Technical Paper
Defining Brain Mechanical Properties: Effects of Region, Direction, and Species
2000-11-01
2000-01-SC15
No regional or directional large-deformation constitutive data for brain exist in the current literature. To address this deficiency, the large strain (up to 50%) directional properties of gray and white matter were determined in the thalamus, corona radiata, and corpus callosum. The constitutive relationships of all regions and directions are well fit by an Ogden hyperelastic relationship, modified to include dissipation. The material parameter α, representing the non-linearity of the tissue, was not significantly sensitive to region, direction, or species. The average value of the material parameter µ, corresponding to the shear modulus of the tissue, was significantly different for each region, demonstrating that brain tissue is inhomogeneous. In each region, µ, obtained in 2 orthogonal directions, was compared. Consistent with local neuroarchitecture, gray matter showed the least amount of anisotropy and corpus callosum exhibited the greatest degree of anisotropy.