On the left: A mouse embryo preserved in para-formaldehyde. On the right: A mouse embryo soaked in Scale for two weeks.

What’s the News: The trouble with brains, organs, and tissues in general, from a biologist’s perspective, is that they scatter light like nobody’s business. Shine a light into there to start snapping pictures of cells with your microscope, and bam, all those proteins and macromolecules bounce it around and turn everything to static before you’ve gotten more than a millimeter below the surface. Scientists at RIKEN in Japan, however, have just published a special recipe for a substance that makes tissue as transparent as Jell-O, making unprecedentedly deep imaging possible.

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Researchers at Wake Forest University in North Carolina have now learned that Nazca boobies perpetuate a “cycle of violence”: bullied chicks tend to become bullies and pass on the pain. When parent birds leave their nests to eat, baby boobies are often visited by sexually and physically abusive non-breeding adults; the chicks, when grown, are more likely to abuse unrelated chicks. “The link we found indicates that nestling experience, and not genetics, influences adult behaviour,” lead researcher David Anderson told BBC.

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What’s the News: The human brains, capable as it is of amazing mental feats, comes with a downside: it shrinks as we get older, contributing to memory loss, reduced inhibitions, and the other cognitive dysfunctions of age. But even chimpanzees, our closest living relatives, don’t suffer this sort of brain loss, according to a study published online yesterday in Proceedings of the National Academy of Sciences. This unusual shrinkage of the human brain, the researchers say, may be a result of our long lifespan. (more…)

What’s the News: It’s always a gamble when a record company decides to sign a new band, as they can never truly predict which artists will be successful. Sometimes marketing firms will use focus groups to guess at future musical gold mines, but conflicting motivations, among other things, can hamper results. Now, researchers have found that while you may not be able to consciously pinpoint which songs will be hits, your brain just might.

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When you engage in a long cell phone conversation, a new study says, the phone radiation may increase the brain activity in regions nearest to the antenna. It’s the newest entry into the long-running debate about whether cell phones carry health risks, but the scientists behind the research in the Journal of the American Medical Association caution that they don’t know what this localized change in brain activity means—or even how it’s happening.

Many previous studies of cell phone safety have looked into the question of whether the phones’ radiation could cause cancer (there’s no solid evidence that it could) or looked at the effects of the heat that phones create. But Nora Volkow and colleagues investigated something else: The metabolism of the brain regions nearest to the phone—that is, how quickly they are burning energy. To do it, Volkow’s team recruited 50 people and subjected them to PET scans while an active cellphone sat next to their heads.

To blind the participants, the authors strapped two cell phones on their heads, one to each ear (the cellphone used in this work is a standard Samsung CDMA flip phone). Both were kept muted, and only one was activated by a call—the side that was activated was flipped in two different recording sessions. The calls started 20 minutes before a dose of radioactive glucose, and kept going for a half an hour afterwards to provide a long-term picture of metabolic activity. The data from one of the subjects ended up not being used because the cell company dropped the call. [Ars Technica]

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How we talk about numbers plays a big role in how we think about numbers—that much is clear. But this week, new research makes the case that language is not a key part of thinking about numbers, but the key part, overriding other influences like cultural ones.

The study in the Proceedings of the National Academy of Sciences by psychologist Elizabet Spaepen focuses on a group of deaf Nicaraguans called the homesigners, who invented their own form of sign language—a form that lacks a numerical vocabulary.

That’s a common trait in many hunter-gatherer societies, where the numbering system is often one-two-three-many. For example, the Munduruku Amazonian people in rural Brazil don’t have any words for exact numbers larger than five. Their neighbors, the Piraha, no exact number words at all. [USA Today]

There are two things that make the homesigners extremely scientifically interesting. One is the fact that they spontaneously invented this language when brought together at a home for the deaf in the 1970s. And the other—the one that’s important for this study—is that they’re not an isolated tribe in which nobody uses numbers. They live within Nicaragua, surrounding by a Spanish-speaking society that’s as number-dependent as any other country. Thus, Spaepen’s team reasoned, if the homesigners struggle to conceptualize larger numbers, the reason would have to be linguistic and not cultural.

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Scientists are devising cleverer and cleverer means to see inside the brain—and creating some amazing pictures along the way.

These psychedelic images come from one of two studies in the journal Nature Methods, which present similar but slightly different ways to color the connections between neurons in a fruit fly. The projects build upon similar research from 2007 that achieved this “brainbow” effect in mice, and they could allow for new ways to track the formation and purpose of brain cells.

