Quantification of functional alterations after in vitro traumatic brain injury

Traumatic brain injury (TBI) is caused by mechanical forces, producing tissue deformation at the moment of injury. Complex cellular, neurochemical and metabolic alterations are initiated by the deformation and result in delayed cell death and dysfunction. Using an in vitro model of TBI based on organotypic brain slice cultures, we have quantitatively studied the relationship between tissue deformation and functional outcome. Specifically, we studied the effects of low levels of tissue deformation on the functional outcomes as measured by electrophysiology recordings. In response to 5% and 10% biaxial Lagrangian strain, the maximal evoked response and the excitability of neural networks were found to be decreased. Additionally, the different anatomic subregions of the hippocampus displayed different levels of impairment to the injuries. These results suggest that the network function was affected by low levels of applied strain which induced minimal cell death in previous studies.