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bioRxiv · 10.1101/2025.07.28.667304

Preparatory Cortical Modulations for Stepping Tasks with Varying Postural Complexity

Doroodchi, A.
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Abstract

We examined whether preparatory cortical activity indexed by the contingent negative variation (CNV) scales with postural complexity during step initiation. Participants performed straight and diagonal stepping in a Warning-Go paradigm while EEG was recorded; CNV epochs spanned the 2s fore period and were summarized into eight 0.25-s bins for electrode and eLORETA source-level analyses using linear mixed-effects models (n=31). Diagonal stepping produced greater early CNV negativity at the scalp (bin 1: C1, CP3, CP1, P1, FC4; bin 2: F1, F3, FC1, Fz, F2, F4, FC2, FCz), with no electrodes favoring straight stepping. Source analysis showed stronger engagement for diagonal stepping in bins 1-3 (0-0.75 s) across fronto-parietal sensorimotor regions, including paracentral, transverse frontopolar, superior frontal (gyrus/sulcus), supramarginal, superior parietal, intraparietal, and precentral sulcus; no regions were greater for straight stepping. These effects concentrated in the early CNV suggest enhanced anticipatory selective attention and sensory up-weighting under higher postural demands, providing a richer state estimate for scaling anticipatory postural adjustments.

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Doroodchi, A.. 2025-07-31. Preparatory Cortical Modulations for Stepping Tasks with Varying Postural Complexity. https://doi.org/10.1101/2025.07.28.667304

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