Tuesday, October 26, 2010

DOGS MAY BE PESSIMISTIC TOO

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A study has gained new insight into the minds of dogs, discovering that those that are anxious when left alone also tend to show ‘pessimistic’ like behaviour.

The research by academics at the University of Bristol, and funded by the RSPCA is published in Current Biology (12 October). The study provides an important insight into dogs’ emotions, and enhances our understanding of why behavioural responses to separation occur.

Professor Mike Mendl, Head of the Animal Welfare and Behaviour research group at Bristol University’s School of Clinical Veterinary Science, who led the research, said: “We all have a tendency to think that our pets and other animals experience emotions similar to our own, but we have no way of knowing directly because emotions are essentially private. However, we can use findings from human psychology research to develop new ways of measuring animal emotion.

“We know that people’s emotional states affect their judgements and that happy people are more likely to judge an ambiguous situation positively. What our study has shown is that this applies similarly to dogs – that a ‘glass-half-full’ dog is less likely to be anxious when left alone than one with a more ‘pessimistic’ nature.”

In order to study ‘pessimistic’ or ‘optimistic’ decisions, dogs at two UK animal re-homing centres were trained that when a bowl was placed at one location in a room (the ‘positive’ position) it would contain food, but when placed at another location (the ‘negative’ position) it would be empty. The bowl was then placed at ambiguous locations between the positive and negative positions.

Professor Mendl explained: “Dogs that ran fast to these ambiguous locations, as if expecting the positive food reward, were classed as making relatively ‘optimistic’ decisions. Interestingly, these dogs tended to be the ones who also showed least anxiety-like behaviour when left alone for a short time.

“Around half of dogs in the UK may at some point perform separation-related behaviours - toileting, barking and destroying objects around the home - when they’re apart from their owners. Our study suggests that dogs showing these types of behaviour also appear to make more pessimistic judgements generally.”

Dr Samantha Gaines, Deputy Head of the Companion Animals Department from RSPCA, said: “Many dogs are relinquished each year because they show separation-related behaviour. Some owners think that dogs showing anxious behaviour in response to separation are fine, and do not seek treatment for their pets. This research suggests that at least some of these dogs may have underlying negative emotional states, and owners are encouraged to seek treatment to enhance the welfare of their dogs and minimise the need to relinquish their pet. Some dogs may also be more prone to develop these behaviours, and should be re-homed with appropriate owners.”

(Photo: U. Bristol)

University of Bristol

FIRST COMPREHENSIVE SURVEY OF GUT, MOUTH AND ARTERIAL BACTERIA FINDS LINKS TO HEART DISEASE

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The same types of bacteria found in arterial plaque, which causes atherosclerosis, are also found in the mouth and gut, according to the first general survey of all bacteria found in plaques from the mouth, gut and blood.

The study, conducted by researchers from Cornell and University of Gothenburg, Sweden and published online in the Proceedings of the National Academy of Sciences, may one day offer new ways to detect heart disease and could lead to drugs that target these bacteria to reduce arterial plaque and atherosclerosis.

In atherosclerosis, a fatty material called plaque collects along the walls of arteries, where it thickens, hardens (forming calcium deposits) and may eventually block the arteries.

"Our survey shows that bacteria are pretty good at getting out of the mouth and gut and into the blood stream," said Ruth Ley, Cornell assistant professor of microbiology and a senior author of the study with Frederik Bäckhed, a cardiovascular researcher from the University of Gothenburg. Omry Koren, a postdoctoral researcher in Ley's lab, is the paper's lead author.

The study used samples from the mouth and feces (to determine bacteria in the gastrointestinal tract) from 15 heart disease patients who had plaque removed from their arteries. Samples were also taken from a control group of 15 healthy individuals who matched the heart disease patients by sex and age.

The findings show that such bacteria as Veillonella and Streptococcus were the most abundant microbiota found in plaque. Furthermore, when a lot of these two types of bacteria were found in the mouth, the researchers found a corresponding abundance of the same bacteria in the arterial plaque.

Previous studies have provided evidence that bacteria from the mouth and gut may play a role in the formation of arterial plaque, leading to coronary disease. Studies have shown that mice, whose immune systems were compromised in such a way that they could not detect bacteria, were resistant to atherosclerosis, leading researchers to suspect that arterial plaque forms partly due to the body's immune reactions to bacteria.

