Archive for the ‘LiveScience’ Category

Everyone knows it’s easier to learn about a topic you’re curious about. Now, a new study reveals what’s going on in the brain during that process, revealing that such curiosity may give a person a memory boost.

When participants in the study were feeling curious, they were better at remembering information even about unrelated topics, and brain scans showed activity in areas linked to reward and memory.

The results, detailed October 2 in the journal Neuron, hint at ways to improve learning and memory in both healthy people and those with neurological disorders, the researchers said.

“Curiosity may put the brain in a state that allows it to learn and retain any kind of information, like a vortex that sucks in what you are motivated to learn, and also everything around it,” Matthias Gruber, a memory researcher at the University of California, Davis, said in a statement. “These findings suggest ways to enhance learning in the classroom and other settings.”

Gruber and his colleagues put people in a magnetic resonance imaging (MRI) scanner and showed them a series of trivia questions, asking them to rate their curiosity about the answers to those questions. Later, the participants were shown selected trivia questions, then a picture of a neutral face during a 14-second delay, followed by the answer. Afterward, the participants were given a surprise memory test of the faces, and then a memory test of the trivia answers.

Not surprisingly, the study researchers found that people remembered more information about the trivia when they were curious about the trivia answers. But unexpectedly, when the participants were curious, they were also better at remembering the faces, an entirely unrelated task. Participants who were curious were also more likley than others to remember both the trivia information and unrelated faces a day later, the researchers found.

The brain scans showed that, compared with when their curiosity wasn’t piqued, when people were curious, they showed more activation of brain circuits in the nucleus accumbens, an area involved in reward. These same circuits, mediated by the neurochemical messenger dopamine, are involved in forms of external motivation, such as food, sex or drug addiction.

Finally, being curious while learning seemed to produce a spike of activity in the hippocampus, an area involved in forming new memories, and strengthened the link between memory and reward brain circuits.

The study’s findings not only highlight the importance of curiosity for learning in healthy people, but could also give insight into neurological conditions. For example, as people age, their dopamine circuits tend to deteriorate, so understanding how curiosity affects these circuits could help scientists develop treatments for patients with memory disorders, the researchers said.

http://www.livescience.com/48121-curiosity-boosts-memory-learning.html

They say laughter is the best medicine. But what if laughter is the disease?

For a 6-year-old girl in Bolivia who suffered from uncontrollable and inappropriate bouts of giggles, laughter was a symptom of a serious brain problem. But doctors initially diagnosed the child with “misbehavior.”

“She was considered spoiled, crazy — even devil-possessed,” Dr. José Liders Burgos Zuleta, ofAdvanced Medical Image Centre, in Bolivia, said in a statement.

But Burgos Zuleta discovered that the true cause of the girl’s laughing seizures, medically called gelastic seizures, was a brain tumor.

After the girl underwent a brain scan, the doctors discovered a hamartoma, a small, benign tumor that was pressing against her brain’s temporal lobe.The doctors surgically removed the tumor, and the girl is now healthy, the doctors said.

The girl stopped having the uncontrollable attacks of laughter and now only laughs normally, the doctors said.

Gelastic seizures are a form of epilepsy that is relatively rare, said Dr. Solomon Moshé, a pediatric neurologist at Albert Einstein College of Medicine in New York. The word comes from the Greek word for laughter, “gelos.”

“It’s not necessarily ‘hahaha’ laughing,” Moshé told Live Science. “There’s no happiness in this. Some of the kids may be very scared,” he added.

The seizures are most often caused by tumors in the hypothalamus, especially in kids, although they can also come from tumors in other parts of brain, Moshé said. Although laughter is the main symptom, patients may also have outbursts of crying.

These tumors can cause growth abnormalities if they affect the pituitary gland, he said.

The surgery to remove such brain tumors used to be difficult and dangerous, but a new surgical technique developed within the last 10 years allows doctors to remove them effectively without great risk, Moshé said.

The doctors who treated the girl said their report of her case could raise awareness of the strange condition, so doctors in Latin America can diagnose the true cause of some children’s “behavioral” problems, and refer them to a neurologist.

The case report was published June 16 in the journal ecancermedicalscience.

Thanks to Michael Moore for sharing this with the It’s Interesting community.

http://www.cbsnews.com/news/girls-uncontrollable-laughter-caused-by-brain-tumor/

By Tanya Lewis

Just as humans lament not pursuing a lover or bemoan having eaten that extra slice of chocolate cake, rats may experience feelings of regret, too, new research suggests.

