There really is something special about a mother's voice, science confirms.

Children's brains respond more strongly to their mothers' voices than to the voices of strangers, even when heard for only a fraction of a second, according to a new study published May 16, in the journal Proceedings of the National Academy of Sciences.

hearing a mother's voice activates areas of the brain linked to rewards

"We know that hearing [their] mother's voice can be an important source of emotional comfort to children. Here, we're showing the biological circuitry underlying that," Daniel Abrams, an instructor of psychiatry and behavioral sciences at Stanford University School of Medicine in California and the lead author of the study, said in a statement.

In the study, the researchers did brain scans on 24 healthy kids, who were between ages 7 and 12. During the scans, each child listened to short clips (less than 1 second long) of nonsense words spoken by the child's biological mother, as well as clips spoken by two women the child did not know.

The children were able to identify their mothers' voices 97 percent of the time, even though the sounds were very brief and contained only nonsense words, the researchers found.

Indeed, a number of previous studies have shown that children prefer their mother's voices over other people's voices, the researchers wrote in the study. For example, even in the first days of life, newborns can identify their mother's voice among the voices of other women, research has shown.

But the results of the new study showed that hearing a mother's voice affected areas of the brain beyond those involved in listening. The researchers found that when children heard their mothers' voices, parts of the brain related to emotions, rewards and facial recognition lit up more than when the children heard the voices of women the kids did not know.

"The extent of the regions [of the brain] that were engaged was really quite surprising," Vinod Menon, a psychiatry professor at Stanford, said in statement.

Moreover, the involvement of so many areas of the brain may help explain why children are able to identify their mothers' voices so rapidly, the researchers said. Some researchers have suggested that because hearing a mother's voice activates areas of the brain linked to rewards, the brain becomes trained to identify her voice more quickly, in order to reap the rewards.

The researchers also looked at connectivity among these brain regions when the children heard the voices. Results showed that children with greater connectivity were better at communicating socially.

The patterns of connection in children who have good social-communication skills form a "neural fingerprint," the researchers wrote. In future studies, the investigators hope to use this "neural fingerprint" to study the brains of children who have trouble communicating socially, such as children with autism, the researchers said. 

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