A recent study conducted at Stanford University School of Medicine has found that children’s brains are far more engaged and show wider activation when hearing their mother’s voice as opposed to those of other people. Findings indicate that this brain response can predict a child’s social communication ability.
Brain regions that respond more strongly to the mother’s voice extend beyond auditory areas to include those involved in emotion and reward processing, social functions, detection of what is personally relevant and face recognition.
Many of our social, language and emotional processes are learned by listening to our mom’s voice, said lead author Daniel Abrams, PhD, instructor in psychiatry and behavioral sciences. But surprisingly little is known about how the brain organizes itself around this very important sound source. We didn’t realize that a mother’s voice would have such quick access to so many different brain systems.
Many years of research have shown preferences of a child for their mother’s voices through physiological responses such as infants sucking harder on a dummy when they hear the sound of their mum’s voice compared to the voices of other women. However, the mechanism behind this preference has never been explored previously.
Nobody had really looked at the brain circuits that might be engaged, senior author Vinod Menon, PhD, professor of psychiatry and behavioral sciences, said. We wanted to know: Is it just auditory and voice-selective areas that respond differently, or is it more broad in terms of engagement, emotional reactivity and detection of salient stimuli?
The study looked at children’s brains scanned via MRI as they listened to short clips of the nonsense-word recordings, produced either by their own mother or by the control women. Children were able to identify their own mother’s voices with greater than 97 percent accuracy, even in very short clips less than a second long.
The brain regions that were more engaged by the voices of the children’s own mothers than by the control voices included auditory regions, such as the primary auditory cortex; regions of the brain that handle emotions, such as the amygdala; brain regions that detect and assign value to rewarding stimuli, such as the mesolimbic reward pathway and medial prefrontal cortex; regions that process information about the self, including the default mode network; and areas involved in perceiving and processing the sight of faces.
It has long been known that hearing a mother’s voice can be an important source of emotional comfort for children and this study shows the biological circuitry underlying that. Children with stronger degrees of connection between brain regions when hearing their mom’s voice also showed the strongest social communication ability, suggesting that increased brain connectivity between the regions is a physiological marker for greater social communication abilities in children.
These findings open up new avenues for investigating social communication deficits in children with disorders such as autism. These researchers are now planning another study focusing on individuals with autism, as well as further studies into adolescents’ responses to their mother’s voice and changes to these responses as people mature into adulthood.
Voice is one of the most important social communication cues, Menon said. It’s exciting to see that the echo of one’s mother’s voice lives on in so many brain systems.