80beats » Mind & Brain

Can a Genetic Variation Boost Empathy and Reduce Stress?

Brett Israel — Wed, 18 Nov 2009 11:06:07 +0000

One single difference in the human genome may play a role in behaviors such as empathizing and responding to stress. The research, published in the journal Proceedings of the National Academy of Sciences, focused on a single gene, called OXTR, which carries the design and production blueprint for cells scattered throughout the heart, uterus, spinal cord and brain that serve as docking stations for a chemical called oxytocin [Los Angeles Times]. Oxytocin is a chemical produced in the brain that makes us feel all warm and fuzzy when we interact with others in a nurturing or bonding way; it has also been shown to help mice stay calm when under stress.

The researchers decided to investigate a region on the OXTR gene associated with decreased social interaction in humans to see if small changes correlated to a person’s sociability and ability to handle stress. They put 192 college students through experiments to measure empathy and stress. One in four of the subjects had a particular variation of that gene region, and those subjects were significantly better at accurately reading the emotions of others by observing their faces than were the remaining three-quarters of subjects [Los Angeles Times]. The people in this subset were also less likely to startle during the stress test, and reported that they were generally chill folks.

Study coauthor Sarina Rodrigues provides the usual caveat that genes alone don’t determine our behavior and cautioned against reading too much into their discovery. Lots of people without the gene variation are able to understand and care about other people’s emotions, Rodrigues said [Telegraph]. So what are we supposed to do with this information? That’s not entirely clear, and the results need to be repeated in a larger group. Still, the work is “one solid step forward” in understanding the role of oxytocin in human social behavior, says neuroeconomist Paul Zak, … who has studied the effects of oxytocin on economic decisions [ScienceNOW Daily News].

One thing we do know is that, starting this weekend, if your employer somehow finds out that you are prone to high stress, at least they can’t fire you for it.

Image: flickr / le venti le cri

Beware Friends Who Are Bad With Money: It Could Be Contagious

Andrew Moseman — Thu, 12 Nov 2009 15:48:15 +0000

Yawning is contagious. So too, it seems, are being fat, being sad, and a host of other things that we social creatures tend to pick up from each other. In a study published this week in the Journal of Experimental Social Psychology, scientists picked out one more trait that could be contagious among connected people: making bad business decisions.

Researchers had already confirmed that people have a hard time letting go of their own bad investments. For example, someone who buys a lemon of a car or a dilapidated house will, instead of owning up that it was a mistake and cutting their losses, continue to commit to the project and pour more money, effort and emotions into it [Los Angeles Times]. The key finding in this study, however, was that this bad business psychology can spread to others.

On a computer screen, the study participants watched text updates of two supposed volunteers (who were actually played by a computer program) bidding on a prize that supposedly equal $4.45 in real money. When the first “decision-maker” neared the bidding threshold at which they would be losing money on the investment, the real study subject was asked to take over bidding for him or her.

Study subject had all the information to know that it made no business sense to keep going. But the volunteers who felt an identification with the fictitious player (i.e., those told by the researchers that they shared the same month of birth or year in school) made almost 60% more bids and were more likely to lose money than those who didn’t feel a connection [ScienceNOW Daily News]. Thus, the scientists suggest, humans can unconsciously adopt the psychology of friends, business partners, or simply people to whom we feel connected, and become similarly incapable of cutting our losses on a bad investment.

Image: flickr / anglerp1

Who Needs Sunglasses? New Contact Lenses Respond to Light

Andrew Moseman — Tue, 10 Nov 2009 18:22:47 +0000

Contact lenses provide a number of convenience advantages over glasses, but one they come up short in one area—you can’t get contacts that automatically adjust to the sun’s UV light and darken, like the photochromic lenses many bespectacled people enjoy. But that could soon change: Researchers in Singapore led by Jackie Ying have now created a contact lens that responds to UV light.

Transition lenses for glasses are coated with a dye that is transparent when out of the sun, but responds to UV light by changing shape and darkening. Few previous attempts have been made to design transition contact lenses, largely because it’s difficult to apply dye coatings uniformly to the delicate, soft surface of a contact lens. Ying and her colleagues got around this by developing a contact lens that embeds dyes uniformly throughout the material [Technology Review].

