Processing Asymmetry in Object-modifying Relative Clauses: Evidence from Functional Connectivity

Area of Science:

• Linguistics
• Cognitive Neuroscience
• Psychology

Background:

• Relative clauses (RCs) allow recursive sentence embedding.
• Subject-modifying (SM) RCs have been used to study processing asymmetries between subject-extracted RCs (SRCs) and object-extracted RCs (ORCs).
• Previous studies may be confounded by differing initial sequences in SM-SRCs and SM-ORCs.

Purpose of the Study:

• To investigate processing differences between object-modifying subject-extracted RCs (OM-SRCs) and object-modifying object-extracted RCs (OM-ORCs) in Chinese.
• To examine brain activation and functional connectivity during the processing of these specific RC types.
• To test the structural distance hypothesis regarding RC processing.

Main Methods:

• Participants read OM clauses (OM-SRCs and OM-ORCs) in Chinese sentences during fMRI scanning.
• Analyzed brain activation patterns.
• Conducted Granger causality analyses to assess interregional brain connectivity.

Main Results:

• No significant differences in brain activation were found between OM-SRCs and OM-ORCs.
• Granger causality analyses revealed greater ORC-specific connectivity than SRC-specific connectivity.
• Specifically, increased connectivity from the left inferior frontal gyrus to the superior temporal gyrus was observed for ORCs, suggesting greater interregional interaction.

Conclusions:

• Processing Chinese OM-RC sentences shows a subject-extracted relative clause (SRC) advantage.
• This SRC advantage is primarily reflected in functional connectivity, rather than activation differences.
• Findings support the structural distance hypothesis in relative clause processing.