Ley and colleagues found a positive correlation between amounts of bacteria and leukocytes (white blood cells) in arterial plaque, supporting the theory that higher levels of arterial plaque lead to an immune response and inflammation.

Also, Chryseomonas bacteria were found in all samples of atherosclerotic plaque, suggesting that the bacteria may contribute to its development. Also, Streptococcus in the mouth and gut were positively correlated with HDL ("good") cholesterol, while a number of other gut bacterial were positively correlated with LDL ("bad") and total cholesterol.

The study, which used high throughput DNA sequencing techniques to get more comprehensive data than in previous research, was funded by the Swedish Research Council, National Institutes of Health, National Science Foundation and others.

(Photo: Ian Hewson)

Cornell University

UT SOUTHWESTERN RESEARCHERS CREATE EXPERIMENTAL VACCINE AGAINST ALZHEIMER'S

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Researchers at UT Southwestern Medical Center have created an experimental vaccine against beta-amyloid, the small protein that forms plaques in the brain and is believed to contribute to the development of Alzheimer’s disease.

Compared with similar so-called DNA vaccines that the UT Southwestern researchers tested in an animal study, the new experimental vaccine stimulated more than 10 times as many antibodies that bind to and eliminate beta-amyloid. The results appeared in the journal Vaccine.

Future studies will focus on determining the safety of the vaccine and whether it protects mental function in animals, said Dr. Roger Rosenberg, director of the Alzheimer’s Disease Center at UT Southwestern and senior author of the study.

“The antibody is specific; it binds to plaque in the brain. It doesn’t bind to brain tissue that does not contain plaque,” Dr. Rosenberg said. “This approach shows promise in generating enough antibodies to be useful clinically in treating patients.”

A traditional vaccine – an injection of beta-amyloid protein itself into the arm – has been shown in other research to trigger an immune response, including the production of antibodies and other bodily defenses against beta-amyloid. However, the immune response to this type of vaccine sometimes caused significant brain swelling, so Dr. Rosenberg and his colleagues focused on developing a nontraditional DNA vaccine.

The DNA vaccine does not contain beta-amyloid itself but instead a piece of the beta-amyloid gene that codes for the protein. In the current study, the researchers coated tiny gold beads with the beta-amyloid DNA and injected them into the skin of the animals’ ears. Once in the body, the DNA stimulated an immune response, including antibodies to beta-amyloid.

The next step in the research is to test long-term safety in animals, Dr. Rosenberg said.

“After seven years developing this vaccine, we are hopeful it will not show any significant toxicity, and that we will be able to develop it for human use,” he said.

(Photo: UTSMC)

UT Southwestern Medical Center

LARGE STUDY SHOWS FEMALES THE EQUAL OF MALES IN MATH SKILLS

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A research team that includes UC Berkeley Graduate School of Education Professor Marcia Linn is again offering proof that the mathematical skills of boys and girls, as well as men and women, are substantially equal.

Linn and her fellow researchers examined existing studies between 1990 and 2007 that looked mainly at grade- and high-school students and published the results in the current online edition of journal Psychological Bulletin, an American Psychological Association publication. Linn has been part of three other large studies on gender differences in mathematics and/or science achievement.

One portion of the new study looked systematically at 242 articles that assessed the math skills of nearly 1.3 million people. A second portion of the new study examined the results of several large, long-term scientific studies, such as the National Assessment of Educational Progress.

In both cases, the difference between the two sexes was so close as to be meaningless according to Linn and co-authors Sara Lindberg, a post-doctoral fellow in women’s health at the University of Wisconsin School of Medicine and Public Health; and Janet Hyde, a professor of psychology and women’s studies at the University of Wisconsin-Madison.

The idea that both genders have equal math abilities is now widely accepted among educational researchers, Linn says, but remains surprising to many teachers and parents, who may guide girls away from courses and careers in the sciences and engineering.

Scientists now know that stereotypes affect performance according to Hyde. “There is lots of evidence that what we call ‘stereotype threat’ can hold women back in math,” says Hyde. “If, before a test, you imply that the women should expect to do a little worse than the men, that hurts performance.”