The scientists crafted their contacts with a structure that includes nano-sized tunnels to hold the dye. The lens’ porous structure allows the dye to change shape quickly, which team member Edwin Chow says reduces response time. “When your car suddenly goes into a tunnel, the amount of light is very dim, so you need your lenses to transform back immediately,” says Chow. [Technology Review].

First things first: the team tested its lenses on rabbits to make sure they were bio-compatible, and tests continue test to make sure the lenses don’t leak dye. However, there’s no word yet on whether near-sighted rabbits prefer contacts to glasses.

Image: Institute for Bioengineering and Nanotechnology

The Birds’ Sixth Sense: How They See Magnetic Fields

Eliza Strickland — Thu, 29 Oct 2009 14:32:30 +0000

Some migratory birds that have to navigate across continents have an extremely useful tool at their disposal–an internal compass that points unerringly towards magnetic north. Researchers already knew that some birds possess these biological compasses, but their mechanism has been unclear. “This is basically the sixth sense of biology, but no one knows how it works…. The magnetic sense is by far the least understood sense in the natural world,” [Science News], says study coauthor Henrik Mouritsen.

Now, researchers have determined that light-sensing cells in the eye convey the crucial message to a special visual center of a robin’s brain, called cluster N. Special proteins called cryptochromes in the birds’ eyes may mediate this light-dependent magnetic sensing, Mouritsen says. Light hitting the proteins produces a pair of free radicals, highly reactive molecules with unpaired electrons. These electrons have a property called spin which may be sensitive to Earth’s magnetic field. Signals from the free radicals may then move to nerve cells in cluster N, ultimately telling the birds where north is [Science News].

The research also laid to rest the previous theory that it was actually iron-based receptors in the bird’s beak cells that sensed magnetic fields and sent the message to the bird’s brain. In the study, published in Nature, the researchers tested 36 European robins and found birds with damage to ”cluster N” were unable to orientate themselves using the Earth’s magnetic field. But damage to another nerve channel necessary for a beak-sensing system had no effect [Telegraph].

Image: H. Mouritsen

Phantom Limbs Can Move in Anatomically Impossible Ways

Brett Israel — Wed, 28 Oct 2009 14:03:15 +0000

Phantom limb syndrome is an eerie condition, in which amputees have the physically painful sensation that their missing limbs are still present. Now, a small new study has shown that people can twist those ghostly limbs in anatomically impossible ways, while still feeling that the limb is real and present. In essence, each amputee’s brain reshaped his understanding of where his body was. The findings show that the brain can alter how we perceive our bodies all by itself, without input from our senses [Reuters].

Researchers had patients with “vivid phantoms” try to move their wrists in a physically impossible way—a 360 degree spin of the wrist around the long axis of the forearm—and found that 4 of the 7 patients could move their wrists this way. Some patients that were able to move their wrists later reported that their phantom hands were now more difficult to move from side to side because of changes in their phantom arms’ shapes.

To corroborate that the individuals had really learned the new movement (after all, the scientists couldn’t see the phantom limbs) the researchers had them perform a task known as left-right hand judgement before and after their training. The ability to twist the phantom wrist in a new way allowed the participants to react to this task faster than they could before they had learned the impossible move [Science News].

The study, published in the Proceedings of the National Acadmey of Sciences, may lead to treatments that help alleviate the pain associated with phantom limb syndrome by helping patients learn to move their phantom limbs into a more comfortable position. The findings also raise the “speculative, but not outrageous” possibility that patients could cope with movement problems due to stroke, back pain, or pain in other regions of the body, by being trained to change the image of that body part, according to the researchers [Reuters].

Image: iStockphoto

Science Explains: Why You Can’t Drink Red Wine With Fish

Brett Israel — Fri, 23 Oct 2009 17:35:07 +0000

Snooty wine pairing rules, such as the edict that one must only drink white wine with fish, now have a little data behind them, according to a new study. Researchers found a correlation between the high iron content of red wine and a nasty, fishy aftertaste when the reds are sipped with seafood. In the experiment, tasters ate a bit of scallop, tasted some wine and evaluated the aftertaste on a scale of 1 to 4. The diners found the unpleasant aftertaste was more intense with wines that had a higher iron content, the researchers say [Los Angeles Times]. The researchers were able to block the aftertaste by adding a compound that masks the iron.