When rats were given the option of visiting rooms that contained different foods, and they skipped a good deal for a worse one, they glanced back at the former room, rushed through eating the snack and were more likely to tolerate longer wait times for what they considered the more desirable food , researchers found.

Furthermore, the rats’ brain activity represented the missed opportunity, suggesting the animals were, in fact, experiencing regret over their choice.

“The rat is representing the counterfactual — the ‘what might have been,'” David Redish, a neuroscientist at the University of Minnesota in Minneapolis, and senior author of the study detailed today (June 8) in the journal Nature Neuroscience.

No other studies have shown convincingly that any animal besides humans experience regret, though some studies hinted it was possible, the researchers said.

How do you define regret? You can’t exactly ask a rat if it feels regret, but even if you could, it wouldn’t be proof, just as it can be difficult to tell if a human feels regret just by asking them.

It’s important to distinguish between regret and disappointment, Redish told Live Science. Regret occurs when you make a mistake, but recognize there’s an alternate action you could have taken that would have resulted in a better outcome, he said. Disappointment happens when “the world’s just not as good as you hoped, but it’s not necessarily your fault,” he said.

To test whether rats could feel regret, Redish and his graduate student Adam Steiner designed a kind of “restaurant row” for the animals — a circular enclosure with pathways leading off it to “restaurants” with different kinds of food, which were dispensed after some delay.

As a rat passed each pathway, it heard a tone that told the animal how long it would have to wait for the food (like being told the wait time at a restaurant). Each rat had its own favorite food, such as banana or chocolate, and would wait longer to get it, Redish said. Each rat was given an hour to explore the enclosure, during which it could only move in one direction between restaurants.

If the rat passed up a good deal — for instance, bypassing a food it liked in favor of a shorter wait time — and encountered a worse deal at the next restaurant, it would glance backward at the one it passed up. Not only that, the rat rushed through eating its chosen food, much like a regretful human would, and was more likely to take a “worse deal” in the future, the researchers said.

But the rats’ behavior was only part of the story. The researchers also made electrical recordings of the rats’ brains during the task, from neurons in the orbitofrontal cortex, the part of the brain that is active in human brain scans when people feel regret. Decoding these signals allowed the researchers to “read the rat’s mind,” Redish said.

Surprisingly, when the rats were looking back at the restaurant they ultimately passed up, their brains showed a representation of entering that restaurant — not of the food they missed. The findings suggest the animals were expressing regret over their actions, rather than just disappointment, the researchers said.

If rats can feel regret, what about other animals? Redish speculates that any mammal might be capable of the feeling, because they have many of the same brain structures as rats and humans.

“Regret is something we think of as very human and very cognitive,” Redish said, but “we’re seeing that the rats are much more cognitive than we thought.”

http://www.livescience.com/46184-rats-experience-regret.html

The genome of the termite has just been sequenced, and it is revealing several clues about how the pests create their rigid social order.

For instance, the new genome, detailed today (May 20) in the journal Nature Communications, uncovers some of the underpinnings of termites’ caste system, as well as the roots of the males’ sexual staying power.

Like other social insects— such as ants, honeybees and some wasps — termites live in highly structured “caste systems,” with each creature programmed to perform a rigidly defined job. A select few termite kings and queens reproduce, while drones and soldiers work, defend the colony or care for young.

Yet termites evolved their social structure independently from ants and bees, which belong to an order known as Hymenoptera.

To understand how this happened, Jürgen Liebig, a behavioral biologist at Arizona State University, and his colleagues collected dampwood termites(Zootermopsis nevadensis nuttingi) that lived in Monterey, California. The researchers then sequenced the genome of the insects and measured how those genes were expressed, or turned on and off.

The research revealed several insights about termite sexual and social behavior.

Termite society is roughly half males and half females. Termites have sexually active kings as well as queens, and kings make sperm throughout their lifetimes. Dampwood termite males also have testes that shrivel and grow seasonally.

Ants and honeybees, in contrast, live in predominantly female societies, and ant sex is a one-time affair.

“Their societies generally consist of females — the males are only there to fly out, mate and die,” Liebig told Live Science.

Sure enough, the termites had more gene variants associated with sperm production and degradation, and those genes were expressed to a greater extent than in ants, Liebig said. That finding suggested those genetic differences contributed to male termites’ sexual longevity.

