Your mother's soothing voice may do far more than you'd expect, a new study suggests.

Researchers from the Stanford University School of Medicine discovered that for little kids, hearing their mother's voice actually activates and lights up many different regions in the brain.

These regions are involved in reward processing, emotions, facial recognition, and detection of what is subjectively relevant, the study said.

This incredible neurological reaction, however, was reserved for mom's voice alone. Kids' brain regions were more affected by the voice of their mothers than by voices of other women, scientists said.

Daniel Abrams, one of the authors of the study and an instructor in behavioral sciences at the university, said most of our language, emotional, and social processes are learned by listening to our mothers. Despite this, scientists did not understand how the brain arranges itself around the sound source.

But with the results of the new study, Abrams said they did not realize that the voice of a mother would have such quick access to so many different brain regions.

Preference For Mom's Voice

Decades of research have shown that kids favor their mom's voice over others.

In a classic study, scientists found that babies sucked harder on a pacifier whenever they heard the sound of their mother's voice, compared to the voice of other women.

In 2014, a pacifier-activated music player (PAM), which plays the mother's voice when the baby sucks correctly, proved that it could help babies feed themselves the right way. Babies who used PAM eventually ate twice as fast as the babies who did not use the device.

Until now, the science behind this preference has not been identified.

"Nobody had really looked at the brain circuits that might be engaged," said Professor Vinod Menon, senior author of the study.

Menon said he and his colleagues wanted to know whether it was just the voice-selective areas and auditory regions that respond differently or whether there was something more in the aspects of emotional reactivity.

The research team then examined 24 kids who were aged 7 to 12 years old. All kids had IQs of at least 80, had no developmental disorders, and were raised by their biological moms.

Parents of the participants had to answer a questionnaire about their child's ability to relate and interact with others.

The parents had to record three nonsense words, while two mothers whose kids were not involved in the study also recorded three nonsense words.

Menon said they chose nonsense words because they did not want to use words that had meaning, which could trigger a different set of brain circuitry.

As the kids listened to the recordings of both their mom's voices and other women's voices, their brains were scanned through the use of MRIs.

In the end, researchers said the kids identified the sound of their mom's voice with more than 97 percent accuracy.

The kids' brain regions that were engaged by their mothers' voices were the following:
- auditory region, including the primary auditory cortex;
- the amygdala and other regions that regulate emotions;
- regions that assign value and detect rewards, including the medial prefrontal cortex;
- regions that process information about the self;
- regions that perceive and process the sight of faces.

Kids whose brains displayed strong degrees of connection between these brain regions as triggered by their mom's voice also had the strongest ability to communicate, suggesting that heightened brain connectivity marks greater communication abilities.

Why The Study Is Important

The details of the study, which are featured in the journal Proceedings of the National Academy of Sciences, are important for investigating social communication deficits in kids, such as those with autism and other disorders.

Menon said they plan to conduct similar research in kids with autism. They are also in the process of studying how adolescents respond to their mom's voice to determine whether the response of the brain changes as people grow up into adulthood.

Photo : Richard Leeming | Flickr

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