Effect of TBI on material properties of rat brain tissue

Traumatic brain injury (TBI) caused by direct impact or sudden movement of the head is one of the major causes of fatality and severe disabilities. To study TBI, the material properties of brain need to be well understood. In this study, changes in the viscoelastic material properties of rat brain tissue due to traumatic diffuse axonal injury (DAI) and the effect of preconditioning were investigated. The impact acceleration model was used to generate DAI in the rat brain stem. The viscoelastic material properties of brain tissue along the corticospinal tract (CSpT) in the brain stem were characterized using an indentation technique. A quasi-linear viscoelastic model was proposed to characterize the behavior of the brain tissue due to deformation. The results show significant reduction in the elastic response of brain tissue due to injury and preconditioning. In regions with significantly more DAI, larger changes in the elastic force response were observed in both un preconditioned and preconditioned tissues. These findings can improve the injury predictability of computational models of brain injury.