Traumatic brain injuries (TBI) are the result of a mechanical force causing deformation to the brain during loading. In recent years there has been a lot of attention to TBI sustained by people in sports, military, and car accidents that are related to moderate and severe cases of TBI. However, a main part of TBI is related to mild traumatic brain injuries (mTBI), which has been estimated to be 10 times more common than moderate and severe cases of TBI. A common pathological feature of mTBI is diffuse axonal injury (DAI) and the challenge associated with DAI is that a large part of the injury occurs in the extended period of time following the initial head trauma, making it difficult to quantify the progression of the injury in living humans due to limitations in current noninvasive imaging methods
Although animal models have inherent limitations with not being an exact representation of humans, it is essential to establish a repeatable animal model to better understand the injury and how it progresses over time. The model for this study is based on a modified version of the Marmarou Model with mice, which utilizes a drop tower in which a cylindrical weight is released on the head of a mouse positioned on a spring-loaded base below the drop tower. When the weight impacts the head, it results in the downward displacement of the head as the spring compresses followed by an upward rotation of the head. Using high speed video recording, the motion of the head can be tracked, with an emphasis on the impact forces and rotational acceleration of the head. Initial testing has shown there are a variety of factors that may also contribute to the injury, making it critical to determine how these variables of interest relate to the injury. The goal of this model will be to relate a range of variables to the mechanical response of the head and corresponding diffuse axonal injury in the brain, with an initial focus on impact forces and rotational accelerations.