The iron content of a wine depends on the composition of the soil in which the grapes were grown, the dust on the berry, contamination during harvesting, transportation, and crushing, and the conditions during fermentation [Telegraph]. The new research, published in Journal of Agricultural and Food Chemistry, suggests that some low-iron red wines are OK to drink with fish. While red wines tend to have more iron than whites, it varies according to the type of grape, country of origin, and vintage.

But the iron is only half the story. The researchers report that they haven’t yet isolated the compound in the scallops that reacts with the wine, but they suspect it’s an unsaturated fatty acid, which could be breaking down rapidly and releasing the decaying fish smell when exposed to iron [ScienceNOW Daily News].

Image: flickr / yashima

Is Playing College Football Enough to Damage a Brain for Life?

Eliza Strickland — Thu, 22 Oct 2009 19:03:24 +0000

Scientists who have been investigating the link between professional football and severe brain damage have a troubling new piece of evidence: The brain of a deceased man who stopped playing football after college also showed the distinctive signs of damage. The man, the former Western Illinois wide receiver Mike Borich, died at 42 of a drug overdose in February after a downward spiral of depression and substance abuse that is generally associated with the type of tissue damage found in his brain [The New York Times].

The findings suggest that the damage isn’t only associated with professional football players who have played at the highest level of competition for years, but might be a fundamental byproduct of the sport itself. The cumulative effect of the many blows to the head that many football players experience may simply be too much for the brain to handle, researchers say.

Several neuroscientists have been investigating football players with a condition called chronic traumatic encephalopathy (C.T.E.). Scientific progress is slow because the condition can only be diagnosed after death, when the brains donated by players can be sliced, stained, and examined for protein deposits and fibrous tangles. So far, researchers have identified C.T.E. in eight NFL players who died between the ages of 36 and 52–many of whom had extreme emotional problems in their last years. It has been found in every player of those ages examined by the two groups doing such research [The New York Times].

Says Ann McKee, one of the researchers: “I’ve looked at more than 1,000 brains, and I’ve never seen this in any individual living a normal life — it’s only through head trauma…. These changes are devastating — they’re extreme and they’re throughout the brain,” McKee said. “They’re in the cortex where we think and make judgments, where we do most of the thought that make us humans” [The New York Times].

Concussion specialist Robert Cantu says C.T.E. isn’t associated only with full-on concussions, the kind that knock football players unconscious and send them out of the game. People with C.T.E., Cantu says, “aren’t necessarily people with a high, recognized concussion history. But they are individuals who collided heads on every play—repetitively doing this, year after year, under levels that were tolerable for them to continue to play” [The New Yorker]. Cantu says that linemen are particularly vulnerable to the condition, since they can get hit in the head 1,000 times in a typical football season.

While McKee says she won’t be able to come to any firm conclusions until she has seen at least 50 football players’ brains with C.T.E., the evidence is mounting. However, neither the NFL nor anyone else has come forward with suggestions on what to do about the problem.

Who Needs Sleep? Drug Corrects Memory Problems in Sleep-Deprived Mice

Eliza Strickland — Thu, 22 Oct 2009 15:01:09 +0000

Researchers have found a pharmaceutical way to clear some of the cognitive fog that results from a sleepless night. In a new study using lab mice, researchers corrected the memory problems in sleep-deprived mice through a drug that suppressed levels of a certain enzyme in a brain region called the hippocampus, which plays an important role in memory and learning.

The study, published in Nature, helps tease out the specific effects of sleep deprivation on the brain. Says lead researcher Christopher Vecsey: “One of the main problems is that sleep deprivation does a lot of things to the brain, and it’s easy to get caught in a mish-mash of different effects” [Nature News].

