Brain Mechanics Drive Cavitation and Fracture Response*

Roughly 1.7 million cases of Traumatic Brain Injury occur in the U.S. every year. It has been suggested that impact injuries and non-impact injuries due to explosive blasts result in “cavitation-related damage.” This cavitation event is the formation of bubbles in the brain that can lead to fracture upon collapse. Therefore, it is essential to understand how brain mechanics contributes to the propagation of cavitation and fracture related damage in vivo. Needle-induced cavitation (NIC) is a useful technique to study localized deformation within brain tissue and how modulus and strain rate contribute to fracture. Utilizing the techniques of NIC and indentation we observe a significant correlation between modulus and strain rate. This strain rate dependency for NIC can result in visible fracture of specific brain regions of varying moduli at large strains. With the help of modeling, we use the NIC measurements to understand the fracture properties of brain tissue. By understanding the strain rate deformation of specific areas of the brain, we aim to gain further insight into how cavitation-related events lead to irreversible damage.