A computational study of the mouse brain under multidirectional rotational loading

Traumatic brain injury (TBI) induced by rotational loading is a major contributor to neurological dysfunction, yet the biomechanical mechanisms underlying these injuries remain poorly understood. In this study, a high-resolution, anatomically accurate three-dimensional finite element model of the mouse brain (FEM-MB) was developed. The FEM-MB was validated against previously published experimental data, showing good agreement in both the timing and magnitude of strain responses. The FEM-MB was then subjected to unidirectional and multidirectional rotational loading scenarios at low (100 rad/s), moderate (150 rad/s), and high (200 rad/s) peak angular velocities to investigate the mouse brain's response to multidirectional rotational loading. The FEM-MB results consistently revealed that deep brain regions, particularly the thalamic-hippocampal region, hypothalamus, and brainstem, experienced the highest maximum principal strains. These results highlight that not only the magnitude, but also the direction and temporal asymmetry of rotational loading, significantly affect the strain distribution across brain regions. In particular, the thalamic-hippocampal and brainstem regions had the highest strains under coronal and axial plane rotations, aligning with known injury patterns. These findings underscore the critical role of rotation direction and loading profile on strain magnitude and distribution in the mouse brain under dynamic rotational loading. Overall, the FEM-MB provides a robust in silico platform to investigate the effects of dynamic rotation loading in preclinical models of TBI.