In the experiment, two groups of mice were either allowed to rest over a five-hour period or were constantly disturbed by handling. The sleep-deprived group demonstrated particular problems when it came to performing a basic retrieval test, which they had learned before [BBC News]. When the researchers examined the brains of the sleep-deprived mice, they found that these mice made more of an enzyme called phosphodiesterase 4 (PDE4). In turn, the surplus of PDE4 caused a shortfall of a compound called cAMP, which is involved in forming new memories in a brain area called the hippocampus [WebMD]. When the researchers gave sleep-deprived mice a drug that stops PDE4 from working, the mice aced their memory tests.

While the study appears to point the way toward drugs that could help out sleep-deprived humans, overworked and overstressed people shouldn’t be clamoring for a prescription, says sleep specialist Neil Stanley, who wasn’t involved in the research. “We are always going to need drugs for people with serious disorders, but we don’t want to end up medicalising lifestyles. We need to go back to basics and think about the way we as a society lead our lives, and the impact this has on our sleep, rather than looking for a cure” [BBC News].

Image: C. Vecsey et al, Nature 2009

Cheesecake Is Like Heroin to Rats on a Junk-Food Diet

Brett Israel — Thu, 22 Oct 2009 11:00:45 +0000

The next time a friend says he’s addicted to bacon, you should know he probably isn’t joking. The brains of rats fed only on junk food—like bacon, Ho Hos, cheesecake, and sausage—look similar to the brains of heroin-addicted rats, according to new a study. Pleasure centers in the brains of rats addicted to high-fat, high-calorie diets became less responsive as the binging wore on, making the rats consume more and more food [Science News]. The findings suggest that drug addiction and overeating have similar biological mechanisms, according to the scientists from the Scripps Research Institute. The work is not yet published, but was presented at the Society for Neuroscience’s annual meeting.

The rats fed on junk food displayed a hallmark of addiction. After just five days on the junk food diet, rats showed “profound reductions” in the sensitivity of their brains’ pleasure centers, suggesting that the animals quickly became habituated to the food. As a result, the rats ate more food to get the same amount of pleasure. Just as heroin addicts require more and more of the drug to feel good, rats needed more and more of the junk food [Science News]. To test the depths of the rats addiction, researchers shocked rats every time they ate junk food. Rats that had not previously binged on Ho Hos quickly stopped eating the high-fat foods. However, the fat rats kept eating junk food even though they knew the shock was coming. Now that’s an addiction.

Image: flickr / asplosh

Lasers Write False, Fearful Memories into the Brains of Flies

Eliza Strickland — Tue, 20 Oct 2009 14:25:03 +0000

It sounds like a scene from an insect version of Total Recall: Using genetically engineered fruit flies and laser beams, researchers have found a way to embed false, fearful memories in the flies.

Researchers first tested normal flies in a chamber where a jets of air on either side brought two different odors into the container. The researchers delivered an electric shock each time a fly strayed into a particular odour stream, which taught the flies to prefer the other one: the flies learned to move in the direction of the shock-related odour 30 per cent less often [New Scientist].

Next, the researchers created a strain of genetically engineered flies with certain neurons that would be activated by a laser blast. Lead researcher Gero Miesenböck explains that with this technique, called optogenetics, researchers can use light to activate particular cell types that have been genetically engineered to express a light-responsive protein. When laser pulses hit the brain, cells expressing the light-sensitive protein activate. “It’s like sending a radio signal to a city but only those houses with a radios set to the right frequency will get the signal,” says Miesenböck [Nature News].

The flies were then put back in the chamber with the two jets of air, and every time they wandered into one of the odor streams, the laser was fired. Many of the flies were unaffected, but a select group quickly learned to avoid the odor stream associated with the laser pulse. Miesenböck says these flies feared that smell as if they had been conditioned to associate an electric shock with it. “Stimulating just these neurons gives the flies a memory of an unpleasant event that never happened,” he says [New Scientist].

In the genetic engineering process, the scientists had tweaked different neurons in different groups of flies. The contingent that did react to the laser all had 12 particular light-sensitive neurons, according to the study published in the journal Cell. Those 12 brain cells may be the root of associative learning, researchers say–at least in flies.

Image: flickr / Image Editor

Electrodes Stuck in the Brain Show How Thought Becomes Speech

Eliza Strickland — Mon, 19 Oct 2009 14:12:46 +0000

A curious experiment has given scientists an unprecedented look into the human brain as it goes about a vital and everyday task: processing and speaking words. The study, published in Science, found that the brain carries out three steps of the task in about half a second, and that all the activity happens sequentially in the same small brain region, known as Broca’s area.

