Sentence translation in proficient bilinguals: a direct electrostimulation brain mapping

Area of Science:

• Neuroscience
• Cognitive Science
• Neurolinguistics

Background:

• Bilingualism involves complex language processing.
• Understanding language function localization is crucial for neurosurgery, especially in bilingual patients.
• Direct cortical stimulation is a method to map brain functions during surgery.

Purpose of the Study:

• To investigate cortical areas involved in translation in bilingual individuals.
• To determine if translation engages distinct brain regions compared to other language tasks.
• To assess the utility of translation tasks for functional brain mapping in neurosurgery.

Main Methods:

• Direct cortical electrostimulation was applied to seven bilingual patients undergoing brain tumor resections.
• Patients performed naming, reading, and translation tasks (second to native language) in both languages.
• Electrostimulation effects on language performance were recorded to identify functional sites.

Main Results:

• 26 language functional sites were identified, affecting naming or reading.
• Only 3 sites showed interference with translation, all in frontal regions.
• No cortical site was exclusively involved in translation; translation sites were rarely on the convexity.

Conclusions:

• Cortical translation function appears less localized and less distinct than other language functions like naming and reading.
• Translation tasks provide limited additional information for cortical brain mapping in bilingual neurosurgical patients.
• Subcortical stimulation might be more effective for detecting translation-specific interference.