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BUCKINGHAMSHIRE: The brains of young babies are much more attuned to human voices and emotions than previously thought, according to new research.
Through a series of experiments it was found that even when asleep, infants can extract subtle information from human speech, such as a range of voices and emotions, at a remarkably early stage of development. The researchers claim that the study's conclusions fundamentally advance our understanding of infant development, and could have an impact on brain disorder research.
"Our results suggest that the infant temporal cortex is more mature than previously reported; it is a rare demonstration that specialised areas exist in the brain very early in development," said lead author Evelyne Mercure, of University College London (UCL) of the study published in Current Biology.
"It is probably because the human voice is such an important social cue that the brain shows an early specialisation for its processing," added co-author Anna Blasi, also from UCL.
Measuring a infant's response
Earlier evidence has shown that infants are perceptive to human speech, indicating that newborns are more receptive to their mother's voice. Infants can also tell the difference between the voices of not only men and women, but also children and adults.
But a new collaborative study involving researchers at Birbeck College and Kings College in the UK revealed in far greater level of the response in babies' brains. Instead of just their mother's voice, infants are receptive to a range of human noises and emotions.
To find this information, researchers used functional magnetic resonance imaging (fMRI) in order to record the brain responses in sleeping babies as they were presented with emotionally neutral, positive, or negative speech from humans, as well as non-vocal environmental sounds.
Responding to sad sounds
The team found that three- to seven-month-old infants had far more brain activity when they heard emotionally neutral sounds, such as sneezing, coughing or yawning, than when they heard familiar sounds like those of toys or water.
This activity was found in an area of the temporal lobe, previously known in adults as where the brain processes human speech.
On top of this, babies had a greater response when played sad sounds to neutral ones, this time in a part of the brain that is used for processing emotion in adults. "This may represent the very first step in social interactions and language learning," said Blasi.
Increased understanding of disorders?
As well as increasing our understanding of the development of babies' brains, the study also calls into question what happens in this part of the brain when babies go on to develop behavioural or neuropsychological disorders where social communication is affected, such as autism and schizophrenia.
This leads on to further study which may shed light on the proliferation of such disorders. "We are now carrying out more research in this area to help us understand how differences in brain development arise, if we can use these to accurately identify babies who will go on to suffer from disorders such as autism, and if they can be used to help measure the effectiveness of interventions," added co-author Declan Murphy from UCL.
Biomedical scientist Victoria Drummond-Hay of Kings College London in the UK, who was not involved in the study, said that the results are important because they, "show a fundamentally different level of infant development than was previously thought".