The authors hope the new results will slow the trend toward single-sex schools, which are sometimes justified on the basis of differential math skills. It may also affect standardized tests, which gained clout with the passage of No Child Left Behind, and tend to emphasize lower-level math skills like multiplication, the authors say.

"We found that the tests used for high-stakes testing have too few items that require complex problem solving,” says Linn. “These tests deter teachers from emphasizing problems that are important in everyday situations such as interpreting data about health treatment alternatives."

The new findings reinforce a recent study that ranked gender dead last among nine factors, including parental education, family income and school effectiveness, in influencing the math performance of 10-year olds.

Women have made significant advances in technical fields. Half of medical-school students are female, as are 48 percent of undergraduate math majors. However progress in physics and engineering is much slower.

“Teachers, by encouraging girls in mathematics, can help reduce stereotypes that inhibit persistence in mathematics and science," says Linn, “and they can use this evidence to guide girls to take courses such as physics and computer science that build on mathematics ability.”

UC Berkeley

UF RESEARCH PROVIDES NEW UNDERSTANDING OF BIZARRE EXTINCT MAMMAL

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University of Florida researchers presenting new fossil evidence of an exceptionally well-preserved 55-million-year-old North American mammal have found it shares a common ancestor with rodents and primates, including humans.

The study, appeared in the Oct. 11 online edition of the Zoological Journal of the Linnean Society, describes the cranial anatomy of the extinct mammal, Labidolemur kayi. High resolution CT scans of the specimens allowed researchers to study minute details in the skull, including bone structures smaller than one-tenth of a millimeter. Similarities in bone features with other mammals show L. kayi’s living relatives are rodents, rabbits, flying lemurs, tree shrews and primates.

Researchers said the new information will aide future studies to better understand the origin of primates.

“The specimens are among the only skulls of apatemyids known that aren’t squashed completely flat,” said study co-author Jonathan Bloch, an associate curator of vertebrate paleontology at the Florida Museum of Natural History on the UF campus. “They’re preserved in three dimensions, which allows us to look at the morphology of the bones in a way that we never could before.”

Scientists have disputed the relationships of Apatemyidae, the family that includes L. kayi, for more than a century because of their unusual physical characteristics. With can opener-shaped upper front teeth and two unusually long fingers, apatemyids have been compared to a variety of animals, from opossums to woodpeckers.

“There are only a few examples in the history of mammals where you get such an incredibly odd ecological adaptation,” Bloch said.

Like a woodpecker’s method of feeding, L. kayi used percussive foraging, or tapping on trees, to locate insects. It stood less than a foot tall, was capable of jumping between trees and looked like a squirrel with a couple of really long fingers, similar to the aye-aye, a lemur native to Madagascar, Bloch said.

Apatemyids have been preserved for tens of millions of years and are well known from Europe and North America.

The skeletons analyzed in the publication were recovered from freshwater limestone in the Bighorn Basin by co-author Peter Houde of New Mexico State University. Located just east of Yellowstone National Park in Wyoming, the site is known as one of the best in the world for studying the evolution of mammals during the 10 million years following the extinction of the dinosaurs, Bloch said.

Mary Silcox, first author of the study and a research associate at the Florida Museum, said scans of the specimens began about 10 years ago, during her postdoctoral work at The Pennsylvania State University.

“It’s not like medical CT, it’s actually an industrial CT scanner,” said Silcox, an assistant professor of anthropology at the University of Toronto Scarborough. “Because this is a small animal, we needed to be able to study it at a very high resolution. The high resolution CT data were a critical part.”

Doug Boyer of Stony Brook University is also a co-author of the study, part of the team’s larger research to understand the relationships of apatemyids to other mammals. Bloch and colleagues are currently writing a detailed analysis of L. kayi’s skeleton.
John Wible, curator of mammals at the Carnegie Museum of Natural History and one of the researchers who reviewed the study, said it provides valuable information for understanding the evolutionary relationships of mammals.

“It is now clear that any assessment of the origins of primates in the future will have to include apatemyids,” Wible said. “Apatemyids are not some freakish dead-end, but significant members of our own history.”

