Babies learn language at a high rate, much faster than adults. It only takes them a few months to understand basic words, and after a year they begin to articulate words on their own. Scientists have even suggested that language acquisition begins before birth, as the fetus can already hear by the sixth or seventh month of pregnancy and newborns prefer their mother’s voice to other female voices. Research published today in the journal Science Advances addresses this area and suggests that speech stimulation in prenatal stages from the mother’s voice already produces changes in the baby’s neural activity that contribute to newborns’ language processing learning: from before birth the baby’s brain begins to model itself from these first experiences with language to understand its native language.
In the final stages of pregnancy, the fetus can hear sounds from outside but is weakened. The uterus acts as a kind of filter that dampens frequencies above 600 Hertz: individual sounds are suppressed, only the melody and rhythm of speech are retained. Definitely enough for newborns to prefer their mother’s voice to others and turn to the language the surrogate mother spoke during pregnancy rather than other languages.
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Until now, it was not known how children’s brains were shaped by these first language experiences and whether this prenatal experience could actually improve their ability to learn language in the first stages of life. “It was still not clear how much babies learn from prenatal experiences,” admits study author Judit Gervain, researcher at the Center for Neuroscience at the University of Padua (Italy). “Previous studies, including studies from our laboratory, have shown that this prenatal experience is filtered [por los tejidos maternos] It effectively shapes babies’ ability to perceive language and shapes the brain mechanisms associated with language. What’s new about our study is that we show learning as it develops. “We found that the activity of the newborn’s brain changes in real time, even several minutes after hearing speech in the native language, that is, the language heard before birth,” explains the author.
The researchers used encephalography to analyze the neuronal activity of 33 newborns of French-speaking mothers. They placed caps with a dozen electrodes near brain areas associated with hearing and speech perception and monitored their activity. “We first measured activity at rest for three minutes. The babies then listened in seven-minute blocks to speech in three different languages: French, Spanish and English. Finally, resting activity was measured again for three minutes,” explain the authors. The speech stimuli were quiet recordings directed at an infant with sentences from the story “Goldilocks and the Three Bears” translated into the three languages.
By comparing resting states with cycles of linguistic stimulation, the researchers wanted to decipher whether exposure to language influences neural dynamics in the infant brain. “Plastic changes immediately following exposure to language can affect infants’ ability to learn about the sound patterns they hear. “We wonder whether exposure to language causes lasting changes in neuronal dynamics and thus supports learning and memory,” the authors explain. Another question to be answered was whether these plastic changes in the brain occur after exposure to all languages or only to the language heard in the prenatal stage. That is, if prenatal experiences already shape neural circuits in some way. “If prenatal experiences already have an influence, newborns can show stronger plastic changes after contact with language heard prenatally than after exposure to unknown languages,” say the researchers.
After conducting the studies, the scientists concluded in their article that “the electrophysiological activity of newborns shows wide-ranging temporal correlations.” [LRTC, por sus siglas en inglés] increased after language stimulation, particularly for language heard before birth, indicating the early emergence of brain specialization for native language.” LRTCs are a measure that, according to Gervain, indicates “how similar a signal, in this case that of brain activity, resembles itself on large time scales”. “We found that babies’ brain activity after stimulation with their native language is more similar to their previous state than before stimulation. So that’s a sign of learning,” says the scientist.
So when newborns are exposed to their mother’s language, the baby’s brain activity organizes itself so that the activity is repeated or similar over long periods of time. “We could say that it retains a certain kind of memory of its own reactions to previous events and that the same reactions become more frequent,” translates Gervain. Experiencing language in the prenatal stage can therefore begin to shape the brain and contribute to learning. “The results show that brain activity shows more “memory” of previous states in French, the language heard prenatally, but not in two unfamiliar languages. This shows learning the language that was heard before birth,” says Gervain.
Non-deterministic impact
What the research makes clear is that while their findings suggest that the prenatal period lays the foundation for broader language development, “its impact is not deterministic.” “It means that it supports and supports learning the same language. However, if the language the baby heard before birth is not the one it will learn after birth, for example due to adoption, moving, etc., the lack of prenatal experience does not have much detrimental effect. Newborns can learn languages to which they were not exposed prenatally in a typical and normal way,” emphasizes the researcher.
Jordi Costa Faidella, researcher at the Institute of Neuroscience at the University of Barcelona and at the Research Institute of Sant Joan de Déu, believes that this study “adds evidence to a booming field, such as that studying the effects of prenatal exposure to auditory stimulation.” the mother or ambient noises. In his opinion, the most innovative thing is the methodology used. “This study provides the idea that the learning with which the baby is born is very specific: the baby’s brain activity matches the mother’s language, the brain rhythm adapts to the mother’s rhythm,” explains Costa Faidella. The scientist emphasizes that this study, in which he did not participate, opens up possibilities for early interventions in babies at risk of having problems in language acquisition: “If plastic changes are already produced in the womb as a result of this exposure, can Interventions may be needed earlier in babies who are born at risk of future language-related problems. “For example, babies with low or high birth weight, who are more likely to suffer some delay in language acquisition,” suggests the researcher.
In practice, the importance of dealing with language is already recognized as a key element of neurological development. In the neonatology department of the Vall d’Hebron Hospital in Barcelona, which cares for premature babies, voices are usually used as a neurostimulation tool. “Especially the mother’s voice. We try to stimulate him with his voice when he is in the incubator,” says Fátima Camba, neonatologist in this service. They are aware of how important it is that these premature babies are also exposed to voice and speech before their time outside the womb: all this is key to neurological development, emphasizes the doctor. “If the baby is born prematurely, we try to arrange its development to resemble life in the womb, because we know that the external stimuli it receives are unsuitable for it and can affect it. Therefore, when a baby is born prematurely, we try to simulate the environment in the womb and look for a quiet environment where the mother talks to the baby in a way that is similar to what she would hear in the womb “, he explains.
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