Category: Science News

{Trait increases tolerance, improves decisions, study says.}

“Intellectual humility” has been something of a wallflower among personality traits, receiving far less scholarly attention than such brash qualities as egotism or hostility. Yet this little-studied characteristic may influence people’s decision-making abilities in politics, health and other arenas, says new research from Duke University.

In a time of high partisanship, intellectual humility — an awareness that one’s beliefs may be wrong — is nonpartisan. Researchers measured levels of the trait, and found essentially no difference between liberals and conservatives or between religious and nonreligious people.

“There are stereotypes about conservatives and religiously conservative people being less intellectually humble about their beliefs,” said lead author Mark Leary, a professor of psychology and neuroscience at Duke. “We didn’t find a shred of evidence to support that.”

As defined by the authors, intellectual humility is the opposite of intellectual arrogance or conceit. In common parlance, it resembles open-mindedness. Intellectually humble people can have strong beliefs, but recognize their fallibility and are willing to be proven wrong on matters large and small, Leary said.

The researchers, whose work is featured in the March 15 issue of Personality and Social Psychology Bulletin, conducted four separate studies to measure the trait and learn more about how it functions. In one study, participants read essays arguing for and against religion, and were then asked about each author’s personality. After reading an essay with which they disagreed, intellectually arrogant people gave the writer low scores in morality, honesty, competence and warmth. By contrast, intellectually humble people were less likely to judge a writer’s character based on his or her views.

People who displayed intellectual humility also did a better job evaluating the quality of evidence — even in mundane matters. For instance, when presented with arguments about the benefits of flossing, intellectually humble people correctly distinguished strong, fact-based arguments from weak ones.

The characteristic also affected people’s views on politicians who “flip-flop.” Intellectually humble Republicans were more likely than other Republicans to say that they would vote for a politician whose position on an issue changed over time, due to new evidence. They were also less likely to criticize that politician for “flip-flopping.” There was less variability among Democrats: Democrats, whether intellectually arrogant or humble, were generally less likely to criticize a politician for changing his mind.

Leary said intellectual humility bears further examination.

“If you think about what’s been wrong in Washington for a long time, it’s a whole lot of people who are very intellectually arrogant about the positions they have, on both sides of the aisle,” Leary said. “But even in interpersonal relationships, the minor squabbles we have with our friends, lovers and coworkers are often about relatively trivial things where we are convinced that our view of the world is correct and their view is wrong.”

The quality has potential benefits in the business world, too, he said.

“If you’re sitting around a table at a meeting and the boss is very low in intellectual humility, he or she isn’t going to listen to other people’s suggestions,” Leary said. “Yet we know that good leadership requires broadness of perspective and taking as many perspectives into account as possible.”

Leary and his co-authors suggest that intellectual humility is a quality that could be encouraged and taught. And some of their colleagues hope to do just that. Leary’s team worked in collaboration with other psychologists and philosophers to refine their studies. One of those philosophers helped launch a charter school in California, the Intellectual Virtues Academy of Long Beach, aimed at promoting qualities such as intellectual humility.

Leary applauds the effort.

“Not being afraid of being wrong — that’s a value, and I think it is a value we could promote,” he said. “I think if everyone was a bit more intellectually humble we’d all get along better, we’d be less frustrated with each other.”

Source:Science Daily

{Study estimates that an 80 year old from the Tsimane (pronounced chee-MAH-nay) group had the same vascular age as an American in their mid-fifties.}

The Tsimane people — a forager-horticulturalist population of the Bolivian Amazon — have the lowest reported levels of vascular aging for any population, with coronary atherosclerosis (hardening of the arteries) being five times less common than in the US, according to a study published in The Lancet and being presented at the American College of Cardiology conference.

The researchers propose that the loss of subsistence diets and lifestyles in contemporary society could be classed as a new risk factor for heart disease. The main risk factors are age, smoking, high cholesterol, high blood pressure, physical inactivity, obesity and diabetes.

“Our study shows that the Tsimane indigenous South Americans have the lowest prevalence of coronary atherosclerosis of any population yet studied,” said senior anthropology author, Professor Hillard Kaplan, University of New Mexico, USA. “Their lifestyle suggests that a diet low in saturated fats and high in non-processed fibre-rich carbohydrates, along with wild game and fish, not smoking and being active throughout the day could help prevent hardening in the arteries of the heart. The loss of subsistence diets and lifestyles could be classed as a new risk factor for vascular aging and we believe that components of this way of life could benefit contemporary sedentary populations.”

