Archive for February 2012
Researchers at the RIKEN-MIT Center for Neural Circuit Genetics have discovered an answer to the long-standing mystery of how brain cells can both remember new memories while also maintaining older ones.
They found that specific neurons in a brain region called the dentate gyrus serve distinct roles in memory formation depending on whether the neural stem cells that produced them were of old versus young age.
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Few of our ancestors have been so thoroughly poked and prodded as Neolithic Tyrolean Iceman “Ötzi,” discovered melting out of an Alpine glacier in 1991. Researchers have probed his stomach and bowels for traces of his last meal and analyzed his teeth for cavities. Now, an international team has sequenced his entire genome, and it turns out Ötzi still has some surprises in store.
Earlier computer scans had revealed Ötzi’s severe arteriosclerosis, or hardening of the arteries. But the new analysis shows that Ötzi had a genetic predisposition to the condition, despite the fact that as a hunter-gatherer he had none of what are currently believed to be the relevant risk factors, such as being overweight, getting too little exercise, and smoking or drinking. “This new data suggests that we might be less able to prevent arteriosclerosis than we believed,” notes cardiologist and mummy expert Gregory Thomas of the University of California, Irvine, who was not involved in the new work.
Doctors struggle to keep squirming children still for long scans. Now, thanks to faster magnetic resonance imaging (MRI), they may no longer have to worry about keeping their patients still for so long. The above image of the blood flow through the heart of a 6-year-old with a congenital heart defect was acquired in 10 minutes rather than an hour, as with traditional MRI.
Credit: Michael Lustig, Shreyas Vasanawala, Marcus Alley
Imagine a piece of technology that would let you control an apparatus simply by thinking about it. Lots of people, it turns out, have dreamed of just such a system, which for decades has fired the imaginations of scientists, engineers, and science fiction authors. It’s easy to see why: By transforming thought into action, a brain-machine interface could let paralyzed people control devices like wheelchairs, prosthetic limbs, or computers. Farther out in the future, in the realm of sci-fi writers, it’s possible to envision truly remarkable things, like brain implants that would allow people to augment their sensory, motor, and cognitive abilities.
That melding of mind and machine suddenly seemed a little less far-fetched in 1999, when John Chapin, Miguel Nicolelis, and their colleagues at the MCP Hahnemann School of Medicine, in Philadelphia, and Duke University, in Durham, N.C., reported that rats in their laboratory had controlled a simple robotic device using brain activity alone. Initially, when the animals were thirsty, they had to use their paws to press a lever, thus activating a robotic arm that brought a straw close to their mouths. But after receiving a brain implant that recorded and interpreted activity in their motor cortices, the animals could just think about pressing the lever and the robotic arm would instantly give them a sip of water.
llustration: Bryan Christie Design
Fruit bats in Guatemala are hosting a novel subtype of influenza A virus, according to a study published today in the Proceedings of the National Academy of Sciences.
The virus — designated H17 — appears to have diverged from known influenza viruses long ago, shedding light on their evolution. Therefore, it seems to pose no immediate threat to humans. However, it is similar enough to other subtypes that genetic exchange with them could pose a risk. “We can’t say don’t worry about it, nor can we say it’s not dangerous. We just don’t know yet,” says study co-author Ruben Donis, chief of molecular virology and vaccines in the influenza division at the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia.
Donis and his colleagues are now testing bats in South America, Africa and Asia to document the geographical distribution of influenza — the first step towards determining whether bats are a reservoir behind outbreaks in humans
Jaroslav Flegr is no kook. And yet, for years, he suspected his mind had been taken over by parasites that had invaded his brain. So the prolific biologist took his science-fiction hunch into the lab. What he’s now discovering will startle you. Could tiny organisms carried by house cats be creeping into our brains, causing everything from car wrecks to schizophrenia?
NO ONE WOULD accuse Jaroslav Flegr of being a conformist. A self-described “sloppy dresser,” the 53-year-old Czech scientist has the contemplative air of someone habitually lost in thought, and his still-youthful, square-jawed face is framed by frizzy red hair that encircles his head like a ring of fire.
Certainly Flegr’s thinking is jarringly unconventional. Starting in the early 1990s, he began to suspect that a single-celled parasite in the protozoan family was subtly manipulating his personality, causing him to behave in strange, often self-destructive ways. And if it was messing with his mind, he reasoned, it was probably doing the same to others.