Schedule of Events | Symposia

The role of dorsal and ventral white matter tracts in phonological and semantic specialization in beginning readers – a combined fMRI and DTI study.

Poster Session E - Monday, March 31, 2025, 2:30 – 4:30 pm EDT, Back Bay Ballroom/Republic Ballroom

Avantika Mathur¹ (avantika.mathur@vanderbilt.edu), Sriya Kondapavuluru¹, Marjolein Mues¹, Christiana Werner¹, James R Booth¹; ¹Vanderbilt University

The Interactive Specialization (IS) theory proposes that cortical regions become specialized through activity-dependent interactions during development. This pre-registered study examines IS hypothesis that specialization of cortical regions is determined by their connectivity patterns. Functional specialization is measured by comparing activation during phonological versus semantic tasks in temporal and frontal regions, and structural connectivity is measured with fractional anisotropy (FA) of white matter tracts connecting these cortical regions. Specifically, we explore whether (1) phonological specialization within posterior superior temporal gyrus (pSTG) and dorsal inferior frontal gyrus (dIFG) is associated with structural connectivity in the left arcuate fasciculus (AF), and (2) if semantic specialization within posterior middle temporal gyrus (pMTG) and ventral inferior frontal gyrus (vIFG) is associated with structural connectivity in the left inferior fronto-occipital fasciculus (IFOF). 102 participants (7.39 ± 0.31 years) DTI and fMRI data on auditory rhyming and meaning judgment tasks is analyzed. Phonological and semantic specialization are indexed using average beta estimates from top-250-voxels within anatomical masks. Automatic-Fiber-Quantification is performed on DTI scans to map and segment white matter tracts. Partial correlation analyses are conducted to assess the relationship between functional specialization and the tract-integrity (FA) of tracts at node-level. Results revealed that tract-integrity of (1) AF show positive-correlation with phonological specialization within dIFG (nodes-69-75) and (2) IFOF show negative-correlation with semantic specialization within pMTG (nodes-44-50). Conclusively, the positive-correlation for phonology suggests that specialization is still developing for the dorsal pathway and the negative-correlation for semantics suggests that specialization is relatively mature for the ventral pathway.

Topic Area: LANGUAGE: Development & aging