Although the Tsimane lifestyle is very different from that of contemporary society, certain elements of it are transferable and could help to reduce risk of heart disease.

While industrial populations are sedentary for more than half of their waking hours (54%), the Tsimane spend only 10% of their daytime being inactive. They live a subsistence lifestyle that involves hunting, gathering, fishing and farming, where men spend an average of 6-7 hours of their day being physically active and women spend 4-6 hours.

Their diet is largely carbohydrate-based (72%) and includes non-processed carbohydrates which are high in fibre such as rice, plantain, manioc, corn, nuts and fruits. Protein constitutes 14% of their diet and comes from animal meat. The diet is very low in fat with fat compromising only 14% of the diet — equivalent to an estimated 38 grams of fat each day, including 11g saturated fat and no trans fats. In addition, smoking was rare in the population.

In the observational study, the researchers visited 85 Tsimane villages between 2014 and 2015. They measured the participants’ risk of heart disease by taking CT scans of the hearts of 705 adults (aged 40-94 years old) to measure the extent of hardening of the coronary arteries, as well as measuring weight, age, heart rate, blood pressure, cholesterol, blood glucose and inflammation.

Based on their CT scan, almost nine in 10 of the Tsimane people (596 of 705 people, 85%) had no risk of heart disease, 89 (13%) had low risk and only 20 people (3%) had moderate or high risk. These findings also continued into old age, where almost two-thirds (65%, 31 of 48) of those aged over 75 years old had almost no risk and 8% (4 of 48) had moderate or high risk. These results are the lowest reported levels of vascular aging of any population recorded to date.

By comparison, a US study of 6814 people (aged 45 to 84) found that only 14% of Americans had a CT scan that suggested no risk of heart disease and half (50%) had a moderate or high risk — a five-fold higher prevalence than in the Tsimane population.

In the Tsimane population, heart rate, blood pressure, cholesterol, and blood glucose were also low, potentially as a result of their lifestyle. The researchers also note that the low risk of coronary atherosclerosis was identified despite there being elevated levels of inflammation in half of the Tsimane population (51%, 360 of 705 people).

“Conventional thinking is that inflammation increases the risk of heart disease,” said Professor Randall Thompson, cardiologist at Saint Luke’s Mid America Heart Institute, USA. “However, the inflammation common to the Tsimane was not associated with increased risk of heart disease, and may instead be the result of high rates of infections.”

Because the study is observational it cannot confirm how the Tsimane population is protected from vascular aging, or which part of their lifestyle (diet, physical activity or smoking) is most protective. The researchers suggest it is more likely to be a result of their lifestyle than genetics, because of a gradual increase in cholesterol levels coinciding with a rapidly changing lifestyle.

“Over the last five years, new roads and the introduction of motorised canoes have dramatically increased access to the nearby market town to buy sugar and cooking oil,” said Dr Ben Trumble, Arizona State University, USA. “This is ushering in major economic and nutritional changes for the Tsimane people.”

The researchers did not study whether coronary artery hardening in the Tsimane population impacted on their health, but note that deaths from heart attacks are very uncommon in the population so it is likely that their low levels of atherosclerosis and heart disease are associated. The researchers are investigating this in further research.

“This study suggests that coronary atherosclerosis could be avoided if people adopted some elements of the Tsimane lifestyle, such as keeping their LDL cholesterol, blood pressure and blood sugar very low, not smoking and being physically active,” said senior cardiology author Dr Gregory S. Thomas, Long Beach Memorial Medical Centre, USA. “Most of the Tsimane are able to live their entire life without developing any coronary atherosclerosis. This has never been seen in any prior research. While difficult to achieve in the industrialized world, we can adopt some aspects of their lifestyle to potentially forestall a condition we thought would eventually effect almost all of us.”

Source:Science Daily

{Big, small, broad, narrow, long or short, turned up, pug, hooked, bulbous or prominent, humans inherit their nose shape from their parents, but ultimately, the shape of someone’s nose and that of their parents was formed by a long process of adaptation to our local climate, according to an international team of researchers.}

“We are interested in recent human evolution and what explains the evident variation in things like skin color, hair color and the face itself,” said Mark D. Shriver, professor of anthropology, Penn State. “We focused on nose traits that differ across populations and looked at geographical variation with respect to temperature and humidity.” The researchers noted today (Mar. 17) in PLOS Genetics that “An important function of the nose and nasal cavity is to condition inspired air before it reaches the lower respiratory tract.”

