Anyone who’s ever watched a horror film will know that the sound of two clashing notes evokes a visceral response in most people. Among Western listeners there’s a strong preference for consonance, which exists even from infancy; consonance is the pleasing mixture of two tones, while dissonance is their clashing. (For a good example of both, see this video.) It’s controversial whether the same preferences exist in other cultures, but new research indicates the preferences might be wired in our brains.
The prevailing theory of music in the brain is that dissonant combinations share frequencies that are a bit too close. When these frequencies are perceived by the cochlea, the part of the inner ear that translates sounds to nerve impulses, they can’t be well distinguished. Because similar frequencies are processed next to one another on the cochlea, their nerve signals can interfere with one another. The perception is a grating effect, called “beating.” Read More
Our cognitive abilities tend to decline when we get older, as we have trouble remembering old facts and skills and learning new ones. But a little young blood reverses some ill effects of old age, at least in mice, researchers reported at the Society for Neuroscience conference last week.
Neuroscientist Saul Villeda and his team gave elderly mice infusions of blood from younger, sprightlier members of their species. The old mice fortified with young blood improved on learning and memory tasks, such as finding a platform submerged in water and getting conditioned (think Pavlov’s dogs) to fear situations associated with electric shocks.
When a brain-damaged person seems unresponsive, the uncertainty is excruciating. Is the person in a vegetative state, awake but not conscious, or are they minimally conscious, still retaining some shreds of awareness? Scientists can now distinguish between people in vegetative and minimally conscious states by measuring brain waves, a Belgian research team announced at the Society for Neuroscience conference last week, which could lead to a more clear-cut, objective way to make the diagnosis.
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.
We all knew the kid who couldn’t be pried away from her book—and the kid for whom each page was an exquisite torture. Why do people take to reading with such varying amounts of ease? A new study that looked at the differences in the brain development between children with different reading abilities may help answer the question. The researchers monitored subjects over a three-year period and found some interesting correlations between reading ability and neuronal wiring.
Kids are natural scientists, it turns out.
In an article published last week in Science, psychologist Alison Gopnik reviewed the literature about the way young children learn, and she finds that the way preschoolers play is very similar to the way scientists do experiments: Kids come up with general principles, akin to scientific theories, based on the data of their daily lives. Gopnik argues that the research should steer educators and policy makers away from more-regimented, dogmatic kinds of preschool instruction.
Some women always have men on the brain. And some women literally have men in their brains. A new study in PloS ONE found that quite a few female brains contain male DNA. This genetic material presumably passes into a mother while she is pregnant with a male fetus. Although we already knew that fetal cells can enter a mother’s body, until now, it was unknown whether the cells could pass into the brain as well, because the blood brain barrier normally blocks large molecules and foreign substances from entering the brain.
To explore the possibility of brain microchimerism—the presence of genetically distinct cells in a host’s body—researchers examined autopsy specimens from 59 deceased female subjects, who either had no neurological disease or had suffered from Alzheimer’s. The scientists found that 63 percent of the brains contained male cells distributed throughout the organ, and that this microchimerism did not fade away over time: the brain of one 94-year-old woman still contained male cells. And interestingly, the brains of subjects with Alzheimer’s disease were less likely to contain male DNA, and when they did, they generally had less of it than the healthy brains did.
We humans aren’t the most logical creatures. Take information processing: if we were perfect reasoners, we would absorb all the new facts we learn and use them to modify our view of the world. But while we do something like this with good news, bad news tends to go in one ear and out the other. While this good news / bad news effect gives you a more positive outlook on life, it can make you blindly optimistic, unprepared for the real consequences of medical problems or natural disasters.
Selfishness is good for us—thinking “me (and my relatives) first” lets humans ensure their survival and that of their genes. But generosity can be good, too; it binds humans into safe communities. So if both behaviors are beneficial, which one dominates? A new Nature paper suggests that it all comes down to timing: when we have to make a fast decision, we act more generously than when we have time to think about our choices.