Language lateralization shifts with learning by adults

Area of Science:

• Neuroscience
• Cognitive Science
• Psycholinguistics

Background:

• Language function is predominantly lateralized to the left hemisphere in most individuals.
• Brain imaging studies suggest language lateralization develops during childhood, potentially due to maturation or skill acquisition.
• The precise mechanisms driving these lateralization shifts remain under investigation.

Purpose of the Study:

• To investigate whether skill acquisition, independent of age-associated brain maturation, can alter language lateralization.
• To examine short-term changes in brain activity and lateralization patterns during the process of learning an unfamiliar language.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to scan adults learning a new language.
• Participants underwent three successive fMRI scans while being exposed to an unfamiliar language (Norwegian).
• Brain activation patterns were analyzed during auditory tasks involving language stimuli versus control stimuli (complex tones).

Main Results:

• Consistent activation was observed in the superior temporal gyrus (STG) in both hemispheres when participants were exposed to Norwegian sentences.
• With repeated exposure and learning of the unfamiliar language, activation within the STG became progressively more left-lateralized.
• These observed shifts in lateralization occurred rapidly, within the learning context of the study.

Conclusions:

• Language lateralization in the brain can be dynamically altered through the process of skill acquisition.
• Short-term learning experiences, independent of developmental maturation, can induce significant changes in language network lateralization.
• This finding highlights the brain's plasticity in response to new language learning.