They considered a variety of nose measurements, looking at the width of the nostrils, the distance between nostrils, the height of the nose, nose ridge length, nose protrusion, external area of the nose and the area of the nostrils. The measurements were made using 3D facial imaging.

Differences in the human nose may have accumulated among populations through time as a result of a random process called genetic drift. However, divergent selection — variation in natural selection across populations — may also be the reason that different populations have differing noses. Teasing the two apart is difficult, especially in humans.

The researchers found that the width of the nostrils and the base of the nose measurements differed across populations more than could be accounted for by genetic drift, indicating a role for natural selection in the evolution of nose shape in humans. To show that the local climate contributed to this difference, the researchers looked at the spatial distribution of these traits and correlated them with local temperatures and humidity. They showed that the width of the nostrils is strongly correlated with temperature and absolute humidity The researchers noted that “the positive direction of the effects indicate that wider noses are more common in warm-humid climates, while narrower noses are more common in cold-dry climates.”

“It all goes back to Thompson’s Rule (Arthur Thompson),” said Shriver. “In the late 1800s he said that long and thin noses occurred in dry, cold areas, while short and wide noses occurred in hot, humid areas. Many people have tested the question with measurements of the skull, but no one had done measurements on live people.”

One purpose of the nose is to condition inhaled air so that it is warm and moist. The narrower nostrils seem to alter the airflow so that the mucous-covered inside of the nose can humidify and warm the air more efficiently. It was probably more essential to have this trait in cold and dry climates, said Shriver. People with narrower nostrils probably fared better and had more offspring than people with wider nostrils, in colder climates. This lead to a gradual decrease in nose width in populations living far away from the equator.

Shriver notes that this is not the only explanation for nose-shape variation in humans. The researchers also found differences between men and women in nose features across the board. This sexual dimorphism is not unusual, as human men tend to be larger than human women, and their noses would be larger as well.

He thinks another way that the cross-population differences in nose size may occur is through sexual selection. People may choose mates simply because they find a smaller or larger nose more attractive. If an entire group thinks small is better, then those with large noses will have less success in reproducing and fewer large-nosed people will be in the group. Over time, the nose size in the group will shrink relative to other groups where large noses are favored. These notions of beauty may be linked to how well-adapted the nose is to the local climate.

Ecological selection and sexual selection could reinforce each other, according to the researchers. However, whether this connection between the two types of selection was important in the evolution of the nose requires further investigation.

Source:Science Daily

{Genetic ‘toggle switch’ reveals regulation of sociability in autism mouse model.}

Researchers at Beth Israel Deaconess Medical Center (BIDMC) have gained new insight into the genetic and neuronal circuit mechanisms that may contribute to impaired sociability in some forms of Autism Spectrum Disorder. Led by Matthew P. Anderson, MD, PhD, Director of Neuropathology at BIDMC, the scientists determined how a gene linked to one common form of autism works in a specific population of brain cells to impair sociability. The research, published in the journal Nature, reveals the neurobiological control of sociability and could represent important first steps toward interventions for patients with autism.

Anderson and colleagues focused on the gene UBE3A, multiple copies of which causes a form of autism in humans (called isodicentric chromosome 15q).Conversely, the lack of this same gene in humans leads to a developmental disorder called Angelman’s syndrome, characterized by increased sociability. In previous work, Anderson’s team demonstrated that mice engineered with extra copies of the UBE3A gene show impaired sociability, as well as heightened repetitive self-grooming and reduced vocalizations with other mice.

“In this study, we wanted to determine where in the brain this social behavior deficit arises and where and how increases of the UBE3A gene repress it,” said Anderson, who is also an Associate Professor in the Program in Neuroscience at Harvard Medical School and Director of Autism BrainNET Boston Node. “We had tools in hand that we built ourselves. We not only introduced the gene into specific brain regions of the mouse, but we could also direct it to specific cell types to test which ones played a role in regulating sociability.”