The researchers took advantage of a rare procedure in which epilepsy patients allow doctors to implant dozens of electrodes directly into their brains. While they are awake, the patients answer questions so that doctors can determine which parts of the brain are necessary to maintain language and which parts can be safely removed to treat epileptic seizures [Los Angeles Times]. Three such patients agreed to take part in the language experiment, were given long lists of verbs, and were asked to change some of them to the past or present tense before saying them out loud.

The electrodes picked up regular pulses of activity in the brain region called Broca’s area, which lies beneath the left temple. The area of the brain is named after a 19th century physician named Pierre Paul Broca, who became famous for his study of two patients who couldn’t speak [NPR News]. While neuroscientists have long believed Broca’s area plays an important role in speech, they’ve previously had little luck in determining exactly what goes on inside the brain region, since standard brain scans like fMRIs don’t have enough resolution.

Electrical activity spiked 200 milliseconds, 320 milliseconds and 450 milliseconds after being presented with a new word. The researchers concluded that those peaks corresponded to the times when the brain decided on the appropriate word to use, picked the proper grammatical form, and figured out how to pronounce it [Los Angeles Times]. The findings negate a previous theory that Broca’s area is involved only in speaking, and another region, Wernicke’s area, handles reading and hearing.

Image: Ned Sahin

Solving a Bubbly Puzzle: How We Taste Carbonization

Brett Israel — Fri, 16 Oct 2009 17:46:29 +0000

Cracking open a cold can of Coke and taking a bubbling swig will have your taste buds dancing—and now scientists know why. A new study shows that cells in taste buds that respond to sour stimuli also seem to be the ones responsible for tasting the carbonation’s fizz [NPR].The fact that we can taste the carbon dioxide in a fizzing soda has previously puzzled scientists, since the human tongue is usually thought to only sense five flavors—bitter, sweet, salty, sour, and umami (also called savory). However, the new study, published in Science, shows that the sour taste buds have an enzyme that interacts with carbon dioxide, so it’s not the bursting bubbles that you taste, it’s the C0₂ itself.

The researchers discovered this tricky bit of chemistry by studying mice. They gave the animals sips of club soda or a little buzz of carbon dioxide gas and recorded how the tongue signaled the sensation to the brain. Both soda and the gas produced similar sensations. But when they tested mice bred to have no sour taste buds, the brain never got its sensory alert. Further probing uncovered the enzyme responsible [AP]. The mechanism should be the same in humans, according to the scientists.

The discovery of a C0₂-sensing taste bud is not only interesting to soft drink manufacturers, but also to evolutionary biologists. After all, Coca-Cola didn’t usher in a new era of carbonated beverages until the late 1800s, so why would our sour-tasting cells have evolved to taste carbon dioxide? The study’s authors write, “CO₂ detection could have evolved as a mechanism to recognize CO₂-producing sources—for instance, to avoid fermenting foods.” One happy irony of such a hypothesis is that the very same mechanism that allowed our deep ancestors to recognize and avoid fermentation allows modern humans to intentionally create the fermented beverages beer and champagne. Or, our carbonation-detecting skills could be an accident. The sour-cell enzymes might be maintaining the pH balance of the taste buds, and the tang of soda water is just fallout [Wired.com].

Image: flickr / roland

Power + Incompetence = a Bullying Boss

Eliza Strickland — Thu, 15 Oct 2009 20:02:03 +0000

Here’s some gratifying news for any employees out there who are feeling bullied by a tyrannical boss: That aggressive behavior may have little to do with you, and a lot to do with your boss’s feelings of incompetence. A new study in Psychological Science found that when managers are made to feel insecure about their job performance, their aggressiveness skyrockets. “Power holders feel they need to be superior and competent. When they don’t feel they can show that legitimately, they’ll show it by taking people down a notch or two” [New Scientist], says study coauthor Nathanael Fast.

