Neuropsychologists have discovered how learning a second language changes connections in the brain
When adults learn a second language, there are significant changes in the brain's interneuronal connections. This has been shown by a new study in Germany involving Syrian refugees.
The work, which was published in the journal Proceedings of the National Academy of Sciences, was conducted by a team of neuropsychologists from the Max Planck Institute for Cognitive and Brain Sciences in Leipzig, Germany.
As part of the project, the scientists organized intensive language courses for Arabic-speaking people who were forced to move to Germany. With the help of magnetic resonance imaging, the researchers observed the transformations of interneuron connections, thanks to which the foreigners began to understand and use their new language for communication.
The researchers used an advanced MRI tractography technique to track the course and structural changes in the brain's conductive pathways. Over a six-month period, the neuropsychologists studied and methodically compared high-resolution MRI images of 59 Arabic-speaking participants who were examined at the beginning of the language intensives, as well as at three and six months, i.e., at the middle and end of the course.
Analysis of the images showed increased inter-neuronal connections in the language network in the white matter of the brain and the involvement of additional areas in the right hemisphere during the process of learning a second language.
"Connections between language brain areas in both hemispheres increased as learning progressed. Learning new words strengthened lexical and phonological subnetworks in both hemispheres, especially in the second half of the training program, during the consolidation phase," said Xuehu Wei, one of the authors of the paper.
Interestingly, in parallel, neuropsychologists found a decrease in the connections between the right and left halves of the brain, which connects the corpus callosum (corpus callosum). According to the researchers, this reduction in interhemispheric connections suggests that when learning a second language, the control of the left hemisphere, where language function is centered, over the right hemisphere is weakened. This frees up additional resources in the right hemisphere for learning the new language.
The authors noted that the dynamic changes in brain connectivity correlated directly with improved performance on the Goethe Institute's language test.
Overall, the study showed how the adult brain adapts to new cognitive demands by modulating structural connections within and between hemispheres. The scientists emphasized that the new data helped to better understand how people acquire languages and how the brain functions in doing so.