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Prediction of Handedness and Language Hemispheric Dominance Using Homotopic Connectivity of Language Areas

Poster Session F - Tuesday, March 10, 2026, 8:00 – 10:00 am PDT, Fairview/Kitsilano Ballroom

Cesar Avila¹ (), Esteban Villar-Rodriguez², Maria Baena³, Cristina Cano⁴, Maria-Antonia Parcet⁵; ¹Jaume I University, ²Departament of Psyschology

The development of language functions in the brain progresses from an initially interhemispheric control of the involved cortical regions to an intrahemispheric control, which is generally lateralized to the left hemisphere. Recent studies have shown that high interhemispheric connectivity between language areas is a relevant factor in understanding atypical patterns of lateralization (Labache et al., 2020; Andrulyte et al., 2025). In this study, we analyzed 54 right-handers with typical language lateralization, 203 left-handers with typical language lateralization, and 58 left-handers with atypical language lateralization using resting-state fMRI. Language lateralization was assessed with a verb generation task during fMRI. Using the resting-state data, we computed the homotopic connectivity of the 18 language areas included in the SENSAAS atlas (Labache et al., 2019). Discriminant analysys showed that this homotopic connectivity successfully classified 99% of the right- and left-handed participants (Wilk’s lambda=.27): values were higher in the superior temporal gyrus, SMA, and angular gyrus for right-handers, whereas left-handers showed higher values in the supramarginal gyrus, IFG_opercularis, medial superior frontal gyrus, and dorsal STG. To predict hemispheric language lateralization, a multiple regression analysis was conducted using the LI as the dependent variable and the homotopic connectivity of the 18 language areas as independent variables. A significant model was obtained (R = .34; R² = .12), in which lower connectivity in the superior temporal gyrus and higher connectivity in the IFG_opercularis and adjacent IFG areas were associated with atypical language lateralization. These results highlight the relevance of homotopic connectivity in both manual and hemispheric dominance.

Topic Area: LANGUAGE: Other