MONTREAL - Hearing from Mom can be a source of comfort for little ones, but new research suggests her voice is capable of more than just soothing stress — it can noticeably impact the baby's brain shortly after birth.
Researchers in Quebec applied electrodes on the babies' heads and found that hearing Mom's voice can activate parts of the newborn's brain responsible for language learning.
While it's long been known that a baby reacts to a mother's voice at birth, what remained unknown was what was going on in the infant's brain, said lead researcher Maryse Lassonde of the University of Montreal's department of psychology and Sainte-Justine University Hospital Research Centre
For the small study, published in Cerebral Cortex, researchers looked at 16 full-term babies born at Sainte-Justine, including Lassonde's own granddaughter, Maika.Researchers recorded the mother's voice making the short "A" vowel sound, like in the French word "allo." They also recorded the research nurse's voice uttering the same sound, Lassonde said.
Within 24 hours of birth, each mom and baby were taken to a lab where the newborn's head was outfitted with a small net containing sponges in which electrodes were embedded.
While in the mother's arms and with the baby's heart rate and temperature being monitored, the newborn heard utterances of the "A" vowel sound by Mom or the nurse, Lassonde said. She said the baby's brain responded very strongly to the mother's voice, but they wanted to see what was going on in the brain circuits.
After finding the place in the brain where the signal was coming from, researchers discovered the mother "constantly elicited" the language comprehension areas of the brain in the left hemisphere of the brain, Lassonde said. Meanwhile, the nurse only stimulated the voice recognition system found in the brain's right hemisphere.
More important, a fraction of a second later, after having seen the signal in the language area, they detected signals in the motor speech area, Lassonde said.
"What it means is we saw a circuitry from the language to the expression of language right at birth, and this is elicited by the mother," she said in an interview Thursday. "It's as if the mother was the instigator of the development of the language in the baby's brain."
The same results were seen in all 16 babies.
Lassonde, who holds the Canada Research Chair in developmental neuropsychology, said the auditory system develops very early during pregnancy. The baby hears the mother's voice constantly whether she is talking to her little one or other people, she noted.
"She is the voice that the baby hears the most during the nine months of pregnancy and we believe that hearing the mother's voice really triggers a prenatal circuit of language development."
While mom's voice clearly has an impact, what about the dads?Lassonde said they recorded her son-in-law's voice mixed with another male voice, and that Maika reacted very strongly to her father's voice. But they haven't been able to do the computation to determine whether he triggered the language area of the brain.
When it comes to further research, Lassonde said one thing they would like to know is whether premature children have the same reaction to their mother's voice.
Even though they haven't been exposed as long as full-term babies to their mother's voice in utero, Lassonde said they're curious to know whether it will also trigger language circuits.
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