The researchers gave the insects genes for a red, a green, and a blue fluorescent protein. The genetic control system they devised spurs each cell to make a different amount of each of the three proteins. Like the red, blue, and green pixels on a TV screen, the combination of the three proteins causes each cell to glow a unique color. [ScienceNOW]

The inserted genes come from naturally glowing jellyfish. They allow not just individual cells to be seen, but also connections:

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Getting better at chess, it turns out, isn’t merely a matter of thinking harder, or using one specific area of the brain—it has more to do with the neural links between brain regions. Neuroscientists from Japan studied the brainy blood-flows of both professional and amateur shogi players (a chess-like game from Japan) and found that professionals have certain brain circuits that may allow them to put on their intuitive thinking caps.

The study, published in Science, used functional magnetic resonance imaging (fMRI) to examine which brain areas showed the most blood flow as professional and amateur shogi players tested their mettle during a match. The experts showed more activity in two regions: the precuneus region in the parietal lobe, which is involved in pattern recognition, and the caudate nucleus, an area in the basal ganglia that is involved in learning, memory, and cognition.

The research team found that the precuneus-caudate connection showed up consistently when professionals were asked to come up with a rapid-fire choice of moves, but not as much for the amateurs. “These results suggest that the precuneus-caudate circuit implements the automatic, yet complicated, processes of board-pattern perception and next-move generation in board game experts,” the researchers reported. [MSNBC]

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It sounds like the start of a science fiction movie: a lethal brain disease that goes airborne. But while scientists have indeed found that the prions responsible for mad cow disease and other neurological ailments can float on the breeze and infect those who inhale, they say there’s no reason to barricade your gas-masked family inside your house.

Prions are misfolded proteins that cause brain degeneration; in mad cow disease they’ve typically been transmitted when one cow eats the infected brain or spinal cord tissue of another (something that agricultural institutions now agree shouldn’t happen in the first place). Other prion diseases, including the human variant Creutzfeldt-Jakob disease, are also passed along through body fluids and tissue. But for a new study published in PLoS Pathogens, researchers decided to find out if airborne prions could serve as infectious agents.

The short answer: Yes.

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Contrary to the erroneous early reports that U.S. Representative Gabrielle Giffords was killed during the attack on her campaign event Saturday, the Congresswoman survived the attempt on her life. She’s considered lucky to be alive–gunman Jared Loughner shot her in the head at close range.

Now, as she enters the long, unpredictable journey back from serious brain injury, there are at least good signs.

The optimism expressed Sunday was based on Ms. Giffords’s ability to communicate by responding nonverbally to the doctors’ simple commands, like squeezing a hand, wiggling toes and holding up two fingers. The tests are part of a standard neurological examination after head injuries. In Ms. Giffords’s case, the doctors were encouraged because the simple tests showed that she could hear and respond appropriately, indicating that key brain circuits were working. [The New York Times]

This morning, the news remained positive—reportedly the swelling in Giffords’ brain is not getting any worse. That swelling is the real danger in the immediate aftermath of injury if the person survives the initial shock, as Giffords did. Fortunately, she found herself in the care of Dr. Peter Rhee, who was a Navy doctor for 24 years, tending to Marines and soldiers and learning emergency response to brain injury.

Dr. Michael Lemole, chief of neurosurgery at the University Medical Center in Tucson, explains that a large piece of Giffords’ skull has been removed to prevent the swollen brain from pressing against the rigid skull, which would cause further damage.

“The key is making a wide opening in the skull so that the brain can relax into it. Decompression has allowed us to save soldiers with horrible blast injuries,” said Lemole, who removed a wedge from the left side of Giffords’ skull, above the area pierced by a bullet. After the swelling subsides, he said, the bone will be put back into place, closing the gap in her skull. [USA Today]

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Large amygdalas, it seems, are social amygdalas.

These paired regions, typically referred to as almond-shaped (indeed their name comes from the Greek for almond), are known to be part of the brain responsible for sociability as well as fear and other deep-seated emotions. Lisa Feldman Barrett and colleagues sought to find out whether size matters in the amygdala, and according to their study in Nature Neuroscience, there is a connection between people having big amygdalas and having big, complex social networks.

The researchers measured two social network factors in 58 adults. First, they calculated the size of a participant’s network, which is simply the total number of people that are in regular contact with the participant. Second, they measured the network’s complexity, based on how many different groups a participant’s contacts can be divided into. … Linear regression revealed a positive correlation in amygdala size with both social network size and complexity. [Ars Technica]

The team’s MRI scans found a wide variation in amygdala size, from about 2.5 cubic millimeters to more than five. But other factors like a person’s happiness didn’t match up with amygdala size. And the subjects’ hippocampus, which the scientists used as a control, showed no variation when compared to a person’s social network. Only the amygdala size showed the connection, Barrett says.

