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bioRxiv · 10.64898/2026.10.27.762371

Effect of Neck Muscle Strength and Passive Cervical Viscoelasticity on Regional Brain and Axonal Tissue Response

Chowdhury, S.
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Abstract

This study evaluated how neck muscle strength and passive cervical viscoelasticity influence global brain motion, intracranial pressure, and regional predicted axonal strain during rapid head loading. An MRI-derived human head-neck finite element model with 5000 diffusion-derived axonal tracts represented by 90,692 embedded beam elements was evaluated using a 4 by 4 factorial design, with four levels each of muscle strength and passive ligament/disc viscoelasticity. The 16 cervical configurations were simulated under a 15 g acceleration-driven inertial load and a 7000 N frontal impact, resulting in 32 simulations. Increasing muscle strength from S25 to S95 at the reference passive-viscoelasticity level reduced mean regional 95th-percentile predicted axonal strain by 22% under inertial loading and 18% under frontal loading, with regional reductions ranging from 10% to 58% and 7% to 31%, respectively. Increasing passive cervical viscoelasticity from D25 to D95 at the reference strength level produced larger reductions in mean regional axonal strain of 35% and 33%, with regional reductions ranging from 14% to 70% and 16% to 56%. Passive viscoelasticity also reduced brain center-of-mass angular acceleration by 16% and 13%, compared with reductions of only 1% and 2% with increased muscle strength. Regional intracranial pressure decreased by 9%~21% under inertial loading and 5%~12% under frontal loading with increased passive viscoelasticity, whereas greater muscle strength reduced axonal strain without a corresponding reduction in pressure. The effects of the two cervical factors also depended on one another: under inertial loading, the mean axonal-strain reduction from increasing strength increased from 21% at D25 to 28% at D95, while the corresponding passive-viscoelasticity effect increased from 32% at S25 to 38% at S95. These findings show that cervical mechanical properties can substantially alter regional brain and axonal response, with passive cervical viscoelasticity producing larger effects than muscle strength across the ranges evaluated.

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Chowdhury, S.. 2026-10-29. Effect of Neck Muscle Strength and Passive Cervical Viscoelasticity on Regional Brain and Axonal Tissue Response. https://doi.org/10.64898/2026.10.27.762371

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