A two-dimensional finite element model of the head complex was used to evaluate the sensitivity of brain response to brain material properties and brain-skull boundary conditions. Ten different models were developed based on published head finite element models and brain experimental tests. Maximum principal strain, shear stress, von Mises stress, and pressure were used to evaluate relative differences between the models when excited by dynamic angular inputs. The importance of the cerebrospinal fluid was demonstrated in determining the time history of von Mises and shear stresses. In addition, the results did not support simplifying the brain-skull interface using either frictional effects or elastic materials. Bridging veins influenced the response of the brain both locally at the insertion points and globally throughout the brain. Finally, the results showed that viscoelastic characteristics of brain tissue with decay rates higher than 100 s-1 and material nonlinearity alter the model response even for short duration dynamic impacts.