When Anderson and colleagues compared the brains of the mice engineered to model autism to those of normal — or wild type (WT) — mice, they observed that the increased UBE3A gene copies interacted with nearly 600 other genes.

After analyzing and comparing protein interactions between the UBE3A regulated gene and genes altered in human autism, the researchers noticed that increased doses of UBE3A repressed Cerebellin genes.

Cerebellin is a family of genes that physically interact with other autism genes to form glutamatergic synapses, the junctions where neurons communicate with each other via the neurotransmitter glutamate. The researchers chose to focus on one of them, Cerebellin 1 (CBLN1), as the potential mediator of UBE3A’s effects. When they deleted CBLN1 in glutamate neurons, they recreated the same impaired sociability produced by increased UBE3A.

“Selecting Cerebellin 1 out of hundreds of other potential targets was something of a leap of faith,” Anderson said. “When we deleted the gene and were able to reconstitute the social deficits, that was the moment we realized we’d hit the right target. Cerebellin 1 was the gene repressed by UBE3A that seemed to mediate its effects.”

In another series of experiments, Anderson and colleagues demonstrated an even more definitive link between UBE3A and CBLN1. Seizures are a common symptom among people with autism including this genetic form. Seizures themselves when sufficiently severe, also impaired sociability. Anderson’s team suspected this seizure-induced impairment of sociability was the result of repressing the Cerebellin genes. Indeed, the researchers found that deleting UBE3A, upstream from Cerebellin genes, prevented the seizure-induced social impairments and blocked seizures ability to repress CBLN1.

“If you take away UBE3A, seizures can’t repress sociability or Cerebellin,” said Anderson. “The flip side is, if you have just a little extra UBE3A — as a subset of people with autism do — and you combine that with less severe seizures — you can get a full-blown loss of social interactions.”

The researchers next conducted a variety of brain mapping experiments to locate where in the brain these crucial seizure-gene interactions take place.

“We mapped this seat of sociability to a surprising location,” Anderson explained. Most scientists would have thought they take place in the cortex — the area of the brain where sensory processing and motor commands take place — but, in fact, these interactions take place in the brain stem, in the reward system.”

Then the researchers used their engineered mouse model to confirm the precise location, the ventral tegmental area (VTA), part of the midbrain that plays a role in the reward system and addiction. Anderson and colleagues used chemogenetics — an approach that makes use of modified receptors introduced into neurons that responds to drugs, but not to naturally-occurring neurotransmitters — to switch this specific group of neurons on or off. Turning these neurons on could magnify sociability and rescue seizure and UBE3A-induced sociability deficits.

“We were able to abolish sociability by inhibiting these neurons and we could magnify and prolong sociability by turning them on,” said Anderson. “So we have a toggle switch for sociability. It has a therapeutic flavor; someday, we might be able to translate this into a treatment that will helps patients.”

Source:Science Daily

{Judges and juries always ponder whether people act “knowingly” or “recklessly” during criminal activity — and neuroscience has had little to add to the conversation.}

But now, researchers, including computational neuroscientist Read Montague of the Virginia Tech Carilion Research Institute, have discovered that brain imaging can determine whether someone is acting in a state of knowledge about a crime — which brings about stiffer penalties — or a state of recklessness, which even in capital crimes such as homicide, calls for less severe sentences.

The discovery, scheduled for publication this week in the online Early Edition of the Proceedings of the National Academy of Sciences, will not have a bearing on court proceedings, but it is an inroad in the emerging field of “neurolaw,” which connects neuroscience to legal rules and standards.

In a brain imaging study of 40 people, researchers identified brain responses that indicated whether people knew they were committing crimes or if they were instead acting recklessly with the risk that they might be committing a crime.

The researchers provided the first neurobiological evidence of a detectable difference between the mental states of knowledge and recklessness, an exploration that historically has been confined to the courtroom.

“People can commit exactly the same crime in all of its elements and circumstances, and depending on their mental states, the difference could be one would go to jail for 14 years and the other would get probation,” said Montague, who is the Virginia Tech Carilion Vernon Mountcastle Research Professor and director of the research institute’s Human Neuroimaging Laboratory. “Predicated on which side of the boundary you are on between acting knowingly and recklessly, you can differentially be deprived of your freedom.”

The research was conceived under the direction of the MacArthur Foundation Research Network on Law and Neuroscience at Vanderbilt University and carried out by researchers at Virginia Tech Carilion Research Institute and Yale University.

