Tracking the microstructural properties of the main white matter pathways underlying speech processing in...

Area of Science:

• Neuroscience
• Cognitive Science
• Linguistics

Background:

• Professional simultaneous interpreters (SIs) offer insights into experience-dependent brain properties due to high linguistic and cognitive demands.
• The impact of intensive adult language training on white matter microstructure in language pathways remains largely unknown.

Purpose of the Study:

• To investigate microstructural white matter changes in language-related pathways in professional SIs compared to multilingual controls.
• To explore the relationship between simultaneous interpreting and the organization of white matter supporting speech and language processing.

Main Methods:

• Utilized automated probabilistic tractography and deterministic manual dissection to analyze white matter microstructure.
• Compared the inferior longitudinal fasciculus (ILF), uncinate fasciculus (UF), and arcuate fasciculus (AF) in professional SIs and controls.
• Examined fractional anisotropy (FA) and radial diffusivity (RD) as indicators of white matter integrity.

Main Results:

• Automated tractography revealed reduced mean FA and increased RD in the left hemisphere fiber tracts of SIs.
• SIs showed reduced mean FA in the bilateral arcuate fasciculus (AF).
• Manual dissection indicated this effect was specific to the anterior AF segment, with increased mean RD; deterministic reconstruction found increased FA in the right and RD in the left long AF segment in SIs.

Conclusions:

• Simultaneous interpreting is associated with altered white matter organization in language-related pathways, particularly in the left hemisphere.
• Findings suggest that intensive language training can induce microstructural changes in white matter supporting speech and language functions.
• The study highlights the brain's plasticity in response to demanding linguistic experience.