Translational models of mild traumatic brain injury tissue biomechanics

Traumatic brain injury (TBI) is a global health concern. Mild TBI (mTBI) accounts for the majority of TBI cases, is hard to detect since often the imaging is normal but can still cause brain damage and long-term sequelae. Physiologically, acute primary damage to the brain is thought to be caused by tissue deformation from the inertial movement of the brain after rapid head rotation. Respecting tissue biomechanics, animal models are often used to understand the pathophysiology of mTBI. We have reviewed the literature focusing on connecting biomechanics with mTBI pathologies at the tissue scale using neuroimaging, neurobehavioral tests, and pathologies across species, particularly studies using strain and strain rate. These studies have found strain and strain rate predict mTBI pathology and strain is generalizable across species, including small animals, large animals, and humans. We propose that researchers can leverage tissue-level strain and strain rate to bridge biomechanics and mTBI pathology.