Assessing multilingual speakers' language processing through functional near-infrared spectroscopy (fNIRS).

Area of Science:

• Neuroscience
• Cognitive Science
• Psycholinguistics

Background:

• Multilingualism involves managing multiple languages within a single cognitive system.
• Research on brain activation in multilinguals using functional near-infrared spectroscopy (fNIRS) is limited.
• Understanding the neural basis of processing three or more languages is a growing area of interest.

Purpose of the Study:

• To investigate prefrontal brain activations in neurotypical multilingual individuals using fNIRS.
• To explore how different language systems (native, first, second) are processed in the brain.
• To identify specific brain regions involved in multilingual language processing.

Main Methods:

• Utilized functional near-infrared spectroscopy (fNIRS) to measure brain activity.
• Employed a picture-naming task involving native, first (Urdu), and second (English) languages.
• Recruited 26 right-handed multilingual participants from four major provinces of Pakistan.

Main Results:

• Demonstrated significant activation in the right prefrontal cortex alongside left laterality in multilingual adults.
• Observed increased activation in specific brain regions indicating a heavier cognitive load when processing English compared to native or first languages.
• Identified significant activation patterns in channels correlating with cognitive load during language tasks.

Conclusions:

• The right dorsolateral prefrontal cortex and right medial prefrontal cortex are implicated in language processing.
• Multilingual language processing involves both left and right prefrontal cortical regions.
• Peripheral activation in the brain during word retrieval, processing, and production is a plausible aspect of multilingualism.