Scientists scanned the brains of 40 subjects and asked them to decide whether to carry a suitcase across the border, varying the probability that the suitcase contained drugs.

Using noninvasive functional brain imaging and machine-learning techniques, in which a computer learns to find patterns in data, the scientists accurately determined whether the research subjects knew drugs were in the case, which would make them guilty of knowingly importing drugs, or whether they were uncertain about it, which would make them innocent.

The researchers showed that knowing and reckless mental states corresponded to detectable neurological states, and that those mental states can be predicted based on brain imaging data alone.

The researchers cautioned that the assessment of the mental state of a defendant should not be reduced to the classification of brain data.

“In principle, we are showing these brain states can be detected when the activity is taking place,” Montague said. “Given that, we can start asking questions like, which neural circuits are engaged by this? What does the distribution look like across 4,000 people instead of 40 people? Are there conditions of either development, states of mind, use of pharmacological substances, or incurred injuries that impinge on these networks in ways that would inform the punishment?”

The study was informed by a judge and researchers at Vanderbilt University, the University of Pennsylvania, the University of Virginia, the University of Kentucky, and the Ohio State University.

“Scientists and lawyers speak different languages,” Montague said. “A translation goes on when you bring these groups together that gives new meaning to interdisciplinary. Lawyers think of people as being conscious and deliberative, and the law sees people that way — you are an independent agent and you make choices for yourself. That picture ignores the scientific fact that 99 percent of the decisions made in your nervous system never make their way to consciousness. You are being driven by things to which you don’t even have conscious access — that difference was something we had to work through to design the experiment.”

Source:Science Daily

{Researchers of Ghent University analysed data on volunteering, employment and health of more than 40,000 European citizens. Their results, just published in PLOS ONE, show that volunteering is associated with better employment and health outcomes.}

{{Volunteers are as healthy as 5 years younger non-volunteers}}

Even after controlling for other determinants of health (gender, age, education level, migrant status, religiosity and country of origin), volunteers are substantially in better health than non-volunteers. Doctoral researcher Jens Detollenaere: “This association is comparable in size to the health gains of being a man, being five years younger or being a native (compared to being a migrant).” This direct association between volunteering and health is highly statistically significant so that it is ruled out that this association is occurring by coincidence.

{{Partly explained by higher income among volunteers}}

When decomposing the total association between volunteering and health in a direct association and an indirect association via income, the researchers found that the indirect association accounts for about one fifth. Volunteers have, after controlling for the aforementioned personal characteristics, a higher income and this higher income is associated with better health. Professor Stijn Baert: “This finding corroborates with previous research showing that volunteering activities on one’s cv yield higher employment opportunities, especially for non-natives.”

{{Other explanations}}

The researchers put forward three other explanations for an association between volunteering and health. Professor Sara Willems: “Firstly, volunteering may improve access to psychological resources (such as self-esteem and self-efficacy) and social resources (such as social integration and access to support and information), both of which are found to have an overall positive effect on health. Secondly, volunteering increases physical and cognitive activity, which protects against functional decline and dementia in old age. Finally, neuroscience research has related volunteering to the release of the caregiving-related hormones oxytocin and progesterone, which have the capacity to regulate stress and inflammation.”

{{Method}}

The research results are based on data from the sixth round of the European Social Survey (conducted in 2012 and 2013). This survey measures the beliefs, preferences and behaviour of more than 40000 citizens of 29 European countries (Belgium, Bulgaria, Cyprus, Czech Republic, Germany, Denmark, Spain, Estonia, Finland, France, United Kingdom, Hungary, Ireland, Italy, Lithuania, Netherlands, Poland, Portugal, Slovakia, Slovenia, Sweden, Albania, Iceland, Israel, Kosovo, Norway, Switzerland, Russia and Ukraine). These data were analysed by means of a state-of-the-art mediation model with self-reported volunteering and health as main variables.

Source:Science Daily

{A new UCLA study could change scientists’ understanding of how the brain works — and could lead to new approaches for treating neurological disorders and for developing computers that “think” more like humans.}

The research focused on the structure and function of dendrites, which are components of neurons, the nerve cells in the brain. Neurons are large, tree-like structures made up of a body, the soma, with numerous branches called dendrites extending outward. Somas generate brief electrical pulses called “spikes” in order to connect and communicate with each other. Scientists had generally believed that the somatic spikes activate the dendrites, which passively send currents to other neurons’ somas, but this had never been directly tested before. This process is the basis for how memories are formed and stored.

