Palsticité du développement cérébral chez le nouveau-né

Babies can spot language, even when it’s not spoken.

Babies are as primed to learn a visual language as they are a spoken one. That’s the conclusion of research presented here today at the annual meeting of AAAS, which publishes Science. Parents and scientists know babies are learning sponges that can pick up any language they’re born into. But not as much is known about whether that includes visual language. To find out whether infants are sensitive to visual language, Rain Bosworth, a psychologist at the University of California, San Diego, tracked 6-month-olds’ and 1-year-olds’ eye movements as they watched a video of a woman performing self-grooming gestures, such as tucking her hair behind her ear, and signing. The infants watched the signs 20% more than the 1-year-old children did. That means babies can distinguish between what’s language and what’s not, even when it’s not spoken, but 1-year-olds can’t. That’s consistent with what researchers know about how babies learn spoken language. Six-month-olds home in on their native language and lose sensitivity to languages they’re not exposed to, but by 12 months old that’s more or less gone, Bosworth says. The researchers also watched babies’ gazes as they observed a signer “fingerspelling,” spelling out words with individually signed letters. The signer executed the fingerspelling cleanly or sloppily. Again, researchers found the 6-month-old babies, who had never seen sign language before, favored the well-formed letters, whereas the 12-month-olds did not show a preference. Together that means there’s a critical developmental window for picking up even nonverbal languages. As 95% of deaf children are born to hearing parents, they are at risk for developmental delays because they need that language exposure early on, the scientists say.

 

Babies can recover from strokes (AVC in french).

Strokes are common in old age, but these devastating events also strike babies. That’s likely because birth is stressful and particularly hard on the body’s blood vessels and circulation. But unlike adults, babies who suffer a stroke in the area of the brain that deals with language retain the ability to communicate. In new work presented here yesterday at the annual meeting of AAAS, which publishes Science, researchers found that as teenagers, individuals who experienced strokes around the time of birth are able to understand language as well as their healthy siblings. To find out how adults who had strokes as infants compensated for such severe brain damage, the team imaged their brains while they listened to sentences read forward and backward. In healthy adults, the test causes language processing areas on the left side of the brain to light up with activity (pictured above on the left). In the stroke survivors, who had lost brain tissue in this region, the activity had shifted to an area in the right hemisphere that’s the mirror image of the normal language region (above, right). This right hemisphere region is almost never used for understanding language in healthy people, and adults who have had a stroke do not enlist it for speech processing. The researchers suspect that the infants benefit from a unique window during development when the brain is flexible enough to make these accommodations. Figuring out what allows for that elasticity may one day help adult stroke survivors regain the ability to speak and understand language, the researchers say.

 

Cognitive Capacity of Very Young Children

Children between 2 years, 6 months old and 3 years, 2 months old correctly discriminate the relative number of objects in two rows; between 3 years, 2 months and 4 years, 6 months they indicate a longer row with fewer objects to have "more"; after 4 years, 6 months they again discriminate correctly. The discriminative ability of the younger children shows that the logical capacity for cognitive operations exists earlier than previously acknowledged.