Individual Differences in the Emerging Reading Network: A GIMME Investigation of Functional Connectivity in Beginning Readers

Poster Session D - Monday, April 15, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Rebecca Marks^1,2 (rmarks@mit.edu), Xin Sun^1,3, Jocelyn Caballero⁴, Florence Bouhali⁴, Olga Kepinska^4,5, Adriene Beltz¹, John Gabrieli², Joanna Christodoulou⁶, Fumiko Hoeft^4,7, Ioulia Kovelman¹; ¹University of Michigan, ²Massachusetts Institute of Technology, ³University of British Columbia, ⁴University of California, San Francisco, ⁵University of Vienna, ⁶MGH Institute of Health Professions, ⁷University of Connecticut

Rapid specialization of reading-related regions is apparent within the first few months of schooling, particularly within the Visual Word Form Area (VWFA). However, little is known about how this increasingly specialized region connects to existing language systems to form a cohesive network. Furthermore, existing knowledge is largely based on group averages, potentially obscuring important individual differences. This study takes a data-driven approach to understanding functional connectivity of the emerging reading network. N=100 kindergarteners (mean age = 5.6 years) completed a reading task during fMRI as well as standardized cognitive assessments. Using subgroup group iterative multiple model estimation (S-GIMME) with a Walktrap community detection algorithm, we examined person-specific connectivity between a priori regions of interest (ROIs). At the group level, participants consistently demonstrated contralateral connectivity between language regions. GIMME further identified three subgroups of individuals with similar network features. Subgroups differed significantly in their mean network density, centrality of language regions, and centrality of the VWFA node within an individual’s network. The three groups also differed significantly in their mean literacy skill. The group with the highest reading performance also demonstrated greater VWFA centrality, more left-lateralized networks, and the strongest connectivity in the phonological loop (IFG-STG). These differences were not attributable to demographic factors or language ability. These findings shed light on a critical developmental stage to suggest that beginning readers largely rely on more distributed, bilateral associations between language and vision hubs, and reading skill is associated with an increasingly efficient, left lateralized circuit.

Topic Area: LANGUAGE: Other