(Photo: Kristen Grace/Florida Museum of Natural History)

University of Florida

FLORIDA STATE STUDY FINDS WATERMELON LOWERS BLOOD PRESSURE

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No matter how you slice it, watermelon has a lot going for it –– sweet, low calorie, high fiber, nutrient rich –– and now, there's more. Evidence from a pilot study led by food scientists at The Florida State University suggests that watermelon can be an effective natural weapon against prehypertension, a precursor to cardiovascular disease.

It is the first investigation of its kind in humans. FSU Assistant Professor Arturo Figueroa and Professor Bahram H. Arjmandi found that when six grams of the amino acid L-citrulline/L-arginine from watermelon extract was administered daily for six weeks, there was improved arterial function and consequently lowered aortic blood pressure in all nine of their prehypertensive subjects (four men and five postmenopausal women, ages 51-57).

"We are the first to document improved aortic hemodynamics in prehypertensive but otherwise healthy middle-aged men and women receiving therapeutic doses of watermelon," Figueroa said. "These findings suggest that this 'functional food' has a vasodilatory effect, and one that may prevent prehypertension from progressing to full-blown hypertension, a major risk factor for heart attacks and strokes.

"Given the encouraging evidence generated by this preliminary study, we hope to continue the research and include a much larger group of participants in the next round," he said.

Why watermelon?

"Watermelon is the richest edible natural source of L-citrulline, which is closely related to L-arginine, the amino acid required for the formation of nitric oxide essential to the regulation of vascular tone and healthy blood pressure," Figueroa said.

Once in the body, the L-citrulline is converted into L-arginine. Simply consuming L-arginine as a dietary supplement isn't an option for many hypertensive adults, said Figueroa, because it can cause nausea, gastrointestinal tract discomfort, and diarrhea.
In contrast, watermelon is well tolerated. Participants in the Florida State pilot study reported no adverse effects. And, in addition to the vascular benefits of citrulline, watermelon provides abundant vitamin A, B6, C, fiber, potassium and lycopene, a powerful antioxidant. Watermelon may even help to reduce serum glucose levels, according to Arjmandi.

"Cardiovascular disease (CVD) continues to be the leading cause of death in the United States," Arjmandi said. "Generally, Americans have been more concerned about their blood cholesterol levels and dietary cholesterol intakes rather than their overall cardiovascular health risk factors leading to CVD, such as obesity and vascular dysfunction characterized by arterial stiffening and thickness –– issues that functional foods such as watermelon can help to mitigate.

"By functional foods," said Arjmandi, "we mean those foods scientifically shown to have health-promoting or disease-preventing properties, above and beyond the other intrinsically healthy nutrients they also supply."

Figueroa said oral L-citrulline supplementation might allow a reduced dosage of antihypertensive drugs necessary to control blood pressure.

"Even better, it may prevent the progression from prehypertension to hypertension in the first place," he said.

While watermelon or watermelon extract is the best natural source for L-citrulline, it is also available in the synthetic form in pills, which Figueroa used in a previous study of younger, male subjects. That investigation showed that four weeks of L-citrulline slowed or weakened the increase in aortic blood pressure in response to cold exposure. It was an important finding, said Figueroa, since there is a greater occurrence of myocardial infarction associated with hypertension during the cold winter months.

"Individuals with increased blood pressure and arterial stiffness –– especially those who are older and those with chronic diseases such as type 2 diabetes –– would benefit from L-citrulline in either the synthetic or natural (watermelon) form," Figueroa said. "The optimal dose appears to be four to six grams a day."

Approximately 60 percent of U.S. adults are prehypertensive or hypertensive. Prehypertension is characterized by systolic blood pressure readings of 120-139 millimeters of mercury (mm Hg) over diastolic pressure of 80-89 mm Hg. "Systolic" refers to the blood pressure when the heart is contracting. "Diastolic" reflects the blood pressure when the heart is in a period of relaxation and expansion.

(Photo: FSU)

Florida State University

ARGONNE SCIENTISTS WATCH THE BIRTH OF NANOPARTICLES FOR THE FIRST TIME

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A team of scientists at the U.S. Department of Energy's (DOE) Argonne National Laboratory and the Carnegie Institution of Washington has succeeded in "watching" nanoparticles grow in real time.

The revolutionary technique allows researchers to learn about the early stages of nanoparticle generation, long a mystery due to inadequate probing methods, and could lead to improved performance of the nanomaterials in applications including solar cells, sensing and more.

