Changes in functional connectivity within the fronto-temporal brain network induced by regular and irregular Russian...

Area of Science:

• Neuroscience
• Psycholinguistics
• Cognitive Science

Background:

• Neural mechanisms of complex language processing, particularly inflectional morphology, are not fully understood.
• Previous research primarily used subtractive analyses, focusing on functional segregation rather than integration.
• Limited functional connectivity (FC) evidence exists for inflectional morphology, especially in production tasks and morphologically rich languages.

Purpose of the Study:

• To investigate functional connectivity between brain areas during the processing of regular and irregular verb and noun morphology in Russian.
• To utilize psychophysiological interaction (PPI) analysis in a verb/noun generation task to understand neural integration.
• To differentiate between effects of regularity and processing difficulty in morphological processing.

Main Methods:

• Functional magnetic resonance imaging (fMRI) experiment involving participants generating word forms.
• Whole-brain, voxel-wise analysis of context-dependent functional connectivity using psychophysiological interaction (PPI).
• Comparison of functional connectivity patterns for regular verbs, irregular verbs, and nonce stimuli in an inflectionally rich language (Russian).

Main Results:

• Significantly greater functional connectivity between the left inferior frontal gyrus (LIFG) and bilateral superior temporal gyri (STG) for regular real verbs compared to irregular ones.
• A positive covariance between errors in irregular verb trials and increased functional connectivity between LIFG and the right anterior cingulate cortex (rACC).
• Demonstrated dissociation between regularity effects and processing difficulty effects within the language network.

Conclusions:

• The findings highlight the functional interplay within the LIFG-bilateral STG language network during complex morphological processing.
• Results suggest a crucial role for fronto-temporal functional connectivity in handling complex morphology.
• The study calls for a reconsideration of previous findings and emphasizes the dynamic nature of neural networks in language production.