Scientists have believed that this was dendrites’ primary role.

But the UCLA team discovered that dendrites are not just passive conduits. Their research showed that dendrites are electrically active in animals that are moving around freely, generating nearly 10 times more spikes than somas. The finding challenges the long-held belief that spikes in the soma are the primary way in which perception, learning and memory formation occur.

“Dendrites make up more than 90 percent of neural tissue,” said UCLA neurophysicist Mayank Mehta, the study’s senior author. “Knowing they are much more active than the soma fundamentally changes the nature of our understanding of how the brain computes information. It may pave the way for understanding and treating neurological disorders, and for developing brain-like computers.”

The research is reported in the March 9 issue of the journal Science.

Scientists have generally believed that dendrites meekly sent currents they received from the cell’s synapse (the junction between two neurons) to the soma, which in turn generated an electrical impulse. Those short electrical bursts, known as somatic spikes, were thought to be at the heart of neural computation and learning. But the new study demonstrated that dendrites generate their own spikes 10 times more often than the somas.

The researchers also found that dendrites generate large fluctuations in voltage in addition to the spikes; the spikes are binary, all-or-nothing events. The somas generated only all-or-nothing spikes, much like digital computers do. In addition to producing similar spikes, the dendrites also generated large, slowly varying voltages that were even bigger than the spikes, which suggests that the dendrites execute analog computation.

“We found that dendrites are hybrids that do both analog and digital computations, which are therefore fundamentally different from purely digital computers, but somewhat similar to quantum computers that are analog,” said Mehta, a UCLA professor of physics and astronomy, of neurology and of neurobiology. “A fundamental belief in neuroscience has been that neurons are digital devices. They either generate a spike or not. These results show that the dendrites do not behave purely like a digital device. Dendrites do generate digital, all-or-none spikes, but they also show large analog fluctuations that are not all or none. This is a major departure from what neuroscientists have believed for about 60 years.”

Because the dendrites are nearly 100 times larger in volume than the neuronal centers, Mehta said, the large number of dendritic spikes taking place could mean that the brain has more than 100 times the computational capacity than was previously thought.

Recent studies in brain slices showed that dendrites can generate spikes. But it was neither clear that this could happen during natural behavior, nor how often. Measuring dendrites’ electrical activity during natural behavior has long been a challenge because they’re so delicate: In studies with laboratory rats, scientists have found that placing electrodes in the dendrites themselves while the animals were moving actually killed those cells. But the UCLA team developed a new technique that involves placing the electrodes near, rather than in, the dendrites.

Using that approach, the scientists measured dendrites’ activity for up to four days in rats that were allowed to move freely within a large maze. Taking measurements from the posterior parietal cortex, the part of the brain that plays a key role in movement planning, the researchers found far more activity in the dendrites than in the somas — approximately five times as many spikes while the rats were sleeping, and up to 10 times as many when they were exploring.

“Many prior models assume that learning occurs when the cell bodies of two neurons are active at the same time,” said Jason Moore, a UCLA postdoctoral researcher and the study’s first author. “Our findings indicate that learning may take place when the input neuron is active at the same time that a dendrite is active — and it could be that different parts of dendrites will be active at different times, which would suggest a lot more flexibility in how learning can occur within a single neuron.”

Looking at the soma to understand how the brain works has provided a framework for numerous medical and scientific questions — from diagnosing and treating diseases to how to build computers. But, Mehta said, that framework was based on the understanding that the cell body makes the decisions, and that the process is digital.

“What we found indicates that such decisions are made in the dendrites far more often than in the cell body, and that such computations are not just digital, but also analog,” Mehta said. “Due to technological difficulties, research in brain function has largely focused on the cell body. But we have discovered the secret lives of neurons, especially in the extensive neuronal branches. Our results substantially change our understanding of how neurons compute.”

Source:Science Daily

{A new UCLA study could change scientists’ understanding of how the brain works — and could lead to new approaches for treating neurological disorders and for developing computers that “think” more like humans.}

The research focused on the structure and function of dendrites, which are components of neurons, the nerve cells in the brain. Neurons are large, tree-like structures made up of a body, the soma, with numerous branches called dendrites extending outward. Somas generate brief electrical pulses called “spikes” in order to connect and communicate with each other. Scientists had generally believed that the somatic spikes activate the dendrites, which passively send currents to other neurons’ somas, but this had never been directly tested before. This process is the basis for how memories are formed and stored.

