| Статья про работу мозга при изучении второго языка |
| 1 | Significance The neuroplastic changes induced by learning a second language (L2) in adulthood open new perspectives for understanding brain function. The current study shows structural changes in the language network of Arabic native speakers who learned German intensively in two phases of 3 mo each. We found a marked change in the left-hemispheric lexical-semantic system and the right fronto-temporal pathway, accompanied by decreased connectivity in the corpus callosum during L2 learning, which occurred mainly in the second period of L2 acquisition. |
| 2 | The reduced interhemispheric connectivity suggests that the inhibitory role of the corpus callosum, relevant for native language processing, is reduced in the L2 learning phase. Our findings demonstrate a clear experience-dependent structural plasticity in the human brain during L2 learning. Abstract Adult second language (L2) learning is a challenging enterprise inducing neuroplastic changes in the human brain. |
| 3 | However, it remains unclear how the structural language connectome and its subnetworks change during adult L2 learning. The current study investigated longitudinal changes in white matter (WM) language networks in each hemisphere, as well as their interconnection, in a large group of Arabic-speaking adults who learned German intensively for 6 mo. We found a significant increase in WM-connectivity within bilateral temporal-parietal semantic and phonological subnetworks and right temporal-frontal pathways mainly in the second half of the learning period. |
| 4 | At the same time, WM-connectivity between the two hemispheres decreased significantly. Crucially, these changes in WM-connectivity are correlated with L2 performance. The observed changes in subnetworks of the two hemispheres suggest a network reconfiguration due to lexical learning. The reduced interhemispheric connectivity may indicate a key role of the corpus callosum in L2 learning by reducing the inhibition of the language-dominant left hemisphere. |
| 5 | Our study highlights the dynamic changes within and across hemispheres in adult language-related networks driven by L2 learning. Cognitive functions develop in parallel with the plastic adaptation of the brain (1-6). This suggests that the gray and white matter of the brain is altered by the acquisition of new skills and thus is modulated by lifelong experiences, such as the acquired native language (7). |
| 6 | Second language (L2) learning in adulthood is a complex task that requires the adaptation of multiple brain systems related to a wide range of novel tasks to be mastered. To date, changes associated with L2 learning were reported to extend beyond the brain regions of the native language network in the left hemisphere (8-10), with additional involvement of the right hemisphere (11, 12), as well as plasticity in the white matter connections between the two hemispheres (13, 14). |
| 7 | How these changes in the gray and white matter might develop during L2 learning is described in a model (15) called the Dynamic Restructuring Model (DRM). The DRM postulates three distinct phases of structural adaptation that depend on the quantity and quality of the language learning and language switching experience. In the earliest phase, L2 learning leads to changes in the gray matter areas that support the processing of the new language. |
| 8 | Next, in the intermediate consolidation phase, the white matter pathways connecting the language processing areas show a structural modulation. Finally, in the peak efficiency phase, the model predicts further changes in brain structure, including increased frontal white matter connectivity, leading to highly efficient L2 processing and language switching performance. However, longitudinal studies of white matter change in L2 learning in large samples of adults who have achieved proficiency beyond the beginner level are still lacking. |
| 9 | The present study aims to investigate different phases of longitudinal white matter changes within each hemisphere and across hemispheres, and to describe the brain mechanisms involved in L2 learning. L2 learning comprises the acquisition of a new vocabulary, which includes learning novel phonemes, phonetic categories as well as word meanings, in addition to a new grammar. At the behavioral level, it has been previously reported that lexical-semantic processing of newly learned words and simple grammar is relatively easy to acquire, and native-like performance can be achieved in L2 learners (16). |
| 10 | In contrast, it is more difficult for late L2 learners to perform real-time syntactic analysis, and they do not achieve automatic, highly proficient syntax processing until a late stage of learning (12, 16). At the neurofunctional level, brain imaging studies have shown that low proficient L2 learners have less overlap in brain activation between first and second language processing than high proficient L2 learners (17) and recruit additional brain areas in the right hemisphere (18). |
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