Petting feels good. You can see it in a cat’s slowly closing eyes or the contented panting of a dog getting his belly rubbed. In fact, all mammals enjoy being caressed, including humans. Researchers looked at this phenomenon in lab mice and found that stroking stimulates a very specific set of neurons that have to do with hair.
Some sensory neurons are relatively non-discriminatory. They respond to touch, temperature and pretty much anything that comes into contact with the skin. A few years back, researchers identified a rare type of neuron called MRGPRB4+, which is linked specifically to hair follicles. In lab tests on a patch of mouse skin, these neurons didn’t respond to a single stimulus. But with live mice the researchers got much more promising results, published in Nature on Wednesday.
An oligodendrocyte—the type of cell that manufactures myelin.
At first, the infants seem to be progressing normally. But it soon turns out they may have vision or hearing problems, and when the time comes to lift their heads, the milestone comes and goes. It often gets worse from there. Children with the rare Pelizaeus–Merzbacher disease, like others who lack the usual insulating sheaths on their neurons, have trouble controlling their muscles, and often develop serious neurological and motor problems early in life. There is no cure for the genetic disorder. Nor is there a standardized treatment.
PMD, as it’s called, and related diseases are some of the leading candidates for potential treatment with stem cells. The idea is that if stem cells that produce the missing insulator, the fatty substance called myelin, can be successfully implanted in the brains of patients, perhaps they will pitch in what the patient’s native cells cannot.
What’s the News: When prions or amyloids make the news, it’s usually because they cause mad cow disease or Alzheimer’s—prions, after all, cause any proteins they touch to become as misfolded as they are, and amyloids, which are large clumps of wadded-together proteins, can jam the workings of cells.
But a new study in Cell suggests that a prion-like protein that forms amyloids has a normal, vital function in the brain. Far from being a memory destroyer, this protein, called CPEB, is necessary for long-term memory in fruit flies.
The many-times-magnified photos of the Nikon Small World photomicrography contest entrance us year after year, with mesmerizing close-ups of nature’s microscopic marvels. Now, in the first Small World in Motion movie competition, we get to see the world’s wee wonders in action. The three winning films and eleven honorable mentions chronicle circulating blood, budding yeast, gestating eggs, and more.
First Place: This time-lapse video, at 10x magnification, traces the path of ink injected into an artery of a three-day-old chick embryo. As the ink spreads through the chick’s vascular system, the branching blood vessels and beating heart become clearly visible.
A protein tangle in an Alzheimer’s-afflicted neuron
Exactly how Alzheimer’s disease proliferates through the brain, overtaking one region after another, has eluded scientists. As the disease progresses, tau—a malformed protein that forms snarls and tangles inside neurons—shows up in more and more brain areas. Researchers have wondered whether tau, and the disease, are working their way out from a single area of origin or mounting numerous, distinct attacks on vulnerable parts of the brain. Two new studies in mice provide strong support for the first idea: Tau seems to pass from affected cells to their neighbors, spreading much the same way a virus or bacteria infection would.
Party hats out, everyone! Stephen Hawking turned 70 years old yesterday, 49 years after being told he had fewer than four left to live.
The Cambridge professor suffers from a motor neuron disease related to Lou Gehrig’s disease that has gradually taken from him his ability to move, feed himself, and speak, except through a synthesizer that he operates using a cheek muscle (unfortunately, his control of that muscle is also fading). But despite these handicaps, he has survived to an incredible ripe old age—the average for an Englishman is currently 77.2—and has continued his work as a cosmologist and physicist throughout. How has he managed to live so much longer than expected? Read More
The colors that letters and numbers appear to a synesthete
What’s the News: For most of us, our senses stay relatively separate: that is, we hear what we hear and see what we see. People with synesthesia, however, actually see words as colors, taste a particular flavor when they hear a familiar song, or experience other strong, automatic linkages between senses. The neurological underpinnings of the condition—how the brain connects two usually distinct senses—have remained a mystery. But researchers have now found a possible cause, they reported yesterday: neurons in the area responsible for the second sensation, such as the color that goes with the word, may be unusually excitable.
Neurons damaged by Parkinson’s disease
What’s the News: Scientists have reversed Parkinson’s disease-like brain damage and motor problems in mice and rats using neurons grown from human embryonic stem cells. The new technique, described online in Nature earlier this week, brings scientists closer to similar treatments for people with Parkinson’s.
What’s the News: Trouble sticking to your diet? It may not be entirely your fault. Scientists, reporting in the journal Cell Metabolism, have now learned that when you starve yourself of calories, your brain cells also starve, causing your neurons to begin eating parts of themselves for energy. The self-cannibalism, in turn, cranks up hunger signals. This mouse study may lead to better treatments for human obesity and diabetes.
What’s the News: Scientists have built a brain implant that can restore lost memories and reinforce new ones. The implant, tested in a recent study in rats, brings back a memory by recording and replaying the electrical activity of neurons in a part of the hippocampus, the brain’s long-term memory center. While the device is far from ready for use in humans, it’s an important step toward memory-boosting implants that could one day help patients who have developed dementia or suffered a stroke.