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What can eating M&Ms—or, rather, thinking about eating M&Ms—tell us about overeating?

From Ed Yong:

The more we expose ourselves to a something, the more we get used to it. This process, known as ‘habituation’, applies to all sorts of things – bright lights, level of wealth and, yes, the taste of food. The first bite of chocolate is heavenly but the fifteenth usually feels less so. Now, Carey Morewedge from Carnegie Mellon University has found that people habituate to the taste of food even if they just imagine themselves eating it.

He asked 51 recruits to imagine either eating 33 M&Ms one at a time; putting 33 quarters into a laundry machine; or inserting 30 quarters and then eating 3 M&Ms. Afterwards, everyone was given a bowl containing 40 grams of real M&Ms, and allowed to snack to their hearts’ content. On average, Morewedge found that everyone who imagined shoving quarters ate around 4 grams of candy, while those who stuffed their imaginary faces ate around half as much.

Check out the rest of this post—with subsequent M&M experiments—at Not Exactly Rocket Science.

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Image: flickr / FlyNutAA

Traumatic brain injury has become the signature war wound for soldiers serving in Iraq and Afghanistan–and new research suggests that soldiers may not be adequately protected against the explosions that cause these injuries. By modeling how blast waves propagate through a soldier’s head, an MIT research group found that current combat helmets don’t offer much protection, because the blast waves from improvised explosive devices (IEDs) can enter the skull through the face.

“There’s a passageway through those soft tissues directly into the brain tissue, without having to go through bone or anything hard,” said Raul Radovitzky, an aeronautical engineer at the Massachusetts Institute of Technology. [LiveScience]

In the study, which was published online in Proceedings of the National Academy of Sciences, the researchers created their own computer model based on a real person’s brain scans; what they found actually contradicted findings from earlier, rougher models. A previous study, published in August, suggested that current helmet design actually increases brain injuries during an explosion by focusing and intensifying the blast waves inside the helmet.

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When you were born, your brain was more elongated than it is now; it rounded out into its more globular shape as you grew up and crammed it full of knowledge. Neanderthals, it appears, were born with brains in that same elongated shape. But in their case it never changed: Adult Neanderthals’ brains didn’t move to the more rounded shape like ours, according to a study now out in Current Biology.

Scientists have long known that Neanderthals had brains that were about as big as our own, but this study may help explain how their cognitive abilities differed.

[The researchers used CT scans] to study nine fossil Neandertals, including a newborn, a year—old baby, and three children. Because the brain does not fossilize, they studied endocasts, imprints of the brain left in the skull. They found that at birth, both Neandertal and modern human infants had elongated braincases that were similar in shape, although Neandertal faces were already larger. But by age 1 or so, modern humans had grown globular brains, whereas Neandertal babies had not. [ScienceNOW]

Neanderthals, in keeping the same basic brain shape throughout life, maintain the pattern of brain development seen in chimpanzees. In contrast, modern humans have evolved a unique pattern, says lead researcher Philipp Gunz:

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New neuroscience research is not only adding to our understanding of math and number processing in the brain, it’s also suggesting a way to improve learning in the math-deficient.

A small new study published in Current Biology involved electrical stimulation of the parietal lobe, a part of the brain involved in math learning and understanding. When this area was stimulated, students performed better on a math problem test. Said study leader Cohen Kadosh:

“We’ve shown before that we can induce discalculia [an inability to do math], and now it seems we might be able to make someone better at maths, so we really want to see if we can help people with dyscalculia…. Electrical stimulation is unlikely to turn you into the next Einstein, but if we’re lucky it might be able to help some people to cope better with maths.” [BBC News]

Dyscalculia is a learning disability similar to dyslexia, in which a person has an innate difficulty with learning or understanding math. People with this condition can have trouble with daily arithmetic, telling left from right, and telling time on analog clocks. Some studies estimate up to five percent of the population suffers from dyscalculia, and about 20 percent have less severe troubles with math.

For the experiment, 15 students were hooked up to a transcranial direct current stimulation (tDCS) machine, which stimulates the brain through the skull with 1 milliamp of electricity, and were given either a positive (right to left) zap to their parietal lobe for 20 minutes, a positive zap for 30 seconds, or a negative (left to right) zap for 20 minutes (five students per group). The current produced a tingling sensation in the scalp, but it didn’t hurt. Then the students were trained to learn the assigned number values of made-up symbols.

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