, and Development
Link ID: 25285 - Posted: 08.02.2018

In the wake of a mass shooting — or any other senseless tragedy — the search for answers begins. How could it happen? Could it have been prevented? What can we do to prevent this from happening again? The question of whether there is a relationship between mental illness and violence — and the potential threat it may pose to public safety — was renewed this week after the family of Faisal Hussain, the gunman in Sunday night's deadly shooting rampage in Toronto, said he was mentally ill. "Our son had severe mental health challenges, struggling with psychosis and depression his entire life," the statement said. Two people were killed and 13 others injured in the attack, jolting a city already rattled by escalating gun violence. Hussain died from a gunshot wound moments after exchanging gunfire with Toronto police officers. Little is known about Hussain's condition or treatment beyond the statement released by his family. And while some explanation of what may have tormented or even motivated Hussain may add to our understanding, experts agree mental illness is just one of many potential red flags and not a reliable predictor of behaviour. People leave flowers at a memorial Tuesday honouring the victims of the mass shooting on Toronto's Danforth Avenue. (Mark Blinch/Canadian Press) ©2018 CBC/Radio-Canada.

Related chapters from BN8e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders; Chapter 11: Emotions, Aggression, and Stress
Link ID: 25252 - Posted: 07.26.2018

by Amy Ellis Nutt The possibility of using brain stimulation to help prevent future violence just passed a proof of concept stage, according to new research published Monday in the Journal of Neuroscience. In a double-blind, randomized controlled study, a group of volunteers who received a charge to their dorsolateral prefrontal cortex — the part of the brain that lies directly behind the forehead and is responsible for planning, reasoning and inhibition were — were less likely to say they would consider engaging in aggressive behavior compared to a similar group that received a sham treatment. The experiment looked at aggressive intent as well as how people reasoned about violence and found that a sense of moral wrongfulness about hypothetical acts of aggression was heightened in the group receiving the transcranial direct current stimulation (tDCS). This form of brain stimulation delivers targeted impulses to the brain through electrodes placed on a person's scalp. "Zapping offenders with an electrical current to fix their brains sounds like pulp fiction, but it might not be as crazy as it sounds," said Adrian Raine, a neurocriminologist at the University of Pennsylvania and one of the study's investigators. "This study goes some way toward documenting a causal association by showing that enhancing the prefrontal cortex puts the brakes on the impulse to act aggressively." © 1996-2018 The Washington Post

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 25171 - Posted: 07.03.2018

Darby Saxbe Flinching as a gunshot whizzes past your window. Covering your ears when a police car races down your street, sirens blaring. Walking past a drug deal on your block or a beating at your school. For kids living in picket-fence suburbia, these experiences might be rare. But for their peers in urban poverty, they are all too commonplace. More than half of children and adolescents living in cities have experienced some form of community violence – acts of disturbance or crime, such as drug use, beatings, shootings, stabbings and break-ins, within their neighborhoods or schools. Researchers know from decades of work that exposure to community violence can lead to emotional, social and cognitive problems. Kids might have difficulty regulating emotions, paying attention or concentrating at school. Over time, kids living with the stress of community violence may become less engaged in school, withdraw from friends or show symptoms of post-traumatic stress, like irritability and intrusive thoughts. In short, living in an unsafe community can have a corrosive effect on child development. Few studies, though, have specifically looked at the toll community violence may take on the growing brain. Recently, I studied this question in collaboration with a team of researchers here at the University of Southern California. Our goal: to see whether individuals exposed to more community violence in their early teen years would show differences in the structure and function of their brains in late adolescence. © 2010–2018, The Conversation US, Inc.

Related chapters from BN8e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 11: Emotions, Aggression, and Stress
Link ID: 25087 - Posted: 06.14.2018

Imagine having superhuman hearing. You’re at a noisy, cocktail party and yet your ears can detect normally inaudible sounds made by your friends’ muscles as they lean in to dish the latest gossip. But, unlike normal hearing, each of these sounds causes your ears to react in the same way. There is no difference between the quietest and loudest movements. To your superhuman ears, they all sound loud, like honking horns. According to a study funded by the National Institutes of Health, that may be how a shark’s electrosensing organ reacts when it detects teensy, tiny electrical fields emanating from nearby prey. “Sharks have this incredible ability to pick up nanoscopic currents while swimming through a blizzard of electric noise. Our results suggest that a shark’s electrosensing organ is tuned to react to any of these changes in a sudden, all-or-none manner, as if to say, ‘attack now,’” said David Julius, Ph.D., professor and chair of physiology at the University of California, San Francisco and senior author of the study published in Nature. His team studies the cells and molecules behind pain and other sensations. For instance, their results have helped scientists understand why chili peppers feel hot and menthol cool. Led by post-docs Nicholas W. Bellono, Ph.D. and Duncan B. Leitch, Ph.D., Dr. Julius’ team showed that the shark’s responses may be very different from the way the same organ reacts in skates, the flat, winged, evolutionary cousins of sharks and sting rays, and this may help explain why sharks appear to use electric fields strictly to locate prey while skates use them to find food, friends, and mates. They also showed how genes that encode for proteins called ion channels may control the shark’s unique “sixth sense.”

