Independent Lateralization of Language, Attention, and Numerical Cognition Across Task and Rest

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Contents

• Background
• Reference
• Code Release
• Data
• Other related papers that might interest you
• Questions

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Background

Hemispheric functional complementarity is a core organizational principle of the human brain, yet the extent to which lateralization in one domain constrains that of others remains unclear. Two main accounts have been proposed: the causal hypothesis, in which dominance for one function drives complementary dominance in another, and the statistical hypothesis, in which each function lateralizes independently. Using multimodal fMRI in 287 participants from the BIL&GIN cohort, we examined whether language lateralization phenotypes, defined as typical (left-dominant) or atypical (right-dominant), predict hemispheric asymmetries in visuospatial attention and numerical cognition. Task-based activation was measured during line bisection, mental calculation, and numerical interval comparison, and analyzed within domain-specific, functionally defined network atlases. Resting-state functional connectivity metrics were also assessed in the same networks. Across both attention and numerical domains, typical individuals for language showed stronger asymmetries, whereas atypical individuals exhibited weaker, more bilateral patterns. Critically, atypical participants did not show mirror-reversed asymmetries, and language phenotype did not influence intrinsic connectivity metrics in non-language networks. These findings challenge the notion that atypical lateralization represents an inversion of the canonical template and argue against a universal reciprocal link between language dominance and other cognitive domains. Instead, our results support a domain-specific model in which lateralization profiles are shaped by distinct developmental and functional constraints, highlighting the need for multimodal, multi-domain approaches to brain asymmetry.

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Reference

For usage of the manuscript, please cite:

• Labache, L., Hesling, I., & Zago, L. (2025). Independent Lateralization of Language, Attention, and Numerical Cognition Across Task and Rest. BioRxiv. DOI: 10.1101/2025.11.23.690045

For usage of the associated code, please also cite:

• Labache, L. (2025). loiclabache/Labache_2025_IndLat: Independent Lateralization of Language, Attention, and Numerical Cognition Across Task and Rest (Labache_2025_IndLat_251130). Zenodo.DOI: 10.5281/zenodo.17771776

For usage of the associated atlas, please also cite:

• Labache, L. (2025). loiclabache/LUCA_brainAtlas: Lateralized Underpinnings of Comparison and Arithmetic atlas (LUCA) (Labache_2025_LUCA_251130). Zenodo.DOI: 10.5281/zenodo.17771073

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Code Release

The Script folder includes one R script: Regression&Visualization.R. This R scripts is designed to facilitate the replication of results as detailed in the Method Section of the manuscript.

Note that the R scripts also contain the code to reproduce the figures found in the manuscript. The brain renderings in the paper require Surf Ice.

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Data

All the data necessary to reproduce the results are available in the Data folder.

• BIL&GIN_287participants_ALANsLUCA_TaskRest.txt corresponds to the average brain activity of 287 participants whose language lateralization was characterized using a multi-modal approach (see Labache, L., et al. 2020). The file contains one identifier column, seven demographic-related columns, and 44 dependent-variable columns. The dependent variables correspond to the average brain-activity of each considered network. They are named according to the following structure: Atlas name + (task; only for task-fMRI–related variables) + variable type + Network name + contrast indication (asym or sum or nothing). For example, ALANs_LBJ_weighted_BOLD_ParietoFrontal_Asym refers to the weighted BOLD asymmetry during the LBJ (Line Bisection Task) for the Parieto-frontal network of the ALANs atlas.

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Other related papers that might interest you

• Typical and atypical language brain organization based on intrinsic connectivity and multitask functional asymmetries. Labache, L., et al. 2020. DOI: 10.7554/eLife.58722
• Lateralized visuospatial Attentional Networks; Labache, L., et al. 2024. DOI: 10.1162/imag_a_00208, and related GitHub repository: ALANs
• Lateralized Underpinnings of Comparison and Arithmetic atlas; Labache, L. 2015. DOI: 10.5281/zenodo.17771073, and related GitHub repository: LUCA
• Sentence Supramodal Areas Atlas; Labache, L., et al. 2019. DOI: 10.1007/s00429-018-1810-2, and related GitHub repository: SENSAAS
• Influence of Language Lateralisation on Gradient Asymmetry: Labache, L., et al. 2023. DOI: 10.1038/s41467-023-39131-y, and related GitHub repository: Labache_2022_AO
• The molecular and cellular underpinnings of human brain lateralization: Labache, L., et al. 2025. DOI: 10.1101/2025.04.11.648388, and related GitHub repository: Labache_2025_MolCelLat

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Questions

Please contact me (Loïc Labache) at: loic.labache@rutgers.edu and/or loic.labache@ensc.fr