Effect of inter-species, gender, and breeding on the mechanical behavior of brain tissue.

Mechanical response of brain tissue deforming at high rates are needed to build high-fidelity computer models for traumatic brain injury (TBI) studies. Different types of mammalian brains have been used to obtain the constitutive behavior of tissue. It is necessary to examine how these different brains compare to each other in order to determine which animal might be the best surrogate for human brain tissue. In this experimental study, fresh brain tissue from three different mammals, two types of porcine breeds, and genders were loaded under uniaxial compression over a wide range of strain rates. The experiments at higher rates were conducted with a Kolsky bar modified for soft tissue characterization, whereas lower rate experiments were performed on a conventional hydraulic material test frame. Experimental results did not show any significant difference in high-rate compressive response of the brain tissue of different animals, different breeds, and different genders. However, there was significant rate dependence for all tissues tested, especially in the Kolsky bar range. Further investigation is necessary to identify the source of the rate effects.