The termite genome also contains a high fraction of genes that are turned off by chemical tags, or methyl groups, the researchers found. In honeybees, this process of methylation sets the fate of individual animals, determining their place in the caste system. The new findings suggest a similar process may be at play in termites.

In addition, both ants and termites communicate via chemical smell signals sensed by receptors on their antennas.

But while ants venture out for food, these particular termites spend their whole lives dining on one piece of wood.

The new analysis revealed that the termites have far fewer cell types for recognizing individual chemicals, probably because they rarely face off against foreign termites or search for food. They simply don’t need to recognize as many smells, Liebig said.

However, some termite species, such as Australian mound-building termites, do forage and encounter foreigners along the way, so as a follow-up, the team would like to see if those termites can detect a greater array of chemicals, Liebig said.

http://www.scientificamerican.com/article/termite-genome-reveals-details-of-caste-system/

A battered diamond that survived a trip from “hell” confirms a long-held theory: Earth’s mantle holds an ocean’s worth of water.

“It’s actually the confirmation that there is a very, very large amount of water that’s trapped in a really distinct layer in the deep Earth,” said Graham Pearson, lead study author and a geochemist at the University of Alberta in Canada. The findings were recently published in the journal Nature.

The worthless-looking diamond encloses a tiny piece of an olivine mineral called ringwoodite, and it’s the first time the mineral has been found on Earth’s surface in anything other than meteorites or laboratories. Ringwoodite only forms under extreme pressure, such as the crushing load about 320 miles (515 kilometers) deep in the mantle.

Most of Earth’s volume is mantle, the hot rock layer between the crust and the core. Too deep to drill, the mantle’s composition is a mystery leavened by two clues: meteorites, and hunks of rock heaved up by volcanoes. First, scientists think the composition of the Earth’s mantle is similar to that of meteorites called chondrites, which are chiefly made of olivine. Second, lava belched by volcanoes sometimes taps the mantle, bringing up chunks of odd minerals that hint at the intense heat and pressure olivine endures in the bowels of the Earth.

In recent decades, researchers have also recreated mantle settings in laboratories, zapping olivine with lasers, shooting minerals with massive guns and squeezing rocks between diamond anvils to mimic the Earth’s interior.

These laboratory studies suggest that olivine morphs into a variety of forms corresponding to the depth at which it is found. The new forms of crystal accommodate the increasing pressures. Changes in the speed of earthquake waves also support this model. Seismic waves suddenly speed up or slow down at certain depths in the mantle. Researcher think these speed zones arise from olivine’s changing configurations. For example, 323 to 410 miles (520 to 660 km) deep, between two sharp speed breaks, olivine is thought to become ringwoodite. But until now, no one had direct evidence that olivine was actually ringwoodite at this depth.

“Most people (including me) never expected to see such a sample. Samples from the transition zone and lower mantle are exceedingly rare and are only found in a few, unusual diamonds,” Hans Keppler, a geochemist at the University of Bayreuth in Germany, wrote in a commentary also published in Nature.

The diamond from Brazil confirms that the models are correct: Olivine is ringwoodite at this depth, a layer called the mantle transition zone. And it resolves a long-running debate about water in the mantle transition zone. The ringwoodite is 1.5 percent water, present not as a liquid but as hydroxide ions (oxygen and hydrogen atoms bound together). The results suggest there could be a vast store of water in the mantle transition zone, which stretches from 254 to 410 miles (410 to 660 km) deep.

“It translates into a very, very large mass of water, approaching the sort of mass of water that’s present in all the world’s ocean,” Pearson told Live Science’s Our Amazing Planet.

Plate tectonics recycles Earth’s crust by pushing and pulling slabs of oceanic crust into subduction zones, where it sinks into the mantle. This crust, soaked by the ocean, ferries water into the mantle. Many of these slabs end up stuck in the mantle transition zone. “We think that a significant portion of the water in the mantle transition zone is from the emplacement of these slabs,” Pearson said. “The transition zone seems to be a graveyard of subducted slabs.”

Keppler noted that it’s possible the volcanic eruption that brought the deep diamond to Earth’s surface may have sampled an unusually water-rich part of the mantle, and that not all of the transition-zone layer may be as wet as indicated by the ringwoodite.

“If the source of the magma is an unusual mantle reservoir, there is the possibility that, at other places in the transition zone, ringwoodite contains less water than the sample found by Pearson and colleagues,” Keppler wrote. “However, in light of this sample, models with anhydrous, or water-poor, transition zones seem rather unlikely.”

