Quick: commit this to memory. There will be a quiz.
Neuroscientists implanted artificial memories into slices of rat brain, they reported in Nature Neuroscience online. By jolting the rodent brain cells with electrical current, the researchers produced memory-like patterns of neuron activity that survived for around 10 seconds. This is the first time that researchers have created memory without a brain.
The overlap of green (glial cells) and purple (water channels embedded in the walls of those cells) show the tubes.
Your blood vessels aren’t the only network of tubes winding through your body. The lymph vessels, or lymphatics, shadow blood vessels wherever they go and collect waste from around the body, as well as shuttling around immune cells and performing other functions. But the lymphatics never make it to the brain, scientists were surprised to find some years ago. Some other, mysterious method for removing waste from the brain must exist.
In a new paper in Science Translational Medicine, a team of neuroscientists reports that they’ve discovered a system of tubes that encircle the blood vessels that feed the brain. The walls of these tubes are made up of spindly projections from brain cells called glia, that, in the same way that trees’ arching limbs form a tunnel over a road, arch around the blood vessels to form the tubes. And these tubes seem to drain the way lymphatics do, suggesting that they might be long-sought gutter of the brain.
So. Tired. From reading email.
A day of hard mental labor—writing emails, taking the SAT, competing in the national crossword competition—can leave you beat. But how, exactly, is that possible? You haven’t done any heavy lifting, at least not with your muscles.
Ferris Jabr at Scientific American MIND takes a crack at investigating this phenomenon, exploring the science on whether thinking really hard burns calories, or whether the exhaustion is coming from something else. He writes:
Although the average adult human brain weighs about 1.4 kilograms, only 2 percent of total body weight, it demands 20 percent of our resting metabolic rate (RMR)—the total amount of energy our bodies expend in one very lazy day of no activity.RMR varies from person to person depending on age, gender, size and health. If we assume an average resting metabolic rate of 1,300 calories, then the brain consumes 260 of those calories just to keep things in order. That’s 10.8 calories every hour or 0.18 calories each minute. (For comparison’s sake, see Harvard’s table of calories burned during different activities). With a little math, we can convert that number into a measure of power.
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.
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.
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. Read 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.
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]
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.
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: