Mapping lexical-semantic networks and determining hemispheric language dominance: Do task design, sex, age, and...

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• Blocked and event-related functional magnetic resonance imaging (fMRI) designs are standard for mapping language networks and assessing hemispheric dominance.
• Understanding the influence of design choice and individual differences on fMRI activation patterns is crucial for reliable research and clinical applications.

Purpose of the Study:

• To compare activation patterns between blocked and event-related fMRI designs during a semantic monitoring task.
• To investigate the impact of subject-specific factors (age, sex, language performance) on fMRI activation.
• To determine potential interactions between task design and subject characteristics.

Main Methods:

• A semantic monitoring task was administered to 43 healthy individuals using either a blocked or event-related fMRI design.
• fMRI data were analyzed to compare activation profiles between the two designs.
• The influence of age, sex, and language performance on activation patterns was assessed.

Main Results:

• High concordance in activation was observed between blocked and event-related designs within core language areas (inferior frontal, posterior temporal, basal temporal regions).
• Significant differences in activation emerged within the inferior parietal cortex.
• Subject-specific factors did not influence activation patterns and did not interact with the fMRI task design.

Conclusions:

• While core perisylvian language regions show robust and consistent activation across fMRI designs, methodological differences may explain discrepancies in the inferior parietal cortex.
• Subject characteristics do not appear to confound fMRI language network localization.
• Findings inform the interpretation of fMRI data for meta-analyses and pre-surgical planning.