Related chapters from BN8e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 11: Emotions, Aggression, and Stress
Link ID: 25038 - Posted: 05.31.2018

By Kashmira Gander Scientists have turned off aggressive behavior in mice for weeks at a time by harnessing the power of a little-understood group of brain cells. In a new study, which sheds light on the potential biological cause of aggression, scientists tinkered with neurons in the brains of lab mice. To arrive at their findings, the researchers at the Karolinska Institutet in Sweden investigated the role of a set of neurons in the ventral premammillary nucleus (PMv) of the hypothalamus. Mice generally resort to aggression as a way to assert their dominance rather than cause harm, so the scientists tested their hypothesis using the so-called tube test. This involves pitting two mice against each other in a narrow corridor, in order to document their responses in this socially fraught situation. The study, published in the journal Nature Neuroscience, showed when male mice were confronted with a new male in their home cage, the animals responded aggressively, and showed activity in the PMv neurons. Using a technique where neurons are turned on and off using light, called optogenetics, the researchers were also able to trigger aggressive behavior in mice in scenarios where they were usually calm. In turn, they could stop a mouse mid-attack by turning off the light. What's more, when a generally submissive male was faced with a dominant male, blocking the PMv cells inverted their statuses. As well as aggression, PMv neurons also appeared to be associated with other parts of the brain—the part linked to rewards. © 2018 Newsweek LLC

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 25030 - Posted: 05.29.2018

Susan Milius Pick an animal. Choose wisely because in this fantasy you’ll transform into the creature and duel against one of your own. If you care about survival, go for the muscular, multispiked stag roaring at a rival. Never, ever pick the wingless male fig wasp. Way too dangerous. This advice sounds exactly wrong. But that’s because many stereotypes of animal conflict get the real biology backward. All-out fighting to the death is the rule only for certain specialized creatures. Whether a species is bigger than a breadbox has little to do with lethal ferocity. Many creatures that routinely kill their own kind would be terrifying, if they were larger than a jelly bean. Certain male fig wasps unable to leave the fruit they hatch in have become textbook examples, says Mark Briffa, who studies animal combat. Stranded for life in one fig, these males grow “big mouthparts like a pair of scissors,” he says, and “decapitate as many other males as they possibly can.” The last he-wasp crawling has no competition to mate with all the females in his own private fruit palace. In contrast, big mammals that inspire sports-team mascots mostly use antlers, horns and other outsize male weaponry for posing, feinting and strength testing. Duels to the death are rare. |© Society for Science & the Public 2000 - 2018.

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 24944 - Posted: 05.05.2018

Kas Roussy · You think you have a dysfunctional clan? Check out the family feud involving Humphrey, Charlie and Hugh. In the early '70s, the trio was part of a tight-knit community of wild chimpanzees in Gombe National Park, Tanzania. These are some of the same chimps that British primatologist Jane Goodall was studying at the time, looking at social and family dynamics. "Jane and other researchers who came to Gombe initially had this idea that chimpanzees were these idyllic forest-dwelling species that could provide this model for what humanity could be like," says Duke University researcher Joseph Feldblum. "They thought they were peaceful and egalitarian." They were about to get a reality check of the wild kingdom variety. According to a new study, the same things that fuel deadly clashes in humans — like power, ambition, and jealousy — can also tear apart chimpanzees. You'll recall from all those wildlife documentaries that chimps are our closest animal relatives. In Gombe, Goodall and her colleagues watched a once-unified group of chimps disintegrate into two rival factions. "There's still a bit of uncertainty, even with people who were there at the time, about exactly what happened," Feldblum tells CBC News. But thanks to new digitized data taken from Goodall's own field notes from that period, Feldblum and a team of scientists were able to get a clearer, more detailed picture of what they call "the seeds of the conflict." "We were able to examine the course of the split in more detail and pinpoint when it became obvious more precisely," says co-author and Duke anthropologist Anne Pusey. ©2018 CBC/Radio-Canada

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 24820 - Posted: 04.04.2018

Amy Fleming Charles Ryan has a clinic in San Francisco at which he regularly relieves men of their testosterone. This “chemical castration”, as it is sometimes known, is not a punishment, but a common treatment for prostate cancer. Testosterone doesn’t cause the disease (currently the third most deadly cancer in the UK), but it fuels it, so oncologists use drugs to reduce the amount produced by the testicles. Ryan gets to know his patients well over the years, listening to their concerns and observing changes in them as their testosterone levels fall. Because it involves the so-called “male hormone”, the therapy poses existential challenges to many of those he treats. They know that every day, millions of people – from bodybuilders and cheating athletes to menopausal women – enhance their natural levels of testosterone with the aim of boosting their libido, muscle mass, confidence and energy. So what happens when production is suppressed? Might they lose their sex drive? Their strength? Their will to win? The fears are not always groundless. Side-effects can also include fatigue and weight gain. But Ryan has witnessed positives, too. As professor of medicine and urology at the University of California, he has noticed that the medical students who have passed through his clinic in the 18 years that he has been treating prostate cancer invariably comment: “Dr Ryan, your patients are so nice.” He replies, jokingly: “It’s because they don’t have any testosterone. They can’t be mean.” © 2018 Guardian News and Media Limited

Related chapters from BN8e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders; Chapter 8: Hormones and Sex
Link ID: 24768 - Posted: 03.20.2018