[ad_1]
Unlike adults, where speech and speech understanding are already clearly linked to the left hemisphere, children use both hemispheres for these tasks. This is fortunate because in the case of an early injury to the left hemisphere, the right can still take on the role.
Babies and young children’s brains have superpowers that we lose later, say neuroscientists at Georgetown University Medical Center. While in adults, most circumscribed functions are associated with a specific region of one or the other hemisphere of the brain, children use both the right and left hemispheres to perform the same task. This observation helps explain why children recover much more successfully from brain injuries than adults.
A study published in the Proceedings of the National Academy of Sciences (PNAS), a journal of the US Academy of Sciences, focuses on a specific function, the use of language, and its main finding is that understanding language, more precisely interpreting heard sentences, affects both hemispheres of children. mobilizes. The result is in line with the findings of earlier research led by Elissa L. Newport, a professor of neurology at Georgetown.
“This is very good news for children who have suffered a brain injury for some reason,” says Newport, who is also director of the Center for Brain Plasticity and Recovery, a joint venture between Georgetown University and the National Network of MedStar Rehabilitation. – Using the two hemispheres of the brain together provides the opportunity to compensate for the area lost during the nerve injury. For example, if the left hemisphere is hit by a newborn stroke, which can occur immediately after birth, the child will use the right hemisphere to learn the use of language. With cerebral palsy confined to one hemisphere of the brain [mozgáskiesést okozó agysérüléssel] Children who are born can develop the necessary cognitive skills in the other hemisphere of the brain. Our experiments shed light on how this is possible. “
The study solves a mystery that has long troubled doctors and neuroscientists, Newport said. It has long been known that in adults, almost without exception, sentence processing is only possible in the left hemisphere, as evidenced by brain imaging procedures and language disorders in patients with left hemisphere strokes.
However, in children, injury to either hemisphere of the brain does not usually cause permanent language impairment, and language use is restored in many patients whose left hemispheres have been severely damaged.
This suggests that in the early stages of life, language function is still divided between the two hemispheres of the brain. However, until now, traditional imaging procedures have not shed light on this feature. “It was not clear whether the strong leftist dominance of the language already existed at birth or whether it developed gradually during development,” Newport explains.
In the smallest, both hemispheres are active.
Now, with a more complex analysis of functional magnetic resonance imaging (fMRI) recordings, the researchers found that the left-right pattern of specialization in adults is not yet seen in young children, so both hemispheres are involved in language processing during early development. The brain networks that connect different tasks to one or another hemisphere of the brain begin to form in children, but their development only ends around 10-11 years.
A total of 39 healthy children ages 4 to 13 participated in the research. They were examined at another institution, the Children’s National Medical Center, by research physicians working with the Newport team, William D. Gaillard and Madison M. Berl. In the Newport laboratory, studies were conducted in 14 adult participants and then a comparative analysis of the results was performed in children and adults. The participants were assigned a familiar sentence comprehension task, and to solve it, they all followed the fMRI activation pattern in their two hemispheres. The researchers compared the age groups 4-6, 7-9, 10-13, and 18-29 in terms of location of language-activated brain areas. The result of the analysis for each voxel (spatial pixel, that is, a small volume of the brain) was the percentage of participants in whom linguistic processing resulted in significant activation in that voxel. An additional whole brain scan was designed to explore areas of the brain whose language activation was age dependent.
The results showed that, although at the group level, young children already have a predominance of left-hand language activation,
in the youngest age group, the corresponding right hemispheres of the brain also showed obvious activation.
(In adults, the same areas were activated during completely different tasks, such as processing the emotions expressed by sound. In young children, the relevant areas of both hemispheres of the brain were involved in processing the intellectual and emotional content of speech) .
Newport believes that “the higher level of activation of the right hemisphere in the sentence processing task and the slow deterioration of this activation during development reflect not only an age-dependent change in sentence comprehension strategies, but also a change in the neural distribution of linguistic functions “. it would be a way for his group to do the same analysis with even younger children, “we would experience even greater functional participation of the right hemisphere in language processing than what we saw among our youngest participants, ages 4-6.”
Our data show that the right hemisphere is normally involved in language processing during early childhood, and this opens the possibility of maintaining and developing linguistic function within the right hemisphere in the event of a left hemisphere injury. Newport summarized.
To further evade theory, the researcher and her group are now working with adolescents and young adults who suffered severe left hemisphere strokes at birth.
[ad_2]
