How Bilingualism Affects Your Brain

This piece, by Onno Berkan, was published on 12/10/24. The original text, by Wang and Tao, was published by the Journal of Cognitive Neuroscience on 05/01/24.

This East China Normal University study investigated how the brains of bilingual people manage and switch between two languages. The study specifically looked at two key aspects: how different brain regions connect and work together (functional connectivity) and the physical neural pathways between these regions (structural connectivity).

The researchers conducted their experiment using a picture-naming task in which participants had to name objects in either Chinese or English. The language was indicated by colored boxes around the pictures—red for Chinese and blue for English.

The study found that:

1.  When bilinguals switch between languages, several key brain regions become active, primarily on the left side of the brain. These included areas responsible for executive control and language processing.

2.  The researchers discovered a specific information flow pattern in the brain during language switching. Information first entered a region called dACC/pre-SMA, which helps with attention and error monitoring. Then, it moves to the caudate nucleus, which acts as a relay station for language selection and switching. This area then formed bidirectional connections with the dorsolateral prefrontal cortex. This indicates that bilingual people show enhanced connection between frontal and subcortical regions.

3. Importantly, it was found that the relationship between the brain's physical connections and how these regions functionally work together isn't straightforward or linear. This suggests that the brain's structural and functional organization during bilingual language control is more complex than previously thought.

The research contributes to our understanding of how bilingualism affects the brain in several ways. Previous studies have shown that being bilingual can lead to changes in brain structure, including increased volume in certain regions. The study also aligns with existing models of how bilinguals control their languages, particularly the adaptive control and conditional routing models.

This research is particularly relevant as it helps us understand how the bilingual brain manages multiple languages and suggests that the relationship between brain structure and function is more complex than simple one-to-one connections. The findings support that bilingual experience shapes the brain's structure and functional dynamics, particularly concerning cognitive efficiency and aging. 

If this topic piques your interest, Neurotech will have a project investigating bilingualism and code-switching quite extensively using an EEG next semester, and it will be open to everyone!

In conclusion, this study provides valuable insights into how the bilingual brain works, showing that language control involves a complex network of brain regions working together in complex ways.

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