"Nanocrystal growth is the foundation of nanotechnology," said lead researcher Yugang Sun, an Argonne chemist. "Understanding it will allow scientists to more precisely tailor new and fascinating nanoparticle properties."

The way that nanoparticles look and behave depends on their architecture: size, shape, texture and surface chemistry. This, in turn, depends very much on the conditions under which they are grown.

"Accurately controlling nanoparticles is very difficult," Sun explained. "It's even harder to reproduce the same nanoparticles from batch to batch, because we still don't know all the conditions for the recipe. Temperature, pressure, humidity, impurities—they all affect growth, and we keep discovering more factors."

In order to understand how nanoparticles grow, the scientists needed to actually watch them in the act. The problem was that electron microscopy, the usual method for seeing down into the atomic level of nanoparticles, requires a vacuum. But many kinds of nanocrystals have to grow in a liquid medium—and the vacuum in an electron microscope makes this impossible. A special thin cell allows a tiny amount of liquid to be analyzed in an electron microscope, but it still limited the researchers to a liquid layer just 100 nanometers thick, which is significantly different from the real conditions for nanoparticle synthesis.

To solve this conundrum, Sun found he needed to use the very high-energy X-rays provided at Sector 1 of Argonne’s Advanced Photon Source (APS), which adjoins the laboratory’s Center for Nanoscale Materials, where he works. The pattern of X-rays scattered by the sample allowed the researchers to reconstruct the earliest stages of nanocrystals second-by-second.

"This technique yields a treasure trove of information, especially on the nucleation and growth steps of the crystals, that we had never been able to get before," said Sun.

The intensity of the X-rays does affect the growth of the nanocrystals, Sun said, but the effects only became significant after an especially long reaction time. "Getting a clear image of the growth process will allow us to control samples to get better results, and eventually, new nanomaterials that will have a wide range of applications,” Sun explained.

The nanomaterials could be used in photovoltaic solar cells, chemical and biological sensors and even imaging. For example, noble metal nanoplates can absorb near-infrared light, so they can be used to enhance contrast in images. In one possible case, an injection of specially tailored nanoparticles near a cancer patient's tumor site could increase the imaging contrast between normal and cancerous cells so that doctors can accurately map the tumor.

"The key to this breakthrough was the unique ability for us to work with scientists from the Advanced Photon Source, the Center for Nanoscale Materials and the Electron Microscopy Center—all in one place," Sun said.

(Photo: Yugang et. al, Argonne National Laboratory & Carnegie Institute of Washington)

Argonne National Laboratory

LOVE TAKES UP WHERE PAIN LEAVES OFF, BRAIN STUDY SHOWS

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Intense, passionate feelings of love can provide amazingly effective pain relief, similar to painkillers or such illicit drugs as cocaine, according to a new Stanford University School of Medicine study.

“When people are in this passionate, all-consuming phase of love, there are significant alterations in their mood that are impacting their experience of pain,” said Sean Mackey, MD, PhD, chief of the Division of Pain Management, associate professor of anesthesia and senior author of the study, published online Oct. 13 in PLoS ONE. “We’re beginning to tease apart some of these reward systems in the brain and how they influence pain. These are very deep, old systems in our brain that involve dopamine — a primary neurotransmitter that influences mood, reward and motivation.”

Scientists aren’t quite yet ready to tell patients with chronic pain to throw out the painkillers and replace them with a passionate love affair; rather, the hope is that a better understanding of these neural-rewards pathways that get triggered by love could lead to new methods for producing pain relief.

“It turns out that the areas of the brain activated by intense love are the same areas that drugs use to reduce pain,” said Arthur Aron, PhD, a professor of psychology at State University of New York at Stony Brook and one of the study’s authors. Aron has been studying love for 30 years. “When thinking about your beloved, there is intense activation in the reward area of the brain — the same area that lights up when you take cocaine, the same area that lights up when you win a lot of money.”

The concept for the study was sparked several years ago at a neuroscience conference when Aron, an expert in the study of love, met up with Mackey, an expert in the research of pain, and they began talking.

“Art was talking about love,” Mackey said. “I was talking about pain. He was talking about the brain systems involved with love. I was talking about the brain systems involved with pain. We realized there was this tremendous overlapping system. We started wondering, ‘Is it possible that the two modulate each other?’”