A violent volcanic eruption called a kimberlite quickly carried this particular diamond from deep in the mantle. “The eruption of a kimberlite is analogous to dropping a Mentos mint into a bottle of soda,” Pearson said. “It’s a very energetic, gas-charged reaction that blasts its way to Earth’s surface.”

The tiny, green crystal, scarred from its 325-mile (525 km) trip to the surface, was bought from diamond miners in Juína, Brazil. The mine’s ultradeep diamonds are misshapen and beaten up by their long journey. “They literally look like they’ve been to hell and back,” Pearson said. The diamonds are usually discarded because they carry no commercial value, he said, but for geoscientists, the gems provide a rare peek into Earth’s innards.

The ringwoodite discovery was accidental, as Pearson and his co-authors were actually searching for a means of dating the diamonds. The researchers think careful sample preparation is the key to finding more ringwoodite, because heating ultradeep diamonds, as happens when scientists polish crystals for analysis, causes the olivine to change shape.

“We think it’s possible ringwoodite may have been found by other researchers before, but the way they prepared their samples caused it to change back to a lower-pressure form,” Pearson said.

http://www.livescience.com/44057-diamond-inclusions-mantle-water-earth.html

In 2002, two men savagely attacked Jason Padgett outside a karaoke bar, leaving him with a severe concussion and post-traumatic stress disorder. But the incident also turned Padgett into a mathematical genius who sees the world through the lens of geometry.

Padgett, a furniture salesman from Tacoma, Wash., who had very little interest in academics, developed the ability to visualize complex mathematical objects and physics concepts intuitively. The injury, while devastating, seems to have unlocked part of his brain that makes everything in his world appear to have a mathematical structure.

“I see shapes and angles everywhere in real life” — from the geometry of a rainbow, to the fractals in water spiraling down a drain, Padgett told Live Science. “It’s just really beautiful.”

Padgett, who just published a memoir with Maureen Seaberg called “Struck by Genius” (Houghton Mifflin Harcourt, 2014), is one of a rare set of individuals with acquired savant syndrome, in which a normal person develops prodigious abilities after a severe injury or disease. Other people have developed remarkable musical or artistic abilities, but few people have acquired mathematical faculties like Padgett’s.

Now, researchers have figured out which parts of the man’s brain were rejiggered to allow for such savant skills, and the findings suggest such skills may lie dormant in all human brains.

Before the injury, Padgett was a self-described jock and partyer. He hadn’t progressed beyond than pre-algebra in his math studies. “I cheated on everything, and I never cracked a book,” he said.

But all that would change the night of his attack. Padgett recalls being knocked out for a split second and seeing a bright flash of light. Two guys started beating him, kicking him in the head as he tried to fight back. Later that night, doctors diagnosed Padgett with a severe concussion and a bleeding kidney, and sent him home with pain medications, he said.

Soon after the attack, Padgett suffered from PTSD and debilitating social anxiety. But at the same time, he noticed that everything looked different. He describes his vision as “discrete picture frames with a line connecting them, but still at real speed.” If you think of vision as the brain taking pictures all the time and smoothing them into a video, it’s as though Padgett sees the frames without the smoothing. In addition, “everything has a pixilated look,” he said.

With Padgett’s new vision came an astounding mathematical drawing ability. He started sketching circles made of overlapping triangles, which helped him understand the concept of pi, the ratio of a circle’s circumference to its diameter. There’s no such thing as a perfect circle, he said, which he knows because he can always see the edges of a polygon that approximates the circle.

Padgett dislikes the concept of infinity, because he sees every shape as a finite construction of smaller and smaller units that approach what physicists refer to as the Planck length, thought to be the shortest measurable length.

After his injury, Padgett was drawing complex geometric shapes, but he didn’t have the formal training to understand the equations they represented. One day, a physicist spotted him making these drawings in a mall, and urged him to pursue mathematical training. Now Padgett is a sophomore in college and an aspiring number theorist.

Padgett’s remarkable abilities garnered the interest of neuroscientists who wanted to understand how he developed them.

Berit Brogaard, a philosophy professor now at the University of Miami, in Coral Gables, Fla., and her colleagues scanned Padgett’s brain with functional magnetic resonance imaging (fMRI) to understand how he acquired his savant skills and the synesthesia that allows him to perceive mathematical formulas as geometric figures. (Synesthesia is a phenomenon in which one sense bleeds into another.)

