Most biomechanical models that aim to investigate traumatic brain injury consider the corona radiata as a homogeneous structure. To verify this, indentation-relaxation tests using a custom-designed indentation device were performed on the anterior, superior, and posterior region of the corona radiata in the coronal plane of the porcine brain. Using Boltzmann hereditary integral, a linear viscoelastic model with a Prony series approximation was fitted to the time-dependent shear modulus for different regions of the corona radiata, and the fit parameters were generated. The posterior region was the stiffest and the anterior region was the least stiff. A statistical analysis revealed a significant difference in biomedical properties between the anterior and superior regions, as well as between the anterior and posterior regions in the short time scale. However, the results showed that these differences faded away as the tissue approached equilibrium. No significant difference was observed between the superior and posterior regions along the total time history of relaxation. This is the first demonstration of the regional biomechanical heterogeneity of the corona radiata, and these results will improve future biomedical models of the porcine brain.
Keywords: Biomechanics; Hereditary integral; Heterogeneity; Indentation; Traumatic brain injury; Viscoelasticity.