After the conference, Mackey returned to Stanford and collaborated with postdoctoral scholar Jarred Younger, PhD, now an assistant professor of anesthesia, who was also intrigued with the idea. Together the three set up a study that would entail examining the brain images of undergraduates who claimed to be “in that first phase of intense love.”

“We posted fliers around Stanford University and within hours we had undergrads banging on our door,” Mackey said. The fliers asked for couples who were in the first nine months of a romantic relationship.

“It was clearly the easiest study the pain center at Stanford has ever recruited for,” Mackey said. “When you’re in love you want to tell everybody about it.

“We intentionally focused on this early phase of passionate love,” he added. “We specifically were not looking for longer-lasting, more mature phases of the relationship. We wanted subjects who were feeling euphoric, energetic, obsessively thinking about their beloved, craving their presence.
description of photo

“When passionate love is described like this, it in some ways sounds like an addiction. We thought, ‘Maybe this does involve similar brain systems as those involved in addictions which are heavily dopamine-related.’ Dopamine is the neurotransmitter in our brain that is intimately involved with feeling good.”

Researchers recruited 15 undergraduates (eight women and seven men) for the study. Each was asked to bring in photos of their beloved and photos of an equally attractive acquaintance. The researchers then successively flashed the pictures before the subjects, while heating up a computer-controlled thermal stimulator placed in the palm of their hand to cause mild pain. At the same time, their brains were scanned in a functional magnetic resonance imaging machine.

The undergraduates were also tested for levels of pain relief while being distracted with word-association tasks such as: “Think of sports that don’t involve balls.” Scientific evidence has shown in the past that distraction causes pain relief, and researchers wanted to make sure that love was not just working as a distraction from pain.

Results showed that both love and distraction did equally reduce pain, and at much higher levels than by concentrating on the photo of the attractive acquaintance, but interestingly the two methods of pain reduction used very different brain pathways.

“With the distraction test, the brain pathways leading to pain relief were mostly cognitive,” Younger said. “The reduction of pain was associated with higher, cortical parts of the brain. Love-induced analgesia is much more associated with the reward centers. It appears to involve more primitive aspects of the brain, activating deep structures that may block pain at a spinal level — similar to how opioid analgesics work.

“One of the key sites for love-induced analgesia is the nucleus accumbens, a key reward addiction center for opioids, cocaine and other drugs of abuse. The region tells the brain that you really need to keep doing this,” Younger said.

“This tells us that you don’t have to just rely on drugs for pain relief,” Aron said. “People are feeling intense rewards without the side effects of drugs.”

(Photo: Stanford University)

Stanford University

I WIN, YOU LOSE

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Learning from competitors is a critically important form of learning for animals and humans. A new study has used brain imaging to reveal how people and animals learn from failure and success.

The team from Bristol University led by Dr Paul Howard-Jones, Senior Lecturer in Education in the Graduate School of Education and Dr Rafal Bogacz, Senior Lecturer in the Department of Computer Science, scanned the brains of players as they battled against an artificial opponent in a computer game.

In the game, each player took turns with the computer to select one of four boxes whose payouts were simulating the ebb and flow of natural food sources.

Players were able to learn from their own successful selections but those of their competitor failed completely to increase their neural activity. Instead, it was their competitor’s unexpected failures that generated this additional brain activity. Such failures generated both reward signals in the brains of the players, and learning signals in regions involved with inhibiting response. This suggests that we benefit from our competitors’ failures by learning to inhibit the actions that lead to them.

What’s on your computer’s mind?

Surprisingly, when players were observing their competitor make selections, the players’ brains were activated as if they were performing these actions themselves. Such ‘mirror neuron’ activities occur when we observe the actions of other humans but here the players knew their opponent was just a computer and no animated graphics were used. Previously, it has been suggested that the mirror neuron system supports a type of unconscious mind-reading that helps us, for example, judge others’ intentions.

Dr Howard-Jones added: “We were surprised to see the mirror neuron system activating in response to a computer. If the human brain can respond as though a computer has a mind, that’s probably good news for those wishing to use the computer as a teacher.”

(Photo: Bristol University)

Bristol University

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