Practice builds brain connections for babies learning language, how to speak

July 11, 2006
A six-month-old baby listens to sounds while a magnetoencephalograph measures the baby's brain activity
A six-month-old baby listens to sounds while a magnetoencephalograph measures the baby's brain activity.

Experience, as the old saying goes, is the best teacher. And experience seems to play an important early role in how infants learn to understand and produce language.

Using new technology that measures the magnetic field generated by the activation of neurons in the brain, researchers tracked what appears to be a link between the listening and speaking areas of the brain in newborn, 6-month-old and one-year-old infants, before infants can speak.

The study, which appears in this month's issue of the journal NeuroReport, shows that Broca's area, located in the front of the left hemisphere of the brain, is gradually activated during an infant's initial year of life, according to Toshiaki Imada, lead author of the paper and a research professor at the University of Washington's Institute for Brain and Learning Sciences.

Broca's area has long been identified as the seat of speech production and, more recently, as that of social cognition and is critical to language and reading, according to Patricia Kuhl, co-author of the study and co-director of the UW's Institute for Brain and Learning Sciences.

"Magnetoencephalography is perfectly non-invasive and measures the magnetic field generated by neurons in the brain responding to sensory information that then 'leaks' through the skull," said Imada, one of the world's experts in the uses of magnetoencephalography to study the brain.

Kuhl said there is a long history of a link in the adult brain between the areas responsible for understanding and those responsible for speaking language. The link allows children to mimic the speech patterns they hear when they are very young. That's why people from Brooklyn speak "Brooklynese," she said.

"We think the connection between perception and production of speech gets formed by experience, and we are trying to determine when and how babies do it," said Kuhl, who also is a professor of speech and hearing sciences.

The study involved 43 infants in Finland -- 18 newborns, 17 6-month-olds and 8 one-year olds. Special hardware and software developed for this study allowed the infants' brain activity to be monitored even if they moved and captured brain activation with millisecond precision.

The babies were exposed to three kinds of sounds through earphones -- pure tones that do not resemble speech like notes played on a piano, a three-tone harmonic chord that resembles speech and two Finnish syllables, "pa" and "ta." The researchers collected magnetic data only from the left hemisphere of the brain among the newborns because they cannot sit up and the magnetoencephalography cap was too big to securely fit their heads.

At all three ages the infants showed activation in the temporal part of the brain, Broca's area, that is responsible for listening and understanding speech, showing they were able to detect sound changes for all three stimuli. But the pure perception of sound did not activate the areas of the brain responsible for speaking. However, researchers began seeing some activation in Broca's area when the 6-month-old infants heard the syllables or harmonic chords. By the time the infants were one-year old, the speech stimuli activated Broca's area simultaneously with the auditory areas, indicating "cross-talk" between the area of the brain that hears language and the area that produces language, according to Kuhl.

"We think that early in development babies need to play with sounds, just as they play with their hands. And that helps them map relationships between sounds with the movements of their mouth and tongue," she said. "To master a skill, babies have to play and practice just as they later will in learning how to throw a baseball or ride a bike. Babies form brain connections by listening to themselves and linking what they hear to what they did to cause the sounds. Eventually they will use this skill to mimic speakers in their environments."

This playing with language starts, Kuhl said, when babies begin cooing around 12 weeks of age and begin babbling around seven months of age.

"They are cooing and babbling before they know how to link their mouth and tongue movements. This brain connection between perception and production requires experience," she said.

Co-authors of the study were Yang Zhang of the University of Minnesota, Marie Cheour of the University of Miami and Helsinki University Central Hospital, and Samu Taulu and Antti Ahonen of Elekta Neuromag Oy in Findland. The National Institutes of Health, the National Science Foundation, the Talaris Research Institute and the Apex Foundation, the family foundation of Bruce and Jolene McCaw, supported the research.

Source: University of Washington

Explore further: The emerging science of human screams

Related Stories

The emerging science of human screams

July 16, 2015

Our noisy world is no match for a screaming infant. An airplane could be flying by as a house party rages on downstairs while a literal cat fight takes place outside, and still a wailing baby will win your attention. One ...

Songbirds have a thing for patterns

June 25, 2015

You might think that young children would first learn to recognize sounds and then learn how those categories of sounds fit together into words. But that isn't how it works. Rather, kids learn sounds and words at the same ...

Microsoft Research project can interpret, caption photos

May 29, 2015

If you're surfing the web and you come across a photo of the Mariners' Felix Hernandez on the pitchers' mound at Safeco Field, chances are you'll quickly interpret that you are looking at a picture of a baseball player on ...

Thinking alike changes the conversation

May 19, 2015

As social creatures, we tend to mimic each other's posture, laughter, and other behaviors, including how we speak. Now a new study shows that people with similar views tend to more closely mirror, or align, each other's speech ...

Recommended for you

Researchers build bacteria's photosynthetic engine

July 29, 2015

Nearly all life on Earth depends on photosynthesis, the conversion of light energy into chemical energy. Oxygen-producing plants and cyanobacteria perfected this process 2.7 billion years ago. But the first photosynthetic ...

Yarn from slaughterhouse waste

July 29, 2015

ETH researchers have developed a yarn from ordinary gelatine that has good qualities similar to those of merino wool fibers. Now they are working on making the yarn even more water resistant.

Scientists unlock secrets of stars through aluminium

July 29, 2015

Physicists at the University of York have revealed a new understanding of nucleosynthesis in stars, providing insight into the role massive stars play in the evolution of the Milky Way and the origins of the Solar System.

Studies reveal details of error correction in cell division

July 29, 2015

Cell biologists led by Thomas Maresca at the University of Massachusetts Amherst, with collaborators elsewhere, report an advance in understanding the workings of an error correction mechanism that helps cells detect and ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.