Scientists have believed that this was dendrites’ primary role.

But the UCLA team discovered that dendrites are not just passive conduits. Their research showed that dendrites are electrically active in animals that are moving around freely, generating nearly 10 times more spikes than somas. The finding challenges the long-held belief that spikes in the soma are the primary way in which perception, learning and memory formation occur.

“Dendrites make up more than 90 percent of neural tissue,” said UCLA neurophysicist Mayank Mehta, the study’s senior author. “Knowing they are much more active than the soma fundamentally changes the nature of our understanding of how the brain computes information. It may pave the way for understanding and treating neurological disorders, and for developing brain-like computers.”

The research is reported in the March 9 issue of the journal Science.

Scientists have generally believed that dendrites meekly sent currents they received from the cell’s synapse (the junction between two neurons) to the soma, which in turn generated an electrical impulse. Those short electrical bursts, known as somatic spikes, were thought to be at the heart of neural computation and learning. But the new study demonstrated that dendrites generate their own spikes 10 times more often than the somas.

The researchers also found that dendrites generate large fluctuations in voltage in addition to the spikes; the spikes are binary, all-or-nothing events. The somas generated only all-or-nothing spikes, much like digital computers do. In addition to producing similar spikes, the dendrites also generated large, slowly varying voltages that were even bigger than the spikes, which suggests that the dendrites execute analog computation.

“We found that dendrites are hybrids that do both analog and digital computations, which are therefore fundamentally different from purely digital computers, but somewhat similar to quantum computers that are analog,” said Mehta, a UCLA professor of physics and astronomy, of neurology and of neurobiology. “A fundamental belief in neuroscience has been that neurons are digital devices. They either generate a spike or not. These results show that the dendrites do not behave purely like a digital device. Dendrites do generate digital, all-or-none spikes, but they also show large analog fluctuations that are not all or none. This is a major departure from what neuroscientists have believed for about 60 years.”

Because the dendrites are nearly 100 times larger in volume than the neuronal centers, Mehta said, the large number of dendritic spikes taking place could mean that the brain has more than 100 times the computational capacity than was previously thought.

Recent studies in brain slices showed that dendrites can generate spikes. But it was neither clear that this could happen during natural behavior, nor how often. Measuring dendrites’ electrical activity during natural behavior has long been a challenge because they’re so delicate: In studies with laboratory rats, scientists have found that placing electrodes in the dendrites themselves while the animals were moving actually killed those cells. But the UCLA team developed a new technique that involves placing the electrodes near, rather than in, the dendrites.

Using that approach, the scientists measured dendrites’ activity for up to four days in rats that were allowed to move freely within a large maze. Taking measurements from the posterior parietal cortex, the part of the brain that plays a key role in movement planning, the researchers found far more activity in the dendrites than in the somas — approximately five times as many spikes while the rats were sleeping, and up to 10 times as many when they were exploring.

“Many prior models assume that learning occurs when the cell bodies of two neurons are active at the same time,” said Jason Moore, a UCLA postdoctoral researcher and the study’s first author. “Our findings indicate that learning may take place when the input neuron is active at the same time that a dendrite is active — and it could be that different parts of dendrites will be active at different times, which would suggest a lot more flexibility in how learning can occur within a single neuron.”

Looking at the soma to understand how the brain works has provided a framework for numerous medical and scientific questions — from diagnosing and treating diseases to how to build computers. But, Mehta said, that framework was based on the understanding that the cell body makes the decisions, and that the process is digital.

“What we found indicates that such decisions are made in the dendrites far more often than in the cell body, and that such computations are not just digital, but also analog,” Mehta said. “Due to technological difficulties, research in brain function has largely focused on the cell body. But we have discovered the secret lives of neurons, especially in the extensive neuronal branches. Our results substantially change our understanding of how neurons compute.”