The researchers got 410 volunteers from various workplaces to fill out questionnaires about their position in the workplace hierarchy, how they felt about their job performance, and their aggressive tendencies. They also conducted a series experiments on the volunteers. In one, they manipulated the subjects’ sense of power and self-worth by asking them to write about occasions when they felt either empowered or impotent and then either competent or incompetent. Previous research has suggested that such essays cause a short-term bump or drop in feelings of power and capability [New Scientist]. Next they asked the volunteers to set the level of punishment for (imaginary) university students who got wrong answers on a test. Those people who felt more powerful and more incompetent picked the harshest punishments, the study found.

So what’s to be done with a bullying boss? Coauthor Serena Chen says a little ego stroking may make life easier for everyone. “Make them feel good about themselves in some way,” Chen said, suggesting this might mean complimenting a hobby or nonwork activity provided it is “something plausible that doesn’t sound like you’re sucking up” [San Francisco Chronicle].

Image: iStockphoto

Creepy Cyber-Monkeys Dwell in the Primate “Uncanny Valley”

Brett Israel — Wed, 14 Oct 2009 20:47:39 +0000

Humans typically feel uneasy when they see a very realistic human-looking robot or computer avatar, a phenomenon called the “uncanny valley” response. According to a new study performed with monkeys, that reaction might have an evolutionary basis.

Researchers hypothesize that the response stems from almost realistic images that signal HUMAN! to us, but then fail to live up to the initial excitement. The uncanny valley response has been documented in humans since the 1970s, and has been blamed for the unpopularity of some CGI films with realistic characters [like The Polar Express and Final Fantasy], and it is touted as the reason Pixar stuck to characters with cartoonish features [New Scientist].

The response takes its name from a graph (pictured at left) of human emotional response as a function of a depiction’s human-likeness. As human-likeness increases, a positive emotional response also increases, until likeness reaches somewhere around 80 percent, then the emotional response shoots down to revulsion on par with viewing a human corpse.

Uncanny valley response has never been observed in another species. So to investigate the response’s evolutionary basis, researchers checked monkeys for the reaction. To test their preference, researchers showed macaque monkeys real pictures, digital caricatures and realistic reconstructions of other monkey faces. To the latter, the macaques repeatedly averted their eyes [Wired.com], suggesting that monkeys also fall into the uncanny valley.

However the researchers couldn’t determine for certain whether the monkeys were repulsed by the almost real faces, or were simply more attracted or interested in the others. The best way to do that would be to repeat these experiments while looking for possible signs of unease–sweaty skin, dilated pupils or clenched facial muscles, as examples [Not Exactly Rocket Science]. The study was published recently in the Proceedings of the National Academy of Sciences.

Images: PNAS / Asif Ghazanfar and Shawn Steckenfinger

Learn to Juggle, Rewire Your Brain

Eliza Strickland — Wed, 14 Oct 2009 14:19:41 +0000

Inside the brain of someone who’s learning to juggle, some interesting changes take place. Researchers used MRI scans to study the brains of people before and after a six-week training course in juggling, and say they saw a 5% increase in white matter – the cabling network of the brain [BBC News].

The study, published in Nature Neuroscience, follows up on previous work that found changes in the more famous gray matter of the brain, which consists of the cell bodies of the neurons where processing and computation take place. The white matter, which consists mostly of the axons that stretch away from the cell bodies, can be thought of as the brain’s wiring, and researchers say this is the first time that changes have been observed in the white matter of a healthy adult.

Says lead researcher Heidi Johansen-Berg: “We tend to think of the brain as being static, or even beginning to degenerate, once we reach adulthood…. In fact we find the structure of the brain is ripe for change. We’ve shown that it is possible for the brain to condition its own wiring system to operate more efficiently” [Reuters].

The changes to the jugglers’ brains were found in a rear section called the intraparietal sulcus, which has been shown to contain nerves that react to us reaching and grasping for objects in our peripheral vision. There was a great variation in the ability of the volunteers to juggle but all of them showed changes in white matter [BBC News]. This demonstrates that the brain growth is a result of the time spent training, and isn’t linked to skill level. The researchers also note that juggling isn’t the only activity that could produce such changes–Johansen-Berg says she chose juggling simply because it was a complex task for people to learn.

Image: flickr / brightlightphotographydotcom