“Acquired savant syndrome is very rare,” Brogaard said, adding that only 15 to 25 cases have ever been described in medical studies.

Functional magnetic resonance imaging measures changes in blood flow and oxygen use throughout the brain. During scans of Padgett, the researchers showed the man real and nonsense mathematical formulas meant to conjure images in his mind.

The resulting scans showed significant activity in the left hemisphere of Padgett’s brain, where mathematical skills have been shown to reside. His brain lit up most strongly in the left parietal cortex, an area behind the crown of the head that is known to integrate information from different senses. There was also some activation in parts of his temporal lobe (involved in visual memory, sensory processing and emotion) and frontal lobe (involved in executive function, planning and attention).

But the fMRI only showed what areas were active in Padgett’s brain. In order to show these particular areas were causing the man’s synesthesia, Brogaard’s team used transcranial magnetic stimulation (TMS), which involves zapping the brain with a magnetic pulse that activates or inhibits a specific region. When they zapped the parts of Padgett’s parietal cortex that had shown the greatest activity in the fMRI scans, it made his synesthesia fade or disappear, according to a study published in August 2013 in the journal Neurocase.

Brogaard showed, in another study, that when neurons die, they release brain-signaling chemicals that can increase brain activity in surrounding areas. The increased activity usually fades over time, but sometimes it results in structural changes that can cause brain-activity modifications to persist, Brogaard told Live Science.

Scientists don’t know whether the changes in Padgett’s brain are permanent, but if he had structural changes, it’s more likely his abilities are here to stay, Brogaard said.

So do abilities like Padgett’s lie dormant in everyone, waiting to be uncovered? Or was there something unique about Padgett’s brain to begin with?

Most likely, there is something dormant in everyone that Padgett tapped into, Brogaard said. “It would be quite a coincidence if he were to have that particular special brain and then have an injury,” she said. “And he’s not the only [acquired savant].”

In addition to head injuries, mental disease has also been known to reveal latent abilities. And Brogaard and others have done studies that suggest zapping the brains of normal people using TMS can temporarily bring out unusual mathematical and artistic skills.

Yet Padgett wouldn’t change his new abilities if he could. “It’s so good, I can’t even describe it,” he said.

It’s always possible that having savant skills may come with trade-offs. In Padgett’s case, he developed fairly severe post-traumatic stress disorder and obsessive-compulsive disorder, and he still finds it difficult to appear in public.

http://news.discovery.com/human/life/brain-injury-turns-man-into-math-genius-1405061.htm

Chronic cocaine use may speed up brain aging, a new study suggests.

British researchers scanned the brains of 60 people with cocaine dependence and 60 people with no history of substance abuse, and found that those with cocaine dependence had greater levels of age-related loss of brain gray matter.

The cocaine users lost about 3.08 milliliters (ml) of brain volume a year, nearly twice the rate of about 1.69 ml per year seen in the healthy people, the University of Cambridge researchers said.

The increased decline in brain volume in the cocaine users was most noticeable in the prefrontal and temporal cortex, regions associated with attention, decision-making, self-regulation and memory, the investigators noted in a university news release.

“As we age, we all lose gray matter. However, what we have seen is that chronic cocaine users lose gray matter at a significantly faster rate, which could be a sign of premature aging. Our findings therefore provide new insight into why the [mental] deficits typically seen in old age have frequently been observed in middle-aged chronic users of cocaine,” Dr. Karen Ersche, of the Behavioral and Clinical Neuroscience Institute at University of Cambridge, said in the news release.

The study is published in the April 25 issue of the journal Molecular Psychiatry.

Cocaine is used by as many as 21 million people worldwide, and about 1 percent of these people become dependent on the drug, according to the United Nations Office on Drugs and Crime.

While the study doesn’t conclusively prove cocaine causes brain atrophy and other symptoms of aging, the association is cause for concern, the researchers said.

“Our findings clearly highlight the need for preventative strategies to address the risk of premature aging associated with cocaine abuse. Young people taking cocaine today need to be educated about the long-term risk of aging prematurely,” Ersche said.

However, accelerated aging also affects older adults who have abused cocaine and other drugs since early adulthood.

“Our findings shed light on the largely neglected problem of the growing number of older drug users, whose needs are not so well catered for in drug treatment services. It is timely for health care providers to understand and recognize the needs of older drug users in order to design and administer age-appropriate treatments,” Ersche said.

http://health.usnews.com/health-news/news/articles/2012/04/24/cocaine-habit-might-speed-brain-aging