Source:Science Daily

{North Carolina’s Cape Lookout lighthouse has survived threats ranging from Civil War raids to multiple hurricanes, but the Outer Banks site can’t escape climate-related changes such as rising sea levels, coastal erosion and flooding from stronger storms.}

A North Carolina State University study in Climatic Change found little research exists on how to protect cultural resources like those at Cape Lookout National Seashore, a 56-acre site that includes historic buildings in addition to the iconic lighthouse and scenic beaches.

“Cultural heritage sites provide a lot of benefits, from sociocultural value in giving a community its unique identity to economic benefits from recreation and tourism,” says lead author Sandra Fatorić, a postdoctoral researcher with NC State’s College of Natural Resources. “We see a significant gap in knowledge of how to adapt to climate change and preserve cultural resources for future generations.”

Researchers searched worldwide for peer-reviewed studies of cultural resources — archaeological sites, natural landscapes and historic buildings — at risk due to climate change. About 60 percent of the studies referenced sites in Europe, most commonly in the United Kingdom. Another 17 percent of the research covered sites in North America, a majority of them in the United States. About 11 percent dealt with resources in Australia and the Pacific Islands and 10 percent mentioned Asia, mostly China. All but six of the 124 studies were published in English-language journals, with South America and Africa rarely represented in the research.

“We were struck by how recent much of the research was, with the first article appearing in 2003,” Fatorić says, adding there’s a need for more multidisciplinary work and research that involves local residents and stakeholders. “That process reveals what a community most values about a site.”

Co-author Erin Seekamp, an associate professor and tourism extension specialist in the Department of Parks, Recreation and Tourism Management at NC State, is working with stakeholders to set priorities for protecting cultural resources at Cape Lookout as part of a project with the Department of Interior’s Southeast Climate Science Center. Seekamp and Fatorić are evaluating 17 buildings in terms of their significance and their value to the site’s operations, working with managers from the National Park Service and North Carolina State Preservation Office. The research team, which includes U.S. Geological Survey analysts Mitch Eaton and Max Post van der Burg, is combining this information with earlier research by Western Carolina University’s Rob Young which found that most of the buildings at Cape Lookout are at high risk from flooding, erosion and rising sea levels.

“We’re looking at all of the options for each structure,” Seekamp says. “Which buildings should be maintained? Which could be moved to higher ground? Does that change the character of the site? Does changing a building’s use — from storage to visitor programs, for example — affect its relative value?”

An overview of Seekamp’s research is part of a National Park Service report titled “Cultural Resources Climate Change Strategy,” which ranked as the most downloaded government website document in the week following the 2017 presidential inauguration, according to the Washington Post.

“Park managers face difficult decisions in prioritizing which resources to protect,” Seekamp says. “We hope to develop a method that will help with decisions on protecting Cape Lookout’s historic buildings as well as informing policy for protecting cultural resources at other national parks facing climate adaptation.”

Source:Science News

{Drinking concentrated blueberry juice improves brain function in older people, according to research by the University of Exeter.}

In the study, healthy people aged 65-77 who drank concentrated blueberry juice every day showed improvements in cognitive function, blood flow to the brain and activation of the brain while carrying out cognitive tests.

There was also evidence suggesting improvement in working memory.

Blueberries are rich in flavonoids, which possess antioxidant and anti-inflammatory properties.

Dr Joanna Bowtell, head of Sport and Health Sciences at the University of Exeter, said: “Our cognitive function tends to decline as we get older, but previous research has shown that cognitive function is better preserved in healthy older adults with a diet rich in plant-based foods.

“In this study we have shown that with just 12 weeks of consuming 30ml of concentrated blueberry juice every day, brain blood flow, brain activation and some aspects of working memory were improved in this group of healthy older adults.”

Of the 26 healthy adults in the study, 12 were given concentrated blueberry juice — providing the equivalent of 230g of blueberries — once a day, while 14 received a placebo.

Before and after the 12-week period, participants took a range of cognitive tests while an MRI scanner monitored their brain function and resting brain blood flow was measured.

Compared to the placebo group, those who took the blueberry supplement showed significant increases in brain activity in brain areas related to the tests.

The study excluded anyone who said they consumed more than five portions of fruit and vegetables per day, and all participants were told to stick to their normal diet throughout.

Previous research has shown that risk of dementia is reduced by higher fruit and vegetable intake, and cognitive function is better preserved in healthy older adults with a diet rich in plant-based foods.

Flavonoids, which are abundant in plants, are likely to be an